A Systematic Review of Bioabsorbable Versus Metallic Screws in Anterior Cruciate Ligament Reconstruction

Ethan Lloyd WeisgarberUniversity of Toledo - 2016

ii

Acknowledgments

Thank you to my research mentor, Dr. Jiayong Liu of the Department of Orthopaedic

Surgery at the University of Toledo, who provided both the impetus for the start of this project

and constant guidance throughout.

iii

Table of Contents

Acknowledgments 1Table of Contents 2List of Figures 1Introduction 2Interference Screws 2Anterior Cruciate Ligament Reconstruction 3

Methods 4Study Identification 4Study Characteristics 5Data Analysis 8

Results 9Functional Outcome Comparison 9Other Measures of Function 11

Discussion 13Complications 13Future Directions 14

Conclusion 16References 17Appendix 19Abstract 23

�1

List of Figures

Methods

Figure 1: Study Identification Procedure Page 5

Table 1: Characteristics of the Article Set 6

Appendix

Figure A1: JMP Oneway Analysis and T-test of Lysholm Score by ooooScrew Class

19

Figure A2: JMP Oneway Analysis and T-test of IKDC Score by Screw ooooClass

19

Figure A3: JMP Oneway Analysis and T-test of Percent Negative for ooooPivot Shift by Screw Class

20

Table A1: Complete Numbers Spreadsheet of Data Set Values 21

Table A2: Complete Numbers Spreadsheet of Reported Complication ooooData

22

�2

Introduction

Interference Screws

Metallic interference screws were first used for graft fixation in 1983, and have since

proven to be reliable in both biocompatibility and strength, becoming the gold standard in

surgical fixation. Metallic interference screws are not without their drawbacks, however. They

are known to regularly hinder magnetic resonance imaging due to their material properties. They

are also frequently difficult to remove in the event that revision surgery is necessary, and

complications during the initial surgery are not uncommon, as metallic interference screws have

been known to cause laceration of grafts and/or sutures upon primary insertion1.

Bioabsorbable interference screws have proven to provide a fixation strength comparable

to metallic interference screws with a decreased probability of graft laceration, no MRI

interference, and no need to remove the screw if revision surgery is needed. Still, bioabsorbable

screws have their own set of issues: they are more likely to fracture upon insertion, which

increases the likelihood for subsequent infection, and migration of the screw further into the knee

joint has been observed. There are multiple variations on the material used to manufacture

bioabsorbable screws, which include poly-L-lactic acid (PLLA), polyglycolic acid (PGA), poly-

D,L-lactic acid, PGA with trimethylene carbonate, PLLA with hydroxyapatite, and PLLA with

beta-tricalcium phosphate. PLLA is frequently used with minimal complications, usually

absorbing within a year post-operatively, depending on screw size. Large variations in absorption

time have been noted with some materials, such as PGA, which has been reported to persist

without complete absorption for as long as six years1.

�3

Anterior Cruciate Ligament Reconstruction

Both of the previously mentioned classes of interference screws have been applied in

anterior cruciate ligament (ACL) reconstruction to provide a reliable form of fixation to bind the

torn ligament and reduce long-term morbidity associated with the injury. ACL disruption is

extremely common, especially in sports medicine, with over 50,000 reconstructions being

performed annually. Such a high incidence of this injury and its subsequent corrective surgery

make this an essential topic of analysis1.

With a growing number of randomized controlled trials examining the functional

outcome of bioabsorbable versus metallic screws in anterior cruciate ligament reconstruction, a

systematic review of the relevant literature was completed in order to determine whether

functional outcome is significantly altered when applying a bioabsorbable interference screw in

ACL reconstruction versus a metallic interference screw.

�4

Methods

Literature was searched systematically for all articles accessible through the PubMed

database focusing on a comparison of bioabsorbable and metallic screw fixation in anterior

cruciate ligament reconstruction, specifically randomized controlled trials examined in studies

written in English.

Study Identification

PubMed was initially searched using the term “bioabsorbable screw”, with 479 article

results returned. Over four-hundred of these results were excluded by filtering the results to only

include articles examining randomized controlled trials, leaving a data set of 44 articles. These

articles were initially used for data analysis, as this study was originally intended to compare the

post-operative outcome of bioabsorbable screws versus titanium screws across all surgeries

covered in the datas set: these included studies concerning bioabsorbable screw application in

ankle fracture repair, distal tibiofibular syndesmosis injury fixation, and jaw fracture treatment.

