Total knee replacement with natural rollback.

Area of Science:

• Biomedical Engineering
• Orthopedic Surgery
• Biomechanics

Background:

• Current total knee replacements (TKR) often do not fully replicate natural knee biomechanics.
• This can lead to suboptimal patellofemoral joint loading and anterior knee pain.

Purpose of the Study:

• To introduce and evaluate a novel total knee replacement (AEQUOS G1) with a unique articular surface design.
• To assess its ability to replicate natural knee flexion/extension kinematics, including rollback.

Main Methods:

• The AEQUOS G1 features a convex lateral tibial plateau and a posteriorly shifted lateral femoral condyle.
• This design aims to constrain motion similar to a four-bar linkage, approximating human knee kinematics.
• Pilot studies utilized lateral X-rays to assess in vivo rollback.

Main Results:

• The AEQUOS G1 design approximates the natural four-bar linkage motion of the human knee during flexion/extension, especially during gait.
• Pilot studies showed evidence of natural rollback in vivo.
• This rollback is expected to reduce patellofemoral joint load and retropatellar pressure.

Conclusions:

• The AEQUOS G1 total knee replacement demonstrates potential for improved biomechanical function compared to existing prostheses.
• The design's ability to promote natural rollback may reduce anterior knee pain and minimize wear by favoring rolling over sliding friction.
• Long-term clinical data are required to definitively confirm these benefits.