Effect of partial versus complete plantar fasciotomy on the windlass mechanism.

Eight adult below-knee cadaver specimens were placed in a testing machine and loaded to 350 newtons according to a strict protocol. Arch height and length measurements were obtained in each specimen with the toes resting on the foot plate, dorsiflexed to 30 degrees, and maximally dorsiflexed manually. The plantar fascia was then divided from medial to lateral in one-quarter increments, and the effect on arch height and length measurements was assessed using the same loading protocol. A consistent decrease in the arch-supporting function on sequential sectioning of the plantar fascia was encountered. A less consistent decrease in the arch-supporting function was reflected by the increase in the height of the arch with sequential sectioning of the plantar fascia. The study demonstrates that partial plantar fasciotomy decreases the arch-supporting function of the plantar fascia in addition to weakening the structure. Strict surgical indications for this type of procedure should be maintained.