Fiberscopic Visualization of Total Knee Replacement Contact Kinematics During In Vitro Simulation

Optimization of total knee replacement (TKR) design and wear behavior requires the study of bearing contact mechanics. In this study, a novel fiberscopic imaging method was developed and combined with dynamic TKR simulation to visually quantify dynamic TKR contact areas in vitro. Contact areas between transparent TKR tibial inserts and metallic femoral components were captured using opaque lubricant media and a fiberscopic high-speed video camera within the simulator. Walking and stair descent loading patterns were characterized. Centroid location and contact pathways were calculated to determine pathway velocity and cross-shear characteristics. Overall, contact velocities ranging from 0 to 233mm/sec and crossing angles ranging from near 0 to 90 degrees were found during this study. These results provide a basis for wear testing and cross-shear modeling of TKR materials, leading to more accurate predictions of wear behavior in these implants.