The effects of a medializing calcaneal osteotomy with and without superior translation on Achilles tendon elongation and plantar foot pressures.

BACKGROUND

The medial calcaneal osteotomy (MCO) is a frequently used corrective procedure for posterior tibial tendon (PTT) insufficiency; however, patients often complain of lateral foot pain postoperatively. Published findings have documented the usefulness of MCO in off-loading the plantar surface of the first and second metatarsal heads but with a concomitant increase in peak pressure over the lateral forefoot and heel. Achilles tendon elongation revealed a trend toward shortening of the ventromedial aspect of the tendon. It was then hypothesized that translating the osteotomized posterior aspect of the calcaneus medially and superiorly would reduce lateral forefoot pressure and decrease the amount of lengthening of the Achilles tendon while continuing to relieve medial forefoot pressure.

METHODS

Twenty-eight fresh-frozen cadaver legs were axially loaded on a load-frame device to 100 lbs to assess the effects of a 1-cm MCO in conjunction with either 0.5-cm or 1-cm superior translation on plantar foot pressures and Achilles tendon elongation.

RESULTS

The 0.5-cm superior translation resulted in a greater off-loading of the first and second metatarsals than the MCO alone with a trend toward decreased pressures in the lateral forefoot. The 1-cm superior translation continued to unload the first and second metatarsals; however, lateral forefoot and midfoot pressures were increased. Achilles tendon lengthening remained unchanged in the cadaver foot model.

CONCLUSIONS

Our findings suggest that the addition of a 0.5-cm superior translation to the traditional 1-cm MCO should allow some degree of off-loading of the medial forefoot without increasing lateral forefoot or heel pressures.