Among these studies, however, there was no uniform method of reporting post-operative

functional outcome. The most common procedure examined among this initial data set was

anterior cruciate ligament reconstruction, with 29 articles examining patients undergoing the

procedure. After discussing the issue with the research supervisor, it was decided that the data

analysis would focus exclusively on ACL reconstruction, excluding another 15 articles. Among

the remaining 29 studies, 15 articles were comparing the outcome of bioabsorbable screw

application among various surgical procedures, with no control patients being administered

metallic screw fixation. Fifteen articles were thus excluded from data analysis for the lack of

metallic screw comparison. Of the 14 remaining articles, one study in German (initially

�5

examined due to its inclusion of an English abstract) was excluded, as data required for

comparison was not made available in the study abstract. Thirteen studies concerning

comparison of bioabsorbable and metallic screw fixation in ACL reconstruction remained for

data extraction and analysis. A flowchart of the study identification procedure can be found

below as Figure 1.

Study Characteristics

Characteristics of the studies examined, such as authors, publication year, total number of

patients, mean follow-up time, effective follow-up rate, type of bioabsorbable screw used, type

of metallic screw used, graft material, and timing of rehabilitation can be seen in Table 1 below.

All but one study was published since 20002. Number of patients examined in each study had a

Figure 1: Study Identification Procedure

�6

wide range, with one study examining as few as 40 patients, and another study examining over

200 subjects. The majority of studies were found to have used poly-L-lactic acid (PLLA)

bioabsorbable screws. Similarly, a majority used titanium interference screws for fixation,

although it is important to note that the other six studies examined did not specify the metallic

screw material, and it is a possibility that all studies examined used titanium fixation screws. The

most popular graft material among the data set was BPTB (bone-patellar tendon-bone) autograft,

although hamstring tendon autografts were also common to multiple studies. Lastly, a

rehabilitation plan starting immediately after surgery was frequent among the studies examined,

Authors Publication Year Total Number of Patients

Mean Follow Up Time (months)

Effective Follow-Up Rate

Type of Bioabsorbable Screw

Type of Metallic Screw

Graft Material Timing of Rehabilitation

Benedetto KP, Fellinger M, Lim TE, Passler JM, Schoen JL, Willems WJ

2000 124 12 91.1% PGA/TMC Titanium BPTB Autograft 2 weeks postop

Kaeding C, Farr J, Kavanaugh T, Pedroza A

2005 97 12 100.0% PLLA Titanium BPTB Autograft Unclear

Drogset JO, Straume LG, Bjørkmo I, Myhr G

2005 41 90 82.9% PLLA Titanium BPTB Autograft Unclear

Arneja S, Froese W, MacDonald P.

2004 35 18 85.7% PLLA Unclear Semitendinosus-Gracilis Graft

Immediately After Surgery

McGuire DA, Barber FA, Elrod BF, Paulos LE

1999 204 28.8 80.4% PLLA Unclear BPTB Autograft, BPTB Allograft, Achilles Tendon Allograft, Combination of Autologous and Allogeneic Grafts

Immediately After Surgery

Fink C, Benedetto KP, Hackl W, Hoser C, Freund MC, Rieger M

2000 40 24 92.5% PGA/TMC Titanium BPTB Autograft Immediately After Surgery

Myers P, Logan M, Stokes A, Boyd K, Watts M

2008 114 24 87.7% HA-PLLA Titanium Hamstring Tendon Autograft

Not Mentioned

Arama Y, Salmon LJ, Sri-Ram K, Linklater J, Roe JP, Pinczewski LA.

2015 40 60 95.0% PLLA-HA Titanium Hamstring Tendon Autograft

Immediately After Surgery

Drogset JO, Grøntvedt T, Jessen V, Tegnander A, Mollnes TE, Bergh K

2011 41 24 97.6% PLLA Titanium BPTB Autograft Immediately After Surgery

Moisala AS, Järvelä T, Paakkala A, Paakkala T, Kannus P, Järvinen M

2008 62 24 88.7% PLLA/TMC Unclear Quadrupled Hamstring Tendons Autograft

Immediately After Surgery

Järvelä T, Moisala AS, Sihvonen R, Järvelä S, Kannus P, Järvinen M

2007 77 24 94.8% PLLA Unclear Hamstring Tendon Autograft

Immediately After Surgery

Suomalainen P, Järvelä T, Paakkala A, Kannus P, Järvinen M

2012 90 60 72.2% PLLA/TMC Unclear Hamstring Tendon Autograft

Immediately After Surgery

Drogset JO, Grøntvedt T, Tegnander A

2006 41 24 90.2% PLLA Unclear BPTB Autograft Immediately After Surgery

�1

Table 1: Characteristics of the Article Set 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14

�7

although again there are multiple studies in which the timing of rehabilitation was unclear from

the information given or not mentioned at all.

