Cementless total hip arthroplasty and limb-length equalization in patients with unilateral Crowe type-IV hip dislocation.

BACKGROUND: Total hip arthroplasty in patients with unilateral congenital high dislocation of the hip (Crowe type IV) presents many challenges, including the problem of a marked limb-length discrepancy. The purpose of this retrospective study was to analyze the results of total hip replacement with limb-length equalization in these patients.

METHODS: From 1988 to 1996, fifty-six patients (forty-seven women and nine men) with unilateral Crowe type-IV dislocation of the hip were treated with a cementless total hip arthroplasty at a mean age of 35.4 years. The preoperative limb-length discrepancy averaged 4.9 cm. Prior to the total hip arthroplasty, forty-eight patients with a limb-length discrepancy of >4.0 cm underwent iliofemoral distraction with use of an external fixator for eight to seventeen days. The acetabular cup was placed in the anatomical position in every patient. Shortening femoral osteotomies were not required.

RESULTS: The iliac fixator pins loosened in six patients. No patient had a pin-site infection, hip joint infection, or nerve palsy. At the time of follow-up, at an average of 147.2 months, the Harris hip score averaged 90.2 points. Overall, the mean lengthening after the total hip arthroplasty was 4.6 cm. There were no revisions of the femoral stem. Nine cups were revised, four because of polyethylene wear and five because of loosening.

CONCLUSIONS: We were able to safely place the acetabular cup at the anatomical position without femoral shortening by bringing the femoral head to the normal level preoperatively; thus, we could restore nearly normal limb length. We believe that our twelve-year results are similar to those of total hip arthroplasty in patients without dysplasia.