Acetabular volume.

Reconstructive acetabular osteotomies can affect the acetabular volume. Volume mismatch between the femoral head and the acetabulum should be an important consideration but is rarely evaluated before hip reconstruction. Accurate measurement of the volume of the acetabulum is difficult because of the unusual shape and spatial orientation of the acetabulum. In this study, we used three techniques (physical, two-dimensional computed tomography, and three-dimensional computed tomography reconstruction) to determine the volume of 18 pig, four sheep, and 15 model acetabulae. A comparison of pre- and post-Pemberton osteotomy volumes of three dysplastic acetabulae models and two patients with developmental dysplasia of the hip also was performed. The results indicate that accurate, reproducible volume determinations can be made by using all three techniques, and that certain data-selection modes can reduce the patient's exposure to radiation. In addition, we observed an increase in the volume of the acetabulum after the Pemberton osteotomy.