summary Deep Peroneal Nerve Entrapment, also called Anterior Tarsal Tunnel Syndrome, is a rare compression neuropathy affecting the deep peroneal nerve, most commonly at the fibro-osseous tunnel formed by the inferior extensor retinaculum. Diagnosis can be suspected clinically with dorsal foot pain with radiation to the 1st webspace and a positive Tinel's sign over the DPN. Treatment is a trial of nonoperative management with shoe modifications. Surgical anterior tarsal tunnel release is indicated in patients with persistent symptoms who fail nonoperative management. Epidemiology Incidence rare Demographics adults of all ages and genders Risk factors high heel use compressive shoe wear previous fracture Etiology Pathophysiology site of compression anterior leg/ankle/foot from 1 cm proximal to ankle joint proximally to talonavicular joint distally position of compression ankle inversion and plantar flexion (when traumatic) pathoanatomy intrinsic impingement dorsal osteophytes over tibiotalar or talonavicular joints other bony deformity (pes cavus, post-fracture) ganglion cyst tumor tendinitis or hypertrophic muscle belly of EHL, EDL or TA peripheral edema extrinsic impingement tight laces or ski boots high heels (induces plantar flexion) trauma (including recurrent ankle instability) Associated conditions pes cavus fracture navicular nonunion talonavicular arthritis systemic conditions causing peripheral edema Anatomy Anterior Tarsal Tunnel Anatomy borders superficial inferior extensor retinaculum deep capsule of talonavicular joint lateral lateral malleolus medial medial malleolus contents of anterior tarsal tunnel EDL EHL Tibialis anterior peroneus tertius Deep peroneal nerve within tunnel division of nerve between mixed (lateral) and sensory only (medial) occurs dorsalis pedis artery and vein Presentation Symptoms dysesthesia and paresthesias on dorsal foot lateral hallux, medial second toe and first web space are most common locations vague pain on dorsum of foot Physical exam motor weakness or atrophy of EDB sensory decreased two-point discrimination provocative tests Tinel sign over course of DPN with possible radiation to first web space exacerbation with plantar flexion and inversion (puts nerve on stretch) relief of symptoms with injection of lidocaine (DPN nerve block) Imaging Radiographs recommended views lateral view of foot and ankle findings dorsal osteophytes sequelae of prior fracture CT to define bony anatomy of canal MRI best for evaluation of mass lesions Treatment Nonoperative shoe modifications indications first line of treatment techniques NSAIDs PT (if ankle instability contributing) injection well padded tongue on shoe alternative lacing configurations full length rocker-sole steel shank night splint (to prevent natural tendency for ankle to assume plantar flexion) diuretic if chronic peripheral edema is implicated Operative surgical release of DPN by releasing inferior extensor retinaculum and osteophyte / ganglion resection indications failure of nonoperative treatment symptoms of RSD are a contraindication to release outcomes 80% satisfactory Technique Surgical release of DPN by releasing inferior extensor retinaculum and osteophyte / ganglion resection approach S-shaped incision over dorsum of foot from ankle joint proximally to base of first and second metatarsals distally decompression start distal, identify nerve, and release both branches proximally (nerve lies lateral to EHL) resect osteophytes, debulk hypertrophic muscle bellies postoperative no compressive shoe wear Complications Persistent symptoms following decompression warn patient that recovery is prolonged Prognosis Recalcitrant cases may require surgery, which may yield 80% good to excellent results