Tibialis anterior tendinopathy (TAT) is a painful, debilitating injury commonly caused by inflammation of the tibialis anterior (TA) tendon or degeneration of its tendon sheath.1 Tibialis anterior rupture is classically caused by an acute eccentric contraction in the setting of preexisting tendinosis, and patients often recall immediate pain, swelling, loss of function in ankle dorsiflexion causing chronic equinus, and the presence of foot drop or “steppage gait.”1 Others are unaware because of the recruitment of the long toe extensors.1 If a diagnosis of TA tendon rupture is uncertain after history and physical exam, imaging studies such as an magnetic resonance imaging or ultrasound will help confirm. Nonoperative treatment options include ankle foot orthoses and tendo-achilles stretching. However, most patients benefit from surgery to restore active dorsiflexion and physical function. Options for reconstructing the TA tendon include primary repair, tendon transfers, or reconstruction with graft.1 Primary repair can be done with a primary end-to-end repair or a sliding anterior tibial tendon graft (utilized for deficits 2 to 4 cm in length).2,3 Tendon transfers are used when the deficit is larger than 4 cm.1 Techniques utilized include transfer of the extensor hallucis longus (EHL), extensor digitorum longus (EDL), posterior tibial, peroneus brevis, or allograft tendon. EHL tendon transfer is the most common transfer option reported in literature. In cases where tendon transfer is not available or insufficient, a free tendon autograft or allograft can be used. Techniques reported include harvesting the peroneus tertius, semitendinosus, gracilis, plantaris, or Achilles tendon.3,4 TA tendon rupture is an uncommon pathology, and the literature does not provide conclusive evidence for the best operative intervention. Huh and colleagues utilized allograft for an end-to-end interposition of the ruptured TA tendon with distal fixation in the medial cuneiform through a bone tunnel. Our study utilized plantaris autograft as an overlay on an end-to-end TA anastomosis without any additional fixation. Drawbacks associated with the plantaris tendon autograft have historically centered around the need for an extra incision and access to the superficial posterior compartment of the lower leg. The author’s proposed technique involves the convenient utilization of a plantaris tendon autograft for the anterior tibial tendon repair after the recommended gastrocnemius recession. Gastrocnemius recession is recommended to alleviate the associated chronic equinus positioning of the ankle associated with TAT or rupture and allows for easy access to the plantaris tendon. This procedure is hypothesized to have lower complication rates with equal patient outcomes.

SURGICAL TECHNIQUE

Preoperative magnetic resonance imaging is obtained to determine the extent of the TA tendinosis. The presence or absence of the plantaris tendon can be determined. If the plantaris tendon is absent, then 1 or more strands of the EDL can be harvested through the same anterior incision and used as a free graft. For surgery, the patient is positioned in a supine position with a surgical bump under the ipsilateral hip and the extremity elevated on bone foam. A nonsterile tourniquet is used. The leg is prepared and draped in the sterile manner. A gastrocnemius recession is performed first with a small incision on the posteromedial calf, this procedure alleviates any concern of over tensioning the TA repair. Through this incision, the plantaris tendon is identified and harvested with the assistance of a 4-mm diameter tendon stripper. The harvested tendon is kept in saline before being used for the reconstruction. The TA and EDL tendons are palpated and marked ~5 cm proximal to 5 cm distal to the ankle joint. An ~10 cm long incision is made over the mark indicating the TA tendon. Dissection is performed down to fascia overlying the TA tendon sheath. The tendon sheath is incised longitudinally. The tendon is then completely transected through the middle of the tendinotic segment. After transection, a scalpel is used to thoroughly debride each segment in a conical fashion to remove all the necrotic tissue and tendinosis (Fig. 1). The tendon can be intussuscepted to allow for further debridement along the length of the tendon if necessary. The distal portion of the tendon is then sutured with a running locked 2-0 FiberWire. The proximal portion of the tendon is sutured with a running locking stitch with 2-0 FiberWire. The FiberWire stitch from the proximal end is then used to approximate the 2 segments back together. The proximal and distal ends of the tendon should be overlapped until nondiseased tissue of the proximal tendon is in contact with nondiseased distal tendon (Figs. 2A, B). To maximize the stability of the fixation, an autograft from the plantaris tendon is prepared. The autograft plantaris tendon is then sutured to the TA tendon fixation in 2 layers with 2-0 FiberWire (Fig. 2C). The plantaris tendon is used as an overlay on the end-to-end anastomosis of the TA tendon to increase strength. If the tendon ends are unable to be approximated, then the plantaris tendon will serve as a bridging apparatus. All tendon repair is done with 5 to 7 degrees of dorsiflexion given the concomitant gastrocnemius recession. The surgical site is then irrigated with normal saline. The tendon sheath and fascia surrounding the repaired tendon and graft is subsequently approximated with 2-0 Monocryl. The skin incision is closed with 4-0 Nylon horizontal mattress sutures. A sterile dressing is then applied to the wound (see video, Supplemental Digital Content 1, https://links.lww.com/TIO/A49 demonstrating the technique in its entirety). The patient is splinted postoperatively in the same 5 to 7 degrees of dorsiflexion. Follow-up is scheduled for 2, 6, 12, 24, and 52 weeks. Patient is non–weight-bearing in a splint, followed by a cast for 4 weeks. At 4 weeks, patient is transitioned to a tall boot and is allowed to progress from partial weight-bearing to full weight-bearing as tolerated. Patient is transitioned into an ankle foot orthoses brace with appropriate shoes at 6 weeks. Physical therapy is started at 4 to 6 weeks from the day of surgery. Patients are typically middle aged and return to recreational sport is achievable at 6 months postoperatively.