The data table of all values extracted from the study set can be found attached in the

appendix as Table A1. The total number of patients enrolled in the sum of the studies was

calculated to be 1006, although not all of these patients were available for follow-up. The

number of patients at the mean-follow up point from all studies was found to be 883, with the

average study mean follow-up time calculated as 32.7 months, or approximately two years and

seven months. A total of 528 bioabsorbable interference screw procedures were examined, with a

corresponding 464 metallic interference screw fixations included in the data set. The 64-patient

disparity between the two experimental groups is due to multiple studies that applied

bioabsorbable interference screws to both double-bundle and single-bundle graft procedures to

be compared to a control group of single-bundle, metallic interference screw fixation subjects.

Thus, in these studies, the number of patients receiving a bioabsorbable screw outnumber those

receiving a metallic screw two to one.

Effective follow-up rate was consistently high among the majority of studies, with the

study conducted by Suomalainen et. al.14 reporting the lowest follow-up rate at 72.2%. The

average follow-up rate was calculated to be 89.1% over all studies.

�8

Data Analysis

Upon initial examination of the data set, multiple measures of functional outcome were

noted. There were four measures that were seen in a majority of the studies examined (at least

seven of the thirteen studies): the Lysholm Knee Scoring Scale, the International Knee

Documentation Committee (IKDC) Subjective Knee Evaluation, the Pivot Shift Test, and the

stability measurements obtained via the KT-1000 arthrometer.

Initial data analysis (including average and standard deviation calculations) was

completed on the study set using Apple Numbers version 3.6.2. Further analysis (such as oneway

analyses and t-tests) was done using JMP version 12, developed by the SAS Institute.

�9

Results

Functional Outcome Comparison

The Lysholm Knee Scoring Scale serves to evaluate functional outcomes of knee

ligament surgery, specifically quantifying symptoms of joint instability. Patients are given a

questionnaire in which multiple options are given in reference to individual categories (limp,

support, locking, instability, pain, swelling, stair climbing, and squatting). A lower score in each

of these categories (such as a “severe/constant limp, which is given a score of zero) is indicative

of a worse functional outcome. The scores in each category are summed to give a value, with the

highest possible score being 100. Nine out of thirteen (approximately 69%) of the studies

examined for this review reported scores using the Lysholm Knee Scoring Scale, making this

scoring method the most common among the data set. Scores reported for the Lysholm Knee

Scoring Scale for individual studies can be found attached in the appendix as Table A1. The

average value among all studies for the patients administered bioabsorbable screw fixation was

calculated to be 92.8, with a standard deviation of 3.2. The corresponding average value among

the patients administered metallic screw fixation was found to be 93.0, with a standard deviation

of 3.8.

The IKDC Subjective Knee Evaluation aims to detect improvement or retrogression in

knee function, symptoms of injury, and ability to participate in activities (such as sports) due to

knee impairment. The IKDC Standard Knee Evaluation form was first introduced in 1993 and

has undergone multiple revisions to exist in its current form: an 18 item questionnaire with seven

items focusing on symptoms, nine concerning proficiency of daily activity completion, one

�10

concerning sports participation, and one inquiry about the patient’s current knee function. The

IKDC score falls into one of four classifications: Normal, Nearly Normal, Abnormal, or Severely

Abnormal. As most patients pre-operatively fall into either “abnormal” or “severely abnormal”, a

shift to normal/nearly normal is desired post-operatively. Seven of the thirteen studies

(approximately 54%) reported outcome via IKDC score, which was quantified for analysis as

“percent normal”, calculated by taking the number of patients falling into the “normal” or

“nearly normal” designation as a fraction of the total patients available for follow-up in each

fixation device grouping. Scores reported for the IKDC Subjective Knee Evaluation for

individual studies can be found attached in the appendix as Table A1. The average value among

all studies for the patients administered bioabsorbable screw fixation was calculated to be 88.3,

with a standard deviation of 5.5. The corresponding average value among the patients

administered metallic screw fixation was found to be 87.0, with a standard deviation of 11.5.

