Your patients' everyday activities exert a substantial load on their knee. With those forces often higher than their body weight, this can create elevated stresses on a polyethylene bearing and the fixation interfaces of the surrounding implant. Our Sigma® RP-F posterior stabilised knee implant brings a new design-specific dimension to high-function, low-stress performance that encourages femoral rollback and provides excellent stability. Unlike fixed bearing knees, the self-aligning rotating platform bearing is designed to decouple flexion-extension and rotation into two unidirectional motions and converts shear forces into compression. This avoids excessive torque in high flexion that can lead to increased polyethylene wear, excessive post stresses, and tibial loosening.

 

High Function Meets Low Stress.

By refining the profile of the anterior insert, increased stress relief is delivered to the patella tendon during high knee flexion. Further, the Sigma® RP-F provides increased contact area with high conformity to reduce stresses at the post and condyles during high flexion.
Finally the rotating platform (RP) mobile bearing knee has been shown in studies to be 94% and 79% lower than fixed bearing conventional¹

All huge pluses in the quest to increase long-term implant survival and comfort.

FEATURES & BENEFITS

• Fully supported through 20 degrees rotation 
• Bearing rotation diffuses shear and torsional forces to maintain the curve-on-curve bearing contact and reduce the stresses in the polyethylene throughout the ange of motion. 
• With its proportional, sloped box design, maximises the amount of host bone in the intercondylar notch preserving 31 percent more viable bone in the notch for the average patient