Can Orthotics Address The Faulty Biomechanics Of Metatarsalgia?

Author(s): 
Guest Clinical Editor: Bruce Williams, DPM

    “Ninety-nine percent of the time,” Dr. Williams will modify his orthotics with a first ray cutout, which he takes back to where plantar pressure under the first ray no longer inhibits dorsiflexion of the first MPJ.

   Dr. Yakel emphasizes the importance of plantarflexing the first metatarsal when casting orthotics. Putting more valgus into the cast allows for greater plantarflexion of the first metatarsal, according to Dr. Yakel.

   Dr. Williams also routinely utilizes unilateral heel lifts to accommodate for limb length differences, noting the shorter limb is usually consistent with the more painful side of metatarsalgia. As a last resort, Dr. Williams says one can achieve “great” results by employing a properly placed accommodation or a reverse Morton’s extension.

   If one has sub-second metatarsal capsulitis as a result of rearfoot pronation, Dr. Yakel balances the heel of the cast inverted, incorporates a deep heel cup and medial heel skive, and leaves the anterior edge of the orthotic at its full thickness.

   Dr. Yakel will also commonly treat sub-second metatarsal capsulitis with a metatarsal pad and adds a full-length extension with 1/8 inch of Vylyte or Korex as an accommodation for the sub-second metatarsal. He describes this modification as a combination of a Morton’s extension and a reverse Morton’s extension, which permits the second metatarsal head to “float.”

   To compensate for the lack of bone compression strength that can be associated with a geriatric foot and metatarsalgia, Dr. Beekman uses metatarsal pads and/or toe crests to distribute pressure over a larger area than just the metatarsal heads. He says leather orthotics help him visualize the metatarsal to metatarsal relationships. Dr. Beekman then utilizes this information to even out the pressures among metatarsals (balance padding).

   Q: What non-orthotic modifications will you use in conjunction with custom foot orthotics to help alleviate metatarsalgia symptoms?

   A: For arthritic patients with restricted metatarsophalangeal joint range of motion, Dr. Beekman makes a rocker platform modification to their shoes. He says this eliminates the need for the foot to go through a propulsive phase. Dr. Yakel is also a fan of rocker bottom shoes, noting that the offloading is effective in decreasing forefoot pain. Dr. Beekman adds that some patients need a soft insole to absorb shock.

   When a patient has an elevated first metatarsal, Dr. Yakel notes one can add a Morton’s extension to the shoe insert if one has not already been added to the orthotic. If fat pad atrophy or displacement is the cause of metatarsalgia, Dr. Yakel suggests using additional cushioning in the shoe, orthotic or topcover, or adding a gel metatarsal pad. For patients with pre-dislocation syndrome, Dr. Yakel will use a Budin toe splint along with NSAIDs.

   Dr. Williams regularly uses a manipulation technique, promoted by Howard Dananberg, DPM, to increase ankle joint range of motion.1 As he notes, coupling that technique with proper Achilles tendon stretching exercises usually eliminates the equinus deformity as long as the patient uses custom foot orthotics.

   Dr. Beekman treats equinus with physical therapy, which entails pre-fatiguing the gastrocnemius and soleus, and having the patient stretch. While he recently began using a modification of the aforementioned Dananberg manipulation of the ankle joint, Dr. Beekman found that some patients had a recurrence of equinus on the next visit.

   To determine the cause of recurrence, Dr. Beekman examined the ligaments and retinaculum, and used applied kinesiology to determine which ligament and/or portion of the retinaculum was involved, and the direction in which to mobilize it. “I found that the equinus reduced without the manipulation and this did not recur on subsequent visits,” says Dr. Beekman.

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great article!

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