Paper 101 Title: Biceps Tenodesis versus Tenotomy in Treatment of Lesions of Long Head of Biceps Brachii in Patients Undergoing Arthroscopic Shoulder Surgery Authors: Peter B. MacDonald, MD, FRCS1, Sheila McRae, PhD2, Gregory A. Stranges, MD1, Jason Old, MD FRCSC1, James Dubberley, MD1, Randhir Mascarenhas, MD3, Jeff Leiter, MSc, PhD2, Mark Nassar4, Peter Lapner, MD5. 1Pan Am Clinic, Winnipeg, MB, Canada, 2Pan Am Clinic Foundation, Winnipeg, MB, Canada, 3University of Texas-Houston, Houston, TX, USA, 4University of Manitoba, Winnipeg, MB, Canada, 5The Ottawa Hospital, Ottawa, ON, Canada. Objectives: To compare subjective patient-reported outcomes and objective clinical results between biceps tenotomy and tenodesis in patients with lesions of the long head of biceps tendon (LHBT). Methods: The study is a prospective, randomized, controlled trial targeting patients +18 years undergoing arthroscopic shoulder surgery to manage a lesion of the LHBT (+/- rotator cuff repair). Patients were excluded if they had previous surgery on their affected shoulder or any other significant medical comorbidity that could alter the effectiveness of the surgical intervention. Patients were allocated intraoperatively to undergo tenodesis or tenotomy via computer randomization once a LHBT lesion was confirmed. The primary outcome measure was the American Shoulder and Elbow Society standardized assessment of shoulder function (ASES). Secondary outcomes included: Western Ontario Rotator Cuff index (WORC), surgery time, patient reported pain and cramping, presence of a cosmetic deformity, elbow flexion and supination strength, and power. Study time points were pre, and 3, 6, 12, and 24 months post-operative. Magnetic resonance imaging (MRI) was conducted at 12-months post-operative. Results: Fifty-six participants were randomly assigned to each group. Table 1 summarizes the results to 12-months post-operative (collection of data to 24-months post-operative is ongoing until 2017). There were no significant differences in ASES score at pre- or post-surgery time points. In addition, no significant differences were found in WORC, surgery time, pain, or cramping. There was one significant difference in strength identified, the ratio of affected versus unaffected elbow flexion strength was greater in the tenodesis group (0.9 (SD=0.2)) versus the tenotomy group (0.8 (SD=0.3)) at 6-months post-operative. Otherwise, there were no differences in strength ratio identified for elbow flexion or supination strength or power at any time point. At 12-months post-surgery, the relative risk of cosmetic deformity in the tenotomy group relative to the tenodesis group based on patient report was 1.36 (p=0.41) with 12 out of 33 patients in the tenotomy group reporting a bulge in their upper arm compared to 8 out of 30 in the tenodesis group. Similar results were found based on clinical evaluation with a relative risk of 1.7 (p=0.36). MRI findings were available on 40 patients at the 12-month post-operative period. Of 23 in the tenodesis group, one was not intact and retracted 18 cm and two were partially torn. Of the 17 in the tenotomy group, none appeared retracted.

Conclusion: Arthroscopic treatment of lesions of LHBT, whether tenodesis or tenotomy, was shown to have favourable results. Elbow flexion strength favoured tenodesis at 6-months, but otherwise there were no significant differences between groups. As data continues to be gathered to 24-month post-operative, longer-term benefits and drawbacks of each procedure may become evident.

Paper 102 Title: Randomized Prospective Analysis of Arthroscopic Suprapectoral and Open Subpectoral Biceps Tenodesis: 1 Year Follow-up Authors: Brian Forsythe, MD, William Zuke, Beatrice Go, Adam Blair Yanke, MD, Nikhil N. Verma, MD, Anthony A. Romeo, MD. Midwest Orthopaedics at Rush, Chicago, IL, USA. Objectives: Biceps pathology typically includes pain in the anterior shoulder that is reproduced with provocative maneuvers. However, optimal treatment of patient with this diagnosis is not clear and can include tenotomy or various forms of tenodesis. As tenotomy can lead to cosmetic deformity and anterior humeral discomfort from spasms, many surgeons perform tenodesis. Technique for tenodesis includes intra-articular soft tissue fixation or osseous fixation, suprapectoral osseous fixation, and subpectoral osseous fixation. Focusing on the later two, it is unclear if there is a clinical or surgical benefit of performing an open subpectoral biceps tenodesis (OBT) versus arthroscopic suprapectoral biceps tenodesis (ABT). We therefore designed this randomized clinical trial to assess these two techniques. Methods: Patients diagnosed with biceps tendinopathy meeting the inclusion and exclusion criteria were randomized into the arthroscopic and mini-open biceps tenodesis groups. Prior to surgery, patients were asked a series of questions regarding their anterior shoulder pain and underwent a subsequent shoulder exam. Follow-up was d at 3 months, 6 months, and 1 year time points, during which the shoulder exam and patient questionnaires were also d. Results: A total of 38 patients were enrolled with a mean age of 43.5 ± 10.5 years and a mean BMI of 28.3 ± 5.4. All patients had arthroscopic evidence of biceps pathology and underwent either an ABT (18) or an OBT (20). All patients underwent a concomitant arthroscopic subacromial decompression. The surgical time for the ABT group, 17.2 ± 3.7 minutes, was significantly greater than the OBT group, 11.7 ± 6.1 (p<0.01). One patient was converted from the ABT group to the OBT group due to sheering of a severely attenuated tendon preventing an ABT. One patient in the OBT group required a revision tenodesis. No significant difference (p > 0.05) was found in strength or anterior shoulder pain at 3 months, 6 months, and 1 year. Additionally, no significant difference (p > 0.05) was found in clinical outcome scores (ASES, Constant subjective, WORC, KJOC) between the two groups. Conclusion: This randomized clinical trial suggests there is no clinical difference between the two techniques. Additionally, while the arthroscopic procedure requires more surgical time, the revision rates are not different. Besides the cosmetic concern for an additional scar, we recommend decisions to be made based on surgeon preference and experience.

Paper 103 Title: Biceps Tenodesis in Pitchers Authors: Chase D. Smith, MD, Jeffrey R. Dugas, MD, Benton A. Emblom, MD, E. Lyle Cain, MD. Andrews Sports Medicine and Orthopaedic Center, Birmingham, AL, USA. Objectives: SLAP tears are a common occurrence in baseball pitchers. There is not a clear consensus on the treatment of these injures in the overhead athlete, especially in the setting of a failed SLAP repair. SLAP repair in overhead athletes has had relatively poor results with return to play outcomes in several reports. Biceps tenodesis has become an option for failed SLAP repair or chronic biceps tendinitis in older patients with excellent results, but little has been reported concerning biceps tenodesis in overhead athletes. The purpose of this study was to evaluate the outcomes and function of elite level baseball pitchers after undergoing biceps tenodesis. Methods: Retrospective review was performed of 13 baseball pitchers with primary or repeat SLAP tears or biceps tendinitis who were treated with biceps tenodesis. Results: Twelve of thirteen (92%) players were contacted who underwent biceps tenodesis at mean follow-up of 3.4 years (range 1-12.3 years). Outcome measures included the ASMI labral repair outcomes questionnaire, ASES scoring system, overhead athlete shoulder and elbow score, KJOC, and the veterans rand 12 item health survey (VR-12). Eleven of 12 (92 %) contacted were able to return to playing with the most common complaint being subjective weakness and a decrease in velocity. Patients had an average score on the VR12 physical of 63, VR12 mental of 42, KJOC 79, and ASES 97 Conclusion: Biceps tenodesis in an overhead throwing athlete is an acceptable option for a failed slap repair or biceps tendonitis that fails to respond to conservative treatment. Throwing athletes should expect to get back to baseball with good outcomes, however some pain or discomfort with maximum velocity is common.

Paper 104 Title: What is the Natural History of Patellar Dislocation in Skeletally Immature Patients? Authors: Thomas L. Sanders, MD, Ayoosh Pareek, BS, Timothy E. Hewett, PhD, FACSM, Michael J. Stuart, MD, Diane L. Dahm, MD, Aaron John Krych, MD. Mayo Clinic, Rochester, MN, USA. Objectives: Patellar dislocation can occur in isolation or be associated with chronicinstability. The goals of this study are to describe the rate and factors associated with additional patellar instability events (ipsilateral recurrence and contralateral dislocation), as well as the incidence of patellofemoral arthritis among skeletally immature patients following patellar dislocation. Methods: The study included a population-based cohort of 232 skeletally immature patients who experienced a first-time lateral patellar dislocation between 1990 and 2010. A chart review was performed to collect information related to the initial injury, treatment, and outcomes. Subjects were followed for a mean of 12.1 years to determine the rate of subsequent patellar dislocation (ipsilateral recurrence or contralateral dislocation) as well as clinically significant patellofemoral arthritis. Results: 104 patients had ipsilateral recurrent patellar dislocation. The cumulative incidence of recurrent dislocation was 11% at 1 year, 21.1% at 2 years, 37.0% at 5 years, 45.1% at 10 years, 54.0 % at 15 years, and 54.0% at 20 years. Patella alta (HR: 10.6, 95% CI: 3.6, 36.1), increased TT-TG distance (HR 18.7, 95% CI: 1.7, 228.2), and trochlear dysplasia (HR 23.7, 95% CI: 1.0, 105.2) were associated with recurrence. Similarly, 18 patients (7.8%) had contralateral patellar dislocation. The cumulative incidence of patellofemoral arthritis was 0% at 2 years, 1.0% at 5 years,2.0% at 10 years, 10.1% at 15 years, 17%% at 20 years, and 39.0% at 25 years. Osteochondral injury was associated with arthritis (HR 25.7, 95% CI: 6.2, 143.8). Conclusion: Skeletally immature patients have a high rate of recurrent patellarinstability that is associated with structural abnormalities such as patella alta and trochlear dysplasia. In contrast, the rate of subsequent contralateral dislocation is low. Osteochondral injury is associated with arthritis after patellar dislocation, but the overall incidence of symptomatic arthritis with advanced radiographic changes in pediatric patients is low at 12-year follow-up.

Paper 106 Title: Medial Patellofemoral Ligament Isometry in the setting of Patella Alta Authors: Nicole Belkin, MD1, Andrea Spiker, MD2, Kathleen N. Meyers, MS3, Joseph Nguyen, MPH3, Beth E. Shubin Stein, MD3. 1HSS, New York, NY, USA, 2Hospital for Special Surgery/Cornell Medical Center Program, New York, NY, USA, 3Hospital for Special Surgery, New York, NY, USA. Objectives: Patella alta increases the complexity of decision making in regards to surgical intervention for MPFL insufficiency and resultant patellar instability1. Our objective was to develop a model to evaluate MPFL isometry2 at multiple candidate femoral attachment sites in the setting of patella alta. We hypothesized that a femoral attachment location proximal to that previously described by Schoettle et al would produce a more anatomometric MPFL in the setting of patella alta. Methods: Ten cadaveric knees were stripped of soft tissue leaving the patellar tendon, extensor mechanism, and collateral ligaments. A suture anchor was placed at the upper 41%3 of the medial border of the patella for MPFL reconstruction. The suture emanating from the anchor was utilized as a surrogate MPFL graft. Four separate locations about the medial aspect of the femur were evaluated as candidate attachment sites; that which was described by Schoettle (p00), 5 and 10 mm proximal (p05 & p10) as well as 5 mm distal (d05) to this location (Fig 1a). Change in length of the graft, or anisometry, was assessed by attaching retrorefletive markers on the suture, femur, patella and tibia. A 3D motion capture system was used to track the markers’ motion as the knee was cycled from 0 - 110 degrees of flexion. Three separate degrees of patella alta were then created via tibial tubercle osteotomy, Caton-Deschamps (C-D) 1.3, 1.4 and 1.5. Graft isometry at each candidate attachment site was assessed with tubercle in it’s native position and at each level of C-D. Results: MPFL isometery was defined as an observed change in length less than 2 mm. The p00 location produced an isometric MPFL throughout the initial 70 degrees of flexion when the tubercle was located in the native position only (Fig 1b). With the tibial tubercle in the native location the p00 location was more isometric than the other candidate attachment locations tested (Fig 1c, upper left). In the setting of patella alta with a C-D of 1.3, p05 exhibited more isometry than p00 (Fig 1c, upper right); however no significant differences were found in the average length change between these two location (Table 1, left). With patella alta with a C-D of 1.4, p05 continued to exhibited more isometry than p00 (Fig 1c, lower left) and significant differences were found in the mean change in length at both 40 and 50 degrees, p = 0.007 and 0.034 respectively (Table 1, middle). In the setting of patella alta with a C-D of 1.5, p10 began to exhibit more isometry than p05 (Fig 1c, lower right) and significant differences were found in the mean change in length at 40 degrees, p = 0.023 (Table 1, right). Conclusion: We successfully developed a cadaveric biomechanical model for evaluation of MPFL anatomometricity with the ability to investigate multiple femoral attachment locations and varying degrees of patella alta. With the tibial tubercle in the native location, C-D ~1, the location defined by Schoettle, p00, demonstrated the greatest degree of isometry. With increasing degrees of patella alta, more proximal candidate femoral attachment sites demonstrate decreased change in length compared

to p00. None of the varied femoral attachment produced isometricity over the entirety of the flexion range from 0-70 degrees, suggesting that in cases of significant patella alta, a tibial tubercle distalization may be necessary in order to achieve an anatomometric MPFL reconstruction.

Paper 107 Title: "Pin the Tail on the MPFL" Identification by Palpation - Results Authors: Jason L. Koh, MD, Todd Zimmerman. NorthShore Univ. HealthSyst - Dept of Ortho Surgery, Evanston, IL, USA. Objectives: Medial patellofemoral ligament (MPFL) reconstruction has become increasingly popular to treat patellar dislocation. Studies have noted the importance of recovering the anatomic insertion of the MPFL and that reconstruction should be performed within 5mm of the native insertion site to avoid biomechanical complications. Currently radiographic imaging is used to locate the MPFL insertion site at Schottle’s point. This study investigated the viability of utilizing palpation to locate the MPFL insertion site for proper MPFL reconstruction. Methods: Thirty-eight patellofemoral specialists attending IPSG were selected to participate in this study with a mean of 15.9 years in practice (median 14, range 1-39). Using a single fresh-frozen human cadaveric knee, each specialist individually performed surface palpation of the anatomical landmarks and inserted a dissection pin at the purposed MPFL femoral insertion site. Radiographic images were taken of each pin placement. At conclusion, the cadaveric leg was dissected and forceps were placed at the distal and proximal end of the MPFL insertion with a dissection pin in the middle of the insertion and a radiographic image was taken of this. Images were analyzed using ImageJ software to determine the distance and angle from the MPFL insertion center to the specialist’s pin location. Results: Length and angle measurements were taken three times and averaged for each sample. The bridge of a forceps was utilized as a scale for the images (2.325 pixels/mm). Average distance was found to be 3.18 ± 2.55 mm with an average angle of 161.2 ± 74.4° relative to the anterior direction indicating 0°. Seven of thirty-eight (18%) samples were more than 5mm from the native insertion site. Conclusion: With an average pin displacement of 3.18mm, it was seen that most specialists could accurately determine MPFL insertion location accurately without the use of radiographic equipment. On average, the displacement angle of 161.2° indicates the pin was typically located more posterior than the MPFL insertion site. Seven measurements exceeded 5mm distance from the MPFL insertion, which would be concerning for biomechanical effects on the patellofemoral joint if the repair was placed at the pin location. Clinical Relevance While experienced patellofemoral surgeons were able to identify femoral MPFL origin with reasonable accuracy by palpation, even experienced surgeons had inaccuracies that could compromise outcomes up to 18% of the time. For this reason we recommend the use of radiography along with appropriate exposure to assist in accurately identifying the anatomic femoral attachment of the MPFL during MPFL reconstruction.

Paper 108 Title: Effect of Patellar Tunnel Placement on Fracture Risk after MPFL Reconstruction- A Cadaveric Study Authors: Eric Lukosius, MD, Nicholas Bonazza, MD, Greg Lewis, Evan Roush, Kevin P. Black, MD, Aman Dhawan, MD. Penn State Milton S Hershey Medical Ctr Bone & Joint Institute, Hershey, PA, USA. Objectives: Patella fracture is a rare complication after medial patellofemoral ligament (MPFL) reconstruction. Though many of the cases in the literature have been precipitated by trauma, the surgical factors that may lead to a higher risk of fracture are not well understood. The purpose of our study was to determine if transosseous tunnels that exit through the anterior cortex of the patella, and transverse bone tunnels have lower tensile load to failure as compared to control, and may predispose to post-operative patellar fracture. Methods: Fresh-frozen cadaveric human patellas were randomized to one of three groups: a control group with unmodified intact patellas, a group with two transverse tunnels (TT) drilled in the superior third of the patella that did not violate the anterior cortex, and a group with two transversetunnels that breach anterior cortex of the patella (PA). Patellas were connected to a freeze clamp mechanism via the remaining quadriceps and patellar tendons. A load cell was connected in series with the quadriceps clamp to measure maximum load to failure with a maximum load of 9000N. The angle of pull was fixed at 45 degrees, with the patella set in the trochlear groove of a composite synthetic femur. Patellas were cyclically loaded to 500 N for a total of 100 cycles. Specimens that did not fail during cyclic loading were then loaded to failure defined as fracture or tendon rupture. At failure, fluoroscopy was used to confirm a fracture if present and maximum load was recorded. The mean and standard deviation (STD) for each group were recorded. ANOVA and Student-T tests were used to identify significant differences between groups. Results: A total of 26 patellas were randomized and tested in this study. There were 12 male and 14 female patellas ranging in age from 37-95 years. There was no significant difference in the average age among the groups (Mean = 71.4 years, STD = 11.5 years, P =0.96). None of the patellas failed during cyclic loading alone. Control, TT and PA groups failed at 1915 N (STD= 508N), 1901 N (STD= 884N), and 1640 N (STD= 625N) respectively. This represents a 14% difference in means between Control and PA and Control and TT tunnels. There was no statistically significant difference between control and TT (p=.969), control and PA (p=.321), and TT and PA (p=.488). Subset analysis of fractures only through bone tunnels did not affect the significance. Conclusion: Our results show that breeching of the anterior cortex and transosseous tunnels that do not breach the anterior cortex during MPFL reconstruction do not significantly decrease the load to failure when compared to native patellas and, thus, may not pose an increased risk for patellar fracture. Further research is needed to analyze if other surgical factors may predispose to this complication.

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Paper 109 Title: Forearm Flexor Injuries in Major League Baseball Players: Epidemiology, Performance, and Associated Injuries Authors: Justin Lane Hodgins, MD1, Steve Donohue, ATC2, Mark Littlefield, ATCS3, Mike Schuk, PT/ATC4, Christopher S. Ahmad, MD5. 1Scarborough Centenary Hospital, Toronto Canada, Scarborough, ON, Canada, 2New York Yankees, Katonah, NY, USA, 3New York Yankees, Tampa, FL, USA, 4New York Yankees, Bronx, NY, USA, 5Columbia University, New York, NY, USA. Objectives: The flexor-pronator mass provides dynamic support to the valgus stresses in the throwing elbow and is protective to the ulnar collateral ligament (UCL). Despite evidence highlighting the importance of the forearm flexor muscles in baseball pitching, no studies have reported the epidemiology, return to play, or associated injuries in elite baseball players. The purpose of this study examine the incidence, treatment, and outcomes of forearm flexor injuries in both Major and Minor League Baseball pitchers. Methods: Injury data attributed to forearm flexor injury in Major League Baseball (MLB) and minor league teams was reviewed from 2010 to 2014. This included the numbers of players, seasonal timing of injury, days of competition missed, pre and post-injury performance data, and subsequent elbow surgery. Performance data collected consisted of ERA (earned run average), WHIP (walks plus hits per innings pitched), walks, strikeouts, and percent strikes. Results: In MLB, 134 forearm flexor injuries occurred with a mean player age of 28.6 years and 111 (82.8%) were pitchers. In the minor leagues, 629 injuries occurred with a mean age of 22.8 years where 494 (78.5%) were pitchers. The highest percentage of injuries occurred in the month of July in both MLB (17.2%) and the minor leagues (17%). The median time spent on the disabled list (DL) for MLB players was 42 days (mean 128.1) compared to 28 days (mean 105.7) in the minor leagues. Of the players in MLB who sustained a forearm injury, subsequent injuries included 50 shoulder (37.3%), 48 elbow (35.8%), and 24 forearm (17.9%) injuries. Over the study period, 26 (19.4%) MLB and 56 minor league players (8.9%) required UCL reconstruction within 365 days of sustaining a forearm injury. Performance declined in virtually all categories in the season leading to the injury when compared to the previous season (n = 75) and significant differences were present in walks plus hits per inning pitched (WHIP) (from 1.24 to 1.34, P = 0.04) and strike percentage (63% to 62%, P = 0.036). Conclusion: Flexor-pronator injuries are responsible for considerable time on the DL in elite pitchers. Injury may be preceded with declines in performance and be associated with subsequent injuries to the shoulder and elbow.

Forearm Flexor Strains per Year in Pitchers and Position Players in the MLB Year Injuries Pitchers Position Players 2010 26 20 6

2011 23 19 4 2012 25 19 6 2013 31 27 4 2014 29 26 3 Total 134 111 (82.8% 23 (17.2%)

Paper 110 Title: Comparison of Cyclic Fatigue Mechanics between UCL Repair with Internal Bracing and UCL Reconstruction Authors: Christopher Michael Jones, MD1, David P. Beason, MS2, Jeffrey R. Dugas, MD3. 1University of South Alabama Program, Mobile, AL, USA, 2American Sports Medicine Institute, Birmingham, AL, USA, 3Andrews Sports Medicine & Orthopaedic Center, Birmingham, AL, USA. Objectives: UCL reconstruction has become the preferred treatment for UCL injury in elite throwers desiring a return to throwing. Prior reports of UCL repair demonstrated poor results in professional pitchers, with rate of return to the same or higher level pitching between 0% and 63%. 1,3,6,9,11 However, in young athletes without chronic attritional UCL damage, recent data shows reliable and rapid return to sport with primary UCL repair.2,12,14 We previously introduced a novel UCL repair technique consisting of primary UCL repair, augmented with a spanning tape anchored at either end of the native ligament. Compared to UCL reconstruction, this construct demonstrated significantly greater resistance to gap formation, even at low cycles of valgus loading.8 The purpose of the current study was to compare the high-cycle fatigue mechanics of augmented UCL repair versus modified Jobe UCL reconstruction. We hypothesized that the repaired specimens would have less gap formation compared to the reconstruction group after 10, 100, and 500 cycles of valgus loading. Methods: Twenty fresh-frozen cadaveric upper extremities (10 matched pairs) were dissected to expose the anterior band of the UCL.3 The humeral and ulnar insertions of the UCL were identified and marked to measure ligament displacement.7 Each specimen was potted and mounted on a mechanical test frame.4,5,8,10,13 A 2 N-m valgus preload was applied to the native elbow followed by a 60 s hold and 500 cycles of valgus loading between 2 N-m and 10 N-m. A longitudinal split in the anterior band was created and the distal attachment of the sublime tubercle was released, simulating a distal avulsion tear of the UCL. Ten cycles were repeated in this torn state. Each pair was randomly separated into either a repair or a reconstruction group (Fig 1).

Each specimen was then manually subjected to 100 cycles of flexion-extension range of motion to simulate early rehabilitation protocols. The specimens were again loaded for 500 cycles between 2 N-m and 10 N-m, followed by a ramp to failure at a rate of 1°/s. Torque and rotation were recorded in addition to gap measurements for the 10th, 100th, and 500th cycle of the intact and repair/reconstruction conditions. Gaps were measured optically8 as the change in distance of the two anatomical landmarks between the pre-cycling hold and the peak of the cycle of interest. A two-way ANOVA with repeated measures was used to detect overall differences in addition to post-hoc t-tests and Tukey’s HSD for between the two procedures and three conditions, respectively. Significance was set at p ≤ 0.05. Results: The repair group showed greater resistance to gapping compared to reconstruction after 10 (p=0.008), 100 (p=0.02), and 500 (p=0.004) cycles (Fig. 2) of valgus motion. There was no difference in the intact state; however, the repair group did exhibit a reduction (p=0.007) in gap in the torn state after 10 cycles.

Conclusion: In this preliminary report, UCL repair using internal bracing is more resistant to gap formation under fatigue loading than the gold standard reconstruction technique. The time-zero failure properties of this repair technique are on par with those of traditional reconstruction, although similar differences also seen in the torn state at early cycles may act as a confounding factor. In young throwers with insertional UCL injuries, our UCL repair technique may provide a suitable alternative to reconstruction with similar biomechanical properties and faster return to sport.

Paper 111 Title: Osseus Vascularity of the Medial Elbow Following Ulnar Collateral Ligament Reconstruction: A Comparative Analysis of the Docking and Figure of Eight Techniques Authors: Christopher L. Camp, MD1, Craig E. Klinger, BA2, Lionel E. Lazaro, MD2, David W. Altchek, MD2, Joshua S. Dines, MD3. 1Hospital for Special Surgery/Cornell Medical Center Program, New York, MN, USA, 2Hospital for Special Surgery, New York, NY, USA, 3Hospital for Special Surgery, uniondale, NY, USA. Objectives: The rate of revision medial ulnar collateral ligament (UCL) reconstruction continues to rise annually, and two common modes of failure for are inadequate healing at the bone-tendon interface or bony fracture through drill tunnels. Although, vascularity may play a critical role in these processes, the intra-osseous blood flow to the medial epicondyle (ME) and sublime tubercle (ST) remains undefined. The purpose of this work was to better understand the vascularity of the ME and ST at baseline and to quantify vascular disruption caused by tunnel drilling for the two most common UCL reconstruction techniques: the Figure of Eight and Docking. Methods: Eight matched pairs (16 total specimens) of fresh-frozen cadaveric upper extremities were randomized to one of the two study groups: Docking or Figure of Eight UCL reconstruction. One elbow in each pair underwent drilling of the medial epicondyle and sublime tubercle by the assigned technique, while the contralateral elbow underwent surgical exposure without drilling to serve as a matched control. For all specimens, the brachial artery was cannulated 10 cm distal to the greater tuberosity, and the ulnar artery was cannulated 10 cm proximal to the wrist. All identified remaining vessels were tied off. Pre- and post- gadolinium MRI scans were performed on all study elbows to quantify intra-osseous vascularity by contrast enhancement, which was compared to the contralateral elbow as a matched control. Intra-osseous flow is quantified within a standardized region of interest (ROI) using customized IDL 6.4 software (Exelis, Boulder, Colorado). Following MRI, contrast-enhanced polyurethane latex was injected into all vessels and CT with 3D reconstruction and gross dissection was performed to correlate findings with the MRI and assess vessel integrity. Results: MRI quantification revealed drilling of the ulnar tunnels (which was the same for each group) had a minimal impact on intra-osseous vascularity of the ulna with maintenance of 96% and 99% (p=0.448) of blood flow for the Docking and Figure Eight techniques respectively (Table 1). However, perfusion to the medial epicondyle was reduced 14% (to 86% of baseline) for the Docking Technique and 60% (to 40% of baseline) for the Figure Eight technique (Figure 1). This resulted in a mean difference of 46% in reduced perfusion between the two techniques (p=0.012). Subsequent CT analysis and gross dissection revealed increased disruption of small perforating vessels of the posterior aspect of the medial epicondyle for the Figure of Eight Technique (Figure 1). Conclusion: Although tunnel drilling in the sublime tubercle appears to have minimal effect on intra-osseous vascularity of the proximal ulna, both the Docking Technique and the Figure of Eight Technique reduce flow in the medial epicondyle. This reduction is four times greater for the Figure of Eight Technique, and these findings may have important implications for UCL reconstruction surgery.

Paper 112 Title: Ultra-long-toss vs Straight-line Throwing for Glenohumeral Range of Motion Recovery in Collegiate Baseball Pitchers Authors: Tianyi D. Luo, M.D.1, Gregory Lane Naugher, MD2, Austin Stone, MD, PhD1, Sandeep Mannava, MD, PhD3, Jeff Strahm, ATC4, Michael T. Freehill, MD1. 1Wake Forest Baptist Medical Center, Winston-Salem, NC, USA, 2The San Antonio Orthopaedic Group, San Antonio, TX, USA, 3Steadman Philippon, Vail, CO, USA, 4Wake Forest University, Winston-Salem, NC, USA. Objectives: Repetitive throwing in baseball pitchers can lead to pathologic changes in shoulder anatomy with potential subsequent injury. There have been few studies on throwing regimens and the types of throwing most efficacious for both maintenance and recovery during the baseball season. Limited-distance straight-line throwing (SLT) mimics more normal pitching mechanics, whereas ultra-long-toss (ULT) at greater than physiological throwing distances changes shoulder kinematics, but theoretically offers the advantage of stretching the posterior capsule. Debate exists as to whether ULT or SLT is superior for glenohumeral range of motion (ROM) recovery after baseball pitching. We hypothesize that ULT, via a potential mechanism of posterior shoulder capsular stretching, will be more effective in returning a pitcher’s baseline external rotation (ER), internal rotation (IR), and total range of motion (TROM) when compared to SLT in a cohort of collegiate pitchers. Methods: Sixteen Division-I collegiate baseball pitchers were randomized to ULT (n=8, mean age 20.1 ± 1.4 years) or SLT group (n=8, mean age 20.0 ± 1.1 years). Measurements (dominant and non-dominant ER, IR, and TROM) were taken at five time-points across three days: before and immediately after a standardized bullpen (BP) session on day 1; before and immediately after a standardized ULT or SLT session on day 2; and before practice on day 3. Data were analyzed using mix design ANOVA. Post hoc analysis was used to detect differences between time-points. Results: In the ULT group (Table 1), dominant ER significantly increased from baseline to final measurements (129° to 136°, p=0.006). Significant increase in ER was observed between pre- and post-long-toss throwing (+6.2°, p=0.004). Dominant IR significantly decreased from baseline to final measurements (57° to 50°, p=0.002). TROM did not significantly change across time-points. In the SLT group, dominant ER increased from baseline to final measurements (139° to 142°), but failed to reach statistical significance. Dominant IR did not vary significantly across time-points, nor did TROM. Conclusion: Our results do not support our initial hypothesis. ULT yielded greater increases in ER and decreases in IR in comparison to SLT. Total range of motion did not change over time in either throwing group; however, the overall arc of motion changed more significantly in ULT pitchers, secondary to the greater ER and less IR. We had anticipated an increase in IR with ULT due to the theoretical advantage of posterior capsule stretching. The observed IR decrease suggests ULT may cause additive microtrauma resulting in capsular tightness rather than recovering shoulder ROM. Ultra-long-toss throwing should be further evaluated in the context of training, rehabilitation, and injury-prevention.

