The effects of medial soft tissue release for varus deformity during medial open wedge supramalleolar osteotomy: a cadaveric study

Abstract

BackgroundThe supramalleolar osteotomy (SMO) can redistribute the mechanical axis and balance the load on the joint in the varus ankle osteoarthritis. The purpose of this study was to investigate not only the effect of bular osteotomy but the effects of release of medial soft tissue (posterior tibialis tendon (PTT), deep deltoid ligaments) which act as medial stabilizing structures in medial open wedge SMO. MethodsTwelve fresh frozen human legs were obtained and disarticulated below the knee. All experiments were conducted in four steps. First, medial open wedge tibial osteotomy was done. Second, a bular osteotomy was performed in an inferomedial direction at the same level as that of the tibial osteotomy. Third, the deep deltoid ligament was released from the tibial attachments. Last, the total tenotomy of the PTT was performed behind the medial malleolus. After nishing each step, contact area, peak pressure and mean pressure were measured in the tibiotalar and talo bular joints. ResultsFibular osteotomy after medial open wedge SMO signi cantly decreased the mean and peak pressures in the talo bular joint. The medial soft tissue release showed a remarkable lateral shift and decrease in tibiotalar joint loading. ConclusionsSurgeons should take into account these effects of bular osteotomy and medial soft tissue release in open wedge SMO. Adequate release of the deltoid ligament and PTT could be a useful technique to minimize the tibiotalar joint stress.