The Knee Care Press


Study suggests knee replacement surgery with MC-Bearing design could improve patient outcomes and satisfaction

This 2022 study examined the tibiofemoral kinematics and patient outcomes of knee replacement surgery using two different implants – the medial congruent (MC) bearing and the cruciate retaining (CR) bearing.

The results showed that the MC-bearing design provides a greater congruency area between the tibial bearing and femoral implant, more native knee kinematics, and improved patient-reported outcomes (not statistically significant) compared to the CR-bearing design. No knee revisions or deep infections were observed during follow-up.

The MC bearing was designed with an increased anterior lip height and a more posterior dwell point than the CR bearing, which could contribute to the greater congruency area and more native knee kinematics. The design features of the MC bearing are intended to act as a constraint on the femoral condyles from moving anteriorly, preventing the “paradoxical motion” phenomenon associated with mid-flexion instability in TKR patients using CR-bearing designs. The study also found that the MC bearing provides greater tibial external rotation during the extension phase of the swing, which is similar to the screw-home movement in a native knee.

Overall, this study suggests that the MC-bearing design may lead to improved patient outcomes when compared to conventional designs. Its design can provide a larger congruency area, more native knee kinematics, and prevents paradoxical motion and mid-flexion instability. The improved tibial external rotation during the extension phase of the swing may be beneficial for restoring confidence in knee function during daily activities. Therefore, this study has detailed potential benefits of using a MC-bearing design for knee replacement surgery, noting that further research is needed to fully investigate its efficacy in providing improved patient satisfaction.

Medial congruent polyethylene design show different tibiofemoral kinematics and enhanced congruency compared to a standard symmetrical cruciate retaining design for total knee arthroplasty—an in vivo randomized controlled study of gait using dynamic radiostereometry; Toft Petersen et. al.; European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA) 2022.

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