A Guide To Orthotic Treatment For Metatarsalgia

Author(s): 
Jamie Yakel, DPM

Orthotics can be a vital part of treatment for the sometimes vague diagnosis of metatarsalgia. Accordingly, this author expounds on the benefits of orthotics and accommodations such as metatarsal pads and bars for metatarsalgia arising from conditions such as lesser metatarsophalangeal joint instability.

On a daily basis, podiatrists see patients who complain of pain in the forefoot. Some are self-diagnosing patients who tell you they have metatarsalgia based on what they saw on the Internet. Depending on what you read, metatarsalgia is a symptom and not a diagnosis. What really is metatarsalgia?

   Metatarsalgia is a non-specific term for pain in the forefoot. The generally accepted theory is that the pain is occurring in or near the metatarsal heads, the metatarsophalangeal joints (MPJs) or is caused by soft tissue injury. It can be a challenging problem because of the vagueness of the symptoms and the vast conditions it could encompass. The word “metatarsalgia” includes conditions such as Morton’s neuroma, stress fractures, predislocation syndrome/plantar plate tear, capsulitis, plantarflexed metatarsals, Freiberg’s disease, intermetatarsal bursitis, calluses secondary to hammertoes or clawtoes, and rheumatoid arthritis.1

   Scranton found 23 different diagnoses of metatarsalgia in 98 patients.2 Forty-five patients had primary metatarsalgia, 12 of whom had static disorders and 12 of whom had iatrogenic (postoperative etiologies. Thirty-three patients had secondary metatarsalgia, 11 of whom had rheumatoid arthritis and 10 of whom had sesamoiditis. Twenty patients experienced pain under the forefoot.

   Helal classified metatarsalgia as primary or secondary with primary metatarsalgia being an anatomic abnormality resulting in increased pressure under the metatarsal heads.3 Examples include short or long metatarsals, hallux valgus, rigidus and first ray hypermobility. Secondary metatarsalgia is pain not originating within the metatarsal area. Secondary causes include Morton’s neuroma, rheumatoid arthritis, equinus deformities and Freiberg’s infraction.

   Regnauld classified metatarsalgia as diffuse, localized, subcutaneous soft tissue and cutaneous.4 Scranton found that primary and secondary metatarsalgia can occur together.2 Nonetheless, one should determine the etiology and implement a focused treatment plan. Having a fundamental understanding of anatomy and biomechanics, and emphasizing a thorough history and physical can aid in identifying the diagnosis and creating that treatment plan. The mainstay in treating metatarsalgia is non-operative management.

   Orthotics are key components in treating metatarsalgia and one can employ various orthotic modifications after identifying the underlying etiology. Manipulation, shoe modifications, injections and surgery are other treatment options clinicians can use with or instead of orthotics.

   Loss of shock absorption due to distal migration of the fat pad can expose the metatarsal heads to increased pain. This is more pronounced in the cavus foot type with digital contractures and increased declination of the metatarsal heads. The goals with orthotic therapy in this case are to decrease the shock and reduce the pressure on the metatarsal heads. One can accomplish these objectives by using a shock absorbing material such as Spenco, PPT or another material.

Comments

This is an important article as a large percentage of patients with lesser metatarsal pain present with biomechanical issues such as functional equinus, hypermobile first ray, forefoot supinatus/midtarsal joint dysfunction.

It is essential to focus on the midtarsal joint as failure of the midtarsal joint to lock by maximally pronating as propulsive phase is entered is a common finding in such patients. Careful attention to forefoot posting of the orthotic device is required. The forefoot to rearfoot assessment required for orthotic design needs to include assessment with any forefoot supinatus reduced. Forefoot valgus posting and reverse Morton's extensions are commonly used. I like metatarsal elevations pressed into the shell of the orthotic devices and may supplement that with a soft extension to advance the metatarsal support beyond the distal edge of the device.

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