Differences in knee joint kinematics and forces after posterior cruciate retaining and stabilized total knee arthroplasty

Wünschel M, Leasure JM, Dalheimer P, Kraft N, Wülker N, Müller O.

Dec 1, 2013

Knee. 2013 Dec;20(6):416-21. doi: 10.1016/j.knee.2013.03.005. Epub 2013 Apr 8.

Abstract:

Background: Posterior cruciate ligament (PCL) retaining (CR) and -sacrificing (PS) total knee arthroplasties (TKA) are widely-used to treat osteoarthritis of the knee joint. The PS design substitutes the function of the PCL with a cam-spine mechanism which may produce adverse changes to joint kinematics and kinetics.

Methods: CR- and PS-TKA were performed on 11 human knee specimens. Joint kinematics were measured with a dynamic knee simulator and motion tracking equipment. In-situ loads of the PCL and cam-spine were measured with a robotic force sensor system. Partial weight bearing flexions were simulated and external forces were applied.

Results: The PS-TKA rotated significantly less throughout the whole flexion range compared to the CR-TKA. Femoral roll back was greater in the PS-TKA; however, this was not correlated with lower quadriceps forces. Application of external loads produced significantly different in-situ force profiles between the TKA systems.

Conclusions: Our data demonstrate that the PS-design significantly alters kinematics of the knee joint. Our data also suggest the cam-spine mechanism may have little influence on high flexion kinematics (such as femoral rollback) with most of the load burden shared by supporting implant and soft-tissue structures.

Keywords: Arthroplasty; Forces; Kinematics; Knee joint; Robotics.