What is intermetatarsal bursitis?
It is inflammation and swelling of the small fluid-filled sac (bursa) that lies between the metatarsal heads.
What causes intermetatarsal bursitis?
We are unsure of the exact cause but it is thought to be related to increased compression across the front of the foot, possibly related to wearing narrow shoes. Other abnormalities of the joints and soft tissues in and around the metatarsal heads, such as plantar plate tears can also lead to intermetatarsal bursitis. It is often hard to differentiate from an interdigital (Morton’s) neuroma and often they are referred to as a bursal-neuromal complex.
What are the symptoms?
The symptoms can involve swelling over the forefoot with associated pain between the web spaces. Patients describe pain under the forefoot when walking barefooted which is often relieved by wearing well-cushioned shoes.
How is it diagnosed?
The diagnosis is mainly based on the history of the pain and the clinical examination findings. X-rays are useful to rule out other causes of pain in the same region. An ultrasound scan and MRI can be helpful but has limited accuracy and the diagnosis is mainly based on clinical assessment.
What treatments are available?
Initial treatment involves wearing wide soft shoes with minimal heels to allow the foot to spread out reducing the pressure on the nerve. Modification of activities and anti-inflammatory medication can improve symptoms. Orthotics with a metatarsal dome support can be useful. Steroid injections can also be useful.
When is surgery considered?
If all other management fails then the surgery involves an incision over the webspace and excision of the intermetatarsal bursa and occasionally the interdigital nerve.