e386 Copyright © SLACK inCorporAted

n tips & techniquesSection Editor: Steven F. Harwin, MD

Repair of Chronic Tibialis Anterior Tendon RupturesShawn S. Funk, MD; Bethany Gallagher, MD; A. Brian Thomson, MD

The tibialis anterior supplies 80% of the dorsiflexion

power of the ankle. Deficiency results in a significant func-tional deficit.1,2 Tibialis ante-rior tendon ruptures occur trau-matically and atraumatically.

Atraumatic ruptures occur after the age of 45 years following eccentric loading of a degen-erated tibialis anterior tendon against a plantarflexed ankle and often present delayed. Pa-tients with inflammatory ar-

thropathy, gout, and diabetes mellitus and patients receiving corticosteroid treatment are at risk for degeneration and atrau-matic rupture of the tendon.1,3-8 Previous studies have identified a hypovascular zone as 45 to 65 mm in total length starting ap-proximately 5 mm proximal to the insertion site.9-11 A signifi-cant number of ruptures are at the most distal 5 to 30 mm of the tendon, correlating with the hypovascular zone.10-12

Patients present with a triad of findings, including a pseu-dotumor at the anteromedial aspect of the ankle, loss of the contour of the tibialis anterior tendon over the ankle, and the use of the extensor hallucis longus and extensor digitorum longus to dorsiflex the ankle.1,7 Gait is typically foot slap or steppage with a propensity for toe dragging.1 Case studies have described these injuries and potential treatments, but there is no consensus regard-ing treatment.4,8,12-14

Direct repair of the tendon is ideal when possible with adequate healthy tendon stalk proximally and distally. Acute tendon laceration is often ame-nable to direct repair. How-ever, atraumatic ruptures often occur at the distal end of the tendon at the site of bony in-sertion, and often present late due to the difficulty of diagno-sis.7 Current repair techniques involve suture anchor and bone tunnel repair with the use of a tendon graft.4,8,12-14 These techniques frequently imple-ment a graft, with associated morbidity of harvesting, and can result in a bulky repair. Re-pair with pull-out suture over a button on the plantar surface requires bone to tendon heal-ing to afford repair strength once the button is removed, and the button can cause skin complications.13

Distal biceps ruptures are more common and have been thoroughly studied in relation to the biomechanics of differ-

The authors are from the Department of Orthopaedic Surgery, Vanderbilt University, Nashville, Tennessee.

The authors have no relevant financial relationships to disclose.Correspondence should be addressed to: A. Brian Thomson, MD, Elite

Sports Medicine and Orthopaedic Center, 356 24th Ave N, Ste 200, Nash-ville, TN 37203 (andrew.thomson@vanderbilt.edu).

Received: October 10, 2014; Accepted: February 13, 2015.doi: 10.3928/01477447-20160307-05

Abstract: This article presents a novel technique for repair of chronic tibialis anterior tendon ruptures. All chronic tibialis anterior tendon ruptures reviewed were treated with this tech-nique. Patients with chronic tibialis anterior tendon ruptures presenting to the authors’ institution from 2006 to 2012 had preoperative and postoperative Foot and Ankle Ability Mea-sure scores. The average follow-up time was 2.1 years. The average Foot and Ankle Ability Measure score was 66.1% preoperatively and 87.1% postoperatively (P=.002). This technique offers theoretical improved strength and may help avoid the need for tendon graft often required by other tech-niques. [Orthopedics. 2016; 39(2):e386-e390.]

MARCH/APRIL 2016 | Volume 39 • Number 2 e387

n tips & techniques

ent repair techniques. In com-paring repairs using suture anchors, bone tunnels, and the EndoButton (Arthrex, Naples, Florida), the EndoButton has been found to be biomechani-cally superior.15-17 Due to the distal nature of tibialis anterior ruptures, the distal biceps re-pair system offers an excellent solution and has lessened the need for tendon graft. In this article, the authors describe use of the EndoButton.

Materials and MethodsAfter obtaining institutional

review board approval, the electronic medical records of all patients who had a tibialis anterior tendon rupture from 2006 to 2012 were evaluated. For each patient, demographic data and outcome data were de-identified and recorded in a REDCap database.18 The clini-cal outcome used for this study was the Foot and Ankle Ability Measure (FAAM) score, which is a validated outcome measure for foot and ankle injury and disease.19 Seven patients were identified presenting 4 to 25 weeks after the injury.

Patients were contacted and consented for inclusion in the study. A posttreatment FAAM tool was administered. This postoperative outcome was compared with preoperative results previously recorded in the medical record. The activity of daily living ques-tionnaire of the FAAM was analyzed, excluding the sport questionnaire due to average patient age and activity level. Statistical analysis was per-formed with univariate analy-sis with the Mann-Whitney U

test. Stata statistical software, release 11 (StataCorp, College Station, Texas), was used.

