Tarsal tunnel release surgery: candidacy, results and recovery

What tarsal tunnel release is

The tarsal tunnel is a narrow passage behind and below the inner ankle bone. The tibial nerve runs through it, covered by a band of tissue called the flexor retinaculum. In tarsal tunnel release, the surgeon opens that band, frees the nerve and its branches, and removes anything pressing on it, such as a cyst, a bone spur or scar tissue.^[1] It is one form of nerve decompression surgery. To learn about the condition itself, see tarsal tunnel syndrome.

Who may be a candidate

Surgery is discussed when:

• symptoms persist and interfere with daily life despite a well-tried course of non-surgical care, usually several months of footwear changes, orthotics, activity changes, therapy and medication
• the diagnosis is well supported by your history, examination and, when helpful, imaging and nerve studies
• a specific structure, such as a cyst, is clearly compressing the nerve, which can make earlier surgery reasonable
• the likely benefit outweighs the risks for you, taking into account factors such as blood-sugar control, smoking and circulation

Non-surgical care is a real treatment, not just a step before surgery. In a study that followed 76 feet with tarsal tunnel syndrome for at least five years, 65% had a satisfactory result with non-surgical treatment alone. When nerve release was offered to those whose symptoms hadn’t improved after six months (16 feet), the overall rate of satisfactory results rose to 78%. The authors concluded that non-surgical care should be first-line, even when imaging shows the nerve touching a structure, and that release appeared helpful after non-surgical treatment had failed.^[3]

What studies show about results

The evidence is mostly from single-center studies rather than randomized trials, so it can tell us what tends to happen but not compare treatments directly.

• Pain and function. In a study of 39 people, patient-reported scores improved significantly after release. About 62% reached a clinically meaningful improvement in pain interference, and 35% did so for physical function, so many still had some pain and limitation.^[4]
• Which part of the foot improves. In another study of people whose symptoms persisted despite non-surgical care, pain improved significantly in the heel and inner sole, but not in the outer sole.^[6]
• Nerve tests. In a study of 53 people, those with abnormal pre-operative nerve studies and those with normal studies both improved, with no significant difference in recovery.^[5]

What may affect the result

• How long symptoms have lasted. A longer time before surgery was linked to more pain afterward.^[5]
• Diabetes, which was also linked to more residual pain.^[5]
• Foot alignment. In the five-year study, results tended to be better when there was no alignment problem, such as a heel tilted inward (hindfoot varus).^[3]
• A clear cause. Removing a cyst or other lesion tends to give more predictable results than release when no cause is found.^[7,1] One study, however, found no link between a space-occupying lesion and the outcome.^[4]

What the operation involves

The operation is usually done through an incision along the inner ankle, at a hospital or surgery center. The band over the tunnel is divided, the nerve and its branches are followed and released, and any compressing structure is removed. Most people go home the same day. A padded dressing, and sometimes a splint or boot, is applied afterward. For a fuller description, see nerve decompression surgery.

Recovery

• First weeks: keep the foot elevated, keep the dressing dry, and follow the weight-bearing plan you’re given. Stitches are usually removed after about two weeks.
• Return to shoes and activity: gradual, over several weeks, guided by wound healing and comfort. Physical therapy may help with swelling and scar mobility.
• Nerve symptoms: improve gradually. Pain often eases before numbness does, and recovery can continue for many months. Some symptoms may remain.

Risks

All surgery carries risk. Risks discussed before tarsal tunnel release include infection, wound-healing problems (skin on the inner ankle can be slow to heal), a thickened or sensitive scar, bleeding or blood clots, injury to a nerve or blood vessel, and persistent or recurrent symptoms. Complex regional pain syndrome is a rare risk.

If symptoms persist

If symptoms return or never improve, the first step is a fresh evaluation to find out why. Common reasons include an incomplete release of the branches below the main tunnel, scar tissue, or a different cause of the pain. In series of people who had a second operation, most reported a good or excellent result, though results were less predictable in those who also had lower-back disc disease or neuropathy.^[8,9] See revision nerve surgery.

Questions to ask before deciding

• How sure are we that the tibial nerve is the source of my symptoms?
• What non-surgical treatment have I tried, and for how long?
• What is a realistic result for me, given how long I’ve had symptoms and my other health conditions?
• What will recovery mean for my work, driving and exercise?
• What happens if I wait, or choose not to have surgery?

When to seek care

After surgery, contact the office or seek urgent care for fever, spreading redness, wound drainage or opening, calf pain or swelling, or rapidly worsening pain.