Factors influencing joint-preserving operations in the treatment of the late stages of osteoarthritis of the hip

Between November 1983 and December 1992, 136 hips (119 patients) with coxar thritis were operated on using joint-preserving techniques based on the rat ionale of Pauwels' osteotomy, The criterion for selection was a patient in whom the height of the joint space in the weight-bearing area of the hip wa s less than 1 mm, The mean age at operation was 48 years and the mean follo w-up 109 months (60 to 171). Hips were categorised using Bombelli's classif ication of osteoarthritis, into atrophic and non-atrophic types. The endpoi nt was defined as that at which the height of the joint space became less t han 1 mm again. The Kaplan-Meier curve showed that the rate of survival of the non-atrophic group was significantly better than that of the atrophic g roup. Cox's proportional hazard model indicated that the factors influencin g the results of joint-preserving operations included Bombelli's classifica tion, postoperative incongruence of the joint and the height of the joint s pace.