Effect of Wedges on Plantar Fasciitis
Kogler GF, Veer FB, Solomonidis SE, et al. The influence of medial and lateral placement of orthotic wedges on loading the plantar aponeurosis: An in vitro study. J Bone Joint Surg 81(A):1403-1413, 1999
The aim of this study was to quantify the strain in the plantar aponeurosis with different combinations of wedges. A single wedge or combination of wedges was placed under cadaveric models (varus and valgus wedges under the forefoot and/or rearfoot). A load was then applied to the cadaver limb in a walking apparatus, and a strain gauge in the plantar fascia measured the effect.
A wedge under the lateral aspect of the forefoot (valgus wedge) decreased strain in the plantar aponeurosis. A wedge under the medial aspect of the forefoot significantly increased the strain in the plantar aponeurosis. There was no significant change when a wedge was placed under either the medial or lateral aspect of the hindfoot.
SIGNIFICANCE OF THE ARTICLE
Since wedges are incorporated into the orthotic treatment for plantar fasciitis, it is important to know how they contribute to changes in strain on the plantar aponeurosis. The findings of this study revealed that “the placement of a wedge under the lateral aspect of the forefoot appears to be a promising orthotic control mechanism for shielding the plantar aponeurosis from strain”.
The results of this study indicate that a forefoot valgus wedge pronates the midtarsal joint reducing the stretch of the plantar fascia. The midtarsal joint likely contributes to the pathology leading to plantar fasciitis as a result of supination of the midtarsal joint stretching the plantar fascia. This is contrary to the common thought that subtalar joint pronation is the primary contributor to plantar fasciitis. Based on this study, we recommend adding a forefoot valgus wedge to the orthotic when treating plantar fasciitis to pronate the midtarsal joint. If you choose prefabricated orthoses as part of your initial conservative treatment of plantar fasciitis, select one that incorporates a forefoot valgus correction or wedge.