Preoperatively, each pa-tient was assessed for equinus contracture, which can be ad-dressed with Strayer or Achil-les lengthening.

Operative TechniqueAn anteromedial incision

was made overlying the tibialis anterior tendon from the me-dial cuneiform to the level of the superior retinaculum. The proximal end of the ruptured tendon was retracted, and in the cases of chronic rupture, significant pseudotendon had usually formed. The distal stump was identified and was insufficient for direct repair.

The tendon insertion site was debrided of the distal ten-don remnant. The proximal tendon stump and pseudoten-don was minimally debrided to healthy tissue that would hold suture, and length was assessed with traction. The medial cuneiform was the in-sertion site.

Fluoroscopy was used to confirm the starting point of the bone tunnel and the trajec-tory to ensure adequate bone stock surrounding the graft/bone tunnel (Figure 1A). Then, a 3.2-mm drill pin was used to create a bicortical tun-nel and was left in place (Fig-ure 1B). A 7-mm reamer was placed over the guide pin and a unicortical tunnel was reamed, ensuring adequate depth of the tunnel and that the far cortex was not reamed. The drill pin and reamer were removed and the bone tunnel was irrigated to remove any debris.

To confirm the tendon would pass through a 7-mm bone tunnel, the proximal tendon stump was sized with a 7-mm sizing block. The ter-minal 2.5 cm of the proximal stump of the tibialis anterior tendon was then whip stitched using No. 2 FiberLoop (Ar-threx) with a straight needle in a locking fashion. The final throw was locked proximally prior to exiting the tendon end (Figure 1C). In most cases, pseudotendon was incorpo-rated into the repair to extend the working length of the ten-don. The suture was begun in healthy tendon, and only pseudotendon that would hold suture was used.

Using a 7-mm reamer is a deviation from the technique for the distal biceps repair kit. The standard technique for the kit overdrills 1 mm. However, because the tarsal bones have a higher proportion of cancel-

lous bone compared with the proximal radius, the authors have found that overdrilling leads to an inadequately con-strained tunnel.

The FiberLoop suture, which had been previously cut to remove the suture needle, was then threaded on to the BicepsButton (Arthrex), with each limb entering the oppo-site hole and exiting through the entry hole of the opposite suture.

The EndoButton was then placed on the insertor (Fig-ure 1D), which was guided through the medial cuneiform bicortically. After passing through the far cortex, the En-doButton was deployed and flipped into position and the tendon was pulled into the bony tunnel (Figures 2A-B). The authors’ goal was to place 15 to 20 mm of tendon into the tunnel with good tendon ten-sion with the ankle at maxi-

Figure 1: Tibialis anterior rupture repair. Intraoperative anteroposterior radio-graph identifying appropriate bony insertion site (A). Medial cuneiform is drilled with a 3.2-mm guide pin (B). Previously whip stitched tendon is prepared and EndoButton (Arthrex, Naples, Florida) is threaded (C). EndoButton is inserted into the bone tunnel (D).

e388 Copyright © SLACK inCorporAted

n tips & techniques

mum dorsiflexion. A Bio- Tenodesis screw (Arthrex) was then loaded on to the driver and one end of the FiberLoop suture was thread-ed through the driver with the screw loaded. Tension was maintained over both ends of the FiberLoop while driving the screw (Figure 2C). After the screw was seated, the Fi-

berLoop suture was tied over the tenodesis screw (Figures 2D-E). Tendon insertion and the final construct are illus-trated in Figure 3.

Postoperative CarePostoperatively, patients

were immobilized and non-weight bearing for 6 weeks. After 6 weeks, weight bearing

as tolerated in a walking boot for 4 weeks and open chain physical therapy were initiat-ed. At 2 months, regular shoes could be worn and physical therapy continued with impact activities. At 6 months, full ac-tivity could be resumed.

resultsThere were 6 female pa-

tients and 1 male patient with a tibialis anterior rupture (Table). All tibialis anterior ruptures were repaired using a distal biceps repair kit with an EndoButton and/or a Bio-Tenodesis screw. Among the patients with rupture, 4 had comorbidities that could be associated with the rupture (Table). One rupture was trau-matic, 2 ruptures were postop-erative complications from a prior surgery, and 2 ruptures failed repair by other tech-niques. The Achilles lengthen-ing procedure using either the Hoke or the Strayer technique was performed in all but 2 cases.

