The objective of the study was to evaluate the annual costs of hip implants from all hip operations in Norway. The authors also compared the rate of revision of the prosthesis operation. The Charnley implant was used as the 'gold' standard comparison because it was the most frequently used implant in Norway during the time of the study, and had the best outcomes documented in the literature. The authors did not state the perspective from which the economic analysis was conducted. Highly Reputable