Prediction of in-vivo kinematics and contact track of total knee arthroplasty during walking

In vivo kinematics of total knee arthroplasty (TKA) are essential to investigate the articular surface wear of the knee implant. However, the prediction of in vivo knee kinematics and contact track during walking remains challenged. In this study, a previously developed subject-specific musculoskeletal multibody dynamics model was utilized to predict the in vivo kinematics of TKA during the straight gait and right-turn cycles, and the contact position as described by the center of pressure (COP). The predicted in vivo knee motions of the straight gait cycle were found with similar kinematic patterns and ranges of motion to clinical studies. The main internal-external rotations of the femoral component relative to the tibial insert occurred at the stance phase of the straight gait cycle with a lateral rotational pivot point; while the remaining changes in the contact positon mainly exhibited the anterior or posterior translation. For the right-turn cycle, the major changes in the contact positon were the internal-external rotations, and the rotational pivot points were mostly located at the medial compartment. These predictions further demonstrate that in vivo kinematics and contact track are gait pattern-dependent and are important considerations to further investigate the in vivo wear mechanisms of TKA bearings.