The FAAM was used pre-operatively to evaluate pa-tients’ function. The FAAM was administered postopera-tively for 1 case because of function prior to surgery. The average follow-up time was 2.1 years. The average FAAM score was 66.1% preoperative-ly and 87.1% postoperatively (P=.002). No comparative analysis was performed. Fur-ther details regarding mecha-nism of injury and presenta-tion are provided in the Table.

discussionTibialis anterior rupture, a

rare injury that is commonly

misdiagnosed and presents late, causes significant mor-bidity. This process was first described in 1905 by Brun-ing, and no consensus exists regarding treatment.7,20 Sev-eral techniques have been proposed with reasonable results.4,8,12-14 Techniques for tendon repair for other ten-don injuries have been evalu-ated thoroughly, including strength comparisons; howev-er, each pathologic condition represents a unique treatment dilemma.15-17

Tendon repair and recon-struction options for the tibi-alis anterior tendon include direct repair when possible; however, this is rarely pos-sible for chronic tibialis ante-rior tendon ruptures because of their distal nature. Recon-struction options include di-rect repair of tendon-tendon, tendon-bone with or without auto/allograft tendon, or ten-don substitution with extensor hallucis longus transfer.7

No biomechanical studies have been performed compar-ing repair techniques for the tibialis anterior; however, cor-ollaries can be made to the dis-tal biceps, which has had ex-tensive biomechanical testing. The EndoButton has shown superior strength and a higher load to failure than bone tun-nel, suture anchor, or interfer-ence screw in isolation.15-17

This study showed sig-nificant improvement in the FAAM.19 Limitations of the study included small sample size and lack of a control group. Because tibialis anteri-or tendon rupture is rare, stud-ies have had small numbers

Figure 2: Tibialis anterior tendon repair. The EndoButton (Arthrex, Naples, Florida) is deployed and the distal tendon end is pulled into the bone tunnel (A). EndoButton deployment is confirmed on radiograph with anteroposterior (B)and lateral views with intraoperative fluoroscopy. A Bio-Tenodesis screw (Ar-threx) is placed while holding tension to further tighten and augment repair (C). Final repair (D). Final repair confirmed on intraoperative lateral radiograph (E).

Figure 3: Illustration of tibialis anterior tendon repair. Anterior view showing starting point for bone tunnel on medial cuneiform (A). Anterior view of re-paired tendon (B). Lateral view of the foot with small-diameter bone tunnel through both cortices and larger reamed tunnel ending before far cortex (C). Lateral view of tendon repair (D).

MARCH/APRIL 2016 | Volume 39 • Number 2 e389

n tips & techniques

Table

Results o

f Tibialis A

nterior R

epair

FAA

M A

DL

Questionnaire

Score

Patient A

ge, y/Sex

Weeks to

Diagnosis

Mechanism

of Injury

Presenting Symptom

sC

omorbidities

Surgical TechniqueFollow

-up, yC

omplications

PreopPostop

77.9/FU

nknown

Failed tendon re-pair 5 years prior

(suture anchor repair)

Foot drop and fre-quent tripping

OA

, prior foot surgery

Repair to m

edial cu-neiform

with EndoB

utton (A

rthrex, Naples, Florida)

and Bio-Tenodesis screw

(A

rthrex)Strayer technique

1.9993%

100%

53.0/F4

Chronic instabil-ity and pain

No identifiable

injury

Dull pain for a m

onth and m

ass anterior ankle

DM

Repair to m

edial cu-neiform

with EndoB

utton and B

io-Tenodesis screwStrayer technique

0.6658%

94%

71.3/F5

Chronic rupture

No specific injury

Foot drop and pain along tibialis anterior

tendon

OA

Repair w

ith harvest of ham

string tendons for graft

Bio-Tenodesis screw

(no button)

Hoke technique

4.0541%

71%

53.2/F10

Trip forward

Discom

fort and mass

anterior ankleR

epair to medial cu-

neiform w

ith EndoButton

and Bio-Tenodesis screw

Strayer technique

1.8788%

100%

35.2/F25

Injured dur-ing podiatric

surgery (1st TMT

plantarflexion arthrodesis)

Postoperative pain and hyperesthesias

anterior ankle

Repair to m

edial cu-neiform

with EndoB

utton and B

io-Tenodesis screw

2.7761%

80%

57.4/M4

Burning pain

while riding a busN

o identifiable injury

Burning over anterior ankle and foot slap

DM

Repair to m

edial cu-neiform

with EndoB

utton and B

io-Tenodesis screwStrayer technique

0.8261%

70%

46.4/FIm

medi-

ate/revised after chronic

re-rupture at 26 w

eeks

Broken glass

resulting in trans-verse laceration across dorsum

of foot

Obvious tendon laceration

Decreased sensation dorsum

of foot

Primary suture repair

This failed and was

revised

2.63R

epair failure R

evised to Endo-B

utton and Bio-

Tenodesis screw

with allograft

augmentation

61%95%

Abbreviations: A

DL

, activity of daily living; DM

, diabetes mellitus; F, fem

ale; FAA

M, Foot and A

nkle Ability M

easure; M, m

ale; OA

, osteoarthritis; preop, preoperative; postop, postoperative; T

MT, tarsom

etatarsal.