Table 1. Dominant shoulder ROM in the ultra-long-toss group (n=8). Time-point ER IR TROM GIRD 1. Pre-BP 129.4 56.7 186.0 12.8 2. Post-BP 133.7 57.8 191.5 7.0 3. Pre-throw 131.6 49.2 180.8 15.1 4. Post-throw 137.8 52.4 190.2 14.5 5. Final 135.9 50.2 186.1 9.8 p-value <0.001 <0.001 <0.001 0.006

Paper 113 Title: Decreased Shoulder External Rotation and Flexion are Greater Predictors of Injury than Internal Rotation Deficits: Analysis of 132 Pitcher-Seasons in Professional Baseball Authors: Christopher L. Camp, MD1, Alec Sinatro, BS2, Andrea Spiker, MD3, Brian C. Werner, MD4, David W. Altchek, MD2, Struan H. Coleman, MD, PhD5, Joshua S. Dines, MD6. 1Hospital for Special Surgery/Cornell Medical Center Program, New York, MN, USA, 2Hospital for Special Surgery, New York, NY, USA, 3Hospital for Special Surgery/Cornell Medical Center Program, New York, NY, USA, 4University of Virginia Program, Charlottesville, VA, USA, 5Hospital for Special Surgery - SM, New York, NY, USA, 6Hospital for Special Surgery, Uniondale, NY, USA. Objectives: There is a strong desire to identify modifiable risk factors for shoulder and elbow injuries in pitchers, that when corrected, have the potential to reduce injury burden. Although much attention has been paid to Glenohumeral Internal Rotation Deficits (GIRD), less is known about the value of other range of motion (ROM) deficits. Therefore, the purpose of this work was to determine the impact and predictive capacity of shoulder and elbow ROM on shoulder and elbow injuries in professional baseball pitchers. Methods: Over the course of 6 seasons (2010 to 2015), a comprehensive, preseason assessment of ROM was performed on all pitchers (n=132 pitcher-seasons) invited to Major League Baseball (MLB) Spring Training Camp for a single MLB organization. Total range of motion (TROM) and deficits were also calculated. All non-traumatic shoulder and elbow injuries that resulted in at least one day out of play were identified. Using multivariate binomial logistic regression analysis to control for age, height, weight, and all other ROM measures, the factors associated with an increased risk of subsequent shoulder or elbow injury were identified. Results: 53 shoulder (n=25) and elbow (n=28) injuries occurred during 132 pitcher-seasons. The most significant categorical risk factors associated with increased elbow injury rates included the presence of a shoulder ER deficit > 5° (OR 2.40; p=0.069) and shoulder flexion deficit > 5° (OR 2.83; p=0.042). For continuous variables, the most important factors included increasing shoulder ER deficit (OR 1.07, p=0.030), decreased shoulder flexion (OR 1.09, p=0.017), increased IR deficit (OR 1.04, p=0.068), weight (OR 1.10, p=0.012), and decreased shoulder ER (OR 1.06; p=0.076). Conclusion: A number of preseason ROM parameters are independent risk factors for the development of shoulder and elbow injuries during the upcoming season. This is particularly true for shoulder ER and flexion deficits. Although prior work has supported the importance of reducing GIRD in professional pitchers, this study demonstrates that deficits in shoulder ER and flexion are more significant predictors of subsequent injury.

Paper 114 Title: Autologous Conditioned Plasma (ACP) versus Corticosteroid Injections for Plantar Fasciitis: A Randomized Trial Authors: Kevin Willits, MD, FRCS1, Nicole Kaniki2, Dianne Bryant, PhD3, Lyndsay O'Brecht2, Alliya Remtulla2. 1Fowler Kennedy Sport Medicine Cl, London, ON, Canada, 2University of Western Ontario, London, ON, Canada, 3The University of Western Ontario, London, ON, Canada. Objectives: Plantar fasciitis is a chronic, degenerative breakdown of the plantar fascia that spans the bottom surface of the foot. The injury is associated with point tenderness at the medial side of the heel and pain and tightness with weight bearing. Corticosteroid (CS) injections are a fairly common treatment option after exhausting all other non-operative treatments. Autologous conditioned plasma (ACP) injections may optimize the healing environment for tissue regeneration and repair which may provide greater improvements in pain and function compared to corticosteroid injections. Thus, the purpose of this study was to compare the pain, function and quality of life in patients who have received an ACP injection versus a corticosteroid injection for the treatment of plantar fasciitis. Methods: We conducted a randomized controlled trial in patients with plantar fasciitis who were referred to our clinic from local primary care physicians. Patients were stratified by symptom duration (less than and greater than three months) and received either an ACP or CS injection. We measured outcomes at two weeks, six weeks, three months, six months, and one year. Our primary outcome was the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot scale; secondary outcomes included the SF-12v2 Health Survey and the Plantar Fasciitis Pain and Disability scale. We used an analysis of covariance to analyze all outcomes. We calculated the adjusted between-group mean difference with 95% confidence interval and associated probability values. Results: A total of 126 patients were included in the analysis (ACP = 64, CS = 62). For our primary outcome, at six months, the mean and standard deviation of the AOFAS Ankle-hindfoot scale was 67.1±18.3 for the ACP group and 70.8±17.6 for the CS group (mean difference -1.7, CI -7.6 to 4.2, p = 0.6). At one year, the mean and standard deviation was 72.3±19.1 for the ACP group and 75.6±17.0 for the CS group (mean difference -1.3 CI -7.3 to 4.6, p = 0.7). There was no statistically significant differences between treatment groups for any of the secondary outcome measures. Conclusion: ACP does not provide greater self-reported pain relief or function than CS injections in patients with plantar fasciitis. Given the know complications of repeated CA injections, ACP is a reasonable first line treatment option.

Paper 115 Title: Risk Factors for Reoperation and Performance-based Outcomes following Surgical Fixation of Foot Fractures in the Professional Athlete: A Cross-Sport Analysis Authors: Sameer Kumar Singh, BA1, Kevin Larkin, MD2, Anish R. Kadakia, MD1, Wellington Hsu, MD1. 1Northwestern University, Chicago, IL, USA, 2University of Arizona, Tucson, AZ, USA. Objectives: Professional athletes are predisposed to fractures of the foot due to large stresses placed on the lower extremity; these players are concerned with efficiently returning to play at a high level. Return to play rates following operative treatment have been previously reported, yet performance outcomes following such treatment are generally unknown in this population. The purpose of this study was to assess and compare performance-based outcomes following foot fracture fixation among professional athletes of the 4 major North American sports. Methods: Athletes in the National Basketball League (NBA), National Football League (NFL), (Major League Baseball) MLB, and National Hockey League (NHL) undergoing operative fixation of a foot fracture were identified through a well-established protocol confirmed by multiple sources of the public record. Return-to-play rate and time to return were collected for each sport. League participation and game performance were collected before and after surgery. Statistical analysis was performed with significance accepted as P ≤ .05. Results: A total of 77 players undergoing 84 procedures met the inclusion criteria. Overall, 98.7% of players were able to return to play with an average time to return across all sports of 172 ± 22 days. Players returned to preoperative performance levels within one season of surgery. Six players (7.8%) sustained re-fracture requiring reoperation, all of whom were in the NBA. Percentage of games started during the season after primary surgical treatment was a predictive factor for re-injury (99% vs 40%, p = .001). Conclusion: Athletes returned to play following foot fracture fixation at a high rate with excellent postoperative performance levels, regardless of sport and fracture location. NBA athletes sustaining fifth metatarsal and navicular fractures are at a higher risk of re-injury compared to other athletes. Returning to high levels of athletic participation soon after surgery may predispose athletes to re-fracture and subsequent reoperation.

Paper 116 Title: Optimal Time to Return to Play and Performance after Jones Fracture Surgery in the National Football League Authors: Selene G. Parekh, MD, MBA1, Jay Shah2. 1Department of Orthopaedics, Fuqua Business School, Durham, NC, USA, 2Rowan School of Osteopathic Medicine, Stratford, NJ, USA. Objectives: While rare, Jones fractures represent an acute and devastating injury to National Football League (NFL) players. Although Jones fractures in the general population have been researched extensively, not much is known about the epidemiology and post-injury effects of these fractures on the professional football athlete. Furthermore, early season injuries to high-profile NFL players have led to an increased pressure to return to play more quickly. It is unknown how this accelerated timeline to recovery affects post-injury performance and post-surgical complications necessitating repeat surgeries. Therefore, the objectives of our study were to produce an updated epidemiology of Jones fractures and analyze how quicker recovery times affect post-injury performance and refracture rates in NFL players. Methods: Several online sources including a compiled injury database provided by FantasyData, NFL news sites and injury reports, and player registries, were cross-referenced to conduct a retrospective identification of all NFL players sustaining a Jones fracture injury necessitating surgery from the 2010-2015 NFL seasons. For each injury, time to recovery and return to play was obtained, and players were separated into two groups: those returning to play in less than 10 weeks from surgery and those returning greater than 10 weeks after surgery. Each included player was followed to identify future events requiring repeated surgery for the same injury. Yearly player performance metrics were also obtained and recorded for both offensive and defensive players. An “approximate value” algorithm, commonly used to standardize and track player production across positions, was adapted to calculate yearly performance values for each injured player up to 3 years before and after each Jones fracture surgery, allowing each player to serve as his own control. Results: 42 Jones fractures were identified during the 2010-2015 NFL seasons. 15 players returned to the field in 10 weeks or less after surgery, with 9 requiring a second Jones fracture surgery. 27 players returned to the field greater than 10 weeks after surgery, with 4 requiring a second Jones fracture surgery. Compared to all other positions, wide receivers were the most likely to suffer from a Jones fracture. There was an average decrease in performance by 53.2% in those players returning in 10 weeks or less after their first Jones fracture surgery, compared to a 9.4% increase in performance in those players returning after at least 10 weeks from their first Jones fracture surgery. After a second Jones fracture surgery, there was an average decrease in performance by 46.3% and 16.5% in those returning in less than or greater than 10 weeks respectively. Conclusion: The results of this study suggest that a quickened timeline to recovery after Jones fracture injuries to NFL players can lead to poorer outcomes. There was a statistically significant greater decrease in post-injury performance for NFL players returning to play in less than 10 weeks after Jones fracture

surgery as compared to those players returning in greater than 10 weeks. Those players returning in less than 10 weeks after surgery were also more likely to require a second jones fracture surgery. This suggests that although players are frequently pressured to return to play as quickly as possible after these injuries, it may be more advantageous in terms of post-injury performance and career longevity to extend the timeline for recovery.

Paper 117 Title: The Epidemiology of Lisfranc Injuries at the National Football League Combine and its Impact on an Athlete's National Football League Career Authors: Kevin Jude McHale, MD1, Bryan George Vopat, MD2, George Sanchez3, William H. Rossy, MD4, Catherine Logan, MD, MBA,MSPT5, Matthew T. Provencher, MD6. 1University of Pennsylvania Orthopaedic Surgery, Cape May Court House, NJ, USA, 2University of Kansas, Overland Park, KS, USA, 3Steadman Philippon Research Institute Program, Vail, CO, USA, 4Princeton Orthopaedic Associates, Princeton, NJ, USA, 5Massachusetts General Hospital, Boston, MA, USA, 6The Steadman Clinic, Vail, CO, USA. Objectives: Lisfranc injuries may have a detrimental effect on athletic performance and an athlete's career. Understanding the epidemiology of these injuries in collegiate football players and their impact on future performance may assist team physicians in counseling injured athletes and determining optimal treatment. The purposes of this study are to 1) determine the epidemiology of navicular fractures in players participating in the NFL Combine, 2) define positions and demographics that might be at higher risk for sustaining this injury, and 3) evaluate the radiographic healing and eventual impact the injury and radiographic findings has on Lisfranc injuries on NFL draft position and NFL game play compared to matched controls. Methods: All players who sustained a Lisfranc injury prior to Combine evaluation between 2009 and 2015 were evaluated. The prevalence, positions affected, treatment methods, and number of missed collegiate games were recorded. Radiographic outcomes were analyzed via Combine radiograph findings, while NFL performance outcomes were assessed for all Lisfranc injuries (2009-13) compared to matched controls in first two years of play. Results: A total of 41/2162 (1.8%) Combine participants were identified with Lisfranc injuries, of which 26/41 (63.4%) were managed operatively. When compared to players managed nonoperatively, those who underwent surgery were more likely to go undrafted (38.5% vs. 13.3%, p=0.04) and featured a worse NFL draft pick position (155.6 vs. 109, p=0.03). Lisfranc-injured players were noted to have a worse NFL draft position (142 vs. 111.3, p=0.04), NFL career length ≥2 years (62.5% vs. 69.6%, p=0.23) and fewer games played (16.9 vs. 23.3, p=0.001) and started (6.8 vs. 10.5, p=0.08) within the first two years of NFL career versus controls. Radiographs demonstrated 17/41 (41.5%) athletes with residual Lisfranc joint displacement >2mm compared to the contralateral foot. Lisfranc-injured athletes with >2mm residual displacement had lower draft position (111.2 vs. 156.9, p=0.009), and fewer games played (23.3 vs. 14.4, p=0.001) and started (10.5 vs. 3,1, p=0.03) versus matched controls. Moreover, athletes with >2mm residual displacement featured worse outcomes across all assessed NFL variables versus athletes with ≤2mm residual displacement. Conclusion: Lisfranc injuries identified at the NFL Combine have an adverse effect on an NFL athlete’s draft status, draft position and overall play during initial NFL seasons. In particular, residual displacement of the Lisfranc joint has a detrimental impact on the first two seasons of NFL play and may lead to long lasting negative effects on career.

Paper 118 Title: The Role of Platelet-Rich Plasma in Promoting Cartilage Integration and Chondrocyte Migration. Authors: Corey Sermer, BMSc1, Rita Kandel, MD1, Jesse Anderson, MD1, Mark Hurtig2, John S. Theodoropoulos, MD, FRCSC1. 1Mt. Sinai Hospital, Toronto, ON, Canada, 2University of Guelph, Guelph, ON, Canada. Objectives: Current therapies for cartilage repair either do not result in regeneration of articular cartilage, or there is inadequate integration with the host tissue leading to failure of the repair. Thus, there is an interest in developing alternative approaches. The mechanisms of cartilage integration remain relatively unknown, however it is believed that chondrocyte migration is crucial to this process. Previously, we showed that platelet rich plasma (PRP) enhances in vitro cartilage tissue formation. We hypothesized that PRP will enhance the integration of bioengineered cartilage with native cartilage due to increased matrix accumulation at the interface and that PRP could promote chondrocyte migration. Methods: Isolated bovine chondrocytes were seeded on a porous bone substitute and grown in vitro to form osteochondral-like tissue. After 7 days the biphasic constructs were soaked in PRP for 30 minutes prior to implantation into the core of a ring-shaped osteochondral explant. Controls were not soaked in PRP. The resulting implant-explant construct was cultured in a stirring bioreactor for 2 weeks (contact model). Alternatively, the PRP soaked biphasic construct was placed 2mm away from a native cartilage/bone plug of equal dimensions to assess chondrocyte migration between the two tissues (non-contact model). The integration zone was visualized histologically. A push-out test was performed to assess the strength of integration. Matrix accumulation at the zone of integration was assessed biochemically and the gene expression of the cells in this region was assessed by RT-PCR. Cell migration was evaluated by video microscopy over 8 days. Significance (p<0.05) was determined by a χ2 test, a student’s t-test or one-way ANOVA with tukey’s post hoc. Results: PRP soaked implants (contact model) integrated with host tissue in 73% of samples, whereas control implants integrated in 19% of samples (p<0.05). The integration strength was significantly increased in the PRP soaked implant group compared to controls (219 ± 35.4 kPa and 72.0 ± 28.5 kPa, respectively, p<0.05). This correlated with an increase in glycosaminoglycan and collagen accumulation in the region of integration in the PRP treated implant group (p<0.05). Immunohistochemical studies revealed that the integration zone was rich in collagen type II and aggrecan. The cells at the zone of integration in the PRP soaked group had a 3.5 fold increase in matrix metalloproteinase 13 (MMP13) gene expression (p<0.05) compared to controls. In the non-contact cultures, a network of fibers developed to connect the PRP soaked construct to the native plug. No fibers formed when the constructs were not soaked in PRP. Time-lapse videos showed chondrocytes with a round phenotype migrating along the fibers and undergoing cell division within 24 hours. These cells came from the bioengineered cartilage whereas migrating cells from native cartilage were only seen after 5 days in select cultures. After 2 weeks, the cells deposited cartilage-like matrix around the fibers as seen histologically. A single layer of cells expressed MMP13 on the outer aspects of the tissue.

Conclusion: PRP soaked bioengineered cartilage implants showed improved integration with native cartilage compared to non-soaked implants perhaps due to increased matrix accumulation. Chondrocytes grew out from the in vitro formed tissue and migrated along fibers after PRP soaking. The contribution of these cells to integration requires further study.

Paper 120 Title: Cartilage Repair with Mesenchymal Stem Cells (MSCs) Delivered in a Novel Chondroitin Sulfate / Polyethylene Glycol Hydrogel in a Rabbit Animal Model” Authors: Cecilia Pascual-Garrido, MD1, Francisco Rodriguez Fontan, MD2, Jorge Chahla, MD3, Karin Payne, PhD1, Elizabeth Aisenbrey, Researcher4, Stephanie J. Bryant, PhD5, Robert F. LaPrade, MD, PhD6, John C. Clohisy, MD7, Laurie R. Goodrich, MVD, PhD8. 1Colorado University of Denver, Aurora, CO, USA, 2Colorado University of Denver, Denver, CO, USA, 3Steadman Philippon Research Institute, Vail, CO, USA, 4University of Colorado Boulder, Boulder, CO, USA, 5Colorado University of Boulder, Aurora, CO, USA, 6The Steadman Clinic, Vail, CO, USA, 7Washington University School of Medicine, St Louis, MO, USA, 8Colorado State University, Fort Collins, CO, USA. Objectives: To determine whether rabbit bone marrow-derived MSCs embedded in a chondroitin sulfate (ChS)/ poly (ethylene glycol) (PEG) biodegradable hydrogel display enhanced in vivo chondrogenesis as compared to ChS/PEG hydrogel alone, in a critical sized osteochondral defect in a rabbit animal model. Methods: Allogenic MSCs were harvested from bone marrow and expanded in specific media (20% fetal bovine serum, 50 U ml-1 penicillin, 50 mg ml-1 streptomycin, 20 mg ml-1 gentamicin, and 5 ng ml-1 bFGF (fibroblast growth factor) in low glucose Dulbecco’s modified Eagle media) under standard cell culture conditions (37o C with 5% CO2). Surgery was carried out in 10 mature New Zealand white rabbits (8 months old). A critical sized chondral defect (3mm) was performed bilaterally in the trochlear groove of the femoropatellar joint in all ten rabbits. Three treatment groups were established as follows: 1- hydrogel alone (5N), 2- hydrogel with MSCs (3 x 106 cell/ml) (5N), and 3- control defect with no treatment (10N). Animals were left to ambulate freely after surgery. At 6 months postoperative, euthanasia was performed. Macroscopic evaluation of defect repair was performed by four observers unaware of treatment groups using ICRS (International Cartilage Repair Society) scoring. Microscopic evaluation was performed using the O’Driscoll grading system. Using SigmaPlot 11.0 statistical software (Systat Software, San Jose, CA, USA), comparison between groups was performed with an ANOVA test to see if differences existed between treatment groups. Tukey’s correction was used to adjust for multiple group comparisons, and two independent t-tests: 1- between rabbits receiving hydrogel alone vs. their respective controls; 2- between rabbits receiving hydrogel / MSCs vs. their respective controls; for both ICRS and O’Driscoll scores, being a total of six statistical analyses. Results: At time of euthanasia, all hydrogels remained in place. There was no synovial reaction or macroscopic inflammation. Cartilage repair was evident in all groups. Macroscopically, no significant difference was evident according to ICRS scores. The average ICRS score for the groups was: 1 (hydrogel alone): 10 ± 1.73 SD, 2 (hydrogel with MSCs): 10 ± 1.41 SD and 3(control): 11.3 ± 1.06 SD (p= 0.088). Histological average scoring with O’Driscoll system for each group was highest for the hydrogel alone (1: 19.8 ± 5.5 SD, 2: 16 ± 3.54 SD, and 3: 18.5 ± 3.63 SD) (p= 0.227) (Figure 1). One way ANOVA, showed no statistical difference for both ICRS and O’Driscoll scores. The t-tests showed no statistical significance among groups (p>.05), except for ICRS score comparing control vs. hydrogel / MSCs which favored the control group (p=0.046).

Conclusion: Hydrogels remained in place and induced chondrogenesis, especially when hydrogels were placed in the defect without MSCs. Adding MSCs to the hydrogel did not improve cartilage healing. Macroscopically, ICRS score was significantly worse for the MSCs/hydrogel group when compared to the control group. Limitations of this study include small animal model with natural good intrinsic cartilage regeneration. Still, all selected animals were mature, reducing the chances of natural healing. In addition, all animals had an established control defect. Future experiments will include adding transforming growth factor (TFGb) to the encapsulated MSCs to potentially improve chondrogenesis.

Paper 121 Title: Redifferentiated Chondrocytes for the Repair of Articular Cartilage Lesions Authors: Vanessa Juliana Bianchi, B.Sc.1, John S. Theodoropoulos, MD, FRCSC2, Rita Kandel, M.D2, David Backstein, M.D, MEd, FRCSC3. 1Lunenfeld-Tanenbaum Research Institute, Toronto, ON, Canada, 2Mount Sinai Hospital, Toronto, ON, Canada, 3Sinai Health System, University of Toronto, Toronto, ON, Canada. Objectives: Biological therapies such as autologous chondrocyte implantation which use serially passaged chondrocytes to repair cartilage defects, are often unsuccessful as they lead to the formation of fibrocartilage. Fibrocartilage is rich in collagen type 1 (Col1) and lacks the structural complexity, low friction, and load distribution properties of articular cartilage. Fibrocartilage forms as a result of the phenotype of passaged chondrocytes. When serially passaged in monolayer to increase cell numbers, chondrocytes lose their phenotype in a process termed “dedifferentiation”. This is characterized by a loss in the production of collagen type II (Col2) and aggrecan (Acan), the major extracellular matrix molecules of articular cartilage, and an increase in the production of Col1. Therefore, to increase the success of therapies which use passaged chondrocytes, these cells must be redifferentiated to re-establish an articular cartilage phenotype prior to implantation in a cartilage lesion. Transforming growth factor beta (TGFβ) signalling is known to play important roles in both cell differentiation and articular cartilage repair. However, intra-articular injections with TGFβ have been shown to result in osteophyte formation and fibrosis of synovial tissues. Therefore, redifferentiating passaged chondrocytes in vitro using TGFβ prior to their use in vivo may be a better alternative. Fibrin glue is commonly used in orthopaedics to maintain cells in a cartilage lesion, however the effects of fibrin glue on chondrocytes have not been fully investigated. Thus we hypothesize that passaged chondrocytes redifferentiated in vitro with TGFβ will maintain their phenotype and form articular cartilage-like tissue when embedded in fibrin glue in the absence of further exogenous supplementation with TGFβ in vitro. Methods: Chondrocytes were enzymatically isolated from rabbit articular cartilage and serially passaged in monolayer twice (P2) to increase cell number and facilitate dedifferentiation. P2 cells were cultured in scaffold-free 3D using a chondrogenic serum-free media supplemented with 10ng/ml TGFβ3 to facilitate redifferentiation. Redifferentiated chondrocytes were then embedded in fibrin glue (Tisseel, Baxter) at 1.5 x 106 cells/20uL and cultured for 2 weeks in vitro in the absence of TGFβ3. Controls were P2 cells that were not redifferentiated with TGFB3 prior to embedding in fibrin glue. Histology and immunohistochemistry were used to assess tissue formation and cell phenotype. Results: Redifferentiated chondrocytes accumulated more matrix rich in Col2 and Acan than controls (Figure 1). Furthermore, redifferentiated chondrocytes had a round cell shape characteristic of articular chondrocytes. The use of fibrin glue did not impair the ability of redifferentiated chondrocytes to accumulate matrix nor did it affect cell phenotype. Conclusion: Redifferentiated chondrocytes in fibrin glue may be a better alternative to passaged chondrocytes for cell based articular cartilage repair therapies as they accumulate more Col2 and Acan

containing matrix than undifferentiated P2. In vivo studies are required to elucidate the potential for redifferentiated chondrocytes in cartilage repair.

Paper 122 Title: Second Generation Autologous Chondrocyte Implantation in the Patella: Improved Pain Relief and Functional Outcomes among U.S. Army Servicemembers Authors: Brian R. Waterman, MD1, Nicholas Zarkadis, MD2, Michael A. Zacchilli, MD3, Courtney Holland, MD2, Allison Kinsler, MD2, Michael S. Todd, DO, MAJ4, Philip J. Belmont, MD2, Mark P. Pallis, DO2. 1Rush University Medical Center Program, Chicago, IL, USA, 2William Beaumont Army Medical Center, El Paso, TX, USA, 3NYU Hospital for Joint Diseases, New York, NY, USA, 4OSU Orthopaedics and Sports Medicine at Wooster Community Hospital, Wooster, OH, USA. Objectives: To evaluate the functional outcomes of autologous chondrocyte implantation (ACI) for high-grade patellofemoral chondral defects in a predominately young, high-demand military demographic. Methods: We conducted a retrospective review of all United States military and Tricare beneficiaries undergoing ACI for Outerbridge grade III or IV patellofemoral chondral defects at a two high-volume military medical centers between 2007 and 2014. Second generation surgical technique was performed using autologous cultured chondrocytes (Vericel, Inc; Boston, MA) secured with a type I/III collagen bilayer membrane. Inclusion criteria required minimum two-year surveillance, although patients with knee-related medical discharge were also included to limit non-responder bias. Exclusion criteria were applied to individuals with predominately condylar involvement, periosteal patch coverage, and/or procedure miscoding Demographic information, surgical characteristics, and clinical outcomes were extracted from the electronic medical record. Averages were calculated with standard deviations (SD). Univariate analysis was used to determine significant independent predictors of surgical failure, which was defined as revision chondral procedure or conversion to arthroplasty. Relative risk was quantified with use of odds ratios (OR) with 95% confidence intervals (95% CI). Results: A total 57 patients with 58 knees were identified at average 2.13 year follow-up within the military health care system. The median age was 33.8 years (range, 20.3 to 49.9). Males comprised 77% of patients (n=44), and 93% (n=53) were active duty military status. Mean patient body mass index (BMI) was 30.3 kg/m2, tobacco use was documented in at least 19.3% (n=11), and only one patient had failed prior marrow stimulation procedure. The average lesion size for ACI was 502 mm2 (SD 318; range, 121-1600 mm2) and most defects were based on patella (91.3%). The average tibial tubercle-trochlear groove (TT-TG) distance was 13.9 mm (SD 3.5), and nearly all knees underwent concomitant anteromedializing or offloading tibial tubercle osteotomy (n=56; 97%). Additionally, only three patients required proximal realignment procedure. Only 1 patient (1.7%) required revision chondral procedure, and there were no cases of graft site hypertrophy or conversion to knee arthroplasty. With a “high” or “severe” average patient-reported pain level (86%), the average postoperative visual analog scale (VAS) was 2.3 (SD 2.2; median, 2) at final follow-up. At an average of 1.9 years postoperatively, 14 patients (24.6%) underwent medical discharge due to reported persistent, rate-limiting knee pain, although the average patient-reported VAS was 3 (SD 2.3; range, 0 to 6). No demographic or surgical variables were significantly associated with subsequent adverse clinical outcome (p>0.05).

Conclusion: For patellofemoral chondral defects without failed primary procedure, second generation ACI can successful decrease patient-reported anterior knee pain among highly-active and athletic subsets. Approximately 75% of patients resumed modified military duty or preoperative level of function at short-term follow-up, and only 2% underwent revision. Knee related medical discharge occurred in nearly a quarter of patients, but did not preclude significant pain relief or return to lower demand activities.

Paper 123 Title: Hip Arthroscopy Failure in the Setting of Acetabular Dysplasia: A Concerning Trend? Authors: John C. Clohisy, MD1, Tonya An, BS2, Jacob Haynes, MD3, Jeffrey J. Nepple, MD4, Perry Schoenecker, MD5, Geneva Baca, BA4, ANCHOR Group1. 1Washington University School of Medicine in St. Louis, Saint Louis, MO, USA, 2Washington University, Saint Louis, MO, USA, 3Washington Univesity School of Medicine, Saint Louis, MO, USA, 4Washington University School of Medicine, Saint Louis, MO, USA, 5Washington University School of Medicine, St. Louis, MO, USA. Objectives: Despite the success of hip arthroscopy, evidence suggests that arthroscopy alone is inadequate for treatment of conditions such as acetabular dysplasia (AD) due to its failure to correct structural deformity. Our objective was to define the incidence of failed hip arthroscopy in patients with symptomatic AD requiring periacetabular osteotomy (PAO). We secondarily analyzed the patient and structural characteristics of the failed arthroscopy cases. Methods: Utilizing a prospective, multicenter joint preservation database, we identified a cohort of primary AD patients from 2009-2014 who underwent PAO after a single prior ipsilateral hip arthroscopy. A comparison cohort of PAO patients without prior arthroscopy was isolated. Patients with hip disease attributable to cerebral palsy, Perthes, etc. were excluded. Demographic and radiographic data were summarized for each category. We compared the proportion of PAO after failed hip arthroscopy between the beginning and end of the study period by 2-tailed z-test with P&lt0.05 regarded as statistically significant. Results: Ninety-nine patients (99 hips) had received arthroscopic surgery prior to PAO, while 1053 patients (1103 hips) underwent PAO without prior hip arthroscopy. The proportion of PAO procedures after previous ipsilateral hip surgery stayed constant (13-19%); however, the incidence of PAO after previous hip arthroscopy increased from 2.5% in 2009 to 9.8% in 2014 (P=0.004). Over the 6 year period, the rate of all PAO procedures increased 12% per year, whereas rates of PAO after hip arthroscopy grew an average 54% per year. Female sex, increased average LCEA and ACEA, and decreased acetabular inclination were associated with failed hip arthroscopy (P&lt0.01). Conclusion: Over the last six years, we have seen clear increases in the rate of PAO after previous hip arthroscopy. Though the rate of PAO following previous ipsilateral surgery remains constant, hip arthroscopies now constitute almost 60% of those previous surgery attempts. Additionally, we have identified mild dysplastic features and female sex as characteristics that are associated with failure of hip arthroscopy. These results are consistent with prior literature suggesting that inadequately corrected structural deformity is the most common indication for revision surgery. These findings raise concern that isolated hip arthroscopy is being increasingly utilized in patients with acetabular dysplasia and highlight the need for refined surgical indications for hip arthroscopy and further investigation into its impact on subsequent surgeries.

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Paper 124 Title: Magnetic Resonance Imaging Comparison of Repaired versus Non-Repaired Hip Capsule in Patients Undergoing Hip Arthroscopy for Femoroacetabular Impingement: A Double-Blind, Randomized Controlled Trial Authors: Omer Y. Mei-Dan, MD1, Colin Strickland, MD2, Tigran Garabekyan, MD3, Vivek Chadayammuri, BS2, Matthew Brick, MD, FRACS4, Matthew John Kraeutler, MD1. 1University of Colorado School of Medicine, Boulder, CO, USA, 2University of Colorado School of Medicine, Aurora, CO, USA, 3Southern California Hip Institute, North Hollywood, CA, USA, 4Orthosports, North Shore City, New Zealand. Objectives: Techniques used in hip arthroscopy continue to evolve and controversy surrounds the need for capsule repair following surgical intervention. The purposes of this study were to evaluate the magnetic resonance imaging (MRI) appearance of the hip capsule in patients with femoroacetabular impingement (FAI) undergoing hip arthroscopy with capsular repair versus non-repair. Methods: A multicenter clinical trial was performed with 35 patients (50 hips) undergoing hip arthroscopy for treatment of FAI. Each hip was preoperatively randomized to capsular repair versus non-repair. MRI evaluation was performed by a radiologist at 6 and 24 weeks postoperatively. Patients and the radiologist were blinded to the randomization. Capsular defect size and the thickness of the capsule at the capsulotomy site and at locations both proximal and distal to the defect were recorded on each scan to determine their change over time. Results: Compared to patients without capsular repair, those with capsular repair demonstrated significantly decreased mean capsular gapping at articular and muscular portions of the hip capsule at 6 weeks postoperatively (p < 0.001). This difference normalized between the two cohorts by 24 weeks postoperatively, with a significantly decreased mean capsular gapping at articular and muscular attachment sites of the hip capsule compared to 6 weeks postoperatively (p < 0.03). Defects were readily apparent on MRI imaging in regions where the capsule was not repaired. In contrast, irregular capsular thickening without a discrete defect was visible in most cases where the capsule was repaired at the time of arthroscopy. The appearance was variable after 24 weeks. The capsular defects that did close universally showed closure of the defect beginning at the muscular side of the capsule with bridging of capsular tissue then filling in on the articular side. Conclusion: Arthroscopic hip capsule repair results in significantly less capsule gapping at 6-week follow-up compared with non-repair, though the difference in gap size normalizes by 24-week follow-up.

