Symptoms and mechanism
The tibial nerve, vessels and tendons pass beneath a firm retinaculum behind the medial ankle. Compression of the nerve or its plantar and calcaneal branches may cause burning, electric pain, numbness and radiation into the heel, arch or toes.
- Symptoms may worsen with standing or walking and sometimes at night.
- Tapping over the tunnel may reproduce an electric sensation.
- Advanced injury may produce sensory loss and occasionally weakness of intrinsic foot muscles.
Causes and the Baxter nerve
Possible causes include ankle fracture or sprain, scar, varicosities, a ganglion, mass, tendon inflammation or foot deformity. No single cause is found in every case.
Heel pain can also arise from entrapment of the first branch of the lateral plantar nerve—often called the Baxter nerve—and can mimic plantar fasciopathy. “Heel pain” alone is not a sufficient diagnosis.
Diagnosis
Assessment combines the symptom pattern, sensory map and examination of the tibial nerve and each branch. A Tinel sign, provocative tests and foot alignment may support the diagnosis.
EMG and nerve-conduction studies can help, but a normal test does not fully exclude entrapment. Ultrasound or MRI can identify a mass, veins, scar or another compressive process. The differential includes radiculopathy, polyneuropathy, plantar fasciopathy, vascular disease and other pain disorders.
Nonoperative treatment
Care is directed at the cause and may include load modification, footwear or orthotic changes, treatment of local injury or inflammation, physiotherapy, neuropathic-pain medication and a targeted injection in selected cases.
Surgical decompression
Surgery may be considered when symptoms, examination and anatomy localize the compression, when a structural cause is found, or when adequate conservative care has failed. The aim is to release the full zone of pressure rather than a single small point.
The flexor retinaculum is released and decompression may continue into the medial and lateral plantar and calcaneal branches. A mass or substantial scar is addressed when present.
Published outcomes vary widely because causes, diagnostic definitions, symptom duration and techniques differ. A single success percentage should not be applied to every patient.
References
- Vij N, Kaley HN, Robinson CL, et al. Clinical Results Following Conservative Management of Tarsal Tunnel Syndrome Compared With Surgical Treatment. Orthopedic Reviews. 2022;14(3):37539. doi:10.52965/001c.37539
- Ahmad M, Tsang K, Mackenney PJ, Adedapo AO. Tarsal tunnel syndrome: a literature review. Foot and Ankle Surgery. 2012;18(3):149–152. doi:10.1016/j.fas.2011.10.007