The Pivot Shift Test checks for instability of the knee joint, as the degree of instability

acts as a determinant of knee function; a high degree of instability may be associated with the

patient felling that the one is “not secure” or may “give out”. The physician flexes and extends

the leg with the knee pointed inward towards the patient, making the test quite uncomfortable for

the subject, subsequently making accurate results difficult to obtain with a conscious patient after

the first test. Like the IKDC Evaluation, seven of the thirteen studies (approximately 54%)

reported outcomes using the pivot shift test. Results were given as “percent negative”, i.e., the

fraction of patients in each screw group that were not positive for pivot shift. Scores reported for

pivot shift for individual studies can be found attached in the appendix as Table A1. The average

value among all studies for the patients administered bioabsorbable screw fixation was calculated

�11

to be 79.6%, with a standard deviation of 9.1%. The corresponding average value among the

patients administered metallic screw fixation was found to be 74.5%, with a standard deviation of

15.2%.

One-way analyses were completed using JMP Statistical Analysis software. Distribution

of the values analyzed and t-test data can be found in the appendix as Figures A1, A2, and A3 for

Lysholm scores, IKDC values, and pivot shift percentages, respectively. Lysholm Score was first

analyzed by screw class, with a t-test being run subsequently, assuming unequal variances. With

a confidence level of 0.95 [a significance level (alpha) of 0.05], the test indicated that there was

no significant difference in Lysholm score between bioabsorbable and metallic screws, with a p-

value of 0.60. Similarly, the t-test run comparing values by interference screw class for the IKDC

scale returned a p-value of 0.65, again exceeding the significance level of 0.05, indicating that

there was no significant difference in IKDC evaluation scores between the two screw classes.

Lastly, a t-test was applied to compare the values for the percent of patients negative for the pivot

shift test by screw class. A calculated p-value of 0.52 again exceeded the significance level of

0.05, indicating that there was no statistical difference in the percentage of patients testing

negative for the pivot shift test between bioabsorbable and metallic interference screw groups.

Other Measures of Function

The KT-1000 arthrometer is an instrument used to measure the motion of the anterior

tibia relative to the femur before and after ACL reconstructive surgery. Differences in data

reporting in reference to the KT-1000 arthrometer, however, made the outcomes among studies

�12

difficult to compare. Although almost every study made reference to measuring functional

outcome using the KT-1000 arthrometer, five studies reported results as a percent of subjects

within designated motion intervals (such as <3 mm, 3-5 mm, >5 mm), while seven studies

reported an average value with a corresponding standard deviation for motion at follow-up

among each screw group. Without access to the raw data for these studies, it was not possible to

compare the functional outcomes measured via the KT-1000 arthrometer over the entire data set.

One other stability measure seen in multiple studies, usually in conjunction with the

Lysholm Knee Scoring Scale, was the Tegner Activity Level Scale. It was not, however, reported

in a majority of the studies examined.

�13

Discussion

To summarize the results of comparing the three measures of functional outcome

examined in this review, no significant difference was found between interference screw groups

in reference to Lysholm Score, IKDC Evaluation, or the Pivot Shift Test. These results suggest

that while bioabsorbable screw fixation is an acceptable alternative to traditional metallic

interference screw fixation, a better functional outcome is not necessarily expected with one

screw type versus another. This result is in agreement with that found by Shen et. al.1, who

arrived at similar results after conducting a meta-analysis of ten studies comparing bioabsorbable

and metallic screws in randomized controlled trials concerning ACL reconstruction.

Complications

Post-operative complications were discussed in several of the studies examined. A

spreadsheet of complications reported in the data set can be found attached in the appendix as

Table A2. Not all studies addressed post-operative complications, although there were multiple

studies that reported “no complications” among the corresponding subject set at the time of

follow-up. Furthermore, some studies reported the number of complications seen among each

fixation device group, without giving further detail on the nature of the individual problems. The

most common complication reported among the bioabsorbable screw group was effusion, with

14 cases. Reduced range of motion and infection were also somewhat common among this

group, with four cases reported for each. There were also incidences of reflex sympathetic

dystrophy, thrombophlebitis, pain in the lateral compartment, crepitus and laxity, cyst over tibial

tunnel, and reinjury among the bioabsorbable screw patients, with a total of 41 bioabsorbable

�14

screw subjects experiencing postoperative complications among the examined studies. A total of

46 complications were reported among patients receiving metallic interference screw fixation.

