The Charnley versus the Christiansen total hip arthroplasty. A comparative clinical study.

Charnley total hip arthroplasties (THA) and Christiansen THA were carried out in two concurrent groups of patients, consisting of 113 hips in 87 patients and 90 hips in 81 patients respectively. The mean age of the patients was about 65 years, two thirds had idiopathic arthrosis, and only two had rheumatic hip disease. The two groups of patients were similar with regard to sex, age, weight, etiology of arthrosis, and standard laboratory tests, but different with regard to the surgeons who operated on them. Postoperative films showed that the stems of the prostheses were in the neutral and the varus position in the Christiansen group, and in the valgus, neutral and varus position in the Charnley group. Neither group had any deaths, or deep infections in the postoperative period. Only minor postoperative complications were noted. At follow-up, 5-8 years later, the failure (revision) rate of Charnley THA to Christiansen THA was 1 to 7.7 and 1 Charnley cup was revised as against 19 Christiansen cups. The methodological weaknesses in the comparative clinical trial did not explain the inferior long-term results of the Christiansen THA.