The nerve that innervates the foot originates from the inner aspect of the ankle and foot and then passes under the mid-foot. The nerve then subdivides into a number of branches, which extend toward the toes and between each of the knuckles of the toes (MTP joints). Then the nerves split to innervate each side of each toe. Repeated compression of the forefoot either from pressure from underneath the foot or from the sides of the foot can cause irritation and inflammation of the nerve at the branch point between the MTP joints
This nerve irritation and inflammation results in the typical symptoms of pain that is localized between the affected MTP joint. There can also be an associated feeling of radiation of pain, numbness and tingling into the web-space and toes of the affected nerve. Once the symptoms develop during a bicycle ride, they can progressively worsen to the point that one must stop cycling. Squeezing the foot from the sides, wearing narrow foot wear or high-heeled shoes, running, jumping, and even prolonged walking often also bring on one’s symptoms.
The diagnosis of a Morton’s neuroma is usually made based on one’s clinical symptoms and physical examination findings. Sometimes, a diagnostic ultrasound and/or MRI can be used to visualize a neuroma.
The treatment of a Morton’s neuroma is directed at reducing the pressure in the forefoot and the inflammation around the nerve. Ways to reduce the pressure in the forefoot include:
1. Adjusting the forward-backward position of the shoe relative to pedal axel
2. Adjusting the side-to-side position of the cleat on the shoe
3. Selecting large size pedals and/or shoe cleats.
4. Selecting cycling shoes with a wider toe box or adjustable strap tension in the forefoot area.
5. Adhering a metatarsal pad or bar on the top of shoe insole. The position of the pad should be placed behind the MTP joints.
Ideally, this should be done with the guidance of a qualified orthotist to ensure proper placement of the pad (see figure 1).
6. Tilting the inner forefoot with a shim on the inner part of the forefoot that is placed under or on top the shoe insole.
Ways to reduce nerve inflammation including taking oral or applying topical anti-inflammatory medications.
If one’s symptoms persist despite taking the above measures, a corticosteroid injection of the neuroma could be considered. If corticosteroid injections fail or stop working after several have been attempted, then surgical excision of the neuroma (neurotomy) could also be considered. This usually results in some permanent numbness of the affected toes, but no paralysis.
Other possible causes of forefoot pain in cyclists include large toe MTP joint bunions (hallux valgus) or osteoarthritis, hammer toes, and metatarsal stress fractures. A medical physician should be consulted to ensure proper diagnosis and management of one’s foot pain.
WRITTEN BY: Dr. Victor Lun, MSc., MD, CCFP, Dip. Sport Med (CASEM is a Sport Medicine doctor who practices at the University of Calgary Sport Medicine Centre. He is the team physician for several the winter and summer sport Canadian national sport teams and a medical director at the Canadian Sport Centre Calgary.
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