The number of complex revision total hip arthroplasties (THA) is predicted to rise. The identification of acetabular bone defects prior to revision THA has important implications on technique and complexity of acetabular reconstruction. Paprosky et al. proposed a classification system including 3 main types with up to 3 subtypes focused on the integrity of the superior rim of the acetabulum and medial wall. However, the classification system is complex and its reliability has been questioned. The purpose of this study was to evaluate the effectiveness of different radiologic imaging modalities (plain radiographs, 2-D CT, 3-D CT reconstructions) in classifying acetabular defects in revision hip arthroplasty cases and their value of at different levels of orthopaedic training. Patients treated with revision total hip arthroplasty for acetabular bone defects between 2002–2012 were identified and 22 cases selected that had plain radiographs, 2-D CT and 3-D reconstructions available. Bone defects were classified independently by two fellowship-trained adult reconstruction surgeons. Representative sections were chosen and compiled into a timed presentation. Thirty-five residents from PGY-1 to PGY-5 and 4 attending orthopaedic surgeons were recruited for this study and received a 15-minute introduction to the classification system. Chi square analysis was utilized to examine the influence of image modality and level of training on the correct classification of acetabular bone loss using the Paprosky classification system with alpha=0.05.Introduction
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