The classification and radiographic evaluation of bone loss in revision hip arthroplasty.

Many classification systems have been described over the past 10 years for bone loss that is found in association with the failed hip arthroplasty. Most are based on assessments of bone stock that are made intraoperatively. Good-quality plain radiography is the most useful preoperative investigation and provides important information regarding the residual bone stock. There is a need for critical appraisal of the validity of classification systems currently in use and the development of a consensus system that will permit comparison between the published results of different techniques.