Paper 125 Title: Outcome for Arthroscopic Treatment of Anterior Inferior Iliac Spine/Subspine Related Hip Impingement Authors: Benedict Uchenna Nwachukwu, MD, MBA, Brenda Chang, MS, MPH, William W. Schairer, MD, Kara G. Fields, MS, Danyal H. Nawabi, MD, Bryan T. Kelly, MD, Anil S. Ranawat, MD. Hospital for Special Surgery, New York, NY, USA. Objectives: Extra-articular disorders of the hip are under-recognized and under-reported. Extra-articular forms of hip impingement can include anterior inferior iliac spine (AIIS) related subspine impingement. The purpose of this study was to investigate the outcome after arthroscopic treatment of anterior inferior iliac spine (AIIS)/Subspine related hip impingement. Methods: A prospective institutional hip preservation registry was reviewed to identify patients that underwent isolated arthroscopic AIIS decompression. Primary outcome tools captured in the registry included: the modified Harris Hip Score (mHHS), the Hip Outcome Score (HOS) and the international Hip Outcome Tool (iHOT-33). Patients with minimum one-year follow-up were included. Meaningful outcome improvement was determined based on minimal clinically important difference (MCID). Statistical analyses were primarily descriptive. Results: Thirty-three patients with mean follow-up 19.1 months (range: 12-44 months) were identified. All patients were female with a mean age of 26.1 (+ 10.3) years. All patients were found to have an associated labral tear and the mean acetabular version was increased at 2 and 3 o’clock (14.5 and 19.8 respectively). Mean pre-operative outcome scores on the mHHS, HOS activities of daily living (ADL), HOS Sport and iHOT-33 were 57.2 (SD+15.3), 66.9 (SD+18.8), 43.9 (SD+23.6) and 33.5 (SD+18.3) respectively. At final available follow-up, mean scores on these outcome measures were 79.5 (SD+19.0), 86.8 (SD+15.8), 70.4 (SD+32.8) and 65.0 (SD+31.0) respectively. By the one-year follow-up interval MCID had been achieved in the majority of patients across all four tools. Conclusion: There is a paucity of outcome evidence on AIIS/Subspine related hip impingement. This study demonstrates that isolated subspine impingement can be a cause of hip disability even in the absence of FAI. Patients with isolated subspine impingement are more likely to be women and they present with low patient reported outcome scores. Meaningful outcome improvement can be achieved however with arthroscopic AIIS decompression.

Paper 126 Title: Radiographic Risk Factors and Signs of Abductor Tears in the Hip Authors: David Edward Hartigan, MD1, Itay Perets, MD1, John P. Walsh, MA1, Edwin Chaharbakhshi, BS1, Mary Close, BS1, Benjamin G. Domb, MD2. 1American Hip Institute, Westmont, IL, USA, 2Hinsdale Orthopaedics and American Hip Institute, Westmont, IL, USA. Objectives: There is a known increased prevalence of abductor tears in patients with increased age and female gender. This study’s purpose is to identify radiographic risk factors (RRF) and radiographic signs of abductor tendon tears. Methods: Patients with intraoperative diagnoses of abductor tear were included in this study and were matched by age ±5 years, gender, and BMI ±5 with patients who had no abductor pathology by clinical exam and MRI. An AP pelvis radiograph was performed on all patients. The radiographs were evaluated for RRF (pelvic width, body weight moment arm, abductor moment arm, abductor angle, pelvic height) and signs of abductor tendon pathology (greater trochanteric excrescence). Femoral version was measured on MRI when images were available. Results: There were 152 patients with abductor tears identified intraoperatively. All were treated with surgical repair. These patients were matched as described previously. The RRF found were an increased tear drop to tear drop distance (14.8 for abductor tears vs. 14.3 for control; p<0.001), body weight moment arm (11.1 vs. 10.9; p<0.001), abductor moment arm (7.8 vs. 7.6; p<0.001), decreased femoral anteversion (7.6 vs. 10.6; p=0.045), and excrescence presence (41% vs. 3%; p<0.001). An excrescence of the greater trochanter had a specificity of 97%, PPV of 94% and a positive likelihood ratio of 12.8 for abductor tears. Conclusion: Patients with abductor tears have a wider pelvis, longer abductor moment arm, longer body weight moment arm, less femoral anteversion, and have greater trochanteric excrescence noted on nearly half of patients with an abductor tear. Presence of an excrescence was noted to have a positive predictive value of 94%, specificity of 97%, and positive likelihood ratio of 12.75, suggesting that if noted on radiograph, the care provider should have a very high index of suspicion for abductor tendon tear.

Paper 127 Title: Operative Management of Osteochondritis Dissecans: Progression to Osteoarthritis and Arthroplasty in a Population Based Cohort Authors: Thomas L. Sanders, MD1, Ayoosh Pareek, BS1, Nick R. Johnson, BS1, Rohith Mohan, BA1, James L. Carey, MD, MPH2, Michael J. Stuart, MD1, Aaron John Krych, MD1. 1Mayo Clinic, Rochester, MN, USA, 2Penn Sports Medicine Center, Philadelphia, PA, USA. Objectives: Osteochondritis dissecans (OCD) is a disorder of subchondral bone that causes adverse effects on the overlying cartilage and commonly affects the knee. The purpose of this study is to (1) evaluate the rate of arthritis and knee arthroplasty in a population-based cohort of patients with OCD lesions treated operatively and (2) evaluate factors that may predispose patients to knee osteoarthritis and arthroplasty. Methods: 221 patients (mean age 26.1 ± 13.6 years) with OCD lesions treated operatively were identified between 1976 and 2014 and followed for a mean of 16.3 (±11.4) years from diagnosis. Information related to the diagnosis, laterality of lesion, details of treatment, and progression to arthritis was obtained from the medical record. Surgical treatment was classified as palliative (fragment excision) or restorative (lesion drilling, fragment fixation, osteochondral allograft or autograft). Factors predictive of arthritis and arthroplasty were examined. Results: In the palliative group, the cumulative incidence of arthritis was 12.0% at 5 years, 17.0% at 10 years, 26.0% at 15 years, 39.0% at 20 years, and 70% at 30 years. The cumulative incidence of arthroplasty was 2.0% at 5 years, 4.0% at 10 years, 4.0% at 15 years, 10.0% at 20 years, and 32.0% at 30 years. In the restorative group, the cumulative incidence of arthritis was 3.0% at 5 years, 7.0% at 10 years, 16.0% at 15 years, 25.0% at 20 years, and 51% at 30 years. The cumulative incidence of arthroplasty was 0.0% at 5 years, 0.0% at 10 years, 3.0% at 15 years, 6.0% at 20 years, and 11.0% at 30 years. BMI greater than 25 kg/m2 (HR 3.3, 95% CI: 1.6, 7.0), older age at diagnosis (HR 4.9, 95% CI: 1.8, 17.3) and fragment excision (HR 2.3, 95% CI: 1.2, 4.6) were predictive of arthritis. Conclusion: OCD patients treated with fragment excision have a high rate of arthritis and knee arthroplasty at long-term follow-up. In contrast, patients treated with fragment repair or osteochondral restoration have lower rates of arthritis and arthroplasty. BMI greater than 25 kg/m2, older age at diagnosis, and fragment excision were predictive of arthritis.

Paper 128 Title: Moderate Return to High Impact Function after Fresh Osteochondral Allograft Transplantation for Chondral Defects of the Knee Authors: Brian R. Waterman, MD1, Dimitri Thomas2. 1Rush University Medical Center Program, Chicago, IL, USA, 2Munson Army Health Center, Fort Leavenworth, KS, USA. Objectives: The purpose of this investigation was to report the patient-reported and occupational outcomes of military servicemembers after fresh osteochondral allograft transplantation (OCA) of the knee at mid-term follow-up. Methods: A query of the Military Health System was performed to identify all United States Army service members undergoing OCA for Outerbridge grade 3 or 4 chondral lesions between January 2009 and June 2013 with minimum 2-year follow-up. Exclusion criteria were applied to individuals with the following: insufficient follow-up or documentation; treatment of bipolar lesions; and use of cryopreserved, fresh-frozen, or fresh osteochondral allografts used greater than 28 days after harvest. Demographic information, lesion characteristics, and clinical outcomes (Visual Analog Scale for pain, functional duty limitations, and/or revision rates) were extracted from the military electronic medical records system. Statistical measures such as the Chi square test and Poisson multivariable regression analysis were utilized to evaluate for variables associated with rate-limiting, knee disability and/or surgical revision. Results: At 3.8 follow-up, 61 patients met the inclusion criteria with an average age was 32 yrs±8.0. Medial femoral condyles were most common (n=40;65.6%), followed by the patella (n=11;18.0%), lateral femoral condyle (n=8;13.1%), and trochlea (3;5.0%). The average cross-sectional size of treated lesions was 364mm2±193 (48-707mm2). Thirty-seven knees (61.7%) were treated without concomitant procedure, and 21 knees (34.4%) had staged or simultaneous periarticular osteotomies. Average VAS pain scores significantly decreased from 4.1 to 2.5 postoperatively (p<0.01). At final follow up, 65.6% of patients returned to unrestricted or modified military function, whereas 21(34.4%) individuals were unable to return due to persistent knee limitations. Nine (14.7%) patients experienced preoperative complications, Seven patients (11.5%) required secondary revision after OCA, 3 patients underwent chondroplasty, and 1 patient (1.6%) underwent subsequent total knee arthroplasty. Lesion size was not associated with any adverse clinical or surgical outcomes (p>0.05), and lateral femoral condyle and trochlear lesions had a higher rates of revision, although this failed to achieve significance (p=0.22;p=0.26, respectively). Higher preoperative BMI (OR 1.15;p=0.045) and postoperative VAS(OR 1.36;p<0.01) values were associated with increased risk of knee disability. Conclusion: Fresh OCA can reliably decrease knee pain in a highly-active population, with nearly two-thirds of all patients return to military function. However, approximately one in eight individuals may undergo revision after return to preoperative activities, and individuals of high BMI may be at heightened risk of clinical failure.

Paper 129 Title: Performance-based Outcomes among American Professional Athletes Following Microfracture of the Knee: A Cross-sport Analysis Authors: Michael S. Schallmo, BS1, Sameer Kumar Singh, BA2, Ryan Freshman, BS2, Kathryn Barth, BA2, Harry Mai, MD3, Wellington Hsu, MD4. 1Wake Forest School of Medicine, Winston-Salem, NC, USA, 2Northwestern University Feinberg School of Medicine, Chicago, IL, USA, 3Harbor-UCLA Medical Center, Los Angeles, CA, USA, 4Northwestern University, Chicago, IL, USA. Objectives: Damage to the articular cartilage of the knee is a common and potentially career-threatening injury among professional athletes. Microfracture is a technique frequently used to treat chondral defects, but the potential benefits of this procedure in the elite athlete population remain unclear. This study sought to assess outcomes after microfracture of the knee among American professional athletes in different sports. Methods: Major League Baseball (MLB), National Basketball Association (NBA), National Football League (NFL), and National Hockey League (NHL) athletes who underwent primary unilateral microfracture of the knee while on the active roster of a professional team and had a definitive date of surgery were identified through a well-established algorithmic approach based on public sources. Demographic information, as well as both pre- and post-surgery regular season player statistics, was compiled for each player. Successful return-to-play (RTP) was defined as returning for at least one professional regular season game after surgery. RTP time was defined as the number of days elapsed between date of surgery and date of first professional game back. Performance scores were calculated for each sport using previously established scoring systems. Players across different sports were compared by adjusting for season and career length differences between sports and by calculating percent change in performance. Results: A total of 131 professional athletes treated with microfracture from 1991 to 2015 met the inclusion criteria. Of these athletes, 103 (78.6%) successfully returned to play (Figure 1). Average time to RTP was 293±146 days. A player’s total career games started-to-games played ratio (GS:GP) before surgery was a significant positive independent predictor of RTP (p=0.039). NBA athletes who returned showed a significant reduction in adjusted games played during their first season post-surgery (61) compared to baseline (100) (p<0.0001). NBA and MLB athletes demonstrated significantly decreased performance one season after surgery (p=0.029 and p=0.002, respectively), and NBA athletes also demonstrated significantly decreased performance during post-operative seasons 2-3 (p=0.024) (Figure 2). BMI, age, career experience (years), games played during index season and total pre-operative career, and GS:GP during index season and total pre-operative career were not found to be predictors of RTP time, career length after surgery (years and games played), or change in performance score. Conclusion: Microfracture of the knee is a serious procedure that has the potential to negatively impact a professional athlete’s career. NFL athletes demonstrated the lowest probability of returning after

surgery (71.1%), but for those who returned, performance was recoverable to baseline. NBA athletes had a higher-than-average probability of returning to play (82.4%), but those who returned showed a significant decline in performance one season after surgery that was sustained 2-3 seasons post-surgery, and a reduction in games played one season after surgery that was recoverable to baseline by seasons 2-3 post-surgery. Given the small sample size for NHL, microfracture of the knee may be uncommon in these athletes and definitive conclusions cannot be made. The findings of this study demonstrate that outcomes following microfracture vary significantly depending on sport, which is likely due in part to differences in sport-specific tasks.

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Paper 130 Title: Outcomes of Osteochondral Allograft Transplantation with versus without Concomitant Meniscus Allograft Transplantation: A Comparative Matched Group Analysis Authors: Rachel M. Frank, MD1, Simon Lee, MD2, Sarah Glen Poland, BS3, Timothy Sean Leroux, MD, MEd1, Brian J. Cole, MD, MBA3. 1Rush University Medical Center, Chicago, IL, USA, 2University of Michigan Health System, Ann Arbor, MI, USA, 3Midwest Orthopaedics at Rush, Chicago, IL, USA. Objectives: While osteochondral allograft transplantation (OAT) is often performed with concomitant meniscus allograft transplantation (MAT) as a strategy for knee joint preservation, the impact of concomitant MAT on outcomes following OAT has not been assessed. The purpose of this study was to determine clinical outcomes for patients undergoing OAT with MAT compared to a matched cohort of patients undergoing isolated OAT. Methods: A review of consecutive patients who underwent OAT by a single surgeon with a minimum follow-up of 2 years was conducted. Patients who underwent OAT without concomitant MAT were compared to a matched group of patients who underwent OAT with concomitant MAT (age ± 3 years, gender, BMI ± 5 kg/m2, number of previous ipsilateral knee surgeries ± 1, and the presence of concomitant ligamentous surgery). The reoperation rate, failure rate, timing of reoperation, procedures performed, findings at surgery, and patient reported outcome scores were reviewed. Failure was defined by revision OAT, conversion to knee arthroplasty, or gross appearance of graft failure at 2nd look arthroscopy. Descriptive statistics, fisher’s exact or chi-square testing, and Mann-Whitney U testing were performed, with P<0.05 set as significant. Results: A total of 100 patients (average age 32.2±9.9 years; 52 males, 48 females) who underwent OAT (50 isolated, 50 with MAT) with an average follow-up of 4.84±2.7 years (range, 2.0-15.1) were included. These patients underwent an average of 2.6±1.2 prior surgical procedures on the ipsilateral knee prior to OAT. A total of 38 patients underwent reoperation at an average 2.4±2.2 years, with 24% (9/38) undergoing additional reoperations (range, 1-2 additional reoperations). MAT patients did not have significantly different reoperation rates (MAT: 40%; non-MAT: 36%), time to reoperation (MAT: 2.20±2.31 years; non-MAT: 2.56±2.11 years) or failure rates (14% vs. 14%) compared to non-MAT patients. Both MAT and non-MAT patients showed significant improvement in Lysholm, IKCD, KOOS, WOMAC, and SF-12 physical subscale as compared to preoperative values (P>0.05 for all for both groups). The SF-12 mental subscale was not significantly improved at final follow-up for either group. MAT patients demonstrated significantly higher SF-12 physical subscale as compared to non-MAT patients at most recent follow-up (45.81±7.42 vs 42.07±7.97, P<0.05). There were no significant differences detected in the defect size (MAT: 338.64±116.31 mm2; non-MAT: 344.42±171.04 mm2, P>0.05) or defect:condyle size ratio (MAT: 0.19; non-MAT: 0.20, P>0.05). Conclusion: Patients undergoing OAT with MAT have similar survival rates, reoperation rates, and clinical outcomes compared to patients undergoing isolated OAT at an average follow-up of 5 years. This information can be used to counsel patients undergoing concomitant MAT as part of a knee joint preservation strategy.

Paper 131 Title: OCA Transplantation Outcomes for Replacing Large Bipolar Defects in the Knee using Novel Techniques Authors: James L. Cook, DVM,PhD1, James P. Stannard, MD2, Mauricio Kfuri, MD, PhD3, Brett D. Crist, MD3, Matthew Jared Smith, MD1. 1University of Missouri, Columbia, MO, USA, 2Missouri Orthopaedic Institute, Columbia, MO, USA, 3University of Missouri Department of Orthopaedic Surgery, Columbia, MO, USA. Objectives: Objective - Osteochondral allograft (OCA) transplantation can functionally restore large articular cartilage defects in the knee, shoulder, hip and ankle. Studies have reported 10-year survivorship between 71% and 85% and up to 74% survivorship at 15 years. Outcomes after OCA treatment have been good to excellent, even in the athletic population in which 88% of patients returned to sport, including 79% returning to preinjury level of sport. However, OCA transplantations for bipolar defects in the knee have traditionally had less favorable results. With the advent of improved allograft preservation methods and refined surgical techniques, OCA transplantations for bipolar defects in the knee have shown a trend toward better outcomes. Therefore, the objective of this study was to report early functional outcomes associated with OCA transplantations to replace large (>4 cm2) bipolar articular cartilage defects in the knee using novel techniques for graft preservation, enhancing bone ingrowth, and implantation. Methods: With IRB approval, patients were enrolled in a dedicated registry for prospective assessment of outcomes after OCA surgery. Demographic and operative data were collected. Outcomes assessments including VAS pain, VAS level of function, IKDC, SANE and PROMIS Mobility are prospectively collected at 6 months and yearly after surgery. All complications and re-operations are recorded. OCA survival is determined based on maintenance of acceptable levels of pain and function and/or need for revision surgery. Data are compared to pre-operative and/or pre-injury levels using repeated measures analyses with significance set at p<0.05. Results: Large bipolar OCA transplantations were performed in 23 knees: femorotibial (n=19), patellofemoral (n=4). Mean age of patients was 34.6 years. Mean pre-operative pain, function, IKDC, SANE and PROMIS Mobility scores were 4.7, 4.1, 40.8, 40.1 and 42.1, respectively. At 6 months postop (n=17), mean scores improved to 1.3, 6, 56.2, 71.8 and 46.1, respectively. At 1 year (n=11), mean scores further improved to 0.4, 8.4, 76.7, 80.6 and 58.4, respectively (Table). Two (8.7%) meniscotibial grafts failed in the first 6 months after surgery and were successfully revised by a second OCA transplantation, making initial survival 91.3%. Five (21.7%) other patients required minor reoperations for lysis of adhesions to restore range of motion and/or screw removal. All subjects are enrolled in the registry and outcomes assessments are ongoing and will be updated for presentation. Conclusion: Bipolar osteochondral allograft transplantation surgeries for treatment of large (>4 cm2) femorotibial or patellofemoral articular cartilage defects in the knee using novel techniques are associated with significant improvements in levels of pain and function at 1 year after surgery.

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Paper 132 Title: Meniscal Repair Outcomes in Revision ACL Reconstructions Authors: Mars Group. Washington University St. Louis, St Louis, MO, USA. Objectives: Meniscal preservation has been demonstrated to contribute to long term knee health. This has been a successful intervention in the isolated and ACL reconstructed patient. The results of meniscus repair in the setting of revision ACL reconstruction have never been documented to any significant extent. The MARS group offers with its large cohort of revision ACL reconstructions the opportunity to explore this issue. Methods: The MARS Group was assembled with the aim of determining what impacts outcome in an ACL revision setting, and to identify potentially modifiable factors that could improve these outcomes. This collaboration consists of a group of 83 sports medicine fellowship trained surgeons across 52 IRB approved sites. Surgeons are a near equal mix of academic and private practitioners. Surgeons document surgical technique and intraarticular findings including meniscal and chondral damage and their treatment.All revision ACL reconstruction with meniscal repair cases from a multicenter group between 2006 and 2011 were selected. Two-year follow-up was obtained by both phone and email to determine whether any subsequent surgery had occurred to either knee since their initial revision ACL reconstruction. If so, operative reports were obtained, whenever possible, to verify pathologic condition and treatment. Results: 1215 patients were enrolled. 235 repairs were performed in 218 patients (19.5% of the cohort): 170 were medial, 65 lateral and 17 medial and lateral. 178 (76%) were performed with all-inside techniques. 17 repairs failed by 2 year follow up: 15 medial (8.8%; 13 all inside, 2 outside in) and 2 lateral (3.1%; both all inside). 4 of the medial failures were treated in conjunction with a subsequent repeat revision reconstruction. Conclusion: Meniscus repair in the revision setting is a successful treatment choice when appropriate. Failure rates for medial and lateral tears were both less than 10% and consistent with primary ACL reconstruction meniscus repair success rates. Medial tears underwent reoperation for failure at a statistically significant higher rate than lateral tears.

Paper 133 Title: Subsequent Surgery and Prevalence of Osteoarthritis Following Arthroscopic Meniscus Posterior Root Repair: Association with Patient Age and Body Mass Index Authors: Joseph D. Lamplot, MD1, Olivia Lillegraven, BA1, Robert D. Wojahn, MD1, Robert H. Brophy, MD2. 1Washington University in Saint Louis, Saint Louis, MO, USA, 2Washington University Orthopedics, Chesterfield, MO, USA. Objectives: Posterior meniscus root tears disrupt the tibial plateau attachment, leading to a loss of hoop stresses and significant increases in tibiofemoral contact forces. As a result, there is growing interest in surgical repair of these tears. The purpose of this study is to report rates of recurrent surgery and prevalence of osteoarthritis following posterior meniscus root repairs, and associated patient factors, in a North American population. Methods: Arthroscopic posterior meniscus root repair using a pullout trans-tibial suture method was performed by a single surgeon in the United States. Eligible patients d the Knee Injury and Osteoarthritis Outcome Score (KOOS) and reported any subsequent surgeries at minimum two-year follow-up. Patients were categorized as having clinical OA based on their KOOS score. When available, post-operative radiographs were evaluated for radiographic OA using the Kellgren-Lawrence classification and the OA Research Society International (OARSI) atlas. The association of factors with the incidence of clinical and radiographic OA was evaluated. Results: Follow up was collected on 28 of 32 eligible patients (87.5%) at a mean follow up of 2.46 years (range 2.05-3.76 years). At time of surgery, mean age was 44.6 years and mean BMI was 32.7. At follow-up, two patients had undergone subsequent surgery (7%). 14 patients (50.0%) met KOOS criteria for clinical OA. Among the 11 patients with available follow up radiographs, 4 (36%) met OARSI atlas criteria for knee OA. For medial posterior root tears, patients over the age of 45 with BMI over 35 were significantly more likely to develop clinical (85.7% versus 35.0%, p=0.033) and radiographic OA (80.0% versus 0.0%, p=0.015), and undergo additional surgery (40% versus 0%, p=0.036). Conclusion: Arthroscopic repair of posterior root tears in a North American population has a low rate of subsequent surgery despite developing clinical and radiographic OA. Older and heavier patients have a higher incidence of clinical and radiographic OA. Further study is needed to determine optimal treatment for root tears in these patients.

KOOS scores by patient group

KOOS score All patients (mean,95% CI)

Medial meniscal root tear only

ACL and meniscal root tear

p-value

KOOSpain 84.0 (67.6-100) 83.3 (70.4-96.2) 91.3 (80.6-100) 0.197 KOOSsymptoms 79.4 (57.1-99.7) 79.3 (52.3-100) 85.6 (73.9-97.4) 0.478 KOOSADL 88.4 (72.2-100) 86.2 (68.7-100) 98.3 (95.8-100) 0.022 KOOSsport/rec 65.6 (33.4-97.7) 60.7 (34.2-87.1) 83.1 (67.8-100) 0.219 KOOSQoL 66.6 (39.9-93.4) 64.6 (50.0-79.4) 81.3 (65.5-100) 0.107 KOOStotal 381.0 (277.2-484.7) 373.1 (303.4-442.9) 440.1 (385.7-494.5) 0.105

Paper 134 Title: Partial Meniscectomy Provides No Benefit for Symptomatic Degenerative Medial Meniscus Posterior Root Tears Authors: Aaron John Krych, MD1, Nick R. Johnson, BS1, Rohith Mohan, BA1, Diane L. Dahm, MD1, Bruce A. Levy, MD2, Michael J. Stuart, MD1. 1Mayo Clinic, Rochester, MN, USA, 2Mayo Clinic of Rochester Minnesota, Rochester, MN, USA. Objectives: Medial meniscus posterior root tears (MMPRTs) are recognized as a source of pain and dysfunction, but treatment options remain a clinical challenge. Currently, outcomes are unknown following partial meniscectomy for these lesions. To determine (1) the efficacy of partial meniscectomy to treat MMPRTs compared to a matched group of non-operatively treated MMPRTs, and (2) risk factors for worse clinical and radiographic outcome. Methods: This retrospective comparative study was performed to include 27 patients with MMPRTs that were treated with arthroscopic partial meniscectomy (PMM) and a minimum 2-year follow-up. These patients were then matched by age, gender, and BMI to a group of 27 patients with MMPRTs treated non-operatively (control group). Demographic data, radiographic findings, final Tegner and IKDC scores were obtained and compared between the two groups. Risk factors for worse clinical and radiographic outcome in the PMM group alone, including age, sex, BMI, initial K-L grade, subchondral edema, and insufficiency fracture on MRI were determined. Results: Overall, 54 patients were included in the study. 27 patients (10M: 17F) with a mean age of 55±9 and a mean BMI of 32.8±5.3 were treated with PMM and followed for a mean of 5.5±2 years (range 2.3-9.3 years). In the PMM group, final median Tegner score was 3, mean IKDC scores were 67.8±20, median KL grades on weight-bearing AP films demonstrated progressive arthritis (median grade 1 to 2, p=0.001) and more patients had grade II or higher arthritis at final follow-up than baseline (91.3% vs. 36% p<0.01. Overall, 14 of the 27 patients (52%) treated operatively progressed to total knee arthroplasty at a mean of 54.3 months. When comparing the PMM and control groups, there was no significant difference in final median Tegner scores, mean IKDC, median K-L grades, progression to arthroplasty, or overall failure rate. Following PMM, female patients had lower final IKDC scores (74.6±16.7 vs. 44.00±2.8, p=0.02) compared to males, as well as a higher rate of arthroplasty (70.6% vs, 20.0%, p=0.009). Higher BMI correlated with lower IKDC scores (r=-0.91, p=0.01) and meniscal extrusion was associated with higher rate of arthritis at final follow-up (100% vs. 57%, p=0.02). Conclusion: Partial meniscectomy for a MMRT provides no benefit in halting arthritic progression. Patients who undergo arthroscopic debridement for MMPRTs still progress to significant arthritis, poor clinical outcomes and a high arthroplasty rate (52%) at over 5-year follow-up. Compared to a non-operative control group, there was no benefit in any subjective or objective outcome measures from the arthroscopic partial meniscectomy. Female patients, higher BMI, and presence of meniscus extrusion were associated with worse outcomes and a higher rate of subsequent knee arthroplasty.

Paper 135 Title: Surgical Treatment of Pectoralis Major Tendon Ruptures: A Retrospective Review of 134 Patients Tendon Ruptures Authors: Michelle Sugi, MD, MPH1, Daniel Acevedo, MD2, Raffy Mirzayan, MD3. 1Kaiser Permanente, Baldwin Park, CA, USA, 2Kaiser Permante - Panorama City, CA, Panorama City, CA, USA, 3Kaiser Permanente Hospital, Baldwin Park, CA, USA. Objectives: Pectoralis major tendon ruptures are relatively uncommon injuries. The literature is limited to several small case series, the largest containing 24 cases, and systematic reviews. However, still little is known about the demographics of this injury or the outcomes of operative repairs. We present a series of 134 traumatic pectoralis major tendon ruptures, which were treated surgically. This study aims to provide more information on injury demographics and surgical outcomes in order to learn more about making the diagnosis, preferred method of repair, and complications surrounding surgical treatment of both acute and chronic tears. Methods: A retrospective review was performed on 134 acute and chronic traumatic pectoralis major tendon ruptures repaired surgically from 2008 to 2014. Procedures were performed at a multi-surgeon (55 surgeons), multi-center (13 centers) community-based integrated health care system. Pre- and post-operative data were obtained by a retrospective chart and imaging review. Categorical variables were compared using chi-square or Fisher’s exact test. Results: 134 pectoralis major tendon ruptures were treated surgically. The average age was 34 years (15 to 61). 18% were laborers and the most common mechanism of injury was weight lifting (62%). The average time from injury to surgery was 10 weeks. 76% were acute, 8% were subacute, and 16% were chronic ruptures. Operative findings revealed a tendon rupture in 92% of cases (122/134), a musculotendinous rupture in 13% (18/134), and 0.7% partial tears (1/134). Surgical repair techniques consisted of suture anchors (40%), sutures through bone tunnels (25%), suture button (19%), and an end-to-end suture repair (8%). Six patients (4%) needed allograft augmentation at the time of surgery. There were 17 complications (13%): 4 infections, 5 cosmetic wound concerns, 1 transient neuropraxia, 2 fractures, 2 postoperative frozen shoulders, and 3 failures. Surgical treatment with bone tunnels was associated with the highest complication rate in this series (5%), followed by suture anchors (4.4%), end-to-end repair (2.2%), and suture button repair (0.74%). One patient had a re operation, which was for a failed repair (0.7%). The average follow up time was 71 days (1-2268 days). 86% of patients were able to return to their occupation at full capacity. The complications rates between each method of repair seen in our study were not statistically different from one another. When “implant” versus “no implant” was evaluated, we found that use of an implant was associated with a lower re-tear rate (p=.0782), a lower rate of fracture (p=.0782), and a lower rate of post operative stiffness (p=0.0782), and all 3 trended toward significance. Conclusion: This is the largest single series regarding the surgical treatment of pectoralis major tendon ruptures. Our study added to what we know about patient demographics and mechanisms of injury for a pectoralis tendon rupture. Surgical repair of pectoralis major tendon ruptures can be performed safely

with a low re-rupture rate and low risk of complications. Using a suture button had the lowest complication rate, and the use of an implant may potentially minimize complications. Further prospective studies are needed to determine the best surgical repair technique.

Paper 136 Title: Performance-Based Outcomes after Operative Management of Athletic Pubalgia / Core Muscle Injury in National Football League Players Authors: Thomas Sean Lynch, MD1, Radomir Kosanovic2, Daniel Bradley Gibbs, MD3, Caroline Park, BA4, Asheesh Bedi, MD5, Christopher M. Larson, MD6, Christopher S. Ahmad, MD4. 1Columbia University Medical Center, New York, NY, USA, 2New York Medical College, New York, NY, USA, 3Northwestern University Department of Orthopaedic Surgery, Chicago, IL, USA, 4Columbia University, New York, NY, USA, 5Domino's Farms, Ann Arbor, MI, USA, 6Minnesota Orthopaedic Sports Medicine Institute at Twin Cities Orthopedics, Edina, MN, USA. Objectives: Athletic pubalgia is a condition in which there is an injury to the core musculature that precipitates groin and lower abdominal pain, particularly in cutting and pivoting sports. These are common injury patterns in the National Football League (NFL); however, the effect of surgery on performance for these players has not been described. Methods: Athletes in the NFL that underwent a surgical procedure for athletic pubalgia / core muscle injury (CMI) were identified through team injury reports and archives on public record since 2004. Outcome data was collected for athletes who met inclusion criteria which included total games played after season of injury / surgery, number of Pro Bowls voted to, yearly total years and touchdowns for offensive players and yearly total tackles sacks and interceptions for defensive players. Previously validated performance scores were calculated using this data for each player one season before and after their procedure for a CMI. Athletes were then matched to control professional football players without a diagnosis of athletic pubalgia by age, position, year and round drafted. Statistical analysis was used to compare pre-injury and post-injury performance measures for players treated with operative management to their case controls. Results: The study group was composed of 32 NFL athletes who underwent operative management for athletic pubalgia that met inclusion criteria during this study period, including 18 offensive players and 16 defensive players. The average age of athletes undergoing this surgery was 27 years old. Analysis of pre- and post-injury athletic performance revealed no statistically significant changes after return to sport after surgical intervention; however, there was a statistically significant difference in the number of Pro Bowls that affected athletes participated in before surgery (8) compared to the season after surgery (3). Analysis of durability, as measured by total number of games played before and after surgery, revealed no statistically significant difference. Conclusion: National Football League players who undergo operative care for athletic pubalgia have a high return to play with no decrease in performance scores when compared to case-matched controls. However, the indications for operative intervention and the type of procedure performed are heterogeneous. Further research is warranted to better understand how these injuries occur, what can be done to prevent their occurrence, and the long term career ramifications of this disorder.

