A hip joint simulator study using simplified loading and motion cycles generating physiological wear paths and rates

In some designs of hip joint simulator the cost of building a highly comple x machine has been offset with the requirement for a large number of test s tations. The application of the wear results generated by these machines de pends on their ability to reproduce physiological wear rates and processes. In this study a hip joint simulator has been shown to reproduce physiologi cal wear using only one load vector and two degrees of motion with simplifi ed input cycles. The actual path of points on the femoral head relative to the acetabular cup were calculated and compared for physiological and simpl ified input cycles. The in vitro wear rates were found to be highly depende nt on the shape of these paths and similarities could be drawn between the shape of the physiological paths and the simplified elliptical paths.