Anterior Tarsal Tunnel Syndrome/Entrapment of Deep Peroneal Nerve
Compression/entrapment of deep peroneal (anterior tibial) nerve in the fibro-osseous tunnel of the inferior extensor retinaculum, anterior to the ankle (type 2) or over first metatarsocuneiform joint (type 1). Originates from L4, L5 & S1.
Compression could be due to – footwear (especially high heel shoes as foot plantarflexion and toe dorsiflexion will put maximum tension on nerve; tight high top footwear can also constrict nerve); cavus feet have a bony prominence in this area; osteophytes; oedema; post-traumatic fibrosis; plantarflexion and inversion will cause an increased tension in the nerve (eg supinating, cavus foot type); direct trauma.
Burning sensation or paraesthesia radiating onto dorsum of foot toward lateral hallux. May get aching feeling over lateral midfoot. Later can get parathesia and numbness in second interspace. May be worse in bed as foot is in plantarflexed position relieved with movement; two point discrimination test may be reduced; may be able to elicit a positive Tinnel’s sign by palpating anterior tarsal tunnel; nerve conduction studies show reduced latency
Flat shoes with non-constrictive vamp – may take several months. NSAID’s. Orthoses with valgus posts (if indicated); night splints to keep foot dorsiflexed to relieve tension on nerve. Cortisone injections. Surgical decompression.