Morton’s neuroma is a painful fibrotic enlargement of one of the common digital nerves. The majority of neuroma’s are benign but can be cancerous. The term “neuroma” actually means a “tumor of a nerve”. Initially described by a British physician, the problem most often occurs between the bases of the 3rd and 4th toes.
Irritation to the nerve proper occurs as it courses between the metatarsal heads. During normal foot movement the nerve can become irritated by a ligament beneath the metatarsal heads. This irritation can lead to a build up of scar tissue (fibrosis), or “perineural fibrosis,” around the small nerves. This scar tissue becomes enlarged and causes compression on the nerve, which results in decreased blood and oxygen to the affected nerve segment, resulting in pain.
Some people experience a feeling of walking on a ‘lump’ or ‘bump’ under the forefoot. People often associate this feeling with their sock being bunched-up in their shoe, which it is not. Also described are a feeling of sharp pain, numbness or tingling which can radiate into the toes.
A thorough physical exam is necessary to properly diagnose and recommend a course of treatment. Several conditions can mimic the symptoms of a neuroma. These would include capsulitis, tendonitis or arthritis. In a minority of conditions an MRI may be necessary to further evaluate the foot.
Conservative treatment options include metatarsal pads to offload the forefoot and decrease pressure on the MPJ’s and anti-inflammatory medication. Steroid injections and alcohol sclerosing injections are designed to reduce inflammation and decrease nerve function respectively.
Surgical excision of a neuroma will be addressed by your Podiatric surgeon if conservative options have not proven effective.