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Sigma® RP-F Knee System

  • category: Joint Replacement
  • focus: High Flexion Knees
  • product families: AOX™ , P.F.C.® Sigma® Revision Knee System

Sigma® RP-F Knee System
Your patient's 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 stabilized 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 converting 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 on the post and condyles during high flexion. Finally, the proven, rotating platform (RP) mobile-bearing design has been shown in studies to reduce polyethylene wear by as much as 94%. 1


1. McNulty, D. S.W Swope, D.D. Auger and T. Smith.  “The Effect of Crosslinking UHMWPE on In-Vitro Results in Fixed and Mobile Bearing Knees.”  Presented at ASTM Symposium on Crosslinked and Thermally Treated UHMWPE for Joint Replacement, November 2002.


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Aug 18 2014 - 14:04:24