Paper 137 Title: Sports Hernia: Diagnosis, Management and Operative Treatment Authors: Benton A. Emblom, MD. Andrews Sports Medicine and Orthopaedic Center, Birmingham, AL, USA. Objectives: Athletic Pubalgia, also known as sports hernia or core muscle injury, causes significant dysfunction in athletes. Increased recognition of this specific injury distinct from inguinal hernia pathology has led to better management of this debilitating condition. We hypothesize that patients who undergo our technique of athletic pubalgia repair will recover and return to high-level athletics. Methods: Using our billing and clinical database, patients who underwent sports hernia repair by single surgeon at a single institution were contacted for Harris hip score, functional outcome, and return to play data. Results: Of 101 patients who met criteria, 43 were contacted. 93% of patients were able to return to play at an average of 4.38 mo. Normal activities were rated at 95.5% and athletic function was rated at 88.9%. Negative predictors were female sex, multiple operations, and prior inguinal hernia repair. Overall complication rate was 4.6%, and reoperation rate was 4.6%. Conclusion: Our method of adductor to rectus abdominis turn up flap is a safe procedure with high return to play success. Patients who had previously undergone inguinal hernia repair or other hip/pelvic related surgery had a worse outcome.

Paper 138 Title: Accelerated Rehabilitation Following Repair of Proximal Hamstring Avulsion: 4 Year Outcomes Authors: Christopher C. Kaeding, MD, Benjamin Leger-St-Jean, MD, Zylyftar Gorica, Robert A. Magnussen, MD MPH, William Kelton Vasileff, MD. The Ohio State University Sports Medicine Center, Columbus, OH, USA. Objectives: Proximal hamstring tears are relatively uncommon injuries, but can lead to persistent pain and disability. Previous literature has described avulsion of all three proximal tendons, avulsion of two tendons with retraction of over 2cm, and tendon avulsions with failure of non-operative management as indications for operative repair. Most previous studies have utilized post-operative protocols that include some form of brace immobilisation to restrict hip flexion and knee extension and/or a limited weight-bearing period. We hypothesize that proximal hamstring repair utilizing an accelerated rehabilitation protocol that allows full weight-bearing without immobilization immediately post-operative will result in similar outcomes to published series and that better results will be noted in acute repairs (surgery within 4 weeks of injury). Methods: Retrospective chart review identified 47 proximal hamstring tendon repairs in 43 patients performed at our institution between 2008 and 2015. Proximal hamstring tendon repair was carried out with suture anchors by a single sports medicine fellowship-trained orthopaedic surgeon. Post-operative rehabilitation included no immobilization or limited weightbearing. Patients were only instructed to avoid rapid walking for 6 weeks post-operative. Clinical history, radiographic findings, and surgical details were obtained from chart data. Patients were then contacted to by phone to assess outcomes following surgery utilizing the lower extremity functional score (LEFS), the single assessment numeric evaluation (SANE), and Marx activity scale. Complications and repair failures were also noted. Overall patient-reported scores were calculated and results of acute and chronic repairs were compared. Results: Thirty-four patients who underwent a total of 38 proximal hamstring repairs (80.8%) were available for follow-up via phone interview at a mean of 4.1 ± 2.0 years following proximal hamstring repair. There were two re-tears: one rupture at 5 weeks post-op and one partial rupture at 10 weeks post-op. Overall, patients reported high satisfaction with the procedure, with a mean LEFS score of 87± 21%, a mean SANE score of 88.1 ± 11.6, and a Median Marx activity score of 5. The acute repair group was noted to have a higher mean LEFS score (93.7 ± 11.1%) than the chronic repair group (79.8 ± 28.8%), p = 0.046. The average SANE score in the acute group (91.3 ± 8.3) was also significantly higher than in the chronic group (83.8 ± 14.3), p = 0.047. The median Marx Activity scale was similar in the acute (median = 5.5) and chronic (median = 5.0) groups (p = 0.88). Conclusion: Proximal hamstring tendon repair followed by post-operative rehabilitation that included no immobilization or limited weight bearing resulted in patient-reported outcomes scores and repair failure risk that were similar to previously published series that utilized more limiting post-operative protocols. Better patient-reported outcomes were noted in repairs performed within 4 weeks of injury.

Paper 139 Title: A Randomized Trial Comparing Patellar, Hamstring and Double-bundle ACL Reconstruction at 5-yrs. Authors: Nicholas GH Mohtadi, MD, MSc, FRCSC1, Denise S. Chan, MSc, MBT2. 1Univ of Calgary Sports Medicine Centre, Calgary, AB, Canada, 2University of Calgary Sport Medicine Centre, Calgary, AB, Canada. Objectives: This prospective, double-blind RCT compares ACL reconstruction using patellar tendon, quadruple hamstring and double-bundle hamstring grafts, by measuring patient-reported disease-specific quality of life outcome in patients with isolated ACL deficiency of the knee at a 5-years post-op. Methods: Patients (n=330; 183 males, 147 females) aged 14-50 years were randomly allocated and equally distributed to one of three anatomic ACL autograft reconstruction techniques: 1) Patellar Tendon (PT; mean age 28.7 years), 2) Quadruple-stranded Hamstring Tendon (HT; mean age 28.5 years), or 3) Double-Bundle using hamstring tendons (DB; mean age 28.3 years). Computer-generated allocation with varied block randomization was performed intra-operatively. Outcomes were measured at baseline, 3 and 6 months, 1, 2 and 5 years. Two-year results were previously reported. Primary outcome: Anterior Cruciate Ligament Quality-of-Life (ACL-QOL). Secondary outcomes: International Knee Documentation Committee (IKDC) subjective score and objective grades, pivot shift, range of motion, kneeling pain, Tegner activity level, and the Cincinnati Occupational Rating Scale. The proportion of re-ruptures, partial re-ruptures and the combined total traumatic re-injuries were compared. Radiographic evaluation was performed at baseline, 2 and 5 years; this analysis is ongoing. A 5% significance level was used for all outcomes. Results: 315 randomized patients (95%) d 5-yr follow-up. There were 4 withdrawals and 11 patients lost-to-follow-up. Baseline characteristics between the groups were not different. ACL-QOL scores increased significantly from baseline over time for all groups (p=0.000). There was no difference in mean ACL-QOL score at 5-years (p=0.548): PT=82.5 (SD 17.9, 95% CI 79.0-86.0); HT=83.9 (SD 18.2, 95% CI 80.3-87.4); DB=81.1 (SD 19.3, 95% CI 77.4-84.8). At 5-years, there were no differences in the proportion of patients with a Pivot Shift grade 2 or greater (p=0.106): PT=11/98 (11%); HT=16/99 (16%); DB=23/103 (22%). Mean IKDC subjective scores were not different between groups at 5-yrs (p=0.770): PT=83.9 (SD 12.9, 95% CI = 81.4-86.5); HT=85.2 (SD 13.0, 95% CI = 82.7-87.7); DB=84.3 (SD 13.4, 95% CI = 81.7-86.9). Based on IKDC objective grades, the proportions of Normal/Nearly Normal knees at 5-years were not different between groups: PT=85/98 (87%); HT=82/99 (81%); DB=75/103 (76%), p=0.093. 5-yr Tegner activity levels and Cincinnati Occupational Scores were also not different between the groups (p=0.872 and p=0.813, respectively). Kneeling pain remained more common in the PT group (PT=10/98; HT 4/98; DB 2/101; p=0.029). More traumatic graft ruptures occurred in the HT and DB groups (PT=4/103; HT=11/105; DB=11/107; p=0.145). Revision ACL reconstructions were performed on 22 of these patients. There were an additional 11 partial graft re-ruptures (PT=0; HT=5; DB=6), with less total traumatic re-injuries in the patellar tendon group (PT=4; HT=16 and DB=17, p=0.010). Four patients had additional surgery to the index knee, not including the revision surgery between the 2 and 5-yr follow-up.

Conclusion: At 5 years, there was no difference in disease-specific quality-of-life outcome or IKDC grades between the PT, HT and DB techniques for ACL reconstruction. There were significantly more traumatic graft re-injuries in the HT and DB groups compared to the PT group.

Paper 140 Title: O'Donoghue Sports Injury Award 10 Year Outcomes and Risk Factors after ACL Reconstruction: A Multicenter Cohort Study Authors: Kurt P. Spindler, MD1, Laura J. Huston, MS2, MOON Knee Group2. 1Cleveland Clinic Sports Health Center, Garfield Hts, OH, USA, 2Vanderbilt Orthopaedic Institute, Nashville, TN, USA. Objectives: Identify the patient-reported outcomes (IKDC, KOOS, Marx activity scale) and patient-specific risk factors from a large prospective cohort at a minimum 10-year follow-up after ACL reconstruction. Methods: Unilateral ACL reconstructions were identified and prospectively enrolled between 2002 and 2004 from 7 sites in the Multicenter Orthopaedics Outcome Network (MOON). Patients pre-operatively d a series of validated outcome instruments, including the IKDC, KOOS, and Marx activity scale. At the time of surgery, physicians documented all intraarticular pathology, treatment, and surgical techniques utilized. Patients were followed at a minimum of 2, 6, and 10 years post-op, and asked to the same outcome instruments that they d at surgery (T0). Incidence and details of any subsequent knee surgeries were also obtained. Multivariable regression analysis was used to control for patient demographic variables, surgical technique and pathology variables, and incidence of subsequent surgery, in order to identify factors associated with patient-reported outcomes 10 years after ACL reconstruction. Results: A total of 1597 patients were eligible (57% male; median age 23 years). Ten-year follow-up was obtained on 83% (1320) [86% (1379) at 2 years, 86% (1375) at 6 years], while subsequent surgery data was obtained on over 90% of the cohort. Both IKDC and KOOS scores significantly improved after 2 years and were maintained at 6 and 10 years (Figure 1). Interestingly, Marx activity level scores dropped markedly over time, from a median score of 12 pts at baseline, 9 pts at 2 years, 7 pts at 6 years, to 6 pts at 10 years. The patient-specific risk factors for worse 10-year outcomes are shown in Table 1. The significant drivers of poorer outcomes were lower baseline outcome scores, higher BMI, smoker at baseline, history of medial meniscus surgery prior to ACL reconstruction, having a revision ACL reconstruction, grades 3-4 articular cartilage pathology in the medial, lateral and patellofemoral compartments, and having any subsequent ipsilateral surgery. Graft type (autograft BTB, autograft soft tissue, allograft), MCL or LCL pathology, and medial or lateral meniscus surgery at the time of ACL reconstruction were not found to be significant risk factors. Conclusion: Patients are able to perform sports-related functions and maintain a high knee-related quality of life 10 years after ACL reconstruction, although activity level declines over time. Multivariable analysis identified several key modifiable risk factors that significantly influence outcome. This prognostic information will undoubtedly aid physician counseling of patients’ expectations after ACL reconstruction at surgery and at 2 and 6 years to predict 10 year outcome.

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Paper 141 Title: Comparison of Clinical Outcomes Following Anatomic Single vs. Double-Bundle ACL Reconstruction: A Randomized Clinical Trial Authors: James J. Irrgang, PT PhD ATC1, Scott Tashman, PhD2, Charity Moore, PhD, MSPH3, Volker Musahl, MD4, Robin Vereeke West, MD5, Alicia Oostdyk, MPH6, Bryan Galvin, ATC, MS1, Freddie H. Fu, MD7. 1University of Pittsburgh, Pittsburgh, PA, USA, 2University of Texas - Houston, Houston, TX, USA, 3Carolinas HealthCare System, Charlotte, NC, USA, 4UPMC Center for Sports Medicine, Pittsburgh, PA, USA, 5Inova Sports Medicine, Fairfax, VA, USA, 6UPMC Rooney Center for Sports Medicine, Pittsburgh, PA, USA, 7Department of Orthopaedic Surgery - University of Pittsburgh, Pittsburgh, PA, USA. Objectives: The shortcomings of anterior cruciate ligament reconstruction (ACL), including failure to restore normal structure and function of the knee, limited return to pre-injury level of sports participation and failure to prevent the development of post-traumatic knee osteoarthritis (OA) have recently been recognized. Anatomic methods to reconstruct the ACL, including anatomic single-bundle (SB) and double-bundle (DB) reconstruction, have been proposed to improve clinical outcomes after ACL reconstruction. We performed a double-blinded randomized clinical trial to compare clinical outcomes of anatomic SB to anatomic DB ACL reconstruction. We hypothesized that anatomic DB ACL reconstruction with a quadriceps tendon autograft with bone block would result in reduced knee laxity, better range of motion, patient-reported outcomes (PROs), return to sports and reduced risk of re-injury compared to anatomic SB ACL reconstruction. Methods: Individuals between 14 and 50 years of age participating in at least 100 hours of Level 1 or 2 sports activities that presented within 12 months of injury to both bundles of the ACL with or without injury to the medial or lateral meniscus were eligible to participate in this study. Individuals with prior injury or surgery of the ipsilateral or contralateral knee or greater than a grade 1 concomitant knee ligament injury were excluded. If the ACL insertion sites were between 14 and 18mm, as measured with an arthroscopic ruler at the time of arthroscopy, the subject was randomized to undergo SB or DB ACL reconstruction with a 10 mm quadriceps tendon autograft harvested with a patellar bone block. A single, anatomically placed femoral tunnel was used for all cases. For DB ACL reconstruction, the graft was split into to two arms and passed through two anatomically placed tibial tunnels. Subjects were followed at 3, 6, 12 and 24 months after randomization, with the primary endpoints occurring at 24 months. Outcome measures included the KT-1000 (side to side difference) and pivot shift tests, range of motion (ROM), IKDC Subjective Knee Form (IKDC-SKF) and return to pre-injury level of sports participation. Results: Fifty-seven subjects were randomized (29 DB) and two-year follow-up was attained from 51 (89.5%). There were no differences between groups in terms of age, proportion of males, body mass index (BMI), participation in competitive or recreational sports or concomitant meniscus procedures. At 24-month follow-up there were no between groups differences for the pivot shift and KT-1000 tests, ROM and IKDC-SKF scores (Table 1). Twenty-three (85.2%) DB’s and 24 (87.5%) SB’s reported returning to pre-injury level of sports 2 years after surgery (p=0.81). Three subjects (2 SB’s, 5.9% of total) suffered

a graft rupture and 5 individuals (4 SB’s, 9.8% of total) had a subsequent meniscus injury. Conclusion: With the available sample size, we were unable to demonstrate significant differences in clinical outcome between anatomic SB and DB ACL reconstruction when performed with a quadriceps tendon autograft with a bone block in individuals with ACL insertion sites that ranged from 14 to 18 mm. Furthermore, both anatomic SB and DB ACL reconstruction lead to clinical outcomes that are comparable or superior to those reported for non-anatomical ACL reconstruction with minimal recurrent instability.

Table 1 - Clinical Outcomes at 24 Months

Double Bundle (n=27)

Single Bundle (n=24) p value6

Normal Pivot Shift (n, %) 25, 92.6% 23, 95.8% 0.48 KT Arthrometer1 (30 lb) (mean ± SD) 0.5 ± 1.3 0.6 ± 1.6 0.80 KT Arthrometer1 (max manual) (mean ± SD) 0.7 ± 1.2 0.8 ± 1.5 0.79

Passive Extension of Involved Knee2 (mean ± SD) 3.9 ± 3.0 3.8 ± 2.8 0.90

Passive Extension Difference3 (mean ± SD) 2.1 ± 1.9 1.7 ± 2.6 0.53

Active Flexion of Involved Knee4 (mean ± SD) 140.7 ± 5.7 140.2 ± 6.3 0.76

Active Flexion Difference5 (mean ± SD) 0.3 ± 4.2 -1.1 ± 9.0 0.47 IKDC Subjective Knee Score (mean ± SD) 89.4 ± 10.3 90.2 ± 11.1 0.79

1 Values are involved minus non-involved side to side difference in millimeters 2Values are in degrees. Positive values indicate hyperextension 3 Non-involved minus involved knee difference in passive knee extension. Values are in degrees. Positive values indicate a loss of extension of the involved knee 4 Values are in degrees 5 Non-involved minus involved knee difference in active knee flexion. Values are in degrees. Positive values indicate a loss of flexion of the involved knee. 6 Independent t-tests were used for continuous variables and Fisher Exact Tests were used for nominal variables. p values were not adjusted for multiple comparisons.

Paper 142 Title: Anatomic Anterior Cruciate Ligament Reconstruction - A Prospective Evaluation Using Three-Dimensional Magnetic Resonance Imaging Authors: Adam Hart, MD1, Thiru Sivakumaran2, Mark Burman, MD3, Thomas Powell4, Paul A. Martineau, MD, FRCSC3. 1Mcgill University Health Centre, Montreal, QC, Canada, 2McGill, Montréal, QC, Canada, 3McGill University Health Center, Montreal, QC, Canada, 4mcgill, Montreal, QC, Canada. Objectives: The recent emphasis on anatomic reconstruction of the anterior cruciate ligament (ACL) is well supported by clinical and biomechanical research. Unfortunately, the location of the native femoral footprint can be difficult or even impossible to see at the time of surgery. Most surgeons therefore rely on anatomic landmarks, custom drill guides, or general rules-of-thumb to guide femoral tunnel placement; however, the accuracy of these techniques to reconstruct each patient's native anatomy is poorly understood. The objective of this study was to use a previously described isotropic magnetic resonance sequence (3D MRI) to image patients with torn ACLs before and after reconstruction and thereby assess the accuracy of graft position on the femoral condyle in comparison to each patient's native ACL footprint. Methods: Forty-one patients with unilateral ACL tears were prospectively recruited into our study. Each patient underwent a 3D MRI of both the injured and uninjured knees before surgery. The contralateral (uninjured) knee scan was used to define the patient's native footprint. Patients then underwent ACL reconstruction with hamstring autograft by one of four experienced fellowship-trained sports orthopedic surgeons. The injured knee was reimaged after surgery. The location and percent overlap of the reconstructed femoral footprint was compared to the patient's native footprint. Results: The center of the native ACL femoral footprint was a mean of 16.4 +/- 4.6 mm distal and 5.3 +/- 2.9 mm anterior to the apex of the deep cartilage. The position of the reconstructed graft was significantly different, with mean distance of 10.4 +/- 2.7 mm distal (P < 0.0001) and 7.7 +/- 3.1 mm anterior (P = 0.001). The mean distance between the center of the graft and the center of the native ACL femoral footprint (error distance) was 5.7 +/- 3.6 mm. Comparing error distances amongst the four surgeons demonstrated no significant difference using the Kruskal-Wallis one-way ANOVA (P = 0.78). On average, 21% of the graft was within the native ACL femoral footprint. Of the 41 patients, 16 (39%) had the graft placed entirely outside the native ACL footprint. Conclusion: Despite contemporary techniques and a concerted effort to perform anatomic ACL reconstructions by four experienced sports orthopedic surgeons, the position of the femoral footprint was significantly different between the native and reconstructed ligaments. Furthermore, each of the four surgeons uses a different technique but all had comparable errors in their tunnel placements. In order to achieve a truly anatomic reconstruction, surgeons may consider using a pre-operative 3D MRI, which enables excellent visualization of the ACL's native anatomy and could potentially be used as a roadmap to guide anatomic tunnel placement.

Paper 143 Title: Return to Play After Shoulder Instability in National Football League Athletes Authors: Kelechi R. Okoroha, M.D.1, Kevin Taylor, M.D.2, Robert A. Keller, MD3, Nathan E. Marshall, MD4, Vishal Varma, B.S.5, Vasilios Moutzouros, MD6. 1Henry Ford Health System, detroit, MI, USA, 2Henry Ford Hospital, detroit, MI, USA, 3Kerlan Jobe Orthopaedic Clinic, Los Angeles, CA, USA, 4Henry Ford Hospital, Royal Oak, MI, USA, 5Wayne state medical school, Detroit, MI, USA, 6Henry Ford Medical Group, Novi, MI, USA. Objectives: To determine the rate and timing of return to NFL play after a shoulder instability event and to determine what factors predict ability to Return to Play (RTP). Methods: A total of 83 NFL players who sustained an in-season shoulder instability event while playing in the NFL were identified and evaluated. Return to NFL play, incidence of surgery, time to return, recurrent instability events, seasons and games played after injury, and demographic data were collected. Overall RTP was determined and players who had surgery were compared to those who did not have surgery. Playing time after RTP was compared with age, position, size and experience matched control players. Results: Ninety-one percent of NFL players returned to NFL regular season play at an average of 1.6 ± 1.9 weeks (mean ± SD) in those sustaining a shoulder subluxation and 3.7 ± 5.4 weeks in those sustaining a dislocation; p = .53. In players who were able to RTP without surgery, those having a left shoulder instability event were able to return faster (1 week) than those having a right shoulder event (4 weeks); p = .03. A majority of players (62%) underwent surgical stabilization and 86% returned to play the following season. Players who had surgery were more likely to have a second instability event in their career (58% versus 9%); p = .01. No difference was found when comparing playing time after return with matched controls. Conclusion: There is a high rate of RTP following shoulder instability events in NFL players. Players sustaining subluxations in their non-dominant arm return to play at a faster rate. Surgical stabilization of the shoulder following an instability event may not ly eliminate potential for subsequent recurrent events as a high percentage of surgically treated players were found to have another instability event.

Paper 144 Title: A Prospective Outcome Evaluation of Humeral Avulsions of the Glenohumeral Ligament (HAGL) Tears in an Active Population Authors: Matthew T. Provencher, MD1, Francis McCormick, MD2, George Sanchez3, Lance E. LeClere, MD, LCDR, MC, USN4, Christopher B. Dewing, MD5, Daniel J. Solomon, MD6. 1The Steadman Clinic, Vail, CO, USA, 2USA, 3Steadman Philippon Research Institute Program, Vail, CO, USA, 4US Naval Academy, Annapolis, MD, USA, 5The Rockwood Clinic, Spokane, WA, USA, 6Marin Orthopedics and Sports Medicine, Novato, CA, USA. Objectives: Humeral avulsion of the glenohumeral ligament (HAGL) is an infrequent but significant contributor to shoulder dysfunction, instability, and functional loss. The purpose of this study is to prospectively evaluate the clinical history, examination findings, and surgical outcomes of patients with HAGL lesions. Methods: Over a 6-year period, patients with shoulder dysfunction and a HAGL lesion confirmed via magnetic resonance arthrogram (MRA) were prospectively evaluated with a minimum 2-year follow-up. Patient demographics, presentation, examination and surgical findings were documented. Outcomes of return to activity and SANE and WOSI scores were recorded at final follow-up. Anterior HAGL (aHAGL) lesions were repaired with a mini-open approach, while reverse (rHAGL) lesions were repaired arthroscopically. Results: A total of 27 of 28 patients (96%) d the study requirements at a mean of 36.2 months (range 24-68 months). There were 12 females (44%) and 15 males (56%) with a mean age of 24.9 years (range 18-34). The primary complaint was pain in 23 patients (85%) and only 4 (15%) patients complained of instability symptoms. There were 14 patients (52%) with aHAGL lesions, 10 patients (37%) with rHAGL lesions, and 3 patients (11%) with combined anterior and posterior HAGL lesions. Ten patients (37%) had concomitant HAGL lesions and labral tears, whereas 17 patients (63%) presented with an isolated HAGL lesion. The 17 patients (63%) with aHAGL lesions or combined lesions underwent a mini-open surgical repair, while the remaining 10 patients (37%) with rHAGL lesions underwent arthroscopic surgical repair. After surgery outcomes improved from WOSI = 54%, SANE = 50% to WOSI = 88%, SANE = 91% (p<0.01). Conclusion: This study demonstrated that patients with symptomatic HAGL lesions complain predominantly of pain and shoulder dysfunction and present with few instability complaints or findings. After surgery, patients showed predictable return to full activity, improvement in objective and patient-reported outcomes, and patient satisfaction.

Paper 145 Title: Arthroscopic Treatment of Shoulder Instability with Glenoid Bone Loss Using Distal Tibia Allograft Augmentation Authors: Ivan Wong, MD, MACM, Dip. Sports Medicine1, Eyal Amar, MD1, Catherine M. Coady, MD2, Ben Smith, MD3, Mark Glazebrook, MD4, George Konstantinidis5, Daryl B. Dillman, MD2. 1Dalhousie University, Halifax, NS, Canada, 2Dalhousie University and the Division of Orthopaedic Surgery, Queen Elizabeth He, Halifax, NS, Canada, 3Ontario, Burlington, ON, Canada, 4Queen Elizabeth Health Sciences Center, Halifrax, NS, Canada, 5Nova Scotia Health Authority, Halifax, NS, Canada. Objectives: The purpose of this study was to retrospectively analyze prospectively collected data to present the clinical and radiological short term outcomes of patients who underwent anatomic glenoid reconstruction using distal tibia allograft to treat shoulder instability with glenoid bone loss. Methods: Over four years, 44 patients (31 patients were male and 13 female with mean age of 29.73 years) underwent arthroscopic stabilization with capsulelabral Bankart repair and allograft bony augmentation of the glenoid for recurrent shoulder instability with significant bone loss by the same surgeon. 14 patients were revision cases of previous surgery. Preoperative and postoperative functional assessment was performed with the Western Ontario Shoulder Instability Index (WOSI) questionnaire, and radiological assessment was performed with radiographs and CT scans. The Average follow-up was 2 years. Results: 97% (43/44) patients had no dislocations or subluxations at the most recent followup. The mean pre and postoperative WOSI scores were 40.54 and 72.65 respectively (p<0.001). No patients developed nerve injury. One patient presented with hardware failure at 3 years post-op. Two other patients had graft absorption and 6 patients had partial graft resorption but none had symptoms of instability. The mean postoperative active shoulder range of motion was forward flexion 170.1o, abduction 168.9o, internal rotation 69.5o and external rotation 57.5o. Grafts positioning was flush with the glenoid in 93% of cases, vertical positioning was excellent in 89% (35 o’clock). Conclusion: Arthroscopic stabilization of the shoulder with distal tibia allograft augmentation is a good safety profile technique with good results at average of two years follow up.

Paper 146 Title: Medial Posterior Capsular Plication Reduces Anterior Shoulder Instability Similar to Remplissage without Restricting Motion in the Setting of an Engaging Hill Sachs Defect Authors: Brian C. Werner, MD1, Xiang Chen2, Christopher L. Camp, MD3, Andreas Kontaxis2, Joshua S. Dines, MD4, Lawrence Vincent Gulotta, MD5. 1University of Virginia, Charlottesville, VA, USA, 2Hospital for Special Surgery/Cornell Medical Center Program, New York, NY, USA, 3Hospital for Special Surgery/Cornell Medical Center Program, New York, MN, USA, 4Hospital for Special Surgery, uniondale, NY, USA, 5Hospital for Special Surgery, New York, NY, USA. Objectives: In the present study, the efficacy of a posterior medial capsular plication in addition to Bankart repair was examined as an arthroscopic management strategy for an engaging Hill-Sachs defect. Methods: 8 fresh-frozen human cadaveric shoulders were utilized for the study. After testing baseline translation and motion, 30% Hill Sachs lesions were created in each specimen. Three experimental groups were created: 1) isolated bankart repair (HSD), 2) bankart repair with remplissage (RM) and 3) bankart repair with posterior medial capsular plication (PL). Biomechanical testing was performed to determine anterior translation, range of motion and Hill Sachs engagement. Translation and motion measurements were normalized to the baseline laxity measures for each specimen. Results: Significant reduction in anterior translation was noted at 60° of abduction and 60° of ER for both PL and RM groups compared to the HSD group throughout most of the joint loads tested (p < 0.05) [Figure 1], but no significant differences were noted between PL and RM at any load. The RM group had significantly less normalized ER at 60° of abduction compared to the HSD and PL groups (p < 0.05). There were no differences in IR between the groups. All 8 HSD specimens engaged, while no specimens in the RM and PL groups engaged (p < 0.001)

Conclusion: In a cadaveric model, medial posterior capsular plication as an adjunct to Bankart repair offers similar resistance to anterior translation and Hill-Sachs engagement as compared to remplissage in the setting of an engaging Hill-Sachs defect. Medial posterior capsular plication results in less restriction of external rotation compared to remplissage without any significant limitation of internal rotation.

Paper 147 Title: The Frequency of Glenohumeral Cartilage Lesions at the time of Shoulder Instability Surgery: A Multicenter Comparison of Primary and Revision Surgery Patients Authors: Kyle R. Duchman, MD1, Carolyn M. Hettrich, MD, MPH2, Robert W. Westermann, MD3, Natalie Glass, PhD1, John E. Kuhn, MD4, Brian R. Wolf, MD, MS5. 1University of Iowa Hospitals and Clinics, Iowa City, IA, USA, 2University of Iowa, Iowa City, IA, USA, 3Cleveland Clinic, Cleveland, OH, USA, 4Vanderbilt Sports Medicine, Nashville, TN, USA, 5UI Sports Medicine, Iowa City, IA, USA. Objectives: Revision shoulder stabilization procedures present a unique set of challenges that should be recognized by the treating surgeon in order to improve the likelihood of success. The current study aims to compare patient factors, intraoperative findings, and patient reported outcome measures between patients undergoing primary versus revision shoulder stabilization surgery. Methods: The Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort was utilized to identify all patients undergoing primary and revision open or arthroscopic shoulder instability surgery. Patients with concomitant rotator cuff pathology requiring operative repair were excluded. Patient demographic characteristics, intraoperative findings, and patient reported outcome measures at the time of shoulder stabilization were compared between primary and revision shoulder instability surgery patients using univariate methods using chi-square or Fisher exact tests for categorical variables and Wilcoxon rank sum test for continuous variables. Results: Primary shoulder stabilization procedures were performed in 625 (87.0%) patients and revision stabilization procedures in 93 patients (13.0%). Patients undergoing revision surgery were older (25.9 vs. 23.5 years, p<0.001), more frequently smoked (11.8 vs. 6.1%, p = 0.04), had a higher number of reported dislocation events (p = 0.004), and were more likely to undergo an open procedure as opposed to an all arthroscopic shoulder instability procedure (67.7 vs. 5.8%, p<0.001). Patients undergoing revision procedures were more likely to have glenoid or humeral head cartilage lesions at the time of surgery (77.4 vs. 57.8%, p<0.001), with bone loss involving greater than 20% of the glenoid or humeral head more frequently reported in revision procedures (19.4 vs. 2.6%, p <0.001) (Figure 1). However, the presence of glenohumeral bone loss did not negatively impact patient reported outcomes at the time of shoulder instability surgery. Conclusion: Glenohumeral articular cartilage lesions are a common finding at the time of shoulder stabilization procedures and are particularly frequent in patients undergoing revision stabilization procedures. Surgeons routinely performing these procedures should be prepared to deal with the technical challenges associated with glenoid or humeral head bone loss. However, at the time of surgery, the presence of articular cartilage lesions did not appear to negatively influence patient reported outcomes. Future studies should investigate the influence of articular cartilage lesions at mid- and long-term follow-up in this cohort of patients.

