Primary total knee arthroplasty using the P.F.C Sigma®-rotating platform cruciate retaining endoprosthesis--a 6 year follow up.

BACKGROUND: Mobile-bearing Total Knee Replacement allows unconstrained axial rotation. Increased articular conformity minimizes polyethylene contact stresses, thereby reducing linear wear and fatigue failure.
METHODS: We prospectively reviewed a consecutive series of 161 patients with mobile bearing total knee replacements using the PFC Sigma Cruciate Retaining Rotating Platform System. (DePuy, Leeds, United Kingdom) with midterm follow up (minimum 6 and maximum 9 years, mean 7.2 years). One hundred forty-seven patients from February 2001 to March 2004 were followed up till date. Primary osteoarthritis 96%; was the main indication followed by rheumatoid arthritis 3% and one case of psoriatic arthritis. Fifty-seven percent were females with mean age of 69.5 years (Range 51-90 years). Oxford and American Knee Society scores were measured.
RESULTS: Mean Oxford score improved from 43 (Range 29-55) pre operatively to 21(Range 13-44) at last follow up and mean Knee Society score from 53 (Range 43-70) to 80 (Range 58-90). Range of movement improved from 91° (Range 70-110) to 113° (Range 75-130) at last follow up. One patient had dislocation of bearing needing manipulation. One patient had superficial infection treated with antibiotics. No patients had deep infection. There was one case reported of deep vein thrombosis and one of non-fatal pulmonary embolism.
CONCLUSION: The midterm results in our series with PFC Sigma mobile bearing knee replacement are excellent with good outcome scores. Cohort will be followed for long term results. Level of Evidence IV.