The effect of tibial slope angle on clinical and functional results after mobile bearing total knee arthroplasty

The success of a total knee arthroplasty (TKA) is closely related to the correct position of the prosthetic components. Malalignment in the coronal and sagittal planes are the most important cause of mechanical imbalance and patellofemoral (PF) complications. It is also a cause of early failure due to polyethylene wear and stability problems. Neutral posterior tibial slope (PTS) contributes to stability in the sagittal plane. The change in tibial inclination plays a significant role in knee kinematics.1–3 Previous cadaveric and biomechanical studies have shown that kinematics and force distribution are altered by inclination changes. In a study by Kang et al., finite element knee prosthesis models showed that the maximum contact load at the PF joint, quadriceps force, and collateral ligament forces decrease when the PTS is increased. In the mobile-bearing TKA, the rotation of the polyethylene liner and anterior translation provide better compliance with changes in tibial inclination than in the fixed-bearing TKA.5–7 Biomechanical studies show the changes caused by the angle change on knee kinematics. However, the impact of PTS changes on the outcomes of mobile-bearing TKA and patient satisfaction is not yet clear. The aim of this study was to investigate the effects of PTS changes on knee range of motion, knee scores, and overall satisfaction in patients who underwent mobile-bearing posterior cruciate ligament retaining (CR) TKA.