[Development of clear zone after total hip replacement (author's transl)].
For studying the durability of Charnley-Müller's total hip prosthesis, 141 joints of the cases which had past at least 5 years from the operation were followed up by means of X-ray pictures to reveal the processes of CZ (clear zone at the interface between bone and cement) progress and loosening generation. Results 1) CZ which occurred once never disappeared and progressed in many cases. 2) The progress of CZ was supposed to be related to age and disease, but no relation was recognized with biomechanical factors. 3) The incidence of CZ was 83.7% on the acetabular side and 49.6% on the femoral side. 4) CZ of Stage I and II occurred within 1 year after the operation in many cases and CZ of Stage III and IV tended to increase about 3 years and 4 years after the operation, respectively, in the acetabular side, while in the femoral side Stage I occurred within 1 year in many cases, Stage II and III increased about 3 years after and Stage IV did about 4 years after. 5) The term for progressing from a stage to the next one considerably varied till Stage III, including non-progressive cases, but the term from Stage III to Stage IV was within 3 years in all the cases. 6) The durability of Charnley-Müller's total hip prosthesis observed in X-ray pictures was as low as 63.1%, 89 out of 141 joints 5 years after the operation, and it would be lower for a long time. The durability was particularly low in young cases of osteoarthritis. 7) The X-ray findings of loosening preceded clinical findings; thus precise interpretation of X-ray findings is useful for decision of prognosis and therapy.
D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000601:surgery; D005265:Femoral Neck Fractures / Q000601:surgery; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008875:Middle Aged; D010003:Osteoarthritis / Q000601:surgery