Computed tomographic assessment of shelf acetabuloplasty.

Eleven children with cerebral palsy were studied after shelf acetabular augmentation for progressive hip subluxation. Evaluation was based on computed tomography (CT) scans and radiographic measurements. We noted significant improvement in subluxation as measured by migration percentage, without increased subluxation of the nonoperated hip. Preoperatively, our patients had anterior acetabular deficiencies and increased acetabular anteversion, but no posterior deficiency by CT scanning. The acetabular shelves were positioned relatively more anteriorly than posteriorly. This appears to be appropriate owing to the relative anterior deficiencies of the acetabuli in our patients.