Metal-on-metal Hip Replacement MRI Study

This study is being conducted to determine the rate of symptomatic and asymptomatic nonmalignant, noninfective soft tissue mass presence (referred to in the literature as pseudotumour, ALVAL, ARMD, cysts or lesions) in primary metal on metal hip replacement patients. The primary objective of the study is to determine the prevalence of masses in unbiased Metal on Metal (MoM) samples drawn from one study centre. The subjects receiving the Metal on Metal devices will be observed at two specific time points. Secondary objectives are to evaluate whether the occurrence of masses is related to any of several potential factors including patient and implant characteristics and time since the implant procedure took place.