[Long-term results of primary hip total prosthesis with acetabulum reinforcement ring].

The Müller acetabular reinforcement ring has proven very useful, especially in total hip revision when the bone of the acetabulum is of poor quality or deficient. However, the acetabular reinforcement ring may also be indicated in primary total hip replacement, especially in the case of poor quality bone in the acetabular bone stock, e.g. in chronic polyarthritis or protrusio acetabuli, or of deficient morphology of the acetabulum, e.g. in hip dysplasia. We analysed the results recorded in 145 patients operated on between 1977 and April 1983. Each of these patients had received a total hip prosthesis for the first time, with the polyethylene cup supplemented by an acetabular reinforcement ring. This patient group cannot be compared with the usual patient populations reported on in connection with primary hip replacement, since most of our 145 patients had several risk factors and had undergone previous surgery on up to seven occasions on the hip ultimately replaced by a prosthesis. Radiological analysis did not show a significant correlation between malposition of the acetabular reinforcement ring and signs of loosening, except when the acetabular component had been implanted in a most atypical manner. The infection rate was 4.8%, but it must be borne in mind that from 1977 to 1983 there was no routine prophylaxis with antibiotics. The incidence of aseptic loosening of the acetabular reinforcement ring necessitating revision was 0.7% after a mean follow-up of 7.7 years (range 5.5-11 years).(ABSTRACT TRUNCATED AT 250 WORDS)