Implant sizing of the P.F.C. sigma rotating-platform total knee system.

We studied the P.F.C. Sigma rotating-platform total knee arthroplasties performed during 2004 and 2005 to assess implant size variations in men versus women and size variation in bilateral knees. We subsequently studied commercial femoral radiograph templates to compare mediolateral and anteroposterior dimensions. Sixty-four percent of women more frequently had a tibial tray one size smaller with respect to the femur and 63.5% of men had the same-sized femur and tibia. Bilateral knees were the same size in both sides 97% of the time in women, and 90% in men. The template comparison found that the P.F.C. Sigma rotating-platform femur had a mediolateral dimension that was smaller than many knee replacements commercially available.