Total hip arthroplasty in diastrophic dysplasia.

Background: Diastrophic dysplasia results in severe disproportionate growth failure, multiple joint deformities, and early osteoarthritis of the hips. Mortality is increased in early childhood, but thereafter life expectancy is normal. Because of severe flexion deformities, resting pain, and diminished movements of the hip joints, total hip arthroplasty is indicated at an early age. The purpose of our study was to evaluate prospectively the midterm results of total hip arthroplasty in a consecutive series of patients with diastrophic dysplasia.

Methods: Between 1982 and 1996, forty-one total hip replacements were performed in twenty-four consecutive patients with diastrophic dysplasia (mean age, forty-one years) at our hospital. The patients were followed prospectively for a minimum of five years with clinical examination, determination of Harris hip scores, and radiographs. Twenty-two patients (thirty-eight hips) were examined clinically and radiographically at the time of follow-up, and the remaining two patients (three hips) were contacted only by telephone. The mean duration of follow-up was 7.8 years.

Results: The mean Harris hip score increased from 44 points (range, 25 to 66 points) before the operation to 70 points (range, 37 to 89 points) at the final follow-up examination (p < 0.001). Ten complications (24%) were recorded. Five (12%) of the forty-one hips required revision because of aseptic loosening of the acetabular component at a mean of 9.4 years after the primary operation. No revisions were due to aseptic failure of the femoral component.

Conclusions: Implant survival was good and the Harris hip scores increased significantly after total hip arthroplasty in patients with diastrophic dysplasia. However, shortening femoral osteotomy and transposition of the greater trochanter, adductor and flexor tenotomies, and modification of the femoral stem were frequently needed. Total hip arthroplasty is recommended for patients with diastrophic dysplasia and severe degeneration of the hip joints, even for those who are relatively young.

Level Of Evidence: Therapeutic study, Level IV (case series [no, or historical, control group]). See Instructions to Authors for a complete description of levels of evidence.