Painful neuroma of the foot, ankle and leg

What a painful neuroma is and what causes it

When a nerve is cut or badly injured, the fibres on the side nearest the spine start to grow. If those sprouts cannot find the far end of the nerve, they form a tangled mass called a traumatic neuroma.^[2] This is not a tumour. It is a scar-like knot of nerve tissue, and it can be extremely sensitive.

The neuroma may be the result of an injury, or an operation that cut, stretched or crushed a small skin nerve. Traumatic neuromas can cause neuropathic pain, trouble with function, and emotional distress that affects quality of life.^[3] A neuroma can be more disabling than the numbness that first followed the injury.^[1]

This page covers neuromas from injury or surgery. Morton’s neuroma, which is a nerve thickening between the toes, is a different problem and is covered in Morton’s neuroma. Neuromas at the end of an amputated limb are covered in residual limb neuroma pain.

Where neuromas occur in the lower limb

In a study of people treated for 48 symptomatic lower-limb neuromas, about 38% were around the foot and ankle, 29% in the leg, 27% around the knee, and 6% in the thigh.^[3] Nerves involved in other reports include the superficial and deep peroneal nerves, the sural nerve, the medial plantar nerve and nerves between the metatarsal bones.^[4] Around the knee, the infrapatellar branch of the saphenous nerve is a well-known source; see nerve pain after knee replacement.

Symptoms

• Burning, electric or shooting pain, sometimes triggered by a light touch or a shoe
• A small, very tender spot, often over a scar or the path of a known nerve
• Numbness or altered feeling beyond the spot
• Pain that gets worse with pressure, walking or certain shoes

How it is evaluated

Evaluation starts with your story: when the pain began, what injury or surgery came before it, and what makes it worse. Your clinician will examine the area, gently tap along the nerve to find a tender spot (a Tinel sign), and check sensation and strength. Imaging such as ultrasound or MRI can show a neuroma, and a small amount of local anaesthetic placed around the nerve can help confirm the source if the pain temporarily disappears. Nerve testing and diagnostic blocks are arranged with another specialist. Read more in nerve testing for foot pain.

Treatment without surgery

Non-surgical care is usually the first step, and it often includes:

• padding or shoe changes to take pressure off the spot
• desensitization exercises, where the skin is gradually re-accustomed to touch
• medicines used for nerve pain, which help some people; their average effect is modest^[5]
• physical therapy and activity changes

Keep in mind that treating a neuroma is difficult. There is no single treatment that works reliably for everyone.^[1]

Surgical options

Surgery is considered when a well-defined neuroma keeps causing pain despite care. The main approaches include:

• Neuroma removal with relocation of the nerve end into muscle or bone so it sits in a protected place.
• Reconstruction, where the nerve gap is bridged with a graft. In a small study of 12 people with painful lower-limb neuromas, a processed donor nerve graft was used for either reconstruction or for lengthening the nerve and moving it into muscle.^[4]
• Reinnervation techniques, such as targeted muscle reinnervation, which give the nerve a muscle “target” to grow into.^[6] See targeted muscle reinnervation.

A pooled analysis of 32 articles (1,150 neuromas) found good results in about 70% of treated neuromas, with rates between 60% and 92% across techniques. Targeted muscle reinnervation did better than nerve removal alone in a post hoc analysis, but the evidence is mostly from small studies.^[6] A fuller comparison is in neuroma surgery options.

What affects the outcome

In the long-term lower-limb study above, pain fell from an average of 7.3 to 4.9 on a 10-point scale. Smoking and low mood were linked to worse results, which is a reason to address them alongside the nerve.^[3]

When to seek care

Consider an evaluation if you have a spot on the leg, ankle or foot that is very tender or shoots with a light touch, especially after an injury or an operation, and it has lasted more than a few weeks.