e390 Copyright © SLACK inCorporAted

n tips & techniques

of patients. The largest study had 19 patients and was not restricted to chronic ruptures.7 Rare injuries motivate sur-geons to use clinical corollar-ies to aid in the development of treatment methods.

conclusionThe authors have presented

a technique for tibialis ante-rior tendon repair using an EndoButton. This has proved to be an effective treatment and is preferred at the authors’ institution. This technique is biomechanically superior in anatomic corollaries. The straightforward method often alleviates the need for tendon graft by using robust pseudo-tendon. This technique would also permit placement of the tendon insertion in the na-vicular if tendon length was inadequate. Further studies validating this technique are warranted.

references 1. Porter DA, Schon LC. Baxter’s

the Foot and Ankle in Sport. 2nd ed. Philadelphia, PA: Mos-by Elsevier; 2008.

2. Jones DC. Tendon disorders of the foot and ankle. J Am Acad Orthop Surg. 1993; 1(2):87-94.

3. DiDomenico LA, Williams K, Petrolla AF. Spontaneous rup-ture of the anterior tibial tendon in a diabetic patient: results of operative treatment. J Foot An-kle Surg. 2008; 47(5):463-467.

4. Kashyap S, Prince R. Spon-taneous rupture of the tibialis anterior tendon: a case report. Clin Orthop Relat Res. 1987; 216:159-161.

5. Kausch T, Rutt J. Subcutaneous rupture of the tibialis anterior tendon: review of the literature and a case report. Arch Orthop Trauma Surg. 1998; 117(4-5):290-293.

6. Patten A, Pun WK. Spontane-ous rupture of the tibialis an-terior tendon: a case report and literature review. Foot Ankle Int. 2000; 21(8):697-700.

7. Sammarco VJ, Sammarco GJ, Henning C, Chaim S. Surgical repair of acute and chronic tibi-alis anterior tendon ruptures. J Bone Joint Surg Am. 2009;

91(2):325-332.

8. Stuart MJ. Traumatic disrup-tion of the anterior tibial tendon while cross-country skiing: a case report. Clin Orthop Relat Res. 1992; 281:193-194.

9. Geppert MJ, Sobel M, Hanna-fin JA. Microvasculature of the tibialis anterior tendon. Foot Ankle. 1993; 14(5):261-264.

10. Petersen W, Stein V, Bobka T. Structure of the human tibialis anterior tendon. J Anat. 2000; 197(pt 4):617-625.

11. Petersen W, Stein V, Tillmann B. Blood supply of the tibialis anterior tendon. Arch Orthop Trauma Surg. 1999; 119(7-8):371-375.

12. Ellington JK, McCormick J, Marion C, et al. Surgical out-come following tibialis anterior tendon repair. Foot Ankle Int. 2010; 31(5):412-417.

13. Gwynne-Jones D, Garneti N, Wyatt M. Closed tibialis an-terior tendon rupture: a case series. Foot Ankle Int. 2009; 30(8):758-762.

14. Meyn MA Jr. Closed rupture of the anterior tibial tendon: a case report and review of the lit-erature. Clin Orthop Relat Res. 1975; 113:154-157.

15. Greenberg JA, Fernandez JJ,

Wang T, Turner C. EndoButton-assisted repair of distal biceps tendon ruptures. J Shoulder El-bow Surg. 2003; 12(5):484-490.

16. King J, Bollier M. Repair of distal biceps tendon ruptures using the EndoButton. J Am Acad Orthop Surg. 2008; 16(8):490-494.

17. Mazzocca AD, Burton KJ, Ro-meo AA, Santangelo S, Adams DA, Arciero RA. Biomechani-cal evaluation of 4 techniques of distal biceps brachii tendon repair. Am J Sports Med. 2007; 35(2):252-258.

18. Harris PA, Taylor R, Thielke R, Payne J, Gonzalez N, Conde JG. Research electronic data capture (REDCap): a meta-data-driven methodology and workflow process for providing translational research informat-ics support. J Biomed Inform. 2009; 42(2):377-381.

19. Martin RL, Irrgang JJ, Burdett RG, Conti SF, Van Swearingen JM. Evidence of validity for the Foot and Ankle Ability Mea-sure (FAAM). Foot Ankle Int. 2005; 26(11):968-983.

20. Otte S, Klinger HM, Lorenz F, Haerer T. Operative treatment in case of a closed rupture of the anterior tibial tendon. Arch Orthop Trauma Surg. 2002; 122(3):188-190.