Challenges of pre-clinical testing in orthopedic implant development.

The market for orthopedic implants is growing rapidly with the increasing prevalence of orthopedic diseases in an aging society. Different designs and materials have been developed over the years and have, in general, shown excellent results in pre-clinical testing. However, there have been incidences of serious complications when novel implants or materials are put into clinical use, with some well-known cases being metallosis in patients implanted with metal-on-metal hip replacements and osteolysis from polyethylene wear debris generated in hip and knee joint replacements. Unforeseen factors related to new designs, materials and surgical techniques can lead to different outcomes for pre-clinical testing and clinical use. While often an excellent indicator of a device's performance in clinical settings, pre-clinical testing does sometime fail to predict critical flaws in implant development. This article aims to explore the gaps in the current approach to testing. The ISO international standard of pre-clinical testing should be modified to more adequately capture actual clinical use of the implant and simulate daily activities. This article will also introduce modern methods for implant development, such as FEM, 3D printing and computer-aided orthopedic surgery, which can be widely applied to improve pre-clinical testing procedures and reduce the incidence of surgical malalignment by analyzing biomechanical performance, planning surgical procedure and providing surgical guide.