What is an Interdigital Neuroma
Interdigital Neuroma (also known as Morton’s neuroma) is a thickening of the nerve sheath that supplies sensation to the area between the toes. It often presents as pain on the ball of the foot. Neurological symptoms are also common with a neuroma and including burning, tingling, numbness and pain in the region of the forefoot.
Causes of an Interdigital Neuroma
The exact cause of an interdigitial neuroma is unclear. It is thought that a neuroma is the result of a combination of a compression trauma and ischemic (lack of blood flow) entrapment neuropathy of the common plantar digital nerve (see the diagram below of a cross section of the forefoot).
It has been suggested that the common plantar digital nerve is repeatedly compressed between the bottom of the foot and the edge of the transverse inter-metatarsal ligament. The result is a chronic irritation of the nerve results in the subsequent development of a benign fibrotic degeneration within the nerve.
The picture below shoes the changes within a Interdigital neuroma. Of note is the increased disorganisation of the fibrous bands surrounding the nerves.
- Tight fitting footwear
- Hypermobile joints
- Digital deformities (clawtoes or (Hallux valgus) bunions)
- A flat foot
- A high arched foot
Diagnosis of an Interdigital Neuroma
Diagnosis is usually based or symptoms and a complete assessment of your foot and ankle.
At the Foot an Ankle Centre we are able to provide additional information about the presence of a neuroma with ultrasound imaging.
Treatment of an Interdigital Neuroma
Treatment aims to reduce the disorganised mass within the nerve and also offload the forefoot to prevent its re-occurrence.
Reduction of the disorganised mass can include
- Shockwave therapy
- Ultrasound guided injection therapy
Offloading the interdigital mass can be achieved with
- Shoe stretching and modification (rocker sole modification)
- Metatarsal domes
- Custom made Orthotics with a metatarsal dome incorporated into the design
Before modification After modification Take note of where the metatarsal heads are It is very important that the metatarsal dome extends 1-2cm distally from the metatarsal heads as this is how much the foot moves in a shoe.
What else could it be? (differential diagnosis)
Other problems that can cause similar pain to a neuroma include:
Inter metatarsal bursitis
Metatarsal stress fracture
Expert Podiatrists for the treatment of Neuromas servicing the areas of Northcote, Thornbury, Fitzroy, North Fitzroy, Carlton, North Carlton, Alphington, Fairfield, Brunswick, Coburg and Preston
Call The Ankle, Foot and Orthotic Centre for diagnosis and advice on professional management and treatment options.