Depuy | PFC Sigma Knee System | Which Medical Device

Description

From Depuy

The P.F.C. SIGMA Total Knee System is designed to provide the surgeon with surgical solutions for a variety of clinical indications. Based on the clinically successful P.F.C. Total Knee System introduced in 1984, P.F.C. SIGMA continues a history of innovation based on clinical proof. P.F.C. SIGMA is designed to address implant longevity by maximizing femoro-tibial contact area, minimizing peak contact stresses while employing state-of-the-art polyethylene sterilization and packaging. Indicated for use for the surgeon who retains the posterior cruciate ligament, the cruciate retaining components utilize SPECIALIST 2 Instruments that allow easy transition from primary to revision procedures. The PFC SIGMA Fixed Bearing Knee System is intended for cemented use only.

(From Which Medical Device)

Design changes

In 2010 in the UK, (earlier in the US) the Cruciate Substituting femoral component was changed to the "Sigma PS" variant. This had the same sagittal, coronal and cam geometries as the Sigma CS but the radius from the anterior flange of the femoral component to the box for the tibial peg was increased, with the aim of reducing the risk of "patellar clunking" in the box and to change the tracking of the patellar component in flexion. Similarly the radius of curvature at the edges of the femoral component have been changed to reduce the risk of soft tissue impingement.

In 2010 the "Sigma Curved Plus" insert was introduced, with a raised anterior edge and manufactured using cross-linked polyethylene. This is intended to substitute for the PCL without using a posterior stabilised component.

In 2009 the titanium tibial base plate was changed to a highly polished cobalt chrome version.

Notes

In January 2012, Depuy stopped selling a number of custom medical devices including the PFC Sigma Knee System in response to a warning letter from the FDA. Find out more here.