Early outcome of TKA with a medial pivot fixed-bearing prosthesis is worse than with a PFC mobile-bearing prosthesis.
Although the design features of the