Innovation in total hip replacement--when is new better?

Although many designs of total hip replacement have high success rates at followup times of 10 years and more, new designs continue to be introduced. Some of these designs are similar to what is available already, but may offer advantages such as additional sizes or improved materials. In such cases, a key question is whether the new implant will produce the best possible results for routine use. Rather than simply relying on long-term followup data, which would eliminate the widespread use of a new device for a long time, it is suggested that the vast experience and knowledge of the orthopaedic community should be used. The proposal is that an authoritative group of individuals formulate a specification of the design features of total hip replacement which produce successful results. A second key question is how to be reasonably certain that a device with significantly new features, materials or techniques, is better and whether and when it should be used, either routinely or for specific indications. The proposal is that federal funding should be available to the research community for the specification and development of extensively researched and validated test methods. A point which is applicable to all innovations is that rather than relying on only one test or on a limited number of tests to validate the device, the Design Method must be used. This method involves the formulation of a methodical series of tests, preclinical and clinical, covering all combinations of use of the device. There are no simple answers to validating a design, but there are positive signs that new innovations are being introduced more carefully than in the past, and that many of these innovations will lead to improved long-term results.