Computer-assisted periacetabular triple osteotomy for treatment of dysplasia of the hip

Aim: Besides general risks, reorientating periacetabular osteotomies include the risks of over- or undercorrection. Therefore, intraoperative computer-assisted control of the pelvic fragment may allow for precise reorientation of the acetabulum in all planes. Methods: The advantages and problems of a computer assisted periacetabular osteotomy are demonstrated in a 19 year old female with spastic paresis and severe secondary dysplasia of the hip over a postoperative follow up period of 2 years. Because of progressive subluxation of the left femoral head with initial degenerative changes of the hip joint a pelvic triple osteotomy as described by Tonnis and an intertrochanteric derotation-varus osteotomy were performed. The intraoperative control of the acetabular position was optimized by CT based navigation. To compare and evaluate the pre- and postoperative clinical and functional outcome, X-rays, CT scans and a gait analysis were applied. Results: The computer assisted orthopedic surgery (CAOS) technique allows for precise intraoperative control following reorientation of the acetabular fragment in-all three planes. The pre- and postoperative clinical and radiological findings were compared and the result was classified as good. Conclusion: Although the costs and logistics for pelvic osteotomies are increased by CAOS technology, the authors favor this technique for corrective surgery of complex acetabular deformities, although individual parameters need to be considered in each patient.