Adjusting Orthoses: Simple Solutions To Common Complaints

Author(s): 
Larry Huppin, DPM

   These studies indicate that orthoses that prevent first ray dorsiflexion — usually devices that conform close to the arch when the first ray is dorsiflexed — enhance hallux dorsiflexion.

   Although there is evidence that “total contact” orthoses can be more effective for plantar fasciitis, metatarsalgia and hallux limitus, these higher arched orthoses also lead to more potential for direct arch irritation by the orthosis. Accordingly, in order to provide patients with the best possible clinical outcomes, it is imperative that orthotic therapy practitioners be adept at adjusting for this issue.

   The most effective method to adjust for arch irritation depends on the orthotic’s material.

   Polypropylene and other plastics. Arch irritation occurs when there is more force on the foot than the patient finds comfortable. To easily decrease this force on a polypropylene orthosis, grind the orthosis from the bottom to make it thinner and more flexible. One great advantage of this technique is that one can localize the adjustment to the portion of the orthosis that is causing irritation. Another advantage is that clinicians can address the force without changing the shape of the orthosis.

   A recommended technique is to mark the bottom of the orthosis where the patient is feeling excessive pressure. A Sharpie pen works well for this. Then simply grind the orthosis from the bottom just enough to remove the pen mark. This is usually enough to increase the flexibility of the orthosis slightly. Then let the patient try the orthosis. If the patient is comfortable, then you are done. If he or she still feels too much pressure, repeat the procedure until the orthosis feels comfortable. This technique allows a gradual increase in flexibility and helps prevent an overly flexible orthosis.

   Carbon fiber. Carbon fiber orthoses (often called “graphite”) are more difficult to adjust as one cannot grind them thinner without the risk of the device fracturing. Clinicians can heat adjust most of the carbon fiber materials. With this material, this is the most effective method to decrease orthosis arch irritation. The disadvantage of heat adjustment, however, is the risk of losing the shape of the arch. This is a primary reason that I prefer polypropylene orthoses over carbon fiber.

Pertinent Insights On Adjusting Orthoses For Continued Symptoms

Another common reason to adjust orthoses is to accentuate the clinical effectiveness of the orthosis in a situation in which the patient does not achieve adequate relief of his or her symptoms. Let’s look at how we might accentuate orthosis function for the plantar fasciitis and metatarsalgia.

   A 1999 study by Kogler found that valgus forefoot wedging decreased tension on the plantar fascia while varus wedging increased tension.5 Kogler stated that the most effective way to decrease strain on the plantar fascia was to evert the forefoot.

   An easy method to adjust an orthosis in a manner that everts the forefoot so as to decrease plantar fascia tension is to add a valgus extension to the orthosis. One can accomplish this by cutting a piece of 3 mm Korex to fit under the second through the fifth metatarsal heads. Bevel the Korex so it retains full thickness laterally and is paper thin medially. Glue it to the bottom of the topcover under the metatarsal heads.

   In the same George Washington University study noted above, researchers noted that metatarsal pads act by compressing the soft tissues proximal to the metatarsal heads and relieving compression at the metatarsal heads.2 A 2003 study looked at where to place metatarsal pads for the most effective reduction of pressure at a metatarsal head.6 These authors found that one should place the metatarsal pad between 6 mm and 10.6 mm proximal to the metatarsal head.

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