Effusion and infection were most commonly seen (five cases each), with cases of reduced range

of motion, hemarthrosis, pain at the site of tibial staples, pain in the region of inferior patella, and

reinjury also being reported among the data set. Although post-operative complication rate

among metallic screw subjects exceeded that of the bioabsorbable screw group, in order to truly

understand the nature of complications in relation to screw material, further analysis must be

completed.

Future Directions

While the results of this study are in-line with previous analyses conducted in a similar

fashion, research in this area still has room to expand. As mentioned previously, there are

multiple materials being used in the manufacturing of bioabsorbable screws. Although PLLA

appears to be the most commonly used material, investigations should be conducted regarding its

efficacy versus other materials. Also previously mentioned was the application of bioabsorbable

screws in multiple methods of ACL graft reconstruction. For instance, it would be valuable to

understand if a screw type is associated with a better functional outcome when a double-bundle

procedure is used versus a single-bundle graft.

Although meta-analyses have been conducted to examine functional outcome of metallic

versus bioabsorbable screws, they have not been far-reaching in scope. Future analyses should be

done searching multiple databases in order to include all relevant existing literature examining

the subject. Another aim for these future studies is information that would have been valuable

during this research — raw data. Some of the issues encountered during this review would have

�15

been easily remedied with access to individual subject measures of function, such as the

reporting disparity between studies with regard to the KT-1000 arthrometer.

Lastly, the data set examined in this study can be further analyzed. Statistical methods

such as heterogeneity tests and assessment of publication bias can yield information as to the

quality of the data gathered and the conclusions reached. Information such as radiologic results

can also be pooled and quantified.

�16

Conclusion

Although surgical methods applying bioabsorbable fixation devices are still relatively

new, enough literature has emerged on the subject to warrant systematic analysis. With ACL

reconstruction being so prevalent, the procedure lends itself well to study, and the multiple

methods of evaluating functional outcome are easily compared. Like other reviews before it, this

study found no significant functional difference in patients undergoing ACL fixation with a

bioabsorbable interference screw versus a metallic counterpart, at least in reference to the

measures of Lysholm score, IKDC evaluation, and the pivot shift test. Further analysis should be

completed in the future to confirm that bioabsorbable screws are truly a reliable alternative to the

gold standard in graft fixation.

�17

References 1. Shen, C., Jiang, S. D., Jiang, L. S., & Dai, L. Y. (2010). Bioabsorbable versus metallic interference screw fixation in anterior cruciate ligament reconstruction: a meta-analysis of randomized controlled trials. Arthroscopy: The Journal of Arthroscopic & Related Surgery, 26(5), 705-713.

2. Arama Y, Salmon LJ, Sri-Ram K, Linklater J, Roe JP, Pinczewski LA. Bioabsorbable Versus Titanium Screws in Anterior Cruciate Ligament Reconstruction Using Hamstring Autograft: A Prospective, Blinded, Randomized Controlled Trial With 5-Year Follow-up. Am J Sports Med. 2015 Aug;43(8):1893-901. doi: 10.1177/0363546515588926. Epub 2015 Jun 24. PubMed PMID: 26109611.

3. Arneja S, Froese W, MacDonald P. Augmentation of femoral fixation in hamstring anterior cruciate ligament reconstruction with a bioabsorbable bead: a prospective single-blind randomized clinical trial. Am J Sports Med. 2004 Jan-Feb;32(1):159-63. PubMed PMID: 14754739.

4. Benedetto KP, Fellinger M, Lim TE, Passler JM, Schoen JL, Willems WJ. A new bioabsorbable interference screw: preliminary results of a prospective, multicenter, randomized clinical trial. Arthroscopy. 2000 Jan-Feb;16(1):41-8. PubMed PMID: 10627344.

5. Drogset JO, Straume LG, Bjørkmo I, Myhr G. A prospective randomized study of ACL-reconstructions using bone-patellar tendon-bone grafts fixed with bioabsorbable or metal interference screws. Knee Surg Sports Traumatol Arthrosc. 2011 May;19(5):753-9. doi: 10.1007/s00167-010-1353-4. Epub 2011 Jan 14. PubMed PMID: 21234545; PubMed Central PMCID: PMC3076560.

