Failed innovation in total hip replacement : diagnosis and proposals for a cure

Many new hip prosthesis and fixation techniques have been introduced in orthopedics in recent years. Yet, none have provided superior total hip replacements (THR) in comparison to the traditional cemented Charnley concept, which nevertheless has limited long-term endurance. This review article investigates why the THR innovation process has failed. The predominant causes for long-term failure of THR are discussed. A framework of generic failure scenarios is proposed to provide guidelines for a scientifically-oriented approach to THR design, testing and clinical evaluation. It is shown that THR components are subject to incompatible design goals as regards prevention of the different failure scenarios. Neglect of those has been one important factor in the present innovation impasse. A second factor is the trial-and-error culture in orthopedic surgery, in which new devices run through the innovation cycle without proper testing or rigorous postoperative analysis. The third factor is ineffective regulation of marketing approval with respect to orthopedic implants. Scientific research in orthopedics and related sciences has produced new methods for systematic design evaluation, pre-clinical testing and clinical trials. These can provide a basis for self-regulation and self-control by the orthopedic community, in all stages of the innovation process.