Adjusting Orthoses: Simple Solutions To Common Complaints
- Volume 27 - Issue 2 - February 2014
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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.
These studies indicate that metatarsal pads can be an effective modification to add to a foot orthosis for patients suffering from sub-metatarsal pain, calluses and ulcers. Practitioners can make the addition of metatarsal pads simple by initially prescribing their orthoses and leaving the cover unglued on the anterior portion of the orthosis. This allows placement and modification of the metatarsal pad to ensure patient comfort. Although the study above indicates the general area to place the pad for optimum pressure reduction, there is still a subjective component and the patient will tell you where the pad is most comfortable. Let the patients move the pad (they can tape it in place) until they find the most comfortable placement. Only then should one glue the pad to the orthosis and glue the cover anteriorly.
When Patients Return With New Symptoms
The third category that might require adjustment of their orthoses is patients who develop new symptoms when they begin to wear their orthoses. The most common new symptoms I see are pain affecting the knee, hip and/or back when patients are initially wearing their orthoses. The most common cause seems to be orthoses that we prescribe to reduce excessive pronation but do so in a manner that they apply more supinatory torque then the patient can tolerate.
Several studies, for example, have demonstrated that valgus wedging of the heel can reduce varus torque within the knee and symptoms associated with medial compartment osteoarthritis.7,8 Conversely, however, varus wedging may act to increase torque in the medial knee and symptoms associated with medial compartment osteoarthritis. Since in most cases a functional orthosis acts as least partially as a varus wedge, there is certainly risk for increasing medial knee pain with the use of functional orthoses.
The goal when adjusting these orthoses is to decrease the “varus wedge” function. To look at it another way, we want to reduce the supinatory torque that the orthoses are applying around the subtalar joint axis or let the patient pronate a bit more. One of the easier techniques to accomplish this is to increase the flexibility of the devices by grinding them thinner in the arch as I have described above. Other options include removing the rearfoot post and/or adding a valgus extension to the orthosis.
How To Adjust The Orthotic For Shoe Fit
Finally, a skilled orthotic practitioner must be able to adjust for shoe fit. Listed below are a few of many modifications that one can make to allow for improved shoe fit.
Narrowing the orthosis. One should narrow the orthosis only from the medial aspect. If the clinician narrows the device laterally, this allows the entire orthosis to slide laterally in the shoe and the arch of the orthosis will not match the arch of the foot.