Tarsal tunnel release is an operation to decompress the posterior tibial nerve as it passes through the tarsal tunnel behind the inner ankle bone. It is the foot and ankle equivalent of carpal tunnel release in the wrist.
An incision is made behind and below the medial malleolus (inner ankle bone). The flexor retinaculum (the roof of the tarsal tunnel) is divided. The posterior tibial nerve and its branches (medial plantar, lateral plantar, and calcaneal nerves) are decompressed. Any space-occupying lesion (ganglion, varicose vein, accessory muscle) is removed. The operation takes 45–75 minutes.
Surgery is recommended for confirmed tarsal tunnel syndrome causing burning, tingling, or numbness in the sole of the foot that has not responded to orthotics, injection, and activity modification. Results are best when a specific compressive lesion (ganglion, varicose vein) is identified.
Orthotics (to correct hindfoot alignment reducing nerve tension), activity modification, corticosteroid injection into the tarsal tunnel, neuropathic pain medication, and physiotherapy.
Nerve conduction studies to confirm the diagnosis. MRI or ultrasound to identify space-occupying lesions. Clinical correlation is essential — tarsal tunnel syndrome is often overdiagnosed.
Results are less predictable than carpal tunnel release. Approximately 65–80% of patients with a confirmed diagnosis and identifiable compressive lesion achieve good outcomes. Idiopathic (no identifiable cause) tarsal tunnel syndrome has less reliable results.
Results are less predictable than carpal tunnel release.
The medial ankle skin can be slow to heal.
Over the medial ankle.
Branches of the posterior tibial nerve may be damaged during decompression.
Symptoms may recur from scar formation around the nerve.
Chronic pain syndrome.
Wound infection.
General, spinal, or ankle block anaesthesia.
Walking boot for two to four weeks. Weight-bearing as tolerated. Gentle ankle exercises. Normal footwear at four to six weeks. Full nerve recovery takes weeks to months.
Review at two weeks and six weeks.
The tarsal tunnel contains multiple nerve branches with variable anatomy, the diagnosis is less reliably confirmed with nerve conduction studies, and there are more potential causes of sole-of-foot symptoms. Patient selection is critical.
Classic symptoms include burning, tingling, or shooting pain in the sole of the foot, often worse at night or with prolonged standing. A positive Tinel's sign (tapping behind the ankle reproducing symptoms) and supportive nerve conduction studies help confirm the diagnosis.