FIGURE 1:

Tibialis anterior tendon being debrided with a scalpel to remove pathologic tissue.

FIGURE 2:

A, Tibialis anterior is approximated with nonpathologic tissue of the proximal and distal ends. B, The running locked fiberwire stitch construct maintains the approximation of the tibialis anterior tendon. C, The plantaris graft is sutured into the tibialis anterior tendon.

Strengths and Weaknesses

The addition of the plantaris autograft is a strength of this procedure, as it allows to increase the strength of the reconstruction without significant additional morbidity. The running locking sutures provide a rigid approximation for the proximal and distal ends of the diseased and transected tendon. By debriding the tendon of the devitalized pathologic tissue, the fixation will confer better biological response in the tendon and ultimately increase long-term outcomes of the procedure and decrease the risk of rerupture. This procedure is minimally invasive because of the accessibility of the plantaris tendon in the gastrocnemius recession incision and avoids any significant addition operative time. Hamstring grafts and EHL tendon transfer techniques increase the morbidity of the procedure through additional incision sites and increase the potential for iatrogenic complications. Utilization of an autograft plantaris tendon confers better biological host acceptance over an allograft construct and also provides a more cost effective option for the patient.5 This study is not without its own limitations, first there is limited long-term patient data because of the rare nature of the pathology. This could be benefited from longitudinal case series reviews. Second, it can be argued that access to the posterior leg compartment for the plantaris tendon confers excessive morbidity and operating time to the patient. However, in the setting of chronic anterior tibialis tendinopathy or anterior tibialis tendon rupture, gastrocnemius recession is an additive procedure to alleviate the equinus contracture associated with the pathology and therefore does not add any unnecessary time or resources in the harvest of the plantaris tendon.

Expected Outcomes

The expected outcome of this procedure is to provide a stable, long-lasting, and efficient method for reconstructing chronic anterior tibial tendinopathy and anterior tibial tendon rupture. TAT rupture should be treated with gastrocnemius recession to alleviate equinus contracture caused by gastrocnemius shortening. Allowing the ankle to heal in neutral dorsiflexion allows patients to restore preinjury foot position. A previous patient undergoing the proposed procedure with preoperative TA rupture, gastrocnemius contracture, and 0/5 dorsiflexion regained 5/5 dorsiflexion strength and neutral alignment of the foot.1

Complications

Surgical complications include damage to surrounding structures such as the deep peroneal nerve and anterior tibial artery and vein, which lie lateral to the TA muscle proximally and lateral to the extensor hallucis longus at the level of incision distal to the ankle joint. Appropriate visualization of the structures and sound understanding of operative anatomy can help mitigate these risks. The superior and inferior extensor retinaculum help maintain stability of the TA muscle and long toe extensors but may need to be taken down to complete the technique, which can lead to adhesion between the retinaculum and underlying tendons. The retinaculum should be repaired to prevent bowstringing of the tendons. The salvage procedure for an insufficient graft is the utilization of an EHL tendon transfer to restore the function of the ruptured TA tendon.

CONCLUSIONS

In conclusion, surgical debridement of pathologic TA tendon rupture with repair and plantaris tendon autograft is a promising surgical technique for patients with symptomatic TA rupture that does not respond to nonoperative treatment. It is convenient for the surgeon, especially in the setting of concomitant gastrocnemius recession.

REFERENCES 1. Cignetti C, Peng J, McGee A, et al. Tibialis anterior tendinosis: clinical characterization and surgical treatment. Foot (Edinb). 2019;39:79–84. 2. Anagnostakos K, Bachelier F, Fürst OA, et al. Rupture of the anterior tibial tendon: three clinical cases, anatomical study, and literature review. Foot Ankle Int. 2006;27:330–339. 3. Huh J, Boyette DM, Parekh SG, et al. Allograft reconstruction of chronic tibialis anterior tendon ruptures. Foot Ankle Int. 2015;36:1180–1189. 4. Harkin E, Pinzur M, Schiff A. Treatment of acute and chronic tibialis anterior tendon rupture and tendinopathy. Foot Ankle Clin. 2017;22:819–831. 5. Robertson A, Nutton RW, Keating JF. Current trends in the use of tendon allografts in orthopaedic surgery. J Bone Joint Surg Br. 2006;88:988–992.