EFFECT OF CALCANEAL OSTEOTOMY AND LATERAL COLUMN LENGTHENING ON THE PLANTAR FASCIA - A BIOMECHANICAL INVESTIGATION

Medial calcaneal displacement osteotomy or lateral column lengthening fusion has been advocated to augment tendon transfer in planovalgus fo ot deformity associated with chronic posterior tibial tendon insuffici ency. It is hypothesized that plantar fascia tightening occurs with th ese procedures, helping to restore a more normal longitudinal arch. To investigate this further, nine fresh-frozen cadaver below-knee specim ens were used. A flatfoot model was created by sectioning of the poste rior tibial tendon, spring ligament, talonavicular capsule, and deltoi d ligament. A liquid-metal strain gauge, calibrated to measure fractio nal changes in length, was sutured proximally to the origin and distal ly into the thickest portion of the medial band of the plantar fascia. Specimens were axially loaded to 400 N and plantar fascia strain was measured. Fractional length changes in the plantar fascia were then me asured after a medial displacement calcaneal osteotomy and after a lat eral column lengthening through the calcaneocuboid joint. Tightening o f the plantar fascia did not occur with either medial calcaneal displa cement or lateral column lengthening. The plantar fascia became signif icantly less taut with both medial displacement and lateral column len gthening. We found that lateral column lengthening produced significan tly looser plantar fascia than did medial displacement of the calcanea l tuberosity.