Nerve pain after Achilles surgery: the sural nerve

An Achilles repair is meant to get you walking and running again. So it can be unsettling to wake up to a strip of numbness, burning or “zinging” along the outside of your foot. This is a known possibility after surgery around the Achilles tendon, and there are things worth knowing about why it happens and what can be done.

Why the sural nerve is at risk

The sural nerve is a sensory nerve that runs behind the outer ankle bone and along the outer border of the foot.^[2] Sural nerve injury is a reported risk during percutaneous repair of the Achilles tendon.^[1] Scar tissue after ankle fractures or Achilles surgery can also irritate it.^[2] For the anatomy and other causes, see numbness on the outside of the foot: the sural nerve.

How often does it happen?

The honest answer is that it depends on the technique and the study:

• In a systematic review of 253 acute Achilles repairs with a mini-open suture system, 1.2% (3 repairs) had a sural nerve injury.^[3]
• In a comparison of percutaneous repairs at two hospitals, sural nerve-related complications occurred in 18% overall, and all of them were in the group where the nerve was not exposed during the repair. The authors concluded that injuries can be minimized by placing the incisions so that the nerve is exposed and avoided.^[1]
• In a meta-analysis of eight randomized trials (358 patients), minimally invasive repair had fewer overall complications and wound infections than open repair, with no differences in sural nerve injury, reruptures or return to activity. The authors noted that the quality of evidence was low.^[4]

Sural nerve injuries also follow other procedures near the distal leg, ankle and lateral foot, not only Achilles repair.^[6]

What it feels like

Expect some of these along the outer edge of the foot, sometimes reaching the little toe: numbness, tingling, burning, or a tender spot at the scar that sends a zing into the foot when it is tapped. In a review of people with sural nerve injury after surgery, most had pain, numbness and tingling, with tenderness and loss of sensation along the nerve’s territory.^[6]

Some numbness near an incision is common and often improves gradually over months. Symptoms that deserve an evaluation include burning or shooting pain, pain that is getting worse instead of settling, sensitivity that keeps you out of shoes, or numbness that is spreading.

What can be done

• Give it time and protect the area. Many nerve injuries improve gradually.
• Take pressure off with padding or different shoes.
• Desensitization, often with a physical or occupational therapist, to calm an over-sensitive area.
• Medicines for nerve pain, managed with your primary care physician or pain specialist.
• Surgery for a painful neuroma, when pain persists despite well-tried non-surgical care and the injured nerve has been clearly identified. Approaches include removing the neuroma and relocating the nerve end, freeing a nerve from scar tissue, and reconstructing the nerve. Newer techniques aim to give the regrowing nerve a target.^[5] A pooled analysis of 54 studies found a meaningful reduction in pain in about 77% of patients, though study quality varied.^[7]

Be realistic about outcomes. In a small review of nine people with surgical sural nerve injury, four had further surgery on the nerve, and none of them had complete resolution of symptoms.^[6]

Ask early

In that same review, the average time between the operation and imaging of the nerve was about 80 weeks.^[6] If burning, electric or numb symptoms follow your Achilles surgery and aren’t settling, tell your surgeon and consider an evaluation sooner rather than later. Bring your operative report. See nerve pain after surgery or injury, painful neuroma and nerve pain after ankle surgery.

When to see a specialist

Consider an evaluation if burning, electric or shooting pain after an injury or operation lasts more than a few weeks, is getting worse, or keeps you from wearing shoes or sleeping.