INTRODUCTION

Foot drop is a motor disorder characterized by the loss of active dorsiflexion of the ankle, most commonly resulting from injury to the common peroneal nerve and, less frequently, to the posterior tibial nerve. This dysfunction significantly compromises gait biomechanics, leading to instability, recurrent falls, and functional impairment [1,2]. High-energy trauma, such as motorcycle accidents, is a prevalent cause of severe peripheral nerve injury, in which spontaneous regeneration is limited and often insufficient to restore function [3,4].

In this context, tendon transfer techniques constitute a key reconstructive strategy, enabling the restoration of essential motor movements by redirecting functional tendons toward paretic muscles. We present the case of a young patient with foot drop secondary to traumatic injury of the posterior tibial nerve, successfully treated with tendon transfer, highlighting the surgical approach and postoperative outcome.

CASE PRESENTATION

We present the clinical case of a 17-year-old male patient, with no relevant medical history, who sustained a high-speed motorcycle accident with direct impact on the right lower limb. The patient was evaluated in the general surgery department of the hospital, where posterior tibial nerve injury was confirmed through clinical examination and electroneuromyography.

The patient initially underwent a detailed physical examination, with the following findings documented:

         •      Inability to perform active dorsiflexion of the ankle, consistent with foot drop.

         •      Steppage gait.

         •      Partial anesthesia on the dorsum of the foot.

         •      Complete motor deficit of the dorsiflexor and evertor muscles, with preserved plantar flexion.

An electroneuromyography study revealed a severe axonotmesis of the posterior tibial nerve, confirming the absence of spontaneous regeneration within the first three months after trauma.

Due to the lack of functional recovery, a surgical intervention was planned, consisting of a tendon transfer of the posterior tibial muscle. The procedure was performed in two phases:

         1.     First phase: A fascicle of the posterior tibial tendon was separated and anchored to the anterior tibial tendon to restore active dorsiflexion of the ankle.

         2.     Second phase: A second fascicle of the posterior tibial tendon was anchored to the common extensor tendon of the toes to assist in foot mobility and maintain stability.

The surgery was performed under general anesthesia using a subcutaneous tunnel technique to minimize additional complications. A guiding and fixation system was employed during the procedure to ensure proper alignment of the transferred tendons.

The postoperative period was uneventful. An immobilization protocol was implemented with a splint in a neutral position for four weeks to protect the transferred tendon structures and allow for proper healing. Subsequently, a targeted rehabilitation program was initiated, including progressive ankle mobility and strengthening exercises.

The patient was followed clinically for a six-month period. Active dorsiflexion of the ankle, range of motion, gait stability, and overall functionality were assessed. At six months, the patient achieved 20 degrees of dorsiflexion, independent ambulation, and full return to daily activities without the need for orthotic support.

DISCUSSION

Loss of ankle dorsiflexion secondary to traumatic peripheral nerve injuries—such as posterior tibial nerve injury in the present case—represents a significant clinical challenge, particularly in young and active patients. This type of neuropathy, often associated with high-energy trauma such as motorcycle accidents, severely compromises gait biomechanics, increasing the risk of falls, energy expenditure during ambulation, and overall deterioration in quality of life (1,2). Although common peroneal nerve injuries are more frequently implicated in the etiology of foot drop, posterior tibial nerve injuries, as in this case, can produce equally disabling functional deficits due to the loss of active dorsiflexion and foot eversion (3).

Spontaneous regeneration in severe axonotmetic injuries, such as the one documented here, is limited and often insufficient to restore motor function (4). In this context, tendon transfer techniques have emerged as a reconstructive strategy of choice, allowing the restoration of essential movements by redirecting functional tendons to paretic muscles (5). Transfer of the posterior tibial tendon, as performed in this patient, leverages an anatomically favorable force vector, with a muscle that retains its strength and functionality, thus facilitating recovery of active dorsiflexion without significantly compromising plantar biomechanics (6,7).

Several studies have reported functional success rates exceeding 80% with tendon transfer in the management of foot drop, showing optimal results in terms of range of motion, gait stability, and patient satisfaction (6,8). Particularly, intervention during the subacute phase, as in this case (within the first few post-traumatic months), is associated with better outcomes due to reduced muscle atrophy and preserved tendon viability (9). In our patient, posterior tibial tendon transfer to the extensor apparatus of the foot allowed the achievement of 20 degrees of active dorsiflexion at six months—a result consistent with the best outcomes reported in the literature (5,10).

A critical factor in the success of this technique is careful patient selection, which must include a thorough evaluation of muscle and nerve viability through electrophysiological studies such as electroneuromyography, and a detailed analysis of the residual function of donor muscles (11). In this case, preserved plantar flexion allowed the posterior tibial muscle to be used as a donor without compromising foot stability—a decisive factor for the functional result. Moreover, meticulous surgical technique, including the use of subcutaneous tunnels and precise fixation systems, minimized the risk of complications such as tendinous anastomosis dehiscence or loss of tension (12).

