[The hip registry. Good economy for society]

As many as 33,656 total hip arthroplasties (THA) have been recorded in the Norwegian Arthtroplasty Register from the start in September 1987 until January 1994. The annual costs for the about 5,500 THA performed in Norway (4.2 million inhabitants) are 72 million USD. We have documented before that some types of uncemented prostheses (Ti-Fit/ Bio-Fit (cup/stem) and Coxa/Femora) and types of cements (low-viscosity and Boneloc) show higher revision rates than others do. In this paper the costs of these "inferior" implants are estimated. The "inferior" implants were compared with a reference-THA (the Charnley prosthesis with antibiotic-containing high viscosity cement and with systemic antibiotic-prophylaxis (n = 4,970)). In addition, based on data in the literature, comparisons have been made for two earlier commonly used prostheses in Norway: The Christiansen prosthesis (n = 6,500) and the Wagner double-cup prosthesis (n = 2,200). For the period 1987-93, the annual over-all extra cost of using other implants than the reference-THA was 1.71 mill. USD for the first 3-5 years postoperatively. For the Christiansen and the Wagner prostheses the annual extra costs were estimated to 2.65 and 2.38 mill. USD respectively. By documenting poor results early the Register helps to stop the use of the inferior prostheses and cements, and thus reduce both the number of revisions, and, most important, the suffering of the patients.