Enhanced Wear and Corrosion in Modular Tapers in Total Hip Replacement - An in-vitro biomechanical study

Introduction The use of large cobalt chrome femoral heads reduces dislocation and increases the range of motion. However, failure of large head metal on metal hip replacements (LHMMHR) has recently been identified and is believed to be associated with the high torque at the interface of standard modular taper junction leading to fretting and corrosion. Compared with standard 28 mm heads the relative forces at the interface transmitted for larger femoral heads are increased. This is because the offset of the larger femoral head increases the torque transmitted through a standard 12/14 taper. Increasing the femoral head size leads to a reduction in the ratio of the head size to the contact area of the spigot (HS:CA). In this study we investigated the hypothesis that the reduced ratio of the head size with the contact area of the spigot (HS:CA) will increase wear and corrosion on modular tapers.