Total hip arthroplasty in congenital dislocated hips.

Experience with six typical cases demonstrates that total arthroplasty for congenital dislocated hips may be associated with malalignment of the ipsilateral knee, leg-length inequality, pelvic obliquity and structural changes in the lumbosacral spine. The preoperative planning may include computerized tomography scan to obtain accurate information about the optimal placement of the socket and the size and shape of the prosthetic components. Loosening of the stem or socket rather than polyethylene wear is the expected cause of late failure. The design of the femoral component should fit the canal and the shape of the proximal femur. Biological causes for failure, such as granulomatous reaction to wear, particles, and infection, are known but were not encountered in the present series of cases. The surgical technique is designed to obtain complete coverage of the socket in the available bone. A supplementary bone graft provides additional bone stock and is especially important for revision operations. Orientation of the components, stability of the joint, the need for tenotomy of contracted structures, and the improvement of abduction and flexion muscle power are also important considerations. Elderly patients with degenerated, painfully dislocated hips that are refractory to conservative treatment, may be candidates for arthroplasty.