OBJECTIVETo investigate the value of 3-dimensional CT in the treatment of developmental dislocation of hip (DDH).

METHODSFrom 2003.6 to 2007.6, the femoral neck anteversion (FNA) and morphology of acetebulum in 53 patients with DDH (61 hips) were studied by three-dimensional CT imaging. Among the patients, 12 patients were male and 41 patients were female, ranging in age from 3 to 16 years (mean 5.6 years). Thirty-four patients had dislocation in left hip joint, 11 patients had dislocation in right hip joints, and 8 patients had double dislocations. The patients were treated with Pemberton or Chiari acetabuloplasty and femoral osteotomy. After operation all the cases were obeserved by 3-dimensional CT again. The femoral neck anteversions were measured and the shapes of new acetabulum were observed.

RESULTSAmong 61 hips of DDH, the maximum femoral neck anteversion was 90 degrees. The minimum was 35 degrees and the average was (45.6 +/- 11.4) degrees. Among 45 normal hips, the average femoral neck anteversion was (23.5 +/- 10. 2) degrees. The acetabulum were dysplastic according with what were found in the operation. After operation the femoral neck anteversions decreased and averaged (15.6 +/- 5.8) degrees. The femoral head containment improved.

CONCLUSIONThe advantages of 3D CT scan includes manifestation of acetebular morphology, correct measurement of femoral neck anteversion and evaluation of operative procedure and efficacy. The 3-dimensional CT method is deserved to use widely in the treatment of developmental dislocation of hip in children.