PRIMARY CHARNLEY TOTAL HIP-ARTHROPLASTY FOR CONGENITAL DYSPLASIA - EFFECT OF IMPROVED TECHNIQUES OF CEMENTING

We performed Charnley total hip arthroplasties on 64 patients (71 hips ) between 1976 and 1984 for moderate congenital acetabular dysplasia i n which a superolateral cement thickness of less than 20 mm was expect ed when the cup was placed in the true acetabulum at an angle of 45 de grees. Of these, 59 hips mere examined 10 to 17 years after operation; 37 (group A) had been operated on between 1976 and 1982 using Charnle y's original technique of cementing the acetabulum and 22 (group B) be tween 1983 and 1984 using more modern techniques, In group A, aseptic loosening of the socket was observed in ten hips (27.0%) and the 17-ye ar survival rate was 81.5%. In group B, loosening was noted in only on e socket (4.5%) and the 13-year survival rate was 100%. The improved t echniques produced significantly better long-term results in fixation of the cup in dysplastic hips without bone grafting.