Postoperative rehabilitation also plays a crucial role. Structured protocols combining initial immobilization with progressive strengthening and mobility exercises, as applied in this case, are essential to optimize the functional integration of transferred tendons (13). Recent studies have emphasized the importance of initiating early but controlled active rehabilitation to prevent joint stiffness and promote neuromuscular adaptation (14).

This case also underscores the need for timely diagnosis. Electroneuromyography performed within the first three post-traumatic months was key to confirming the severity of the injury and ruling out the possibility of spontaneous recovery, guiding the decision toward early surgical intervention (15). Delays in treatment can lead to secondary complications such as joint contractures or severe muscle atrophy, which limit reconstructive options and compromise functional outcomes (16).

Despite encouraging results, limitations of this report include short-term follow-up (six months) and presentation of a single case, which restrict the generalization of findings. Future studies with larger cohorts and long-term follow-up are necessary to assess the durability of functional outcomes and the incidence of late complications, such as secondary donor muscle weakness or alterations in foot biomechanics (17). Furthermore, comparison between single and double transfer techniques, as performed in this case, could provide additional insights into the optimization of reconstructive strategies (4).

This case reinforces the evidence supporting the efficacy of tendon transfer in the management of traumatic posterior tibial nerve injuries, highlighting the importance of a multidisciplinary approach integrating early diagnosis, precise surgical technique, and structured rehabilitation to maximize functional recovery in patients with foot drop.

CONCLUSION

Posterior tibial tendon transfer is an effective surgical technique for restoring active ankle dorsiflexion in patients with foot drop secondary to traumatic posterior tibial nerve injuries. The outcomes achieved in the present case—with 20 degrees of dorsiflexion at six-month follow-up—demonstrate the effectiveness of this intervention in improving function and patient quality of life. Early surgical decision-making, together with appropriate postoperative rehabilitation, are key factors for optimizing results. This case underscores the importance of timely diagnosis and appropriate surgical intervention in maximizing motor function in young patients with foot drop.

1.  Stewart JD. Foot drop: where, why and what to do? Pract Neurol. 2008;8(3):158-169.

2.  Al-Qattan MM. Tendon transfer for foot drop. J Hand Surg Eur Vol. 2010;35(1):28-33.

3.  Chang J, Jones NF. Tendon Transfers for the Lower Extremity. In: Plastic Surgery. 4th ed. Elsevier; 2018.

4.  Mathieu L, Achour S, Oberlin C, et al. Single versus double tendon transfer for foot drop due to post-traumatic common fibular nerve palsy. Eur J Trauma Emerg Surg. 2022;48(4):1239-1245.

5.  Eisenstein N, Fischer B, Nayagam S. Tibialis posterior tendon transfer for the management of foot drop. Strategies Trauma Limb Reconstr. 2023;18(1):56-62.

6.  Stevoska S, Pisecky L, Stadler C, et al. Tendon transfer in foot drop: a systematic review. Arch Orthop Trauma Surg. 2023;143(2):773-784.

7.  Saaiq M. Presentation and management outcome of foot drop with tibialis posterior tendon transfer. World J Orthop. 2024;15(11):1047-1055.

8.  Vigasio A, Marcoccio I, Patelli A, et al. New tendon transfer for correction of foot drop in common peroneal nerve palsy. Clin Orthop Relat Res. 2008;466(6):1454-1466.

9.  Cho BK, Park JK, Choi SM, et al. The effect of tibialis posterior tendon transfer on foot drop caused by peroneal nerve palsy. Foot Ankle Int. 2019;40(3):321-327.

10.  Yeap JS, Singh D, Birch R. Tibialis posterior tendon transfer for foot drop: clinical outcomes and patient satisfaction. J Foot Ankle Surg. 2001;40(5):312-317.

11.  Giuffre JL, Bishop AT, Spinner RJ, et al. Surgical management of peripheral nerve injuries: a review. J Neurosurg. 2015;123(4):1037-1048.

12.  Hove LM, Nilsen PT. Tendon transfers for foot drop: surgical techniques and outcomes. Foot Ankle Clin. 2011;16(3):455-467.

13.  Myerson MS, McGarvey WC. Tendon transfers for foot drop: indications and techniques. Orthop Clin North Am. 1999;30(3):497-514.

14.  Rath S, Schreuders TA, Stam HJ, et al. Early active motion versus immobilization after tendon transfer for foot drop. J Foot Ankle Surg. 2010;49(4):343-348.

15.  Robinson LR. Traumatic injury to peripheral nerves. Muscle Nerve. 2000;23(6):863-873.

16.  Seddon HJ. Peripheral nerve injuries. J Bone Joint Surg Br. 1963;45(3):447-461.

17.  Morrey BF, Dunn JM. Long-term outcomes of tendon transfers for foot drop. J Bone Joint Surg Am. 2012;94(15):e103.