What is tarsal tunnel syndrome?
Tarsal tunnel syndrome is a compressive neuropathy of the posterior tibial nerve as it passes through the tarsal tunnel. The tunnel refers to a space behind the medial malleolus and underneath the flexor retinaculum at the ankle.
What causes it?
It can be due to anatomical abnormalities:
- Ganglion, cyst, lipoma, talus ossicle
- Osteophytes from ankle osteoarthritis
- Ankle deformities following trauma
- Severe flat feet
- Tenosynovitis associated with rheumatoid arthritis or diabetes mellitus
It can occur without any obvious reason (Idiopathic):
- However it may be more commonly seen in active adults.
Symptoms & Signs
- Pins & needles, tingling sensation affecting the sole of the foot
- The symptoms can be nocturnal with night waking
- It may also lead to numbness in the foot and burning pain at the ankle
- The symptoms tend to be worse after prolonged standing or walking
- The symptoms are relieved by elevation and rest
- In severe cases, there may be wasting of the medial intrinsic muscles of the foot
- Tinel's sign along the course of the nerve may correspond to the site of compression
The diagnosis remains clinical. Neurophysiology is used to confirm the diagnosis. Xrays of the ankle/foot are requested in patients with deformities or arthritis. MRI may be helpful in delineating any space occupying lesion.
- Activity modification
- Pain killers
- Steroid (cortisone) injection
- In those who fail to respond to nonoperative treatment, surgical release of the flexor retinaculum can be considered.
- In those with a definite space occupying lesion, surgical excision of the lesion is recommended.
What should I expect when undergoing a tarsal tunnel release?
- It is performed as a day-case procedure, under general or regional anaesthesia.
- At the end of the procedure, a bulky dressing is applied over the ankle and foot.
- The dressing is reduced within 5 days and the wound is expected to heal within 2 weeks.
What are the risks?
Tarsal tunnel release is successful in the majority of patients. There are however recognised risks of wound infection, nerve injury, pain syndrome, incomplete recovery and recurrence.