Radiographic assessment of primary hip arthroplasty

Assessment of total hip arthroplasty with plain radiography remains the first choice of investigation for postoperative review and investigation of any subsequent symptoms or problems. A working knowledge of the radiographic appearance of hip arthroplasty and how this appearance changes with time is important to identify potential or evolving problems. Most of our knowledge of these radiographic features comes from observations made from arthroplasty outcome studies rather than directed research and as such, is not readily available as a single resource. This article summarizes the features seen after primary total hip arthroplasty and how they may evolve, with a brief review of the underlying biological and biomechanical principles. The technical assessment of the postoperative radiograph is considered, together with important landmarks and subsequent long-term changes. We emphasize the importance of appreciating features that identify patients at risk for revision surgery and reinforce the concept that changes may vary depending on the type of implant used. With basic principles of radiology, biology and biomechanics, orthopaedic surgeons and radiologists can accurately assess the majority of radiographs taken after total hip arthroplasty.