CT-generated 3-dimensional models for complex acetabular reconstruction

Before undergoing complex acetabular reconstruction, 10 patients who met prospectively established criteria for severe acetabular bone deficiency received plain radiographs, computed tomography (CT) scans, and CT-generated 3-dimensional pelvic models. The radiographs, CT scans, and models each were graded according to the American Academy of Orthopaedic Surgery (AAOS) classification for acetabular deficiency. The classifications for the radiographs, CT scans, and models were then compared with findings at surgery. The models predicted acetabular deformity and AAOS classification significantly better than the other imaging modalities. The models agreed with the surgical findings in 9 of 10 cases, compared with 2 of 10 for the CT scans (P =.016) and 4 of 10 for the plain radiographs (P =.063). The models closely predicted the available space for the hemispheric acetabular shells, based on the size of the last reamer used, for the 6 hips reconstructed with standard components. Four patients required custom acetabular components; in 2 of those 4, the need for custom components was not anticipated by plain radiographs or CT scans. Three-dimensional CT-generated acetabular models were found to be useful in preoperative planning of complex acetabular reconstructions.