Footdrop caused by functional loss of anterior compartment musculature from peroneal nerve palsy is one of the most common motor neuropathies that occur in the lower extremity. This video discusses the case presentation of a patient with drop footdrop caused by anatomic loss of the anterior musculature compartment after severe infection. In contrast to many patients with peroneal nerve palsy, the peroneal tendons in this patient were not affected. Therefore, peroneus longus tendon transfer, which is a less commonly used surgical technique for restoring dorsiflexion, was a surgical treatment option. This technique was first used in patients with footdrop caused by leprosy (Hansen disease) because deep peroneal nerve dysfunction does not always occur in these patients. Use of the peroneus longus, preserves the posterior tibialis and the peroneus brevis, which are the primary invertor and evertor of the foot, respectively. This more closely maintains anatomic function of the foot and may prevent the development of pes planus.

This video demonstrates peroneus longus tendon transfer and free gracilis grafting to aid in dorsiflexion in a patient with postinfectious loss of anterior compartment musculature. The video provides an overview of the causes of footdrop followed by a discussion of the treatment options for patients with and without peroneal tendon function. The video discusses the case presentation of a 17-year-old boy with near-complete loss of his anterior compartment musculature. The patient underwent extensive irrigation and débridement of his lower leg for management of an advanced infection and presented with footdrop and functional peroneal tendons and posterior tibialis tendons. Peroneal longus tendon transfer to the remnant distal dorsiflexor tendons and concurrent free gracilis transfer was indicated to restore dorsiflexor function. At 4 months postoperatively, the patient was continuing intensive physical therapy; however, grade 2 to grade 3 toe and ankle dorsiflexion was present, and his steppage gait had improved. Peroneus longus tendon transfer can be used to restore dorsiflexion in patients who have footdrop and functional peroneal tendons. This technique preserves the posterior tibialis and peroneus brevis, allowing for continued functional opposition by the primary invertor and evertor of the foot. Therefore, the technique not only restores dorsiflexion but also more closely maintains anatomic function of the foot and helps prevent pes planus, which may occur if posterior tibialis tendon transfer is performed in patients with a functional peroneus brevis. In addition, if peroneus longus tendon transfer is unsuccessful, revision to posterior tibialis tendon transfer is an option.