6. Drogset JO, Grøntvedt T, Jessen V, Tegnander A, Mollnes TE, Bergh K. Comparison of in vitro and in vivo complement activation by metal and bioabsorbable screws used in anterior cruciate ligament reconstruction. Arthroscopy. 2006 May;22(5):489-96. PubMed PMID: 16651157.

7. Drogset JO, Grøntvedt T, Tegnander A. Endoscopic reconstruction of the anterior cruciate ligament using bone-patellar tendon-bone grafts fixed with bioabsorbable or metal interference screws: a prospective randomized study of the clinical outcome. Am J Sports Med. 2005 Aug;33(8):1160-5. Epub 2005 Jul 6. PubMed PMID: 16000666.

8. Fink C, Benedetto KP, Hackl W, Hoser C, Freund MC, Rieger M. Bioabsorbable polyglyconate interference screw fixation in anterior cruciate ligament reconstruction: a

�18

prospective computed tomography-controlled study. Arthroscopy. 2000 Jul-Aug;16(5):491-8. PubMed PMID: 10882444.

9. Järvelä T. Double-bundle versus single-bundle anterior cruciate ligament reconstruction: a prospective, randomize clinical study. Knee Surg Sports Traumatol Arthrosc. 2007 May;15(5) 500-7. Epub 2007 Jan 10. PubMed PMID: 17216271.

10. Kaeding C, Farr J, Kavanaugh T, Pedroza A. A prospective randomized comparison of bioabsorbable and titanium anterior cruciate ligament interference screws. Arthroscopy. 2005 Feb;21(2):147-51. PubMed PMID: 15689862.

11. McGuire DA, Barber FA, Elrod BF, Paulos LE. Bioabsorbable interference screws for graft fixation in anterior cruciate ligament reconstruction. Arthroscopy. 1999 Jul-Aug;15(5):463-73. PubMed PMID: 10424549.

12. Moisala AS, Järvelä T, Paakkala A, Paakkala T, Kannus P, Järvinen M. Comparison of the bioabsorbable and metal screw fixation after ACL reconstruction with a hamstring autograft in MRI and clinical outcome: a prospective randomized study. Knee Surg Sports Traumatol Arthrosc. 2008 Dec;16(12):1080-6. doi: 10.1007/s00167-008-0593-z. Epub 2008 Sep 2. PubMed PMID: 18762911.

13. Myers P, Logan M, Stokes A, Boyd K, Watts M. Bioabsorbable versus titanium interference screws with hamstring autograft in anterior cruciate ligament reconstruction: a prospective randomized trial with 2-year follow-up. Arthroscopy. 2008 Jul;24(7):817-23. doi: 10.1016 j.arthro.2008.02.011. Epub 2008 Apr 14. PubMed PMID: 18589271.

14. Suomalainen P, Järvelä T, Paakkala A, Kannus P, Järvinen M. Double-bundle versus single-bundle anterior cruciate ligament reconstruction: a prospective randomized study with 5-year results. Am J Sports Med. 2012 Jul;40(7):1511-8. doi: 10.1177/0363546512448177. Epub 2012 Jun 11. PubMed PMID: 22691456.

�19

Appendix

Figure A1: JMP Oneway Analysis and T-test of Lysholm Score by Screw Class

Figure A2: JMP Oneway Analysis and T-test of IKDC Score by Screw Class

�20

Figure A3: JMP Oneway Analysis and T-test of Percent Negative for Pivot Shift by Screw Class

�21

Table A1: Complete Numbers Spreadsheet of Data Set Values

�22

Table A2: Complete Numbers Spreadsheet of Reported Complication Data

�23

AbstractA Systematic Review of Bioabsorbable Versus Metallic Screws in Anterior Cruciate

Ligament Reconstruction

Ethan Weisgarber

Objective: Determine if functional outcome is significantly altered in ACL reconstruction completed with a bioabsorbable interference screw over a metallic screw.

Method: The PubMed Database was systematically searched in order to obtain the relevant literature (13 randomized controlled studies) from which multiple study characteristics were extracted. The data set was subsequently analyzed for values indicating functional outcome, such as Lysholm score, IKDC evaluation, KT-1000 arthrometer testing, and pivot shift prevalence among each fixation device group.

Results: The average values and standard deviations calculated for all three measures among both fixation device groups were found to exceed the significance level of 0.05 after application of t-tests with JMP statistical software.

Conclusion: No statistical significant difference was found between interference screw groups in reference to Lysholm Score, IKDC Evaluation, or the percent of subjects negative for pivot shift.