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Paper 148 Title: Establishing Time to Maximal Medical Improvement in Arthroscopic Rotator Cuff Repairs Authors: Bonnie Gregory, MD, William Zuke, Timothy Sean Leroux, MD, MEd, Austin Black, Brian Forsythe, MD, Anthony A. Romeo, MD, Brian J. Cole, MD, MBA, Nikhil N. Verma, MD. Midwest Orthopaedics at Rush, Chicago, IL, USA. Objectives: Two year follow up has been a general requirement for reporting outcomes following rotator cuff repair. However this time requirement has not been established scientifically and is of increasing importance in the era of value based health care. The purpose of this study was to establish a time frame for MMI following arthroscopic rotator cuff repair (ARCR). Methods: A systematic review of the literature was conducted to identify all studies reporting sequential PROs up to a minimum of two years following ARCR. The primary clinical outcome was PROs at 3-month, 6-month, 1-year, and 2-year follow-up. Secondary clinical outcomes included range of motion (ROM) and strength at similar time points. Mean PROs, ROM and strength were determined at each time point, and a clinically significant improvement in each PRO was defined as a change in mean score that exceeded the minimal clinically important difference (MCID) as defined in the literature. Results: Overall, 19 studies including 1370 patients that underwent ARCR were included. Clinically significant improvement in PROs was seen up to 1 year post ARCR, but no clinically significant change was noted from 1 year to 2 years (table 1).

The majority of improvement in strength and ROM was seen up to six months, but no clinically meaningful improvement was seen thereafter. Forward flexion increased by 18.7° ± 11.1° between 3 and 6 months, but only 5.5° ± 1.7° from 6 months to 1 year. Strength of abduction did not improve from 6 months to 1 year or 1 to 2 years. Conclusion: Following ARCR, a clinically significant improvement in PROs, ROM and strength was seen up to one year post-surgery, but not beyond this. This information is not only important to establish appropriate patient expectations, but to establish time frame for outcome collection following surgery.

Paper 149 Title: Validity and Responsiveness of the Single Alpha-numeric Evaluation (sane) for Shoulder Patients Authors: Charles A. Thigpen, PT, PhD, ATC1, Ellen Shanley, PhD1, John M. Tokish, MD2, Michael J. Kissenberth, MD3, Stefan John Tolan, MD3, Richard J. Hawkins, MD, FRCSC3. 1ATI Physical Therapy, Greenville, SC, USA, 2Steadman Hawkins Clinic of the Carolinas, Greenville, SC, USA, 3Steadman Hawkins Clinic of the Carolinas; Greenville Health System, Greenville, SC, USA. Objectives: The is an ever-increasing demand within the emerging health care arena to demonstrate the efficacy of orthopedic interventions. Widespread implementation of patient reported outcomes are limited in part due to the barriers of clinical infrastructure and resources in a busy orthopedic practice. Prior studies have shown the single alpha-numeric evaluation (SANE) score to correlate at a single point in time with the American Shoulder and Elbow Surgeons(ASES) score. However, no study has validated the SANE in terms of test-retest reliability, responsiveness or clinical utility. Therefore, the purpose of this study was to validate SANE compared to the ASES across a sample of patients with the most common orthopedic shoulder diagnoses. Methods: Shoulder patients (n=105 age=52.7 &#177; 1.2; female=67) undergoing rotator cuff repair (cuff=44), total shoulder replacement (TSA=23), or physical therapy (PT=38) were administered the SANE and ASES less than 14 days apart prior to surgery and again at their 3 month follow up from initial care or surgery. Interclass Correlation Coefficients (ICC(2,1)) and standard error of the measure(SEM) were used to evaluate the test-retest reliability of the SANE and the validity between the SANE and ASES scores. An ANOVA (treatment group by time) was used to evaluate the responsiveness to treatment, and a Receiver Operating Curve was used to establish the minimally important clinical difference (MCID) for the SANE compared to the ASES (&#945; =0.05). Results: The SANE demonstrated good reliability (ICC(2,1) =0.76 &#177; 3.4) similar to the ASES (ICC(2,1) =0.82 &#177; 3.4) pre-treatment. The SANE demonstrated good agreement with the SANE across all treatment groups (Cuff= ICC(2,1) 0.85 &#177; 3.4; TSA- ICC(2,1) =0.72 &#177; 5.2;PT- ICC(2,1) =0.82 &#177; 2.9) pre and post treatment. The SANE displayed similar responsiveness to the ASES after treatment (Figure 1) with similar mean change and standard deviations within each treatment group. The ROC curve revealed an area under the curve of .79 (SE, 0.62; P<.001) and a cutoff of 9.5% on the SANE with a sensitivity of 83% and a specificity of 31% to establish the MCID. Conclusion: Our study is the first to demonstrate the SANE is valid across a range of common shoulder diagnoses to assess patient outcomes across operative and non-operative treatment for shoulder complaints. The MCID of 9.5% is similar to the ASES (11%) suggesting that the SANE is a simple and efficient tool to assess treatment effects for shoulder disorders. Future studies are warranted to confirm these results and compare across other body parts and diagnoses.

Paper 150 Title: Equivalent Knee injury and Osteoarthritis Outcome Score after 1 and 2-year following Anterior Cruciate Ligament Reconstruction - Results from The Swedish National Knee Ligament Register Authors: Kristian Samuelsson, MD, PhD, MSc1, Robert A. Magnussen, MD2, Eduard Alentorn-Geli, MD, PhD, MSc3, Kurt P. Spindler, MD4, Magnus L. Forssblad, MD,PhD5, Jon Karlsson, MD, PhD6. 1Sahlgrenska University Hospital, Molndal, Sweden, 2The Ohio State Univ. Sports Medicine Ctr., Columbus, OH, USA, 3-, -, Spain, 4Cleveland Clinic Sports Health Center, Garfield Hts, OH, USA, 5-, Stockholm, Sweden, 6Sahlgrenska University Hospital Molndal, Molndal, Sweden. Objectives: It is not clear if there is an additional value to assess the Knee injury and Osteoarthritis Outcome Score (KOOS) at both 1 and 2-years after primary Anterior Cruciate Ligament (ACL) reconstruction. The purpose was to investigate within individual patient if there is an equivalence between KOOS at 1 and 2-years after primary ACL reconstruction in The Swedish National Knee Ligament Register. Methods: This cohort study was based on data from the Swedish National Knee Ligament Register during the period of January 1, 2005, through December 31, 2013. The longitudinal KOOS scores for each individual at 1-year and 2-year follow-up were assessed through the Two One-Sided Test procedure with an acceptance criterion of 4. Subset analysis was also performed with patients classified by sex, age, graft type and by patients with meniscus and/or cartilage injury. Results: A total of 23 952 patients were eligible for analysis after applied exclusion criteria’s (women, n=10,116; 42.2% and men, n=13,836; 57.8%). The largest age group was between 16 and 20 years of age (n=6,599; 27.6%). The most common ACL graft was hamstring tendon (n=22,504; 94.0%) of which the combination semitendinosus and gracilis was the most common. A total of 7,119 patients reported on the KOOS Pain domain at both 1 and 2-year follow-up with a mean difference of 0.21 (13.1 SD, 0.16 SE, [90% CI, -0.05 - 0.46], p<0.001). The same results were found for the other KOOS subscales: symptoms (mean difference -0.54, 14.1 SD, 0. SE, [90% CI, -1.05 - -0.39], p<0.001), ADL (mean difference 0.45, 10.8 SD, 0.13 SE, [90% CI, 0.24 - 0.66], p<0.001), sports and recreation (mean difference -0.35, 22.7 SD, 0.27 SE, [90% CI, -0.79 - 0.09], p<0.001), quality of life (mean difference -0.92, 20.0 SD, 0.24 SE, [90% CI, -1.31 - -0.44], p<0.001) and in the combined KOOS-4 score (mean difference -0.41, 14.5 SD, 0.17 SE, [90% CI, -0.70 - -0.13], p<0.001). Analysis with specific subsets of patients all showed equivalent results between the two follow-ups. Conclusion: Equivalent results within a patient can be found in KOOS in 1-year and 2-year follow-up after ACL reconstruction. The finding is consistent across all KOOS subscales and for all evaluated subsets of patients. The implication of this research is that there is no additional value to capture both 1 and 2-year KOOS outcomes following ACL reconstruction.

Paper 151 Title: No Clinically Relevant Change Between 1 and 2 Year Outcomes Following ACL Reconstruction Authors: Joseph Nguyen, MPH, Scott A. Rodeo, MD. Hospital for Special Surgery, New York, NY, USA. Objectives: Anterior cruciate ligament (ACL) injury has an annual incidence of more than 200,000 cases with almost 100,000 undergoing ACL reconstruction (ACLR). Many institutions have built ACL registries to better understand treatment outcomes and raise overall standards of care. One limitation of these registries is the continued compliance of patients to fill out post-operative patient-reported outcome surveys over time, with most beginning data collection 2 years after surgery. With most ACLR patients returning to activities or sport between 1 and 2 years after surgery, and registry attrition rates increasing with every year removed from surgery, it would be beneficial to focus follow-up data collection beginning 1-year post-operatively. The purpose of this study was to evaluate if a clinically meaningful change exists from 1 to 2-year follow-up in patient-reported outcome measures for patients undergoing ACL reconstruction. Methods: Patients who underwent primary ACLR from 2010 and 2012 in our institution’s ACL registry were included. IKDC Subjective and Marx Activity surveys were collected pre-operatively and at 1 and 2-year follow-ups. Two-way repeated measures ANOVA was used to evaluate changes in IKDC and Marx scores. Differences between ages, sex, graft type, and meniscal and cartilage pathology were assessed. Bonferroni-adjusted post hoc tests were used to assess pairwise comparisons of each time point. Chi-square tests were used to compare the proportion of patients who attained minimally clinically important difference (MCID) from 1 to 2 years. Results: 1,037 enrolled patients underwent ACL reconstruction from 2010 to 2012 - 893 being primary procedures. IKDC or Marx surveys were available in 289 patients. Overall, IKDC scores significantly improved from baseline to 1 year (32.9 points, p&lt0.001). Overall change in IKDC was statistically significant from 1 to 2 years; however, mean change was 3.2 points, well below published MCIDs. Only 12% of patients attained clinically relevant change from 1 to 2 years. Range of IKDC scores between various factors was 0.5 to 5.6 points. There was no difference in percentage of those who reach the MCID between factors. Change in Marx scores was significant from baseline to 1 year (-2.2, p&lt0.001), but not significant from 1 to 2 years (0.1, p&gt0.999). Mean change was not significant between groups, with mean scores ranging from -0.6 to 1.0 from 1 to 2 years. Conclusion: Significant and meaningful changes were found in IKDC and Marx scores from baseline to 1-year follow-up. However, no clinically meaningful difference was found in both IKDC and Marx scores from 1 to 2 years follow-up. To our knowledge, this is the first study to look at longitudinal evaluation of patient-reported outcomes at these given time points with a high volume of patients. Future studies should look at why there is no significant change between 1 and 2 year outcomes, but given the lack of a clinically relevant change from 1 to 2 years and the challenges and resources required for patient follow-up, ACL-related studies should consider collecting 1 year outcome surveys to maximize follow-up retention in their patient cohort along with complementing this data with additional relevant outcome

assessments such as radiographic evaluation and functional tests that measure readiness to return to play.

Paper 152 Title: Surgery for Femoroacetabular Impingement in Skeletally Immature Patients: Radiographic and Clinical Analysis Authors: James R. Ross, MD1, Rebecca M. Stone, MS, ATC2, Nicole M. Ramos, BS2, Asheesh Bedi, MD3, Christopher M. Larson, MD2. 1Boca Care Orthopedics, Deerfield Beach, FL, USA, 2Minnesota Orthopaedic Sports Medicine Institute at Twin Cities Orthopedics, Edina, MN, USA, 3Domino's Farms, Ann Arbor, MI, USA. Objectives: The improved recognition of symptomatic femoroacetabular impingement (FAI) has lead to an emphasis of early diagnosis and treatment in the adolescent population. The purpose of this study was to evaluate the radiographic and clinical outcomes in patients with open physes that underwent hip arthroscopy for the treatment of symptomatic FAI. Additionally, we describe the three-dimensional (3D) pathomorphology in this unique population. Methods: We retrospectively reviewed 39 hips (28 patients; 75% male) with a mean age 15.8 years (range, 12.8-19.3 years) with FAI, who additionally demonstrated open physes on pre-operative radiographs. Radiographic parameters included the lateral center edge (LCE), Tonnis angle, AP and lateral alpha angle and head-neck offset ratio (HNOr). Each patient also underwent a pre-operative CT scan, which was utilized for the evaluation for femoral and acetabular measurements and simulated range of motion (ROM) to impingement. Preoperative and post-operative functions were evaluated prospectively using the modified Harris Hip Score (mHHS) and pain on a visual analogue scale (VAS). All patients participated in organized athletics and 50% were in multiple sports year round. Results: All patients (100%) within this cohort had open femoral neck and iliac crest physis. The ischial tuberosity and greater trochanteric physes were open in 95% and 54% of the hips respectively. Although there was no significant difference between pre-operative and post-operative LCE and Tonnis angles, the alpha angle and HNOr were significantly improved (39.7° vs. 61.7°; p<0.001 and 0.19 vs. 0.17; p<0.001). Mean femoral version was 17.6°±7.4°, while the acetabular version at the 1:30 and 3:00 positions were 1.0°±6.7° and 14.0°±4.1°. The mean maximum alpha angle was 72.0°±12.1° and was located on average at the 1:15 position. Simulated ROM to bony impingement was 121.6°±12.1° for flexion, 33.8°±13.3° for internal rotation in 90 degrees of flexion. Mean follow-up was 18.6 months (range, 6.3 - 55.8 months). There was a mean 23.0-point improvement in the mHHS (pre-operative 69.4, post-operative 92.4; p<0.001) and a mean decrease of 3.5 points in the VAS for pain (pre-operative 5.2, post-operative 1.7; p<0.001). 93% percent of patients returned to their preinjury level of sports participation and did not feel limited by their hip. Multivariate analysis demonstrated that a greater pre-operative LCEA correlated with a greater change in the mHHS score (r=0.374, p=0.038). Similarly, a greater pre-operative AP alpha angle and change in the AP alpha angle also correlated with a greater change in the VAS pain score (r=0.411, p=0.038 and r=0.426,p=0.019, respectively). No major complications were noted, but 3 hips (2 patients) underwent revision hip arthroscopy during the follow-up period secondary to further development of cam-type FAI. There were no cases physeal growth arrest, growth disturbance, avascular necrosis.

Conclusion: The arthroscopic approach for the treatment of FAI in adolescents with open physes is a safe and effective and has a high return to sports rate. Risk for recurrent FAI in the presence of open growth plates was noted. Young, highly athletic adolescent patients with a larger FAI pathomorphology demonstrate the most predictable improvement in clinical outcomes after arthroscopicy.

Paper 153 Title: Long-term Osseous Remodeling after Femoral Head-neck Junction Osteochondroplasty Authors: Michael Hellman, MD1, Jeffrey J. Nepple, MD2, John C. Clohisy, MD3. 1Washington University School of Medicine, St. Louis, MO, USA, 2Washington University School of Medicine, Avon, CO, USA, 3Washington University School of Medicine, St Louis, MO, USA. Objectives: Cam-type femoroacetabular impingement (FAI) is characterized by bony deformity of the proximal femoral head-neck junction. Osteochondroplasty at this level removes the impinging bone and has been associated with excellent clinical outcomes. Little is known about how the resection site remodels over long periods of time. Our objective was to describe the osseous remodeling of the femoral head-neck junction after osteochondroplasty at longterm follow-up (minimum of 7-years follow-up). Methods: A retrospective review of all patients that underwent femoral head-neck osteochondroplasty between October 2004 and December 2006 at our institution was performed. All patients with a minimum 7-year frog-leg lateral radiographic follow-up were included. Head-neck offset (HNO), head-neck offset ratio (HNOR) and α angle were measured on all frog-leg lateral radiographs preoperatively and postoperatively. The degree of cortical remodeling at the osetochondroplasty site was also graded as either none (no sclerotic margin was noted at the resection site), partial (sclerosis was present but in ), or (a continuous cortical line was noted) on the frog-leg lateral radiograph. A paired sample t-test was used for all continuous variables. Longitudinal analyses for HNO, HNOR and α angle were carried out using repeated measures ANOVA. An a priori power analysis utilizing data from a previous short-term study showed that 17 hips were required in order to obtain a power > 85% to find a change in HNOR of 0.02. Results: Eighteen hips, 10 left and 8 right, in 17 patients met inclusion criteria. The average age at the time of surgery was 26.8±SD10.3 years (range, 14-43 years) including nine females and eight males. Average radiographic follow-up was 112.1± SD17.4 months (range, 84-143 months). Initial radiographic correction of the cam-deformity was significant for HNO (7.0±SD2.5 vs. 11.3±SD2.5, p < .001), HNOR (0.12±.04 vs. 0.20±.04, p < .001), and α angle (53.2±14.0 vs. 38.9±5.7, p < .001). A small and gradual change in HNO (11.29±SD2.50 vs. 10.56±SD7.16), HNOR (0.199±.039 vs. 0.195±.138) and α angle (38.92±5.70 vs. 39.36±16.68) was observed across longitudinal follow-up but was not statistically significant (p = .645, p = .851; and p = .835; respectively) (see Figure 1). Only two hips (11%) demonstrated a decrease in HNOR > 0.02. One of these hips had an osteophyte in a patient with progression of osteoarthritis who subsequently underwent total hip arthroplasty three months later. After removing the osteoarthritic patient as an outlier, we continued to observe only small and gradual change in HNO (11.27±SD2.59 vs. 12.13±SD3.56), HNOR (0.20±SD.04 vs. 0.22±SD.70), and α angle (38.8±SD5.9 vs. 35.4±SD4.7) that was not statistically significant (p = 0.631, p = 0.312, p = 0.162; respectively). Recorticalization was present in 78% of hips (13 partial and 1 ) at an average follow-up of 22.8 months (range, 10-36 months). Recorticalization was present in 100% of hips (6 partial and 12 ) at final follow-up.

Conclusion: Our study of osseous remodeling of the femoral head-neck junction after osteochondroplasty demonstrated insignificant postoperative changes in HNO, HNOR, and α angle over long-term follow-up. The head-neck junction predictably remodeled to cortical bone at the resection site. This study provides us with additional confidence that an osteochodroplasty at the femoral head-neck junction is durable over long periods of time.

Paper 154 Title: Predictors of Hip Pain and Function in Femoroacetabular Impingement: A Prospective Cohort Analysis Authors: Robert W. Westermann, MD1, Thomas Sean Lynch, MD2, Morgan H. Jones, MD1, Kurt P. Spindler, MD3, Greg Strnad1, William Messner1, James T. Rosneck, MD4. 1Cleveland Clinic, Cleveland, OH, USA, 2Columbia University Medical Center, New York, NY, USA, 3Cleveland Clinic Sports Health Center, Garfield Hts, OH, USA, 4The Cleveland Clinic Sports Health Center, Garfield Heights, OH, USA. Objectives: Joint pain and function at the time of surgery may influence postoperative rehabilitation, recovery and the final outcome of the patient. Little is known about how patient factors or pathologic findings predict hip pain or function in those presenting with femoroacetabular impingement (FAI). We hypothesized that patient factors including mental health would more strongly correlate with subjective assessments of hip pain and function compared to the extent of the intra- or extra-articular pathology (chondral damage, labral tear, cam or pincer deformities) in patients undergoing surgery for FAI. Methods: A prospective cohort of patients undergoing hip arthroscopy for FAI were enrolled between 2/2015 and 9/2016. Patients d HOOS-Pain, HOOS-Physical Function, VR12-MCS, VR12-PCS and UCLA activity questionnaires at the time of surgery. Surgeons documented intra-articular operative findings for each case by a standardized data collection method utilizing a mobile iPhone application. Multivariable linear regression models were created for continuous scores of HOOS-pain, HOOS-Physical Function and VR12-PCS as dependent variables. Independent variables studied included both patient factors and intra-operative anatomic and pathologic findings [Table 1]. Results: During the study period, 396 patients undergoing arthroscopic surgery for FAI were enrolled. The mean patient age was 34±14 years, mean BMI 26.36±5.01 and 71% were female. The mean baseline scores were 45.94±17.07 for HOOS-Pain, 31.68±10.06 for VR-12 PCS and 40.99±17.75 for HOOS-Physical Function. The mean UCLA activity score was 5.04±2.57. Factors associated with worse HOOS-Pain scores include older age (p=0.01), female sex (p<0.001), smoking (p<0.001), years of education (p<0.001), lower VR-12 Mental Component Scores (p<0.001), lower UCLA activity scores (p<0.001) and presence of a labral tear diagnosed on hip arthroscopy (p=0.046) [Table 1]. Factors associated with worse HOOS-Physical function include female sex (p=0.004), smoking (p=0.01), fewer years of education (p=0.02), lower VR-12 MCS (p=0.002), and lower activity level (p<0.001). Factors associated with worse VR-12 PCS include increased age (p<0.001), female sex (p=0.02), smoking (p<0.001), and lower activity level (p<0.001). Conclusion: Patients with lower mental health scores, lower activity levels and those who smoke have predictably worse subjective hip pain and function when controlling for operative variables. While the presence of a labral tear does predict worse pain, the impact on subjective pain is weaker compared to patient factors such as mental health, smoking or female sex. Future studies evaluating patient outcomes after surgery for FAI should consider correcting for these identified patient factors in order to

accurately interpret differences in patient reported outcomes. In order to determine the influence of these factors on the final outcome of the patient, further studies and follow-up are warranted.

Paper 155 Title: Influence of Tönnis Grade on Outcomes of Arthroscopy for FAI in Athletes: A Comparative Analysis Authors: J. W. Thomas Byrd, MD1, Elizabeth Potts, MSN, APN, ACNP-BC2, Kay S. Jones, MSN, RN1. 1Nashville Sports Medicine Foundation, Nashville, TN, USA, 2Nashville Sports Medicine, Nashville, TN, USA. Objectives: Clear radiographic features indicating poor results of arthroscopy in the surgical correction of femoroacetabular impingement (FAI) include less than 2mm of joint space and Tönnis 3 changes. Favorable results may be associated with Tönnis 0 and 1, but Tönnis 2 findings are associated with a broad spectrum of joint damage. The purpose of this study is to define the outcomes based on Tönnis findings among a previously reported cohort; including a comparative analysis of Tönnis grades O and 1 versus Tönnis grade 2 changes. Methods: These authors previously published their initial experience in the first 200 consecutive athletes undergoing arthroscopic correction of FAI with minimum 1 year F/U. For this current study, these previously reported outcomes were correlated with the Tönnis grade, using the Tönnis system commonly adopted by third-party insurance carriers. The Tönnis grade was determined independently by two experienced clinicians. These were subsequently compared, and in cases where an agreement was not reached, the lower of the two grades was used so that the Tönnis grade was not being overestimated. The influence of Tönnis on patient reported outcome scores (modified Harris Hip Score) and return to sport was assessed. Independent variables of gender as a categorical variable and age as both a continuous and categorical (those above and below the median age) variable were evaluated. Results: The average age of this previously reported cohort was 28.6 years (range11-60), with 148 males and 52 females. There were 40 Tönnis 0 (average age 29; 28 males & 12 females), 112 Tönnis 1 (average age 30; 88 males & 24 females), 45 Tönnis 2 (average age 27; 30 males & 15 females), and 2 Tönnis 3 (average age 33; 1 male & 1 female). The Tönnis 3 data was too small for statistical analysis, as only 2 patients with severe femoral deformities were included. The average improvement was Tönnis 0 23.1 points (preop 69.0; postop 92.1), Tönnis 1 20.6 points (preop 73.9; postop 94.5), Tönnis 2 16.4 points (preop 71.6; postop 88.0), and Tönnis 3 23.5 points (preop 61.5; postop 85). As would be expected, there was a trend (p=0.055) towards lower scores with increasing Tönnis grade, but this was not statistically significant. There was both statistically (p<0.01) and clinically (>5pts) significant improvement across all Tönnis grades; and there was no statistically significant difference between Tönnis 0 and 1 compared to Tönnis 2 (p=0.078). The percent that returned to sport was: Tönnis 0 95%, Tönnis 1 92%, Tönnis 2 85%, and Tönnis 3 100%. Similar to outcome scores, there was a trend (p=0.098) towards lower rates of return to sport with increasing Tönnis grade, but it was not statistically significant; and there was no statistically significant difference between Tönnis 0 and 1 compared to Tönnis 2. Within each grade, there was no correlation with age, such that increasing age did not reflect lower scores. There was also no correlation with gender. Conclusion: Tönnis grade is an objective radiographic parameter used in staging the severity of degenerative disease. It is likely that these radiographic features provide a limited representation of the

extent of joint damage. It is equally likely that successful outcomes of arthroscopic intervention may be as much dependent on subjective parameters such as patient expectations and desires. This data supports that successful outcomes can be encountered even among those with Tönnis 2 radiographic features, comparable to those with Tönnis 0 and 1 changes.

Paper 156 Title: The Use of Allograft Tissue for Primary ACL Reconstruction is Associated with Increased Odds of Progression of Patellofemoral Articular Cartilage Damage Between Primary and Revision Surgery Authors: Mars Group. Washington University St. Louis, St Louis, MO, USA. Objectives: Subsequent development of osteoarthritis remains a major problem following anterior cruciate ligament (ACL) injury and reconstruction. Progression of articular cartilage damage likely precedes clinical symptoms of osteoarthritis in these patients. The purpose of this study was to examine risk factors affecting progression of articular cartilage damage in the patellofemoral joint between primary ACL reconstruction and revision ACL reconstruction. Methods: Subjects who had both primary and revision data contained in two prospective cohort studies were included in the analysis. Data reviewed included patellar and trochlear articular cartilage status (modified Outerbridge grade and size) at time of primary and revision; meniscus status at time of primary reconstruction; time from primary to revision ACL surgery; patient age, sex, and body mass index (BMI); smoking status; primary reconstruction graft type; and Marx activity scale prior to revision surgery. Significant patellofemoral chondral surface change was defined as worsened Outerbridge grade or at least 25% enlargement of the area of cartilage damage between primary and revision surgery. Logistic regression using a forward selection methodology used to determine which factors at primary reconstruction were associated with increased odds of progression of patellofemoral articular cartilage damage at the time of revision reconstruction. Results: A total of 134 subjects met inclusion criteria. Progression of patellofemoral articular cartilage damage between primary and revision surgery was noted in 31 of the 134 patients (23.1%). Median age at time of revision was 19.5 years [IQ range 17-25 years] and median time from primary to revision was 15.2 months [IQ range 9.6-34.4 months]. The use of allograft for the primary reconstruction, increased BMI, and increased time from primary to revision surgery were associated with increased risk of progression of articular cartilage damage in the patellofemoral joint. The use of allograft was associated with a 15-fold increased odds of progression of articular cartilage damage relative to a patellar tendon autograft (OR = 15.5, 95% CI = 3.2-75.3, p = 0.001). The use of a hamstring autograft was not associated with significantly increased odds of progression relative to patellar tendon autograft (OR = 4.3, 95% CI = 0.8-22.4, p = 0.08) Each one unit increase in BMI at the time of revision surgery was associated with a 10% increased in the odds of progression of articular cartilage damage (OR = 1.11, 95% CI = 1.00-1.22, p = 0.046). Each one month increase in time from primary to revision surgery was associated with a 2% increased in the odds of progression of articular cartilage damage (OR = 1.02, 95% CI = 1.00-1.04, p = 0.047). No other potential predictors were associated with increased odds of progression, including age, activity level prior to revision surgery, and meniscus status at primary reconstruction. Conclusion: The use of allograft for the primary reconstruction, increased BMI, and increased time from primary to revision surgery were associated with increased risk of progression of articular cartilage damage in the patellofemoral joint. Potential explanations for the association of articular cartilage

damage progression and the use of allograft require further research, but do not appear to be related to patient age or Marx activity level prior to revision ACL reconstruction.

Paper 157 Title: Testosterone Supplementation Increases Lean Mass in Men Undergoing Anterior Cruciate Ligament Reconstruction: A Randomized Controlled Trial Authors: Ido Badash, BA1, Brian Wu, PhD1, Max Berger, MD1, Dan Lorenzana, MPH1, Christianne Lane, PhD1, Jonathan C. Sum, DPT1, George F. Rick Hatch, MD2, E. Todd Schroeder, PhD1. 1Keck School of Medicine of USC, Los Angeles, CA, USA, 2Department of Orthopaedic Surgery, Keck School of Medicine of USC, Los Angeles, CA, USA. Objectives: Surgical reconstruction of the anterior cruciate ligament (ACL) is essential for those who wish to resume athletic activity following ACL rupture. However, the trauma of surgical repair and post-operative immobility can exacerbate muscle loss and strength. This study investigated the effect of perioperative testosterone administration on lean mass recovery following ACL reconstruction in men. The effects of testosterone on leg strength and clinical outcome scores were also investigated. We hypothesized that testosterone would increase lean mass and leg strength, and improve clinical outcome scores 6 and 12 weeks after surgery to a greater degree than placebo. Methods: This was a randomized, controlled, double blinded clinical trial comparing testosterone and placebo for recovery from ACL repair. Thirteen male subjects scheduled for ACL reconstruction were randomized into two groups, testosterone (n=6) and placebo (n=7). Participants in the testosterone group received 200 mg of testosterone administration weekly for 8 weeks starting 2 weeks prior to surgery. Participants in the control group received a saline placebo intramuscularly following the same schedule. Both intervention groups underwent standard physical rehabilitation. The primary outcome was change in total lean body mass at 6 and 12 weeks, measured by whole-body dual-energy x-ray absorptiometry. Secondary outcomes were extensor muscle strength measured using a Cybex Dynamometer, and the Tegner Activity Score (TAS) and Knee Injury and Osteoarthritis Outcome Score (KOOS). Results: Total testosterone levels in the blood increased from baseline to an average of 860 ± 254 ng/dL by 1 day prior to surgery and 746 ± 173 ng/dL at 6 weeks post-surgery for the testosterone group. The differences in serum testosterone levels between the placebo and testosterone groups at 1 day prior to surgery and 6 weeks post-surgery were both statistically significant (p<0.001). We found that testosterone increased lean mass by 2.8 ± 1.7 kg from baseline at 6 weeks following surgery, while the placebo group had a decrease in lean muscle mass of 0.1 ± 1.5 kg (p=0.01) (Figure 1). Extensor strength of the non-injured leg had a greater increase from baseline in the testosterone group (20.8 ± 25.6 Nm) than the placebo group (-21.4 ± 36.7 Nm) at 12 weeks (p=0.02). There were no significant differences in injured leg strength or clinical outcome scores throughout the study period. Conclusion: Despite a catabolic environment, acute testosterone supplementation increased lean mass 6 weeks after ACL reconstruction, and strength of the non-injured leg 12 weeks after surgery, to a greater degree than placebo. These results suggest that testosterone may be a novel, useful adjunct to physical therapy for knee surgery rehabilitation by offsetting perioperative muscle loss from surgery and

immobility. Larger studies are now necessary to elucidate the effects of perioperative testosterone administration on injured leg strength and clinical outcomes following surgery.

