Rotational Movement of Femoral Components of Total Hip Replacements in Response to an Anteriorly Applied Load

Mechanical testing has been performed on total hip replacements implanted in sections of cadaveric femora. A purpose built transducer has been used to measure the rotation of the implant in the bone under loads applied in the anterior-posterior direction. This has been used to assess the effect of cement and also of retaining more of the femoral neck. The retention of the femoral neck improved stability, as did the bone cement, and in the case of the uncemented prosthesis, longitudinal ridges increased the stability of the prosthesis.