Introduction

Although total knee arthroplasty (TKA) has become a successful routine procedure in clinical orthopaedics, up to 20% of patients are not satisfied with the outcome of their surgery. Dissatisfaction in high-demand patients has been associated with the functional limitations of conventional TKA implants, as they do not recreate the natural biomechanics of the knee.

A novel knee prosthesis has been designed to replicate the natural rolling & gliding mechanism of the knee joint, aiming to restore a physiological movement whilst improving implant stability and pain-free function.

This TKR system includes 3 versions (CR, PS, KR); the KR (Kinematic Retaining) preserves the posterior cruciate ligament (PCL); the femoral component incorporates a thin anterior flange and a deep, broad trochlear groove to reduce anterior knee pain and to reproduce physiological patellar tracking without constraining the patella. The sagittal plane multiple radii of the femoral condyles (J-curve) allows the carefully designed femur to physiologically tension the collateral ligaments during the entire flexion/extension cycle. Tibial liners are also asymmetrical, presenting a concave medial shape with a saddle-like lateral shape. These asymmetric articulating surfaces have been designed to reproduce a more natural physiological roll-back and rotation of the femur over the tibia, thus reducing the sliding friction in the early phases of knee flexion. Furthermore, the roll-back motion relieves the stress from the patella and restores the physiological function of the quadriceps.