Tarsal tunnel syndrome involves heel and foot pain due to compression of the posterior tibial nerve as it courses inferior to the medial malleolus. Causes include running, restrictive footwear, edema of pregnancy, posttraumatic fibrosis, ganglion cysts, osteophytes, and tumors. Symptoms include numbness or burning of the sole and may be limited to the heel. Pain is worse at night and after running or standing, in contrast to plantar fasciitis which is worse upon morning standing. Typically, pain is located at the medial malleolus, the heel, the sole, and the distal calf.
The differential diagnosis includes plantar fasciitis and Achilles tendonitis. Percussion inferior to the medial malleolus yields pain radiating to the medial or lateral plantar surface (Tinel sign), and eversion and dorsiflexion worsen symptoms. Treatment includes NSAIDs, rest, and possible orthopedic referral.
Deep Peroneal Nerve Entrapment
Entrapment of the deep peroneal nerve occurs most frequently where it courses beneath the extensor retinaculum at the anterior aspect of the ankle. Recurrent ankle sprains, soft tissue masses, and restrictive footwear represent the most common causes. Symptoms include dorsal and medial foot pain as well as sensory hypoesthesia at the first web space. Prolonged entrapment may cause loss of the ability to hyperextend the toes.
Pain and tenderness can be elicited by plantar flexion during inversion of the foot. Treatment includes NSAIDs, rest, and possible orthopedic referral.