Total hip arthroplasty for congenital dysplasia or dislocation of the hip. Survivorship analysis and long-term results.

Two hundred and thirty-two total hip replacements with cement were performed between 1965 and 1987 in 190 patients who had osteoarthrosis secondary to acetabular dysplasia resulting from congenital dysplasia or dislocation of the hip. Forty-nine patients (fifty hips) who died or who did not have at least three years of clinical and radiographic follow-up were excluded; therefore, the study comprised 141 patients (182 hips), 125 of whom were women and sixteen of whom were men. The mean age at the time of the operation was 42.5 years (range, 19.5 to 76.5 years), and the mean duration of follow-up was 9.9 years (range, 3.1 to 22.8 years). A Charnley low-friction prosthesis with a 22.25-millimeter femoral head was used in all hips. A trochanteric osteotomy was performed in 164 hips. A direct lateral approach was used only when there was a limb-length discrepancy of less than two centimeters. Bulk autogenous graft was not used to augment the fixation of the acetabular component. The hips were divided into two groups on the basis of the degree of subluxation or dislocation according to the classification of Crowe et al. One hundred and thirty-six hips were grade I, II, or III (indicating subluxation) (Group S), and forty-six hips were grade IV (indicating dislocation) (Group D). At the most recent follow-up evaluation, 128 (94 per cent) of the 136 hips in Group S and forty-four (96 per cent) of the forty-six hips in Group D caused no or only slight pain (a score of 6 or 5 points, respectively, according to the system of Merle d'Aubigné and Postel). Nineteen cups (10 per cent) and five stems (3 per cent) failed and were revised. The rate of revision for loosening of the femoral component in Group D (2 per cent [one stem]) was similar to that in Group S (3 per cent [four stems]). In comparison, the rate of revision of the acetabular component in Group D (15 per cent [seven cups]) was almost twice that in Group S (9 per cent [twelve cups]). This study demonstrated satisfactory clinical results at a mean of nearly ten years. The fixation of the femoral components appeared to be satisfactory; however, the failure of the fixation of the acetabular components in Group D (the dislocated hips) is a cause for concern.