Early in Vivo Failure of 36mm Ceramic-on-Metal Hip Prostheses

IntroductionTotal hip prostheses which use a ceramic head within a metal liner are a relatively recent innovation. As such, survivorship rates from independent centres alongside explant analysis are rare. The early clinical experience with this novel ceramic-on-metal (CoM) bearing couple is reported alongside explant analysis of failed devices.Methods and materialsAll CoM hips implanted between 2008 and 2009 at a single hospital by a single surgeon were reviewed. Radiographs were analysed using EBRA software to determine acetabular cup inclination and anteversion angles. Blood metal ion concentrations were measured using inductively coupled plasma mass spectroscopy (ICPMS). Explants were measured for bearing surface and taper wear using a high precision co-ordinate measuring machine (Mitutoyo Legex 322, manufacturer's claimed accuracy 0.8µm). The roughness of the articulating surfaces of heads and liners was measured with a non-contact profilometer (ZYGO NewView 5000, 1nm resolution).ResultsIn 56 patients...