The effect of anatomical positional relationships on kinetic parameters after total hip replacement

The purpose of this study was to evaluate the significance of positional re lationships of the components on gait after total hip replacement (THR). Ga it was analysed using multicomponent force platforms integrated into a trea dmill, in conjunction with an optoelectric measuring system. 26 patients, a fter undergoing total hip replacement, were classified according to the ver tical and horizontal positions of the centre of rotation, the vertical posi tion of the femur and the functional leg length, and compared with a contro l group. Deterioration in parameters of gait was observed following cranial isation of the centre of rotation or of the femur, whereas neither medial m ovement of the centre of rotation nor leg lengthening by up to 1 cm had any effect. This study emphasises the importance of considering, at the time o f preoperative planning, the effect of the position of the prosthesis on th e functional parameters of gait.