Three-dimensional kinematics of total knee replacement systems.

In an in vitro study we collected data relating to three-dimensional kinematics and stability patterns in 40 knee joint specimens. The specimens were tested in an apparatus: the femur was flexed on a fixed transverse axis, while a freely mobile tibial assembly allowed measurement of all passive translational and rotational movements. Translational forces, torques and compression forces were introduced and the results compared with the measurements taken after implantation of different arthroplasty devices. This study compares the kinematics of a knee with mobile meniscal bearings (low contact stress, LCS) with the data relating to a more constrained system (Tricon M). The LCS knee showed the better kinematic behavior compared to the natural knee.