The objective of this review is to assess the effectiveness of cemented or cementless revision of the acetabular or femoral components of a total hip arthroplasty. The specific null hypothesis to be tested is that there is no difference in outcome between cemented and cementless total hip revision. The primary outcome measures will be revision rate and functional assessment. Secondary outcome measures for assessing this will be length of operation, wear rates, intraoperative and postoperative complication rates and bone loss.