Calculated Axial Forces at the Knee in Total Knee Replacement Patients During Chair and Stair Activities

Knowledge of in vivo knee contact forces is essential for evaluating total knee replacement (TKR) designs. This is particularly true for activities other than walking, because there is still a limited understanding of its impact on wear. It has been shown that wear scars from retrieved implants have obvious differences compared with simulator tested components in both size of worn area and in damage mode. The divergence could be related to the omission of other activities than walking when testing components in the simulator. The purpose of this study was to use a parametric numerical model for predicting joint contact forces during stair ascent/descent and chair sitting/rising and compare those to measured forces from a database. We hypothesized that the contact force output of the numeric model would be similar to the measured forces.