Paper 158 Title: Predictors of Patient Reported Outcomes at Two Years Following Revision ACL Reconstruction Authors: Mars Group. Washington University St. Louis, St Louis, MO, USA. Objectives: Revision ACL reconstruction (ACLR) has been documented to have worse outcomes compared with primary ACLRs. The MARS Cohort was formed to elucidate predictors of outcome following revision ACLR. Patient reported outcomes (PROs) are a valid measure of results following revision ACLR. Understanding positive and negative predictors of PROs will allow surgeons to modify and potentially improve outcome for these patients. Methods: Revision ACLR patients were identified and prospectively enrolled by 83 surgeons over 52 sites. Data collected included baseline demographics, surgical technique and pathology, and a series of validated patient reported outcome instruments (IKDC, KOOS, and Marx activity rating score). Patients were followed up at 2 years, and asked to the identical set of outcome instruments. Multivariate regression models were used to determine the predictors (risk factors) of IKDC, KOOS, and Marx scores at 2 years following revision surgery. Regression analysis was used to control for a variety of demographic and surgical factors. Results: 1205 patients met the inclusion criteria and were successfully enrolled. 697 (58%) were males, with a median cohort age of 26 years. The median time since their last ACLR was 3.4 years. At 2 years questionnaire follow-up was obtained on 989 subjects (82%), while phone follow-up was obtained on 1112 subjects (92%). Statistically significant (p < 0.05) positive (+) predictors for the Marx activity level included baseline (T0) higher Marx, younger age, male gender, non-smoker, non-traumatic/sudden onset mechanism of injury, 2nd revision, and prior ACL autograft. Negative (-) Marx predictors were having a biologic enhancement. Significant predictors of the IKDC included (+) higher T0 Marx and IKDC, male, never smoked, longer time since last ACL reconstruction and (-) previous lateral meniscectomy, Grade 3 lateral femoral condyle (LFC) chondrosis and Grades 3/4 medial tibial plateau (MTP) chondrosis. Significant predictors for KOOS symptoms subscale included (+) higher T0 KOOS symptom, longer time since ACLR, interference screw tibial fixation and (-) previous medial and/or lateral meniscectomy, Grades 3/4 MTP chondrosis. KOOS Pain predictors (+) higher T0 Marx and KOOS Pain, longer time since ACLR, (-) prior ACL soft tissue graft, suture+button/endobutton fixation, and previous medial and/or lateral meniscectomy. KOOS ADL predictors included (+) higher T0 Marx and KOOS ADL, longer time since ACLR, interference screw femoral fixation and (-) previous lateral meniscectomy, Grade 3 LFC chondrosis, and Grades 3/4 trochlear groove chondrosis. KOOS Sports/Rec predictors included (+) higher T0 Marx and KOOS Sports/Rec score, never smoked, longer time since ACLR and (-) previous lateral meniscectomy and Grades 3/4 MTP chondrosis. KOOS Knee Related Quality of Life (KRQOL) predictors included (+) higher T0 Marx and KOOS KRQOL score, never smoked, longer time since ACLR and (-) previous contralateral ACLR, 2nd revision, previous lateral meniscectomy, and Grade 4 MFC chondrosis. Conclusion: A variety of factors predict PROs both positively and negatively. Surgeon education regarding the findings in this study can result in potentially improved revision ACLR results for our

patients. When the results are modifiable by the surgeon then outcomes can improve. When factors are unable to be modified then we can still improve our counseling of patients for their expected outcome.

Paper 159 Title: Return to Play After Multi-Ligament Knee Injuries in National Football League (NFL) Athletes Authors: Neil K. Bakshi, MD1, Moin Khan, MD1, Fred Tolbert Finney1, Jeffrey Stotts2, Robby Singh Sikka, MD3, Asheesh Bedi, MD4. 1University of Michigan, Ann Arbor, MI, USA, 2., Little Rock, AR, USA, 3Tria Orthopaedic Center, Bloomington, MN, USA, 4Domino's Farms, Ann Arbor, MI, USA. Objectives: Return to play (RTP) of NFL athletes following isolated ACL tears has been reported in the literature. However, there have been no studies reporting on RTP of NFL athletes following multi-ligament knee injuries. The authors hypothesize that NFL athletes with multi-ligament knee injuries will have lower RTP rates and longer time to RTP compared to athletes with isolated ACL tears, as reported in the literature. We also hypothesize that athletes with ACL and MCL injuries will have higher RTP rates and shorter time to RTP compared to athletes with an ACL tear and a PCL and/or LCL tear(s). Methods: NFL injury surveillance data was reviewed for all multi-ligament knee injuries between 2000 and 2016 with RTP information. Athletes were excluded if RTP was limited due to reasons unrelated to the injury such as suspension, unrelated injury, or personal matters. Extracted data included injury, RTP, time to return to play (months), number of games played, percent of possible games played, and performance. Results: 51 NFL athletes were found to have multi-ligament knee injuries between 2000 and 2016 that met inclusion and exclusion criteria. 47.1% (24/51) of athletes had ACL and MCL tears. 52.9% (27/51) of athletes had ACL and PCL and/or LCL tears. Of the players with ACL and PCL/LCL tears, there were 8 frank knee dislocations. The overall return to play rate following multi-ligament knee injuries was 62.7%. Athletes with ACL/MCL tears had an RTP rate of 70.8%, while the athletes with ACL and PCL/LCL tears had an RTP rate of 55.6% (p=.26). Athletes with frank knee dislocations had a 50% RTP rate. Mean time to RTP for all 51 athletes was 11.9 ± 3.52 months. The mean time to RTP for athletes with ACL/MCL injuries was 10.4±1.6 months compared with 13.7±4.3 for those with combined ACL and PCL/LCL injuries, and for frank dislocations was 20 ±6.1 (p<.001). Athletes with ACL/MCL injuries were more likely to return to prior performance levels 46% vs 18% compared to those with ACL and PCL/LCL injuries (p < .001). Conclusion: This study is the first to provide important prognostic information for NFL players sustaining multi-ligament knee injuries. The RTP rate for athletes with multi-ligament knee injuries is significantly less than the RTP rate for athletes with isolated ACL tears. In addition, athletes with ACL and MCL tears have a higher RTP rate, a significantly shorter time to RTP, and a higher likelihood of returning to prior performance than athletes with combined ACL and PCL/LCL tears.

Paper 160 Title: A Biomechanical Comparison of Knee Stability after Posterolateral Corner Reconstruction: Arciero vs. LaPrade Authors: Gehron Treme, MD1, Gabriel Ortiz2, George K. Gill2, Heather Marie Menzer, MD3, Paul J. Johnson2, Christina Salas, PhD4, Fares Qeadan2, Robert C. Schenck, MD5, Dustin L. Richter, MD4, Daniel C. Wascher, MD6. 1Univ of New Mexico, Albuquerque, NM, USA, 2University of New Mexico, Albuquerque, NM, USA, 3University of Virginia Program, Charlottesville, VA, USA, 4University of New Mexico Program, Albuquerque, NM, USA, 5University of New MexicoDept of Orthopaedics, Albuquerque, NM, USA, 6Univ of New Mexico - Dept of Orthopaedics, Albuquerque, NM, USA. Objectives: The Posterolateral Corner (PLC) is an area of the knee that does not receive adequate research recognition despite its functionality and contribution to the overall stability of the knee. Until recently, its anatomy and biomechanics have been poorly understood which has led to the creation of multiple reconstruction methods. Two frequently used techniques are the Arciero and LaPrade reconstructions. Both have shown promising outcomes, but the two techniques have never been compared against each other from a biomechanical perspective. The objective of this study was to identify which reconstruction technique (Arciero vs. LaPrade) best restores stability to an isolated posterolateral corner (PLC) injury and injuries of the PLC which occur concurrently with injury to the tibiofibular ligament (tib-fib) and the anterior cruciate ligament (ACL), respectively. Methods: Ten matched paired fresh-frozen cadaveric specimens from mid femur to foot were used. The Semitendinosus, Gracilis, and Achilles tendons were harvested from each specimen to use as allografts for the corresponding reconstructions. Mechanical Testing: To examine the significance of PLC instability a custom made testing fixture was created to isolate and test for 10 Nm Varus Angulation (VA) and 5 Nm External Rotation (ER) at 0, 20, 30, 60, and 90 degrees of flexion about the knee joint. Data Acquisition: 8 Optitrack Motion Capture cameras were used to acquire VA and ER data through the use of 3 rigid body marker sets. The motion capture software recorded the initial and final positions of the marker sets under loading. Measures were taken of the intact knee, at post-sectioning of the PLC, and post-reconstruction (Arciero or LaPrade). Subsequently, half the specimens were subject to sectioning of the tib-fib ligament and half to sectioning of the ACL. Measures were collected of each. Data Analysis: Multivariate Analysis of Variance (MANOVA) was used to assess the mean differences over the five angles at each stage. The Wilks' Lambda statistic and significance level of 5% were used to establish statistically significant differences. Results: Data from paired, intact knees were found to be statistically similar confirming that all subsequent tests would not be affected by specimen variabilities. Post-PLC sectioning data for both groups showed significant instability from intact data, but were not different from each other. Data analysis concluded that there was no statistically significant difference between the LaPrade and Arciero techniques post-reconstruction. Both techniques were able to regain >80% of the stability of the intact knee. Post-tib-fib sectioning, ER instability was increased for all Arciero reconstructions at 90º flexion (p=0.01). Additionally, VA instability was increased for Arciero reconstructions at all flexion angles, but

not significantly. A positive post-hoc parallel profile test indicates that the post-tib-fib VA data may have been significant with a larger sample size. Sectioning the ACL showed no difference between the two techniques. Conclusion: The outcome measures of this study show no statistical differences between the Arciero and LaPrade techniques for VA and ER at varying degrees of knee flexion. Post-hoc tests showed that the LaPrade technique may be the preferred option when PLC injury is concurrent with injury to the tib-fib ligament.

Paper 161 Title: Posterolateral Corner Repair versus Reconstruction: 6-year Outcomes from a Prospective Multicenter Cohort Authors: Robert W. Westermann, MD1, Kurt P. Spindler, MD2, Laura J. Huston, MS3, Brian R. Wolf, MD, MS4. 1Cleveland Clinic, Cleveland, OH, USA, 2Cleveland Clinic Sports Health Center, Garfield Hts, OH, USA, 3Vanderbilt Orthopaedic Institute, Nashville, TN, USA, 4UI Sports Medicine, Iowa City, IA, USA. Objectives: Injuries to the posterolateral corner (PLC) may occur concurrently with anterior cruciate ligament (ACL) injury. Restoration of stability to the lateral knee is important for both preventing posterolateral rotatory instability and protecting concurrently addressed cruciate reconstructions. There has been a growing trend towards PLC reconstruction in recent literature, however little is known about how these techniques relate to long-term patient outcomes. The purpose of the present study was to evaluate the outcomes of patients who underwent operative management of PLC injuries concurrently with ACL reconstruction in a prospective multicenter cohort. We hypothesized that there would be no differences in patient outcomes between patients who were treated with repair and reconstruction. Methods: Patients undergoing ACL reconstructions were enrolled into a prospective longitudinal multi-center cohort between 2002-2008. Patients with six-year follow-up data (repeat operations and patient reported outcomes) who underwent concurrent PLC reconstruction or repair at the time of ACL reconstruction were identified. Patients who underwent PLC repair were compared to those who underwent PLC reconstruction in regard to operative delay, need for revision surgery and long-term outcomes at 6-years. Results: Initially, 3028 patients were identified to have undergone primary ACL reconstruction during the identified time frame, with 34/3028 (1.1%) also undergoing PLC surgery: 15 repairs and 19 reconstructions (18 allografts, 1 autograft). There were no differences in the rate of meniscal or chondral injuries between groups. The median time to PLC reconstruction was 121 days compared to 19 days for concurrent ACL reconstruction and PLC repair (p=0.01). Mean preoperative scores were significantly lower in the repair group with respect to KOOS Pain (57.4 versus 74.3), KOOS ADL (62.3 versus 76.2), KOOS KRQOL (17.5 versus 30.9), and IKDC (29.1 versus 48.4, p=0.004). There were no differences between groups in Marx activity scores prior to surgery (p=0.4). At 6-year follow-up, there were no differences between groups with regard to KOOS (p=0.36-0.83) or IKDC scores (p=0.84), however patients treated with lateral reconstructions had lower Marx activity scores at 6-years (4.0 versus 9.4, p=0.02). There was one ACL revision in the PLC reconstruction group and one of the PLC repairs was revised to a reconstruction during the follow-up period. Conclusion: Good outcomes were achieved with both repair and reconstruction of PLC injuries treated concurrently with ACL reconstruction at 6-year follow-up. Patients treated with reconstruction had lower activity levels 6-years after surgery. Lower KOOS and IKDC scores at the time of surgery may be explained by the increased time interval between injury and surgery in the reconstruction group. One of the 15 lateral repairs required a later reconstruction. Contrary to recent reports, our data suggests that

appropriately selected patients may be successfully treated with acute PLC repair with good long-term outcomes.

Paper 162 Title: Does Overexertion Correlate with Increased Injury? Determining the Relationship between Training Load and Soft Tissue Injury in NFL Players using Wearable Technology Authors: Ryan Tianran Li, MD1, Sagar Rambhia2, Joe Sheehan, ATC3, Michael Jonathan Salata, MD4, James Everett Voos, MD5. 1University Hospitals Case Medical Center, Cleveland, OH, USA, 2UH Case Medical Center Dept of Orthopaedic Surgery, Cleveland, OH, USA, 3Cleveland Browns, Berea, OH, USA, 4UH Case Medical Center Dept of Orthopaedics, Cleveland, OH, USA, 5University Hospitals Cleveland, Cleveland, OH, USA. Objectives: The development of injury prevention strategies is important in maximizing athlete health and safety. Increased training loads have been associated with increased odds of injury in collision sports during all phases of training. To date, the relationship between training load and injury has not been investigated in NFL players. The primary objective of this study was to determine the correlation between player workload and soft tissue injury utilizing wearable GPS technology. Methods: Player workloads were assessed during training sessions during the preseason and regular season using GPS and triaxial accelerometer from 2014-2016. Soft tissue injuries were recorded during each season and were divided into ligamentous and myotendinous injuries. Player workload during the week of injury and mean weekly workload in the 4 weeks prior to injury were determined for each soft tissue injury. These variables were also determined in uninjured position-matched controls during the same week. Descriptive statistics were used to summarize player workload for injuries and controls. Subgroup analysis was also conducted to determine whether observed effects were confounded by training period and type of injury. Results: Data was obtained over 2 NFL seasons from 2014-2016. A total of 136 lower extremity injuries were recorded. 62/136 (45%) of injuries were sustained during the preseason. Ankle sprains were the most common type of ligamentous injury (60%) while hamstring strains were the most common type of myotendinous injury (49%). 100 injuries that had a set of GPS data were included in the analysis. Injuries were associated with greater increases in player workload during the week of injury compared to uninjured individuals (193.6, 95% CI 104.6-282.5 versus 101.2, 95% CI 27.7-174.8, p = .0038). Injured players were associated with a 110% increase in training load during the week of injury compared to uninjured players, who were associated with a 73% increase (p = .032). This effect was most pronounced with myotendinous injuries during the preseason as these injuries were associated with significantly greater increases in workload during the week of injury compared to uninjured controls (617.0, 95% CI 318.4-915.6 versus 384.1, 95% CI 137.5-630.8, p = .0095). Injured players were associated with 260% increase in training load during the week of injury compared to uninjured controls who were associated with 165% increase in workload (p = .012). Conclusion: Soft tissue injuries in professional football are associated with large increases in training load during the week of injury. This effect seems to be especially pronounced during the preseason when workloads are generally higher and is primarily applicable to myotendinous injuries. These results suggest that a gradual increase in training intensity is a potential method to reduce risk of soft tissue

injury. Preseason versus regular season specific training programs monitored with wearable technology may assist team athletic training and medical staff with developing programs to optimize player performance.

Paper 163 Title: Economic Impact of Community Sports Coverage by Outreach Athletic Trainers on a Health System: Implications for Program Growth and Sustainability. Authors: Jeannie Buckner, Kirstie Hewson, Michael Barr, PT, DPT, Shane K. Woolf, MD, Thomas Crawford, PhD, MBA, FACHE, Harris Slone, MD. Medical University of South Carolina, Charleston, SC, USA. Objectives: Coverage of high school and community athletics integrated within a comprehensive sports medicine program is becoming the standard of care to optimize medical treatment of athletes. While the economic benefit of clinic-based athletic trainers (AT) has been clearly demonstrated, there has been little published on the benefit of outreach AT. The purpose of the present investigation is to examine the cost-effectiveness of outreach AT for both orthopaedic providers and the health system as a whole. Methods: Review of an electronic prospective database of the outreach AT referrals to our institution was conducted for a four-year fiscal period (July 2011-June 2015). New patients as well as patients with established care at our institution were identified, and cumulative referred episodes of care and downstream revenue were recorded from billing records. New patients were defined as having no association with the hospital in the three years prior to the initial referral. All episodes of care included in this review were referred initially through the AT program; Data were recorded for the ensuing fiscal year of service. Results: Eight thousand five hundred and seventy total episodes of care resulted from 843 patients referred into the system, yielding $2,286,733 in total revenue (Table 1). There were 187 new patients, yielding 1602 referred episodes of care across both professional-based and hospital-based services. On average, each referred patient generated 10.17 episodes of care, with each episode generating an average of $267. Combining revenue from both professional-based and hospital-based care, an average of $2712 per patient was generated through the AT program over the four year period. Combining musculoskeletal revenue from hospital-based services and orthopaedic revenue from professional-based services yielded $761,052 in total revenue, indicating a 33% capture rate of the total profit of the program; the remaining 66% was distributed across the health system. Conclusion: Affiliation between high school and community sports teams and orthopaedists through outreach AT is an economically sustainable, symbiotic relationship. Additionally, there is not only a positive economic impact for providers, but a distinct benefit to the entire health system.

Table 1. FY12-FY15 Professional-Based and Hospital-Based Revenue. Fiscal Year Professional Hospital FY12 $ 110,713.97 $ 411,145.00 FY13 $ 118,670.08 $ 354,562.00

FY14 $ 127,189.86 $ 532,629.00 FY15 $ 202,282.91 $ 429,541.00 Total $ 558,856.82 $ 1,727,877.00 Total Revenue $2,286,733.82

Paper 164 Title: Concussion Symptoms and Symptom Resolution Time in US High School Athletes, 2007/08-2014/15 Authors: Matthew John Kraeutler, MD1, Dustin Currie, MPH2, John Bradley Schrock, BA1, Eric C. McCarty, MD1, Dawn Comstock, PhD2. 1University of Colorado School of Medicine, Boulder, CO, USA, 2Colorado School of Public Health, Aurora, CO, USA. Objectives: There has been increased interest in sports-related concussions from the professional level down to youth leagues in recent years. Symptom types and resolution time are the metrics most often used to monitor concussions. The purpose of this study is to investigate how concussion symptoms, symptom resolution time, and use of diagnostic imaging have changed among US high school athletes from the 2007/08 through 2014/15 academic years. Methods: This study analyzed concussions occurring in all sports available in the High School Reporting Information Online (RIO) database from 2007/08 through 2014/15. Chi-square tests for trend were used to calculate symptom and diagnostic imaging trends over time. Statistical significance was determined at p<0.05. Results: The prevalence of each of the following symptoms was found to significantly decrease over the time period analyzed in athletes diagnosed with a concussion: amnesia (p<0.0001), confusion/disorientation (p<0.0001), dizziness/unsteadiness (p<0.01), loss of consciousness (LOC, p<0.0001), and tinnitus (p<0.0001). Among all athletes diagnosed with a concussion, the prevalence of LOC was 6.6% in 2007/08 and decreased to 2.4% in 2014/15. The prevalence of each of the following symptoms was found to significantly increase over the time period analyzed in athletes diagnosed with a concussion: drowsiness (p<0.01), irritability (p<0.0001), light sensitivity (p<0.0001), and noise sensitivity (p<0.0001). The prevalence of concentration difficulty, headaches, hyper-excitability, and nausea did not change significantly over time. The average concussion symptom resolution time has significantly increased over time (p<0.0001). The use of diagnostic plain radiographs, magnetic resonance imaging (MRI), and computed tomography (CT) scans all significantly decreased over the time period analyzed (p<0.0001 for each diagnostic test). Conclusion: From the 2007/08 to 2014/15 academic years, the prevalence of various symptoms changed significantly in US high school athletes diagnosed with a concussion. The decrease in severe symptoms (LOC, amnesia, disorientation) and the increase in less recognizable symptoms (drowsiness, irritability) may point to a lower threshold used by healthcare providers in diagnosing concussions in more recent years. Improved education among healthcare providers has likely led to increased recognition of lingering symptoms in athletes diagnosed with concussions, thereby leading to a longer average symptom resolution time. Furthermore, the significant reduction in use of all forms of diagnostic head imaging demonstrates an increased recognition of concussions as functional disturbances rather than physical abnormalities detectable on imaging.

Paper 165 Title: Return to Sports and Work after Arthroscopic Superior Capsule Reconstruction in Patients with Irreparable Rotator Cuff Tears Authors: Teruhisa Mihata, MD1, Thay Q. Lee, PhD2, Kunimoto Fukunishi, MD3, Yukitaka Fujisawa, MD4, Takeshi Kawakami, MD, PhD5, Yasuo Itami, MD6, Mutsumi Ohue, MD7, Masashi Neo, MD, PhD8. 1Department of Orthopedic Surgery, Osaka Medical College and Katsuragi Hospital, Osaka, Japan, 2VA Long Beach HCS and University of CA, Long Beach, CA, USA, 3Towakai hospital, Takatsuki, Japan, 4Department of Orthopedic Surgery, Osaka Medical college, Takatsuki, Osaka, Japan, 5Department of Orthopedic Surgery, Osaka Medical College, Takatsuki, Osaka, Japan, 6Department of Orthopaedic Surgery, Osaka Medical college, Takatsuki, Japan, 7Katsuragi Hospital, Kishiwada, Japan, 8Department of Orthopedic Surgery, Osaka Medical College, Takatsuki, Japan. Objectives: Sports and work can be a causative factor in rotator cuff tears, so that these active patients expect to return to sports and work after surgery. However, in case of irreparable rotator cuff tears, it’s not easy to return to sports and work. A new surgical treatment for irreparable rotator cuff tears, arthroscopic superior capsule reconstruction, restores shoulder stability and muscle balance in patients with irreparable rotator cuff tears; consequently, it improves shoulder function—specifically deltoid muscle function—and relieves pain. In this study, we evaluated the rate of return to sports and work in patients treated with arthroscopic superior capsule reconstruction. Methods: From 2007 to 2014, we performed arthroscopic superior capsule reconstruction on 102 shoulders in 100 patients (mean age 66.7 years; range, 43 to 82) with irreparable rotator cuff tears that had failed conservative treatment. Twenty-six patients played sports before surgery (6 golf, 4 table tennis, 4 swimming, 3 martial arts, 2 baseball, 2 yoga, 1 tennis, 1 badminton, 1 skiing, 1 mountain-climbing, and 1 ground golf). Thirty-four patients had been employed before surgery (21 manual workers, 10 farmers, 1 butcher, 1 cook, and 1 athletic trainer). Also physical examination, radiography, and magnetic resonance imaging were performed before surgery; at 3, 6, and 12 months after surgery; and yearly thereafter. The return-to-sports and work rate and healing rate were analyzed. The American Shoulder and Elbow Surgeons (ASES) score, and active shoulder range of motion were compared between before surgery and at the final follow-up (mean, 48 months; range, 24 to 88 months) by using the t and chi-square tests. A significant difference was defined as P < 0.05. Results: All 26 patients who had played sport before their injuries returned fully to their previous sports, although most of the patients had been playing at recreational level before their injuries. Thirty-two patients returned fully to their previous jobs, whereas two patients (1 farmer and 1 manual worker) returned with reduced hours and workloads. Ninety-five of 102 shoulders (93.1%) had no graft tear or no re-tear of the repaired rotator cuff tendon during the follow-up period. Three shoulders (2.9%) with severe fatty degeneration of the infraspinatus tendon had re-tear of the repaired infraspinatus tendon at 3 months after surgery. Four shoulders (3.9%) suffered a postoperative graft tear by 3 months (2 patients) or 1 year (2 patients) after surgery. The average preoperative American Shoulder and Elbow Surgeons (ASES) score was 31.6 points (range, 3.3 to 63.3 points). Average clinical outcome scores after arthroscopic superior capsule reconstruction all improved significantly at final follow-up (ASES, 93.3

points) (P < .00001). The shoulder active range of motion improved significantly after arthroscopic superior capsule reconstruction at the final follow-up: by 56.9° (92.4° to 149.3°) for elevation (P < .001), by 15.7° (26.0° to 41.6°) for external rotation (P < .01), and by three vertebral bodies (L4 to L1) for internal rotation (P < .01). Conclusion: Arthroscopic superior capsule reconstruction restored shoulder function and resulted in high rates of return to recreational sport and work. These results suggest that arthroscopic superior capsule reconstruction is a viable surgical option for irreparable rotator cuff tears, especially in patients who work and enjoy sport.

Paper 166 Title: A Prospective, Quantitative MRI-Based Assessment on the Progression of Fatty Infiltration after Rotator Cuff Repair Authors: Drew Anderson Lansdown, MD1, Sonia Lee, MD2, Craig Sam2, Roland Krug, PhD3, Brian T. Feeley, MD4, Chunbong Benjamin Ma, MD5. 1Rush University Medical Center Program, Chicago, IL, USA, 2University of California, San Francisco, San Francisco, CA, USA, 3UCSF, San Francisco, CA, USA, 4UCSF Orthopedic Institute, San Francisco, CA, USA, 5UCSF Medical CenterDept. of Orthopaedic Surgery, San Francisco, CA, USA. Objectives: Fatty infiltration is a negative prognostic factor for outcomes after rotator cuff repair. Efforts on evaluating fatty infiltration have been limited by the reproducibility of the Goutallier classification. The objective of this study is to evaluate the progression of fatty infiltration before and after surgical treatment using IDEAL MRI, which accurately measures intra-muscular fat content. We hypothesized that patients with isolated supraspinatus tears would show less progression of fatty infiltration than patients with tears involving multiple tendons. We also hypothesized that patients with eventual repair failure would have higher baseline levels of intramuscular fat. Methods: A total of 35 patients with full-thickness rotator cuff tears (61.5 ± 10.5 years, 17 female) underwent a baseline MRI prior to repair and a repeat scan 6 months after rotator cuff repair. Imaging sequences included standard clinical sequences and sagittal six-point IDEAL. The supraspinatus (SS), infraspinatus (IS), subscapularis, and teres minor muscles were segmented on four consecutive sagittal slices, centered at the scapular-Y. The intramuscular fat fraction was calculated from the IDEAL map. Pre-operative tear size and post-operative repair integrity were recorded. Fat fractions before and after rotator cuff repair were compared with t-tests. To investigate the effect of tear size, patients were divided into two groups based on intra-operative findings: isolated supraspinatus tears and multi-tendon tears. Fat fractions were compared between groups based on repair integrity. Statistical significance was defined as p < 0.05. Results: There were 19 patients with an isolated supraspinatus tear, 15 patients with a multi-tendon tear, and 1 patient with an isolated subscapuarlis tear. Intact repairs were present for 26 patients at 6 months, while a failed repair was present in 9 patients. The follow-up fat fractions were significantly higher than baseline fat fractions for the SS (9.8 ± 7.0% vs. 8.3 ± 5.7%, p = 0.025) and IS (7.4 ± 6.1% vs. 5.7 ± 4.4%, p = 0.027) muscles. There was no significant difference for the fat fractions for the subscapularis (8.2 ± 4.5% vs. 8.9 ± 6.5%, p = 0.48) or teres minor (9.9 ± 15.3% vs. 9.4 ± 13.9%, p = 0.50) muscles. Patients with isolated SS tears showed a significant progression in the SS fat fraction from baseline to follow-up (6.8 ± 4.9% to 8.6 ± 6.8%, p = 0.0083). The IS fat fraction also increased though did not reach the level of statistical significance (5.3 ± 4.6% to 6.6 ± 6.6%, p = 0.074). The baseline SS fat fractions were significantly higher in patients with eventual failed repairs as compared to those with intact repairs (11.7 ± 6.8% vs. 7.1 ± 4.8%, p = 0.037). Conclusion: Intramuscular fat content increases significantly following rotator cuff repair. In isolated supraspinatus tears, fatty infiltration advanced over the 6 months following surgical repair. Eventual

repair failure was associated with higher baseline SS fat fractions. This finding suggests that even lower levels of fatty infiltration than previously reported may impact post-surgical outcomes.

Paper 167 Title: Remplissage Versus Modified Latarjet For Off-Track Hill-Sachs Lesions With Subcritical Glenoid Bone Loss Authors: Justin Shu Yang, MD1, Augustus D. Mazzocca, MD, MS2, Robert A. Arciero, MD3. 1Kaiser Permanente, Los Angeles, CA, USA, 2University of Connecticut Health Center, Dept. of Orthopaedic Surgery, Farmington, CT, USA, 3Univ of Connecticut Health Center Dept of Orthopaedic Surgery, Farmington, CT, USA. Objectives: Off track Hill-Sachs lesions have been associated with high rate of recurrent shoulder instability. Both arthroscopic Bankart with Remplissage and modified Latarjet have been described to treat off-track Hill-Sachs lesions. However, few comparative studies exist between the two techniques in heterogeneous populations. The purpose of this study was to examine the outcome of the two procedures in patients with off-track Hill-Sachs lesions with subcritical (<25%) glenoid bone loss, both in the primary and revision setting. Methods: Arthroscopic Bankart with Remplissage was performed in thirty-one patients and modified Latarjet was performed in forty patients with recurrent anterior shoulder instability, off-track Hill-Sachs lesion, and less than 25% glenoid bone loss. Surgeries were performed at two centers. Patients were divided based on if they have had no previous surgical stabilization (Group A) or if they have had one or more previous surgical stabilization (Group B). The mean follow up time was four years. Patients were assessed for their risk of recurrence using the Instability Severity Index score and had preoperative 3-dimensional imaging to assess humeral and glenoid bone loss. Single Assessment Numeric Evaluation (SANE), Western Ontario Shoulder Instability Index (WOSI), radiographs, range of motion, recurrence rate, subsequent procedures and complications were analyzed. Results: In the thirty-two patients of group A, seventeen had remplissage and fifteen had Latarjet performed. Within group A, there were no difference found between the two techniques in regards to SANE, WOSI, range of motion (p>0.35). There were no complications, recurrence or revision with both techniques in group A. In the thirty-nine patients of group B, fourteen had remplissage and twenty-five had Latarjet performed. In group B, the reoperation surgery rate was significantly higher in the remplissage group (36% vs 8%, p=0.044). The reoperation was performed predominately for pain in patients with remplissage and for recurrent instability with Latarjet. Recurrence instability rate were similar between the remplissage and Latarjet group (14% vs 8%, p=0.45). The WOSI score was similar between the remplissage and Latarjet group (405 vs 461, p=0.66). The complication rate was also similar (36% vs 40%, p=1). Conclusion: For off-track Hill-Sachs lesions with subcritical glenoid bone loss, both the remplissage and modified Latarjet can achieve excellent clinical results in the primary setting (no previous instability surgery). However, in the revision setting (one or more previous instability surgery), patients with remplissage may have a higher reoperation rate.

Paper 168 Title: Outcomes of Latarjet versus Distal Tibial Allograft for Anterior Shoulder Instability Repair: A Prospective Matched Cohort Analysis Authors: Rachel M. Frank, MD1, Jae Kim, MA1, Patrick Joseph O'Donnell, MA1, Michael O'Brien, MA1, Jonathan Newgren, MA1, Nikhil N. Verma, MD2, Gregory P. Nicholson, MD2, Brian J. Cole, MD, MBA2, Anthony A. Romeo, MD2, Matthew T. Provencher, MD3. 1Rush University Medical Center, Chicago, IL, USA, 2Midwest Orthopaedics at Rush, Chicago, IL, USA, 3The Steadman Clinic, Vail, CO, USA. Objectives: Recently, the use of fresh distal tibia allograft (DTA) for glenoid reconstruction in anterior shoulder instability has been described, with encouraging short-term outcomes, however, there is little available comparative data to the Latarjet procedure, long considered the gold standard for bone loss treatment. Thus, the purpose of this study was to determine the clinical outcomes for patients undergoing DTA compared to a matched cohort of patients undergoing Latarjet. Methods: A review of prospectively collected data of patients with a minimum 15% anterior glenoid bone loss who underwent shoulder stabilization with either DTA or Latarjet with a minimum follow-up of 2 years was conducted. Consecutive patients undergoing DTA were matched by age, body mass index, and number of previous ipsilateral shoulder surgeries to patients undergoing Latarjet in a 1-to- 1 format. Patients were evaluated preoperatively and at a minimum 2 years post operatively with American Shoulder and Elbow Surgeons (ASES), Single Assessment Numeric Evaluation (SANE), and Western Ontario Shoulder Instability Index (WOSI) outcomes assessments. Complications, reoperations, and episodes of recurrent instability were also analyzed. Statistical analysis was performed with student T-tests, with P<0.05 considered significant. Results: A total of 60 patients (30 Latarjet, 30 DTA) with an average age of 26.5±7.8 years were analyzed at an average 46±17 months (range, 24-87) following surgery. Twenty-two patients (73%) in each group underwent prior ipsilateral shoulder surgery (range, 1 to 3 surgeries) prior to Latarjet or DTA. There were no statistical differences in age, BMI, or number of prior surgeries between the groups. There were no differences between the groups in regards to recurrent instability events, subluxation, or apprehension on final examination (P>0.8). Patients in both groups experienced significant improvements in all outcomes scores following surgery (P>0.05 for all). When comparing final outcomes of Latarjet versus DTA, no significant differences were found in postoperative ASES, WOSI or SANE scores between the groups (P>0.05 for all). In the Latarjet group, 1 patient underwent reoperation (3.3%) with arthroscopic debridement with subacromial decompression for persistent anterolateral shoulder pain. In the DTA group, 1 patient (3.3%) underwent reoperation with DTA revision for asymptomatic hardware failure. There were no cases of neurovascular injuries or other complications in either cohort. Conclusion: At an average follow-up of nearly 4 years, fresh DTA reconstruction for recurrent anterior shoulder instability results in a clinically stable joint with similar clinical outcomes and recurrence rates

compared to Latarjet. Longer-term studies are needed to determine if these results are maintained over time.

Paper 169 Title: Femoral Nerve Blockade versus Adductor Canal Nerve Blockade with Anterior Cruciate Ligament Reconstruction: A Prospective, Randomized Clinical Trial Authors: Joshua Griffin, MD1, Lane Brooks Bailey, PhD, PT2, Christopher D. Harner, MD3, Russell M. Paine, PT4, Walter R. Lowe, MD5. 1University of Texas Health Science Center at Houston Sports Medicine Fellowship, Houston, TX, USA, 2Ironman Sports Medicine Institute - Memorial Hermann, Houston, TX, USA, 3University of Texas at Houston, Houston, TX, USA, 4Memorial Hermann, Houston, TX, USA, 5University of Texas Medical School at Houston, Houston, TX, USA. Objectives: Post-operative pain control is critical to successful outcomes following outpatient anterior cruciate ligament (ACL) reconstruction. Femoral nerve blockade (FNB) has traditionally been employed to provide analgesia for ACLR since its inception in the early 1990’s. Recent studies, however, suggest a significant reduction in quadriceps muscle strength, and increased fall risk with the use of FNB. To mitigate the loss in muscle function and patient safety, surgeons and anesthesiologists have recently been exploring the potential benefits of a motor sparing adductor canal nerve blockade (ACB). To date, however, few comparative studies exist within an ACL reconstruction population to determine its clinical utility. Therefore, the purpose of this study was to compare acute pain control, quadriceps muscle activation and patient function between FNB and ACB following ACL reconstruction out to 4 weeks. Methods: One-hundred and twenty-three patients (ACB, n = 63 and FNB, n= 60) undergoing ACL reconstruction by a single surgeon (WRL) were recruited to participate in this study. Patient demographics were similar for age (28.3 ±11.1 vs 26.7 ±10.0; P =.68), gender (61.9% male vs % male; P =.17), and BMI (26 ±6 vs 27 ±8; P =.79) for ACB and FNB groups, respectively. Pain control was measured within the first 24 hours of surgery using the numeric pain rating scale (NPRS) and opioid use in morphine units (mg). Quadriceps muscle activation was measured using surface electromyography (EMG) and recorded as the deficit between the involved and uninvolved limbs (µV). Quadriceps function was clinically assessed by the number of straight leg raises performed (without a lag), and the ability to meet our criteria for ambulation without an assistive device at 24 hrs, 2 wks, and 4 wks postoperatively. A mixed-model ANOVA (group x time) was used for all statistical comparisons with an a priori α =.05. Results: There were no differences in NPRS score (2.4 ±1.7 vs 2.6 ±2.0; P =.52), and Morphine units (24.1 mg ±16.3 vs 22.8 mg ±15.6; P =.61) for ACB and FNB groups thru 24 hours post-surgery. Quadriceps muscle activation deficits were lower for the ACB group at each testing timeframe (Figure 1); 24 hours (196.2 µV ±21.0 vs 227.6 µV±23.7; P =.02), 2 weeks (87.3 µV ±19.5 vs 179.2 µV ±15.2; P <.01), and 4 weeks (56.4 µV ±18.3 vs 118.9 µV ±17.1; P =.02). The ability to meet criteria for ambulation without an assistive device was higher at 4 weeks for patients receiving ACB versus FNB (98.4% vs 90.0% ; P =.01). No statistical differences were observed for the number of straight leg raises performed at any timeframe (P >.05). Conclusion: The primary results of this study show that ACB provides similar pain control with improved quadriceps muscle activation compared to FNB acutely following ACL reconstruction. Additionally, the

ability to ambulate without an assistive device appears to occur sooner for patients receiving ACB. No differences were observed in the number of straight leg raises performed up to 4 wks post-surgery. Surgeons should consider the potential benefits of ACB for post-operative analgesia when performing ACL reconstruction.

Paper 170 Title: Adductor Canal vs. Femoral Nerve Block in Anterior Cruciate Ligament Reconstruction: A Randomized Controlled Trial Authors: John W. Xerogeanes, MD1, Ajay Premkumar, MD2, William Godfrey, MS 43, Heather Samady, MD4, Michael Brandon Gottschalk, MD4, Poonam Dalwadi, Research Fellow4, Spero G. Karas, MD5. 1Emory Orthopaedic Center, Atlanta, GA, USA, 2Hospital for Special Surgery, New York, NY, USA, 3Emory School of Medicine, Atlanta, GA, USA, 4Emory University, Atlanta, GA, USA, 5Emory Sports Medicine Center, Atlanta, GA, USA. Objectives: Peripheral nerve blocks are commonly performed as a part of multimodal pain control regimens, especially for outpatient surgical procedures. Femoral nerve blocks (FNB) have been the traditional gold standard nerve block in the setting of ACL reconstruction; however, adductor canal blocks (ACB) have emerged as a promising alternative. While early findings show less quadriceps strength deficits following adductor canal blocks, results comparing analgesia from adductor canal nerve blockade to femoral nerve blockade are inconsistent. The purpose of this study was to compare adductor canal nerve block to femoral nerve block for pain control following ACL reconstruction. Methods: This study was a prospective, single-blinded, randomized, controlled, parallel single-center trial. 77 adult patients receiving ACL reconstruction were enrolled between December 2015 and April 2016. All patients received either a traditional FNB or an ACB immediately prior to surgery. All patients were given a post-operative smartphone application to record medication usage, pain scores, hours of sleep, and time to straight leg raise for one week following ACL reconstruction. Results: Of the 77 patients recruited, 64 patients were analyzed (83.1%). 13 patients were lost to follow-up. There were no statistically significant differences in post-operative pain, home medication use, recovery room time, or hours of sleep between the two study groups. Patients receiving an ACB had significantly shorter time to straight leg raise and reported greater satisfaction with acute post-operative pain control. Conclusion: Adductor canal nerve blockade had similar analgesic outcomes, improved post-operative mobility, and greater patient satisfaction with pain control than femoral nerve blockade. Our study supports the use of adductor canal block as a viable alternative to femoral nerve block following ACL reconstruction.

Paper 171 Title: Opioid Demand after Anterior Cruciate Ligament Reconstruction Authors: Chris Anthony, MD1, Robert W. Westermann, MD2, Nicholas Bedard1, Natalie Glass, PhD1, Matthew Bollier, MD3, Carolyn M. Hettrich, MD, MPH1, Brian R. Wolf, MD, MS4. 1University of Iowa, Iowa City, IA, USA, 2Cleveland Clinic, Cleveland, OH, USA, 3University of Iowa Orthopaedic Surgery, Sports Medicine, and Rehab, Iowa City, IA, USA, 4UI Sports Medicine, Iowa City, IA, USA. Objectives: Surgeons and healthcare systems have received a call to action in an effort to curtail the current opioid epidemic in the United States. Postoperative opioid demand after anterior cruciate ligament reconstruction (ACLR) is not well understood. The purpose of this study was to (1) define the natural history of opioid demand after ACLR performed with and without concomitant procedures and to (2) evaluate preoperative opioid demand as a risk factor for postoperative opioid demand. Methods: Arthroscopic ACLRs performed in the Humana Inc. database between 2007-2014 were identified using CPT code 29888. Further categorization of procedures was performed by identifying patients who underwent ACLR with no other procedures, those who underwent ACLR with meniscus repair, those who underwent ACLR with menisectomy, and those who underwent ACLR with microfracture. Postoperative opioid demand was trended by month following surgery for 1 year. The effect of preoperative opioid demand on postoperative opioid demand was evaluated by comparing those who had filled preoperative opioid prescriptions with those who hadn′t. Patients were considered preoperative opioid users if they had filled an opioid prescription in the 3 months preceding surgery. Relative risk of postoperative opioid use was calculated and 95% confidence intervals (CI) were determined. Results: Over the course of the study period, 4,946 arthroscopic ACLRs were performed. Of these, 7.24% were still filling opioid prescriptions at 2-3 months after their procedure; 4.71% of patients were filling opioid prescriptions at 1 year after surgery. Patients undergoing ACLR with microfracture were at increased risk of filling narcotic prescriptions compared to the other procedure groups. At 4-5 months postoperatively, ACLR with microfracture had increased risk of filling narcotic prescriptions compared to ACLR alone 1.96 (CI=1.32-2.92), ACL with meniscus repair 2.38 (CI=1.46-3.88), and ACL with meniscectomy 1.51 (CI=1.03-2.23). Nearly 35% of patients (1,716/4,946) were taking opioid pain medications in the 3 months prior to ACLR. Those filling preoperative opioid prescriptions were 5.34 (CI=4.12-6.94) times more likely to be filling narcotic prescriptions at 2-3 months after ACL reconstruction. Those filling preoperative opioid prescriptions were 7.54 (CI=5.32-10.71) and 6.42 (CI=4.5-9.15) times more likely to be filling opioid prescriptions at 9 and 12 months respectively after ACLR. Conclusion: Opioid demand after ACLR drops significantly in the vast majority of patients by the 3rd postoperative month. Surprisingly, 35% of patients undergoing ACLR were found to be using opioid medications preoperatively and we identify preoperative opioid use to be a strong predictor of postoperative opioid demand with a 5 to 7 fold increased risk in this patient population. Surgeons can

use this data when counseling patients on typical postoperative opioid demand. Surgeons and healthcare systems should be aware a large portion of patients undergoing ACLR are receiving preoperative opioid prescriptions which put these patients at increased risk for extended postoperative opioid demand. In the setting of preoperative care for patients who will undergo ACLR, healthcare providers should pursue non-opioid prescribing regimens in an effort to limit postoperative opioid demand.

Paper 172 Title: Chondrotoxicity of Injectable NSAIDs and Narcotics Authors: Geoffrey D. Abrams, MD1, Wenteh Chang2, Jason L. Dragoo, MD3. 1Stanford University, Stanford, CA, USA, 2stanford University, Redwood City, CA, USA, 3Stanford University Medical Center, Redwood City, CA, USA. Objectives: The administration of intra-articular NSAIDs and narcotics has been frequently performed to augment pain control and to decrease inflammation. The chondrotoxicity of these medications have not been evaluated. Methods: Normal human cartilage was arthroscopically harvested from the intercondylar notch in patients undergoing routine ACL reconstruction (N =16 patients). Medication and treatment duration used in this study includes one NSAID, ketorolac at 0.3% and 0.6% for 10 hours, and three narcotics, fentanyl at 0.0005% and 0.001% for 7 hours, meperidine at 0.5%, 1%, and 1.5% for 6 hours, and morphine at 0.01%, 0.02%, and 0.04% for 4 hours. Each medication was delivered in a custom bioreactor over its clinical duration of action. To validate the chondrogenic characteristics of cultured cells, RT-qPCR was applied for the expression of cartilage-specific proteoglycan, aggrecan, the chondrogenic transcription factor, SOX9, the major collagen in cartilage, type II collagen, and the chondrocyte differentiation index, collagen II/I ratio. Undifferentiated human chondrocytes were used as the control. The acute cytotoxicity was determined by fluorescent vital dye staining, followed by flow cytometric analysis, and presented as percentage of dead cells from the total population. The proliferation/AlamarBlue assay was applied, and the growth curves were generated with a two-day interval for up to two weeks. Results: The treatment of a single dose of 0.3% or 0.6% ketorolac demonstrated a significant increase of cell death (0.3% concentration = 16.28% ± 1.26 loss of viability, p < .0001; 0.6% concentration= 41.88 ± 13.42, p < .05) compared to saline control (4.71% ± 1.21). All tested concentrations of meperidine exhibited significant chondrotoxicity (0.5% concentration = 13.61% ± 1.80 loss of viability, p < .01; 1% concentration= 80.53% ± 10.26, p = .001; 1.5% concentration= 89.53% ± 11.00, p < .001). Additionally, ketorolac exhibited a significant dose-response on cell death between 0.3% and 0.6% (p < .05), and higher ranges of meperidine had significant impact on survival (1%, p < .005; 1.5%, p < .005) compared to 0.5% concentration. Treatment with any concentration of fentanyl (0.0005% concentration= 6.13% ± 2.85; 0.001% concentration= 6.02% ± 3.03) or morphine (0.01% concentration= 6.40% ± 1.00; 0.02% concentration= 7.51% ± 2.08; 0.04% concentration= 8.37% ± 2.33) had no significant effect on cell death compared to saline controls. The fentanyl treatments showed no significant difference compared to saline controls up to 8 days with correlation coefficient at 0.1 for concentration = 0.01%, 0.3 for concentration = 0.02%, and -0.5 for concentration = 0.04%. The treatment of morphine exhibited a similar result with no significant difference between the experimental group and saline with correlation coefficient at 0.9 for concentration = 0.0005%, and 0.6 for concentration = 0.001%.

Conclusion: A single-dose exposure of 0.3% or 0.6% ketorolac or 0.5-1.5% meperidine resulted in a significant increase in chondrotoxicity and, therefore, should not be used for intra-articular injection. Fentanyl and morphine did not exhibit either acute or delayed chondrotoxicity.

Paper 173 Title: Does Patient Education Prior to Arthroscopic Rotator Cuff Repair Decrease Narcotic Consumption? A Randomized Prospective Study Authors: Fotios P. Tjoumakaris, MD1, Usman Ali Mohammed Syed2, Alexander William Aleem, MD3, Charles Dante Wowkanech4, Charles Getz5, Danielle Weekes3, Matthew D. Pepe, MD3, Bradford S. Tucker, MD6, Joseph A. Abboud, MD3, Luke Austin3. 1The Rothman Institute, Egg Harbor Township, NJ, USA, 2The Rothman Institute, Philadelphia, PA, USA, 3Rothman Institute, Philadelphia, PA, USA, 4Rothman Institute, Egg Harbor Township, NJ, USA, 5Rothman Institute, Newtown Square, PA, USA, 6The Rothman Institute, Egg Harbor Twp, NJ, USA. Objectives: In order to help combat opioid addiction, our objective is to see, through a randomized prospective study design, if patient education on proper use of narcotic medication would decrease narcotic consumption in the post-operative period after arthroscopic rotator cuff repair (ARCR). Methods: Patients undergoing primary ARCR at our institution were prospectively enrolled in a randomized fashion to receive either formal education on proper use of narcotics versus no education. The education group received instruction on the proper use of opioids, dosage, side effects, dependence, and addiction while the control group received education regarding the surgery alone. The education program consisted of a 2-minute narrated video in addition to a handout. All the subjects were blind to the randomization and true purpose of the study. Variables such as age, sex, and body mass index (BMI) were recorded. To determine risk of opioid abuse of the patient, the physician d a validated Opioid Risk Tool (ORT). Patients were given the same post-operative medication regimen. Patients filled out questionnaires at their 2- and 6- week follow up querying VAS pain score, refills, and total number of narcotic pills remaining. Standard statistical comparison was performed with t test calculations. Results: 67 patients d 6-week follow-up with 34 patients in the control group and 33 patients in the study group. There were no statistically significant differences in age, sex, BMI, ORT score, preoperative and postoperatively VAS score between the groups (Table 1). Patients who received pre-operative education on average consumed 26 pills compared to 35 in the control group (Table 1). More than 20 pills were consumed by only 48% of the study group compared to 76% in the control group (p = 0.01). Conclusion: Patient education is associated with a significant decrease in the number of patients consuming more than 20 narcotic pills in the acute post-operative period. Although the difference in average amount of narcotics consumed was not statistically significant, the increased frequency of patients in the control group that consumed a high number of narcotics was, suggesting benefit in preoperative education on narcotics. This is the first study to document that preoperative education can help reduce the number of patients consuming high levels of post-operative narcotics. Future recruitment and study analysis will help determine if this effect is long-lasting and can help reduce the incidence of drug dependence and addiction among this patient population.

Table 1: Results and Significance Variable Study Group Control Group p-value Male/Female, n (%) 23 (70%)/10 (30%) 21 (62%) / 13 (38%) 0.49 Average Age (Range), years 60 (42-75) 58 (40-71) 0.29 Average BMI, kg/m^2 31.26 29.58 0.22 Average ORT score 1.75 1.32 0.55 VAS Pain Score, PreOp 5.29 6.61 0.12 VAS Pain Score, PostOp 2.53 3.17 0.17 Average Total Consumption 26 35 0.12

Paper 174 Title: The Influence of a Single Preoperative Ketorolac Dose on Postoperative Opiate Consumption for Ambulatory Knee Arthroscopy: A Double Blinded Placebo Controlled Study Authors: Harris Slone, MD, Thomas Epperson, MD, Cory Furse, MD, Bethany Wolf, PhD, Sylvia Wilson, MD. Medical University of South Carolina, Charleston, SC, USA. Objectives: Ketorolac is a non-steroidal anti-inflammatory known to decrease postoperative opiate requirements. While many studies have examined serial ketorolac doses over 48 hours, the optimal ketorolac dose for analgesia following ambulatory surgery is not established. We examined postoperative opiate consumption in morphine equivalents (ME) for patients receiving a randomized ketorolac dose for knee arthroscopy. Methods: Patients undergoing elective, outpatient knee arthroscopy were randomized a dose of ketorolac (0 mg, 7.5 mg, 15 mg, 30 mg) in a double blinded placebo controlled fashion. Postoperative opiate consumption was the primary outcome. Secondary endpoints were patient satisfaction score, Visual Analog Pain Scores (VAS) pre- and postoperative, side effects and total PACU time. Logistic regression was used to compare the results among the different ketorolac groups. Results: A total of 112 patients were enrolled with comparable patient and procedural characteristics in each group. Mean postoperative opiate consumption in ME was 6.36 mg across all groups. The median VAS at PACU arrival was 3.0 and at discharge was 1.6. Median patient satisfaction across all treatment groups was 9.8 out of 10. In univariate models, increased postoperative morphine consumption was associated with decreased ketorolac dose (P=0.037) and female gender (P=0.021). In a multivariable model, patients that received 7.5 fewer mg of ketorolac consumed on average 0.6 mg more ME postoperatively controlling for other factors (P=0.034). Females consumed an average of 2.3 mg more opiates relative to males after controlling for ketorolac dose (P=0.006). Ketorolac dose was not associated with the occurrence of side effects (P=0.722). Side effects were associated with female gender (P=0.023) and increased BMI (P=0.022). Consumption of each additional 1 mg of postoperative ME had a 13% increase in the odds of having at least one side effect controlling for other factors (P=0.026, 95% CI: 1.02-1.26). Conclusion: Decreased ketorolac dose is associated with increased opiate consumption controlling other factors. Increased opiate consumption may result in increased side effects, although this did not impact patient satisfaction.

Paper 175 Title: Risk Factors for Prolonged Narcotic Use Following Arthroscopic Rotator Cuff Repair Authors: Jourdan M. Cancienne, MD, Frank Winston Gwathmey, MD, Brian C. Werner, MD. University of Virginia, Charlottesville, VA, USA. Objectives: Narcotics are commonly prescribed for management of acute pain in the early postoperative period following arthroscopic rotator cuff repair (RCR), but little is known about the frequency and risk factors for persistent use. The goal of this study was to determine risk factors for prolonged narcotic use following arthroscopic RCR. Methods: A national insurance database was queried for patients undergoing arthroscopic RCR from 2007-2015 using CPT codes. Prolonged narcotic use was defined as a new prescription for a narcotic pain medication between 3 and 6 months following the procedure. Patients without minimum 6 months’ follow-up were excluded. A multivariate logistic regression analysis was utilized to evaluate risk factors for prolonged narcotic use, including a prescription for narcotics within the 3 months before surgery, age, sex, obesity, tobacco use, alcohol use, depression and inflammatory arthritis. The regression analysis was used to control for demographics and numerous medical comorbidities. Adjusted odds ratios (OR) and 95% confidence intervals (CIs) were calculated for each risk factor, with P < 0.05 considered statistically significant. Results: 28,331 patients met inclusion and exclusion criteria. 7,543 patients (27%) were characterized as having prolonged narcotic use. Preoperative narcotic use was the most significant risk factor for prolonged postoperative narcotic use (OR 5.4, p < 0.0001). Age < 50 years (OR 1.4), male sex (OR 1.1), obesity (OR 1.1), morbid obesity (OR 1.4), tobacco use (OR 1.8), alcohol use (OR 1.3), inflammatory arthritis (OR 1.5) and depression (OR 2.0) were also all significant risk factors for prolonged postoperative narcotic use [Table 1].

Conclusion: More than a quarter of patients undergoing arthroscopic RCR continue to receive narcotic prescriptions more than 3 months postoperatively. The most significant risk factor for prolonged narcotic use is the use of preoperative narcotics. Additional risk factors include younger age, male sex, obesity, tobacco and alcohol use, depression and inflammatory arthritis.

Paper 176 Title: Intra-articular "Cocktail" Offers Clinical Advantages over Femoral Nerve Block for Postoperative Analgesia in Patients Undergoing Arthroscopic Hip Surgery Authors: Sean Childs1, Sonia Pyne, MD2, Kiritpaul Nandra, MD3, A. Atif Mustafa, BS2, Wajeeh Bakhsh, MD2, Amy Lalonde, MD2, Derick Peterson, PhD2, Brian D. Giordano, MD2. 1University of Rochester, Rochester, NY, USA, 2University of Rochester Medical Center, Rochester, NY, USA, 3University of Rochester Medical Center, Rochesters, NY, USA. Objectives: Arthroscopic hip surgery has gained considerable popularity over the past several years. Attempts to optimize peri and postoperative pain control continues to represent a challenge and opportunity for clinical improvement. Multiple regional anesthesia strategies have been utilized by arthroscopic hip surgeons, including lumbar plexus and femoral nerve blockade, however these options can be associated with setbacks including technical difficulty, intravascular injection, increased post-operative fall risk and the development of peripheral neuritis. Therefore, exploration of alternative regional anesthesia strategies holds promise for improved clinical outcomes. This study aims to explore the efficacy and complication rate of intra-articular anesthetic administration in patients undergoing arthroscopic hip surgery. Methods: A retrospective analysis of prospectively collected data was conducted to identify all patients undergoing elective arthroscopic hip surgery between November 2013 and April 2015. Subjects were stratified into either a group that had received a preoperative femoral nerve block for perioperative pain control or a group that had an intra-articular injection of local anesthetic administered by the surgical team intraoperatively. Objective data, including pre and post-op pain scores in the PACU, total dose of narcotics required perioperatively, occurrence of falls and development of peripheral neuropathy were collected for analysis. Data was compared between the two groups using linear and logistic regression modeling. Statistical significance was determined as p<0.05. Results: After excluding patients who did not meet the criteria for study participation, a total of 193 patients were included in this study. At the time of surgery, one hundred eighty three patients (95%) demonstrated evidence of labralchondral pathology and bony morphology characteristic of femoroacetabular impingement (FAI). One hundred five patients (54%) received a pre-operative femoral nerve block and 88 patients (46%) received an intra-operative intra-articular injection of anesthetic agents. Linear models for post-operative pain, controlled for patient age and pre-operative pain levels, revealed that patients receiving pre-operative femoral nerve blocks had significantly less pain at discharge (p<0.05). There was no statistically significant difference in pain scores between patients receiving pre-operative femoral nerve blocks and those receiving intra-articular injections at post-operative weeks 1, 3 and 6. Patients receiving pre-operative femoral nerve blocks were found to be 3.6 times more likely to experience a post-operative fall (OR 3.58, p < 0.05) and were 14 times more likely to experience post-operative neuropathy (OR 13.99, p < 0.01) than patients receiving an intra-articular injection.

Conclusion: Intra-articular anesthetic administration was found to be similar in efficacy to pre-operative femoral nerve blocks at reducing post-operative pain in patients undergoing hip arthroscopy. Additionally, patients receiving intra-articular injections had a significantly decreased risk of falling post-operatively or developing peripheral neuritis, known complications of femoral nerve blocks. With this information, intra-articular anesthetic administration appears to be a safe alternative to femoral nerve blocks in patients undergoing hip arthroscopy.

Paper 177 Title: Return to Sport as Outcome Measure for Shoulder Instability: Surprising Findings in Non-Operative Management in a High School Athlete Population Authors: Ellen Shanley, PhD1, John M. Tokish, MD2, Charles A. Thigpen, PT, PhD, ATC1, Lauren Ruffrage3, Douglas J. Wyland, MD4, Michael J. Kissenberth, MD2. 1ATI Physical Therapy, Greenville, SC, USA, 2Steadman Hawkins Clinic of the Carolinas, Greenville, SC, USA, 3CEROrtho, Greenville, SC, USA, 4Steadman-Hawkins Clinic of the Carolinas, Spartanburg, SC, USA. Objectives: Recurrence rates have traditionally been used as a proxy for “failure” when comparing conservatively vs. operatively managed patients with anterior shoulder instability. Return to sport has been evaluated as an outcome proxy after surgical intervention, but no study has compared conservative vs. operative management using sustained return to sport as the main outcome measure. The purpose of this study was to compare the results between conservatively and operatively treated patients as to their ability to return a patient to uninterrupted sport in a subsequent season after an anterior instability event. Methods: We identified and followed 179 scholastic athletes who were treated for a confirmed diagnosis of anterior shoulder instability. 97 were treated initially with conservative management, and 32 were managed surgically. Patients were excluded if they did not have remaining eligibility to play a subsequent season of athletics (high school seniors), or if they were treated with benign neglect (neither conservative nor operative treatment). “Ultimate success” was defined as return and completion of the subsequent season without time loss due to any shoulder related diagnosis. We substratified by age, sport, and type of instability event (subluxation vs. dislocation) using ANOVA and binary logistic regression. Results: In the conservatively managed group, 85% met the definition of ultimate success by returning to play a subsequent season of scholastic athletics in the same sport without any time loss due to a shoulder condition. In the surgical group, 72% were able to achieve this status (p<0.05). Age did not differ between the two groups. Patients were 5x less likely to return to sport if they had sustained a dislocation requiring reduction compared to a subluxation confirmed as an anterior instability event (OR: 4.96, 95%CI= 1.2-9.6). Conclusion: Patients who were treated conservatively for an anterior shoulder instability event were far more likely to have a “successful” outcome than published results if the definition of outcome is changed from no recurrence to completion of a subsequent season in their same sport. Patients sustaining a subluxation were nearly uniformly successful in doing so. While surgical success using this definition was quite lower, there was likely a selection bias in the decision making process due to bone loss, surgeon preference or other factor. Nevertheless, this data would suggest that if a patient’s goal is to return to the same level of sport and “next season”, conservative management is highly effective. Further study to determine whether these results hold out with longer term follow up are warranted, but the routine fixation of the first time dislocator based on better outcomes, is called into question depending on what one’s definition of success is.

Paper 178 Title: Rotator Cuff Repair in Adolescent Athletes. Authors: Michael G. Azzam, MD1, Jeffrey R. Dugas, MD1, James R. Andrews, MD2, Samuel R. Goldstein, MD1, Benton A. Emblom, MD1, E. Lyle Cain, MD1. 1Andrews Sports Medicine & Orthopaedic Center, Birmingham, AL, USA, 2Andrews Research and Education Foundation, Gulf Breeze, FL, USA. Objectives: Rotator cuff tears are rare injuries in adolescents, but can be a cause of significant morbidity if unrecognized. Previous literature on rotator cuff repairs in adolescents is limited to small case series, with little data to guide treatment. The purpose of this study was to investigate the clinical information, demographics, and results of surgical treatment of a consecutive series of adolescent athletes who underwent rotator cuff repair with a minimum 2-year follow-up. We hypothesized that adolescent patients would have excellent functional outcome scores and return to the same level of sports participation after rotator cuff repair, but would have some difficulty returning to the same position in overhead sports. Methods: A retrospective search of the practice’s billing records identified all patients with high-grade (&gt;50%) partial-thickness or rotator cuff tears that underwent rotator cuff repair between 2006 and 2014 with an age of less than 18 years at the time of surgery and a minimum of two years of follow-up. Clinical records were evaluated for demographic information, and telephone follow-up was obtained for return to play, performance, other surgeries and complications, a numeric pain rating scale (0-10) for current shoulder pain, American Shoulder and Elbow Surgeons (ASES) Shoulder Assessment Form, and the Western Ontario Rotator Cuff Index (WORC). Statistical analysis was performed with JMP 10 (SAS Institute, Cary, NC) with p &lt; 0.05 for significance. Descriptive statistics were prepared for all variables, and outcomes were compared according to affected tendon and concomitant procedures using two-sided Fisher’s exact tests and Student’s t-tests. Results: Thirty-two consecutive adolescent athletes (28 boys and 4 girls) with a mean age of 16.1 years (range 13.2-17.9 years, SD=1.3) met inclusion criteria. Twenty-nine patients (91%) had a traumatic event associated with the onset of their shoulder pain, and 27 of these patients (93%) had no symptoms prior to the trauma. The most common tendon affected was the supraspinatus (21 patients, 66%). All seven subscapularis injuries were repaired in open fashion, while all other tears were repaired arthroscopically with either a single-row or double-row configuration depending on tear size and anatomy. Of the 18 partial-thickness tears, eight (44%) were measured intraoperatively to be 50-75% of the footprint, and the remaining ten tears (56%) encompassed greater than 75% of the footprint from medial to lateral. Twenty-seven patients (84%) d the outcome questionnaires at a mean of 6.2 years after surgery (range 2-10 years, SD=2.6 years). The mean ASES score was 93 (range 65-100, SD=9), mean WORC was 89% (range 60%-100%, SD=13%), and mean numeric pain rating was 0.3 (range 0-3, SD=0.8). Table 1 Overall, 25 patients (93%) were able to return to the same level of play or higher. In overhead athletes, 13 patients (93%) were able to return to the same level of play, but 8 patients (57%) were forced to switch positions due to difficulty with throwing. There were no surgical complications, but two patients did

undergo a second operation during the study period. Conclusion: Surgical repair of high-grade partial-thickness and rotator cuff tears yielded successful outcomes in adolescents, with excellent functional outcomes at mid-term follow-up. However, overhead athletes may have difficulty playing the same position after surgery due to difficulty throwing.

Table 1: Patient outcomes and functional scores obtained from telephone follow-up. Patient Outcomes (n = 27 patients)

Time from surgery to follow-up 6.2 years (range 2-10 yrs., SD=2.6 yrs.) Return to sport at same level 25 (93%) Play collegiate athletics 8 (30%) Overhead athletes 14 (52%) Return to play at same level 13 (93%) Forced to switch positions 8 (57%) ASES score mean 93 (range 65-100, SD=9) WORC score mean 89% (range 60%-100%, SD=13%) Numeric Pain Rating Scale (0-10) mean 0.3 (range 0-3, SD=0.8)

Paper 179 Title: Mid to Long Term Outcome after Arthroscopic Fragment Resection for Capitellar Osteochondritis Dissecans in Adolescent Athlete Authors: Yusuke Ueda, MD1, Hiroyuki Sugaya, MD1, Norimasa Takahashi, MD1, Keisuki Matsuki, MD2, Morihito Tokai, MD3. 1Shoulder & Elbow Center, Funabashi Orthopaedic Hospital, Funabashi, Japan, 2Chosei Public HospitalDept of Orthopaedic Surgery, Chiba, Japan, 3Funabashi Orthopedic Sports Medicine Center, Funabashi,Chiba, Japan. Objectives: Capitellar osteochondritis dissecans (OCD) in skeletally immature athletes were often seen in baseball players and gymnasts, and surgeries are indicated for unstable lesions. From 2002 to 2010, we had performed arthroscopic (AS) fragment resection for all inviable lesions regardless of lesion size, though osteochondral grafting have been added for larger lesions since 2010. Several studies have reported short-term outcomes after AS resection for capitellar OCD in adolescent athletes; however, long-term outcomes have not been reported. The purpose of this retrospective study was to investigate functional outcomes and arthritic change in a mid to long-term postoperative period after AS resection for capitellar OCD with small to large lesions in adolescent athletes. Methods: Between 2002 and 2010, 77 elbows in 76 consecutive patients with skeletally immature elbows, which had open epiphyseal lines in the contralateral elbow, underwent AS resection for capitellar OCD. Forty-three elbows in 43 patients (38 males and 5 females with a mean age of 14 years (13-15) who were followed up for at least 5 years (average 8 years; 5-12) were included in this study. Thirty-two patients were engaged in baseball, 7 in gymnastics, and 4 in other sports. The size of OCD lesions was determined with preoperative radiographs. Elbows with a lesion which width did not exceed 1/2 of radial head diameter were assigned to group S (19 elbows), and elbows with a larger lesion to group L (24 elbows). Sports return, DASH score, patient satisfaction, and range of motion (ROM) were reviewed. Radiographs at final follow-up were obtained from 17 and 21 elbows in groups S and L, respectively, and pre- and postoperative osteoarthritis (OA) grade were evaluated. Mann-Whitney’s U test (for sports return and OA progression), paired t test (for pre- and postoperative ROM) and Welch’s T test (for satisfaction, DASH score, and ROM) were used for comparison between the two groups. Results: All patients returned to sports activity, and there was no significant difference in sports return rates between the groups with 17 (89%) and 21 (88%) full-return patients in groups S and L, respectively. DASH score at final follow-up had also no difference. Patient satisfaction (0 to 100 scale) was 91 (70-100) in Group S, and 78 (50-100) in Group L, and the difference was significant (p< 0.01). Flexion ROM at final follow-up did not show significant improvement in both groups compared to preoperative values: Group S, 135 (115-150) to 141 (125-150) degrees; group L, 131 (110-145) to 133 (120-145) degrees. There was a significant difference in flexion ROM at final follow-up between the groups (P=0.001). Extension ROM showed significant improvement in both groups: group S, -8 (-25-5) to 3 (-10-13) degrees (P<0.001); group L -17 (-50-0) to -1 (-15-20) degrees (P<0.001). Group S tended to have better extension than group L, but the differences was not significant (P=0.05). There were no severe OA elbows in both groups. OA change progressed in 2 elbows (12%) in Group S and 4 elbows (19%) in Group L, and the difference was

not significant. Conclusion: Both functional outcomes and radiological findings after AS fragment resection were excellent in elbows with a small lesion. Although, in elbows with larger lesions, overall outcomes were acceptable, ROM and patient satisfaction were inferior to those with small lesions. AS resection can be an effective treatment for elbows with a small OCD lesion as well as for those with a large lesion.

Paper 180 Title: Estimation of the Optimal Shoulder Orientation from the Viewpoint of Minimal Shoulder Joint Load in 183 Adolescent Baseball Pitchers Authors: Hiroshi Tanaka, PhD1, Toyohiko Hayashi, PhD2, Hiroaki Inui, MD1, Tomoyuki Muto, MD1, Hiroki Ninomiya, MD1. 1Nobuhara Hospital and Institute of Biomechanics, Tatsuno, Japan, 2Niigata University, Niigata, Japan. Objectives: Adolescent baseball pitchers are prone to shoulder injury as a result of the extreme force and torque placed on the shoulder, especially tremendous joint force applies to the shoulder near ball release. In our clinical experience, shoulder pain at ball release is common complaint. Little analysis is available about the relationship between shoulder orientation and shoulder joint force at the ball release. Methods: A total of 183 adolescent baseball pitchers (14 to 18 years old) participated after providing written informed consents approved by the hospital’s institutional review board. The procedures to be performed were also explained to their parent(s). Each participant was not currently injured or recovering from an injury at time of testing.For data collection, a set of 14-mm spherical reflective markers was placed on the skin overlying 34 anatomical landmarks. Subsequently, the motion capture automatic digitizing system was used to collect 500-Hz from 7 synchronized cameras was set up around the regulation pitching mound in an indoor laboratory. After stretching and warm-up pitching, each player pitch to 5 fastball pitches. Then, the best pitch thrown for a strike was chosen for kinematic and kinetic analysis.The local coordinate systems were used to calculate 3-dimesional rotation at the shoulder using the typical Eulerian sequence. The standard inverse dynamic equation was used to estimate resultant joint force at throwing shoulder. In order to normalize data between subjects, force was expressed as percent using body weight.To estimate the optimal shoulder orientation at ball release, Rz was defined a shoulder abduction angle, which indicated zero value of shoulder superior/inferior force at ball release by linear regression analysis. Similarly-defined Ry was a shoulder horizontal adduction/abduction angle, which indicated zero value of shoulder anterior/posterior force. Afterward, 2 groups with consideration for variations of shoulder orientations at ball release were created: {A- < Rz - 5, Rz - 5 ≤ A ≤ Rz + 5, Rz + 5 < A+}, {B- < Ry - 5, Ry - 5 ≤ B ≤ Ry + 5, Ry + 5 < B+}. Because shoulder range of motion is generally measured 5 degrees intervals in the orthopaedics. Then, we employed MANOVA to investigate significant differences of averages of inferior/superior and anterior/posterior forces applied to the shoulder at ball release among 2 groups respectively. Results: Superior/inferior force was significantly correlated with shoulder abduction. Also anterior/posterior force was strongly correlated with shoulder horizontal adduction/abduction (Table1). The average superior force at A- and the average inferior force at A+ were significantly greater than that at A. Also, the average anterior force at B- and the average posterior force at B+ were significantly higher than at that B (Table 2). Conclusion: The optimal shoulder orientation for minimizing shoulder force at the instant of ball release was 80.6 degrees of shoulder abduction and 10.7 degrees of shoulder adduction. Excessive shoulder

horizontal abduction can lead to SLAP lesion, internal impingement and any more pitching-related shoulder injuries has been published. The results of this study demonstrated that increasing amounts of shoulder horizontal abduction were shown to increase anterior force on the shoulder. Therefore, excessive shoulder horizontal abduction can be responsible for several pitching-related shoulder injuries from the viewpoint of shoulder joint load.

Paper 181 Title: Single Sport Specialization in Youth Sports: A Survey of 3,090 High School, Collegiate, and Professional Athletes Authors: Patrick S. Buckley, MD, Meghan Bishop, MD, Patrick Kane, MD, Michael C. Ciccotti, MD, Stephen Selverian, BA, Dominique Exume, BS, William D. Emper, MD, Kevin B. Freedman, MD, Sommer Hammoud, MD, Steven B. Cohen, MD, Michael G. Ciccotti, MD. Rothman Institute at Thomas Jefferson University Hospital, Philadelphia, PA, USA. Objectives: Youth participation in organized sports in the United States is rising, with many athletes focusing on a single sport at an increasingly younger age. There is considerable debate regarding the rationale, optimal timing, injury risk, and the psychosocial health of a young athlete specializing early in a single sport. The purpose of our study was to compare youth single sport specialization in high school (HS), collegiate, and professional athletes with respect to the age of specialization, the number of months per year of single sport training, and injury attributed by the athlete to specialization. Methods: A survey was distributed to HS, collegiate and professional athletes prior to their yearly pre-participation physical exam. Demographic information, details of current sport commitment, and future athletic plans were collected. Athletes were asked if they had chosen to specialize in only one sport during their childhood/adolescence, and data was then collected pertaining to when, how, and why this decision was made. Continuous data was analyzed using one-way ANOVA analysis and categorical variables were compared using chi-square analysis. Results: A total of 3,090 athletes d the survey (503 HS, 856 collegiate, and 1,731 professional athletes). 46.3% of HS athletes, 67.7% of collegiate athletes, and 45.9% of professional athletes specialized to play a single sport during their childhood/adolescence (p< 0.00001). Single sport specialization in these groups occurred at a younger age in the HS athletes (12.7 ± 2.4 years old), compared to the college (14.8 ± 2.5 years old) and professional athletes (14.06 ± 2.8 years old) (p<0.001). At the age of specialization, collegiate athletes spent more months per year training for their sport (10.03 ± 2.64 months), compared to HS (8.5 ± 3.4 months) and professional athletes (8.3 ± 3.5 months) (p<0.0001). A lower percentage of professional athletes believed that specialization helped them to play at a higher level (61.7%) compared to HS (79.7%) and collegiate athletes (80.6%) (p<0.0001). Current HS (39.9%) and collegiate athletes (42.1%) recalled a statistically higher incidence of sport-related injury than current professional athletes (25.4%) (p<0.0001). Notably, only 22.33% of professional athletes said they would want their own child to specialize to play only one sport during childhood/adolescence. Conclusion: In our study, 46.3% of current high school athletes specialized to play only one sport. Additionally, high school athletes specialized, approximately two years earlier than collegiate and professional athletes surveyed This trend towards earlier sport specialization is concerning without evidence that early specialization provides any advantage for athletic advancement with potential predisposition towards higher injury risk.

Summary of Youth Single Sport Specialization Survey Results

High School Collegiate Professional p-

value # Surveys 503 856 1731

# sports represented 23 17 2

Age (years) 15.34 ± 1.43

19.56± 1.31

23.55 ± 8.56 <0.001

What age did you begin playing in competitive sports? 7.48 ± 3.05 7.62 ± 3.23 6.02± 2.23 <0.001

Did you quit sports to focus on one sport? Y (45.17%)

Y (67.66%) Y(45.95%) <0.001

If yes, at what age did you quit other sports? 12.69± 2.37

14.79± 2.45

14.74 ± 2.40 <0.001

Did you ever sustained injury that you attributed to specializing to one sport?

Y( 39.02%) Y(42.27%) Y25.36%) <0.001

Do you think specializing to play one sport helps the athlete play at a higher level? Y(79.71%) Y(80.63%) Y(61.69%) <0.001

Do you want your children to specialize to play only one sport during their childhood/adolescence?

Y(30.59%) Y(27.36%) Y(22.33%) <0.001

Paper 182 Title: The Effect of Sport Specialization on Lower Extremity Injury Rates in High School Athletes Authors: Timothy A. McGuine, PhD, David Bell, PhD, Margaret Alison Brooks, MD, Scott Hetzel, MS, Adam Pfaller, BS, Eric Post. University of Wisconsin, Madison, WI, USA. Objectives: Sport specialization has been shown to be associated with increased risk of musculoskeletal lower extremity injuries (LEI) in adolescent athletes presenting in clinical settings. However, the association of sport specialization and incidence of LEI has not been studied prospectively in a large population of adolescent athletes. The objective of this study was to compare the incidence of LEI in high school athletes identified as having low (LOW), moderate (MOD) or high (HIGH) levels of sport specialization. Methods: Subjects (male and female, interscholastic athletes, grades 9 - 12) were recruited from a diverse sample of 29 Wisconsin high schools during the 2015/16 school year to participate in the study. Subjects d a questionnaire identifying all of the interscholastic and club sports they participated in during the previous and current school years, history of previous LEI, their primary sport and the number of primary sport competitions in which they participated in within the previous 12 months. Sport specialization status was determined using a previously published 3 item specialization scale (total score: 0 - 1 = LOW, 2 = MOD, 3 = HIGH). Athletic trainers at each school reported all athletic exposures and LEI that occurred for each subject during each interscholastic sport season they participated in during the school year. Analyses included group proportions, Odds Ratios (OR, [95%CI]) and median days lost due to injury (Med [IQR 25th,75th]. Multivariate Cox Proportional Hazards Ratios (HR, [95%CI]) were calculated to investigate the association between the incidence of LEI and sport specialization level while controlling for gender, grade, history of previous LEI, primary sport and the number of primary sport competitions. Results: A total of N =1,544 subjects (Female = 50%, Age =16.1+1.1 yrs.) enrolled in the study, competed in 2,843 athletic seasons and participated in 167,349 athletic exposures during the school year. Subjects were classified as being LOW (60%), MOD (27%) or HIGH (13%) specialization. Females were more likely to be classified as HIGH than males (OR = 2.07 [1.53 - 2.81, p < 0.001]. The sports with the greatest percentage of HIGH participants were soccer (22%), baseball/softball (19%), volleyball (17%), and basketball (13%). Two hundred thirty five subjects (15%) sustained a total of n = 276 LEI that caused them to miss a median of 7.0 [2.0, 22.8] days. Injuries occurred most often to the ankle (34%), knee (25%), upper leg (13%) and lower leg (12%). LEI were acute (66%) or gradual / recurrent (34%) onset. Common injuries included ligament sprains (41%), muscle / tendon strains (25%) and tendonitis / tenosynovitis (20%). Surgical treatment was required for n = 23 (8%) of the LEI. The incidence of LEI for MOD subjects was higher than LOW subjects (HR = 1.51 [1.04 - 2.20], p = 0.029). The incidence of LEI for HIGH subjects was higher than LOW subjects (HR = 1.85 [1.12 - 3.06], p = 0.017). Conclusion: Interscholastic athletes with MOD or HIGH sport specialization were more likely to sustain a LEI than athletes with LOW specialization. Sports medicine providers need to educate officials of sport

governing bodies, school coaches, parents and interscholastic athletes regarding the increased risk of LEI for athletes who specialize in a single sport.

Paper 183 Title: Biomechanical Evaluation of Pediatric Anterior Cruciate Ligament Reconstruction Techniques with and without the Anterolateral Ligament Authors: James Lee Pace, MD1, Natasha E. Trentacosta, MD2, Melodie Metzger, PhD3, trevor nelson4, Max Michalski3, Landon S. Polakof5, Bert R. Mandelbaum, MD6. 1Children's Hospital Los Angeles, Los Angeles, CA, USA, 2Children's Hospital (Boston) Program, Boston, MA, USA, 3Cedars Sinai Medical Center, Los Angeles, CA, USA, 4Cedars Sinai Medical Center, West Hollywood, CA, USA, 5Washington University, Chesterfield, MO, USA, 6Santa Monica Orthopaedic and Sports Medicine, Santa Monica, CA, USA. Objectives: Management of anterior cruciate ligament (ACL) injuries in skeletally immature patients is controversial and several surgical procedures have been developed. The two most popular physeal sparing procedures are the iliotibial band (ITB) ACL reconstruction (ACLR) and the all-epiphyseal (AE) ACLR. There has been some concern for over-constraint of the knee with the ITB ACLR while the AE ACLR is technically challenging and can still risk growth disturbance. There has been interest recently into the anterolateral ligament (ALL) and its role in rotational stability, but it has not been assessed in the setting of pediatric ACLR techniques. The ITB ACLR includes a lateral tenodesis of the IT band to the femur that closely approximates the ALL. Our hypothesis is that the ITB ACLR and AE ACLR with ALL reconstruction (ALLR) will best replicate the biomechanics profile of the intact ACL. Methods: Eight cadaveric legs were statically loaded with an anterior drawer force and varus, valgus, internal and external rotational moments at 0°, 30°, 60°, and 90° of flexion. Displacement and rotation was recorded in the following conditions: intact ACL/intact ALL, ACL deficient/intact ALL, ITB ACLR/intact ALL, ITB ACLR/ALL deficient, ACL deficient/ALL deficient, AE ACLR/ALL deficient, AE ACLR/ALLR. Results: Both ACLR techniques reduced anterior translation from the ACL deficient state but neither restored translation to the intact state (p<0.05) except in full extension. ALL deficiency increased anterior translation in the ACL deficient state (p<0.05). In rotational testing, only the ACL deficient/ALL deficient state had a significant increase in internal rotation (p<0.05). This was significantly restored at all flexion angles with the ITB ACLR. There was no rotational over-constraint in any flexion angle with the ITB ACLR. The AE ACLR/ALL deficient state and AE ACLR/ALLR improved rotational stability at lower flexion angles, but not at 60° and 90°. There were no significant changes in varus/valgus moments. Conclusion: In this model, the ITB ACLR best corrected both parameters at all angles without over-constraining the knee and without the need for an ALLR. The AE ACLR and AE ACLR/ALLR improved both parameters but not at all flexion angles. The ITB ACLR appears to be the simpler pediatric ACLR technique to regain translational and rotational stability. ALL deficiency in the knee increased anterior displacement and rotational moments in the ACL deficient state.

Paper 185 Title: Mid-term Outcomes of the Subchondroplasty Procedure for Patients with Osteoarthritis and Bone Marrow Edema Authors: Jennifer Marie Byrd, MD1, Sam Akhavan, MD2, Darren A. Frank, MD3. 1Allegheny General Hospital, Pittsburgh, PA, USA, 2Allegheny General Hospital, Department of Orthopaedics, Pittsburgh, PA, USA, 3Allegheny Orthopaedic Associates, Pittsburgh, PA, USA. Objectives: Bone marrow edema (BME) is a negative prognostic factor for patients with knee osteoarthritis (KOA). BME is strongly associated with pain, decreased function, structural deterioration and rapid progression to total knee arthroplasty (TKA). Subchondroplasty (SCP) (Knee Creations, Zimmer, Warsaw, IN) directly addresses BME in the setting of KOA by injecting calcium phosphate cement into the area of BME. The objective of this research was to show clinical results of the SCP procedure. Methods: A retrospective chart review with follow-up questionnaire was conducted on SCP patients in short-term and midterm (>2 years). All patients failed conservative measures and were candidates for TKA. The questionnaire addressed symptoms before and after SCP, further interventions, the perception of and willingness to undergo SCP again. Results: 133 of 143 subchondroplasty patients responded. The average patient was 57 years old (38-84 years) and 47% male. The average follow-up for short-term patients was 14.6 (4-22) months and for mid-term patients was 32.1 (24-43) months. Pain score decreased from 8.3 pre-op to 3.4 post-op in both groups. 35% in the short-term group required injections, increasing to 41% in the mid-term. The short-term group demonstrated satisfaction of 8.3 out of 10, with 82% willing to undergo SCP again and 89% recommending SCP. In the mid-term group, satisfaction increased to 8.5 with 95% willing to undergo SCP again and 96% recommending the procedure. In all, 32 patients (25%) progressed to TKA (Figure 1) at an average of 17.8 months, with 22 (69%) of these occurring before 2 years. Conclusion: SCP is an effective and well received treatment for patients with KOA and BME. In patients who failed conservative measures and were considering TKA, excellent results are seen at 2.5 years follow-up with only 25% of patients requiring TKA. Of all patients not requiring TKA, 93% would undergo SCP again and 98% would recommend it.

Paper 186 Title: Lateral Unicondylar Knee Arthroplasty with Lateral Parapatellar Incision Returns Athletes to Moderate and Vigorous Sports: 2-11 Year Follow-Up Authors: Kevin D. Plancher, MD1, Jeffrey T. Alwine, DO2, Stephanie C. Petterson, PT, PhD2. 1Albert Einstein College of Medicine, New York, NY, USA, 2Orthopaedic Foundation, Stamford, CT, USA. Objectives: Isolated lateral compartment osteoarthritis (OA) accounts for ~10% of all arthritic knees. Improved implant design and durability have increased the use of lateral unicompartmental arthroplasty (UKA) in the treatment of isolated lateral compartment OA, though some suggest lateral UKA results in inferior outcomes compared to medial UKA. We investigate the clinical and functional outcomes after lateral UKA and determine the influence of sporting activities on mid- to long-term outcomes and survivorship of lateral UKA. We hypothesized that all patients will exhibit excellent clinical and functional outcomes at mid- to long-term follow-up with no differences regardless of sporting activities. Methods: Fifty lateral UKA were performed in 46 patients by a single surgeon (2003-2013). A minimum of 2 year follow-up was required for inclusion. Seventeen males and 29 females with an average age of 67±12 years were included. All patients underwent clinical and radiographic evaluation. Pre- and postoperative clinical examination included knee flexion and extension range of motion (ROM) and radiographic evaluation. Subjective questionnaires included Lysholm and HSS scores. Radiographic evaluation included full knee series including standing alignment films to assess for prosthesis wear and progression of osteoarthritis in the contralateral, unoperated compartments. Sports were categorized as moderate or vigorous based on American College of Sport Medicine (ACSM) guidelines. Failure was defined as conversion to TKA. An independent samples t-test was used to assess differences in outcome measures between sports groups. Significance was defined as p˂0.05. Results: Fifteen patients participated in moderate sports (golf, swimming, walking, bowling, cycling, tai chi, dancing, horseback riding, and fishing), 18 patients participated in vigorous sports (tennis, skiing, mountain biking, moguls, hockey, and basketball), and 13 patients did not participate in sports preoperatively. Average follow-up was 5.8±2.1 years (range: 2-11 years). All patients regardless of sporting activity level displayed significantly higher postoperative functional scores compared to preoperative scores (all p<0.05). Patients displayed excellent postoperative functional scores and flexion range of motion with no significant differences between sporting groups (all p<0.05) (Figure). There was one failure in a patient in the moderate sports group (2.2%) and one failure in a patient in the vigorous sports group (2.2%) that occurred at 6 years. Conclusion: We recommend lateral UKA using a lateral parapatellar incision for patients with isolated lateral compartment OA. Intervening earlier in the disease process with a less invasive procedure such as lateral UKA before impairments are magnified and a TKA is necessary may optimize outcomes and allows patients to return to moderate and vigorous sports including tennis, skiing, mountain biking, moguls, hockey, and basketball without negative consequences.

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Paper 187 Title: Distal Femoral Osteotomy Survivorship: A Population-based Study Authors: K Soraya Heidari, BA1, Nathanael Heckmann, MD1, William C. Pannell, MD1, J Ryan Hill, BS1, Braden Michael McKnight, BS1, C. Thomas Vangsness, MD2, George F. Rick Hatch, MD2. 1University of Southern California Keck School of Medicine, Los Angeles, CA, USA, 2Department of Orthopaedic Surgery USC Keck School of Medicine, Los Angeles, CA, USA. Objectives: Malalignment of the lower extremity can lead to functional impairment and degenerative changes at an early age. Distal femoral osteotomies (DFO) are often performed concurrently with arthroscopic procedures to correct malalignment while addressing intra-articular pathology. The aim of this study was to examine survivorship following distal DFO and to identify risk factors for failure. Methods: Data from the California Office of Statewide Health Planning and Development, a mandatory statewide discharge database, was utilized to identify all patients who underwent a DFO from 2000 to 2014. Patients with lower extremity trauma, infectious arthritis, rheumatologic disease, congenital deformities, malignancy, or concurrent arthroplasty were excluded. Patient demographic information was assessed for every patient. Failure was defined as conversion to total or unicompartmental knee arthroplasty. Statistically significant differences between patients who required arthroplasty and those who did not were identified on univariate analysis. A multivariate analysis was performed to account for identified differences and a survivorship curve was constructed to estimate 5 and 10-year survivorship. Results: After exclusions were applied, 420 patients were identified and followed for an average of 5.0 years. Of those, 53 were converted to arthroplasty at an average of 5.9 years. 5-year survivorship was 98.3% and 10-year survivorship was 92.3%. Patients converted to arthroplasty tended to be older (43.6 years versus 36.9 years, p<0.001) and had a higher number of comorbidities (47.2% with at least one comorbidity versus 27.5%, p=0.021). A diagnosis of osteoarthritis at the time of surgery was more prevalent amongst patients who went on to arthroplasty (81.1% versus 53.7%, p<0.001). On multivariate analysis, patients were 4% more likely to undergo arthroplasty for each additional year of age (OR 1.04, p=0.013). Patients with osteoarthritis were also at increased risk of conversion to arthroplasty (OR 2.57, p=0.025).

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Conclusion: Older age and a diagnosis of osteoarthritis at the time of surgery were associated with conversion to arthroplasty. These factors should be taken into account when performing this procedure.

Paper 188 Title: Long-Term Clinical Outcomes after Microfracture of the Glenohumeral Joint: Minimum 7-Year Follow-up Authors: Rachel M. Frank, MD1, Maximilian A. Meyer, BS2, Sarah Glen Poland, BS2, Timothy Sean Leroux, MD, MEd1, Justin W. Griffin, MD1, Charles Patrick Hannon, M.D.1, Nikhil N. Verma, MD1, Anthony A. Romeo, MD2, Brian J. Cole, MD, MBA2. 1Rush University Medical Center, Chicago, IL, USA, 2Midwest Orthopaedics at Rush, Chicago, IL, USA. Objectives: Microfracture is an effective surgical treatment for isolated, full-thickness cartilage defects with current data focused on applications in the knee. Currently, only early outcomes are available analyzing patients undergoing microfracture in the glenohumeral joint. The purpose of this study is to present long-term clinical outcomes of patients undergoing microfracture of full-thickness articular cartilage defects of the glenohumeral joint. Methods: A review of a consecutive series of patients who underwent arthroscopic microfracture of the humeral head and/or glenoid surface with a minimum follow-up of 7 years between 2001 and 2007 was conducted. All patients d surveys containing the Simple Shoulder Test (SST), American Shoulder and Elbow Score (ASES), and visual analog scale (VAS) outcomes scores. Failure was defined by reoperation, including conversion to arthroplasty. Reoperation and failure rates were compared to a previous analysis of these patients at an average follow-up of 28 months. Results: A total of 15 patients (16 shoulders) with an average age of 37.0±14.7 years (8 females, 7 males) were available for analysis at an average 9.3 ± 0.7 years following surgery (range, 8.5 to 10.5 years). The average size of humeral and glenoid defects was 5.07 cm2 (range, 1.0-7.8 cm2) and 1.66 cm2 (range, 0.4-3.8 cm2), respectively. Five patients (5 shoulders) underwent at least 1 reoperation, for an overall reoperation rate of 31%. Of these 5 patients, 4 underwent shoulder arthroplasty (2 initially, 2 after additional arthroscopic procedures) and were considered failures, for an overall failure rate of 25%. Of the patients who did not progress onto arthroplasty, there were statistically significant improvements in SST, VAS, and ASES outcomes scores compared to preoperative values. When compared to short-term follow-up at 28 months, in which 3 patients had already been considered failures, 1 additional patient progressed to failure at 9.6 years after the original microfracture. Conclusion: The management of full-thickness symptomatic chondral defects of the glenohumeral joint is challenging. For some patients, microfracture can result in improved function and reduced pain, however, in this small series, up to 25% of patients required conversion to arthroplasty less than 10 years following the index microfracture procedure. Additional studies with larger patient cohorts are needed.

Paper 189 Title: High Return to Sports after TSA Under 55 Authors: Grant Garcia, MD1, Ryan Degen, MD2, Joseph N. Liu, MD3, David M. Dines, MD4, Lawrence Vincent Gulotta, MD5. 1Hospital for Special Surgery, New York City, NY, USA, 2Hospital for Special Surgery/Cornell Medical Center Program, New York, NY, USA, 3HSS, New York City, NY, USA, 4Hospital for Special Surgery, Uniondale, NY, USA, 5Hospital for Special Surgery, New York, NY, USA. Objectives: Young, active shoulder arthroplasty candidates are a unique group of patients. Not only due they demand longevity and improved function, but they also desire a return to physical activities. Our objective was to determine the rate of return to sports in total shoulder arthroplasty patients’ age 55 and younger. Methods: This was a retrospective review of consecutive patients who underwent total shoulder arthroplasty at a single institution. Exclusion criteria included age at surgery greater than 55 years and less than 2 years of follow up. Final follow-up consisted of a patient-reported sports questionnaire, ASES and VAS scores. Results: 61 shoulders were included with an average follow-up of 61.0 months (23-103) and average age at surgery of 48.9 years (25-55). VAS improved from 5.6 to 0.9 (p<0.001), and ASES improved from 39.3 to 88.4 (p<0.001). 80.3% (49) were done for osteoarthritis. 4 shoulders returned to the operating room, none were for glenoid loosening. There was a 93.2% satisfaction rate and 67.7% (40) stated they had their surgery to return to sports. 96.4% (55/57) restarted at least one sport at an average of 6.7 months. Direct rates of return were as follows: fitness sports (97.2%), golf (93.3%), singles tennis (87.5%), swimming (87.5%), basketball (75%) and flag football (66.7%). 82.4% (47) returned to similar or higher level of sport. 90.3% returned to a high demand sport and 83.8% returned to a high upper extremity use sport. There was no significant difference in rate of return to sport by BMI, sex, age, preoperative diagnosis, revision status, and dominant extremity. Conclusion: In patients age 55 and younger undergoing total shoulder arthroplasty, there was a 96.4% rate of return to sports at an average of 6.7 months. Furthermore, at an average follow up of 5 years, no patients needed revision of their glenoid component despite an 83.8% rate of return to high upper extremity use sports. While caution should still be advised in young active patients undergoing total shoulder replacement, these results demonstrate a high satisfaction rate and improved ability to return patients to most sports after surgery.

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Paper 190 Title: Return to Recreational Sporting Activities Following Total Shoulder Arthroplasty Authors: Sandeep Mannava, MD, PhD1, Marilee P. Horan, MPH2, Salvatore Joseph Frangiamore, MD3, Erik M. Fritz, MD2, Jonathan Alexander Godin, MD3, Jonas Pogorzelski, MD2, Peter J. Millett, MD, MSc4. 1Steadman Philippon, Vail, CO, USA, 2Steadman Philippon Research Institute, Vail, CO, USA, 3Steadman Philippon Research Institute Program, Vail, CO, USA, 4Steadman Clinic, Vail, CO, USA. Objectives: Total shoulder arthroplasty (TSA) is a surgery performed for end-stage shoulder pain and degeneration. Many patients who undergo TSA are limited in their ability to participate in recreational sporting activities secondary to their shoulder dysfunction. The purpose of this study is to examine the ability of patients to return to recreational sport following TSA. We hypothesize that TSA will allow for return to pre-surgical recreational sport following the arthroplasty procedure. Methods: A total of 170 patients who underwent primary TSA by the senior author and indicated they participated in recreational sporting activities met the inclusion criteria and were studied for their ability to return to their recreational activity following surgery. A minimum of 2-years of follow up was required for inclusion in the study. Additionally, ASES, QuickDASH, SANE, SF-12 PCS, and median patient satisfaction on a scale of 1-10 (with 10 being totally satisfied) was compared preoperatively to postoperatively. Patients were excluded from analysis if they were undergoing a revision arthroplasty procedure or indicated they did not participate in recreational sporting activity. Statistical analyses were performed using statistical software SPSS version 11.0 (SPSS, Chicago, IL). Results: A total of 170 patients met inclusion criteria for the study with a mean age of 63.7 years old (range 18-82). A total of n=12 patients required additional surgical intervention after the index TSA procedure, n=8 required lysis of adhesions/debridement and n=4 required revision from TSA to reverse TSA. A total of 131 of the 170 patients more specifically participated in recreational activities. Activities included golf (n=33), tennis (n=14); biking (n=12); swimming (n=5); weight lifting (n=11); snow sports (n=25); and other sports (n=32 including: wrestling, walking, hiking, fishing, throwing, softball, soccer, running, sailing, rancher/farmer, hunting, horseback riding, kayaking, rafting). The type of recreational activity did not make a difference in outcome scores. There was a significant increase preoperatively to postoperatively in the mean ASES (48.5 to 85.9, p<0.05); Quick DASH (40.0 to 16.2, p<0.05); SANE (49.8 to 80.2, p<0.05); SF-12 PCS (57.5 to 48.4, p<0.05); and median satisfaction after surgery was 10. The rate of return to pre-surgical recreational sporting activity following TSA was 69.7%. 24% reported some difficulty and 6.4% reported very difficult or unable to return to recreational activity. Conclusion: Patients undergoing TSA improve from their pre-operative functional level as assessed by their significant improvement in their outcome scores and satisfaction. Additionally, patients who indicated that they participate in recreational sporting activities were able to successfully return to their pre-surgical recreational activities. Patients undergoing TSA can be counseled that they can expect to successfully return to sporting and recreational activities following surgical reconstruction of their shoulder.