Risk Factors for Aseptic Loosening Following Total Hip Arthroplasty

Total hip arthroplasty (THA) is one of the most successful orthopaedic procedures and has relieved pain and improved hip function in millions of patients worldwide. Despite the success of modern prosthetic designs and bearing surfaces, around 10% of THA prostheses still fail within 10 years1. Improvements in surgical technique and prosthesis design have decreased the incidence of deep sepsis, dislocation and fracture, however aseptic loosening, the clinical end point of osteolysis, remains the most frequent complication and in the UK accounts for 63% of all revision surgery (Table 1)2. Prosthesis loosening results in pain and disability, requiring revision surgery. Revision THA is associated with a 3 to 8-fold greater in-hospital mortality, poorer functional outcome, longer hospital stay, and higher cost than primary surgery1,3-5. The problem of osteolysis has been recognized in Judet’s acrylic hemiarthroplasty introduced in the 1940s. Prosthesis loosening complicating THA in the 1950’s and 1960’s was poorly understood and attributed to unconfirmed sepsis6 and prosthesis motion7. In the 1980’s loosening was thought to be the result of “cement disease”8, arising due to a foreign body reaction to methyl methacrylate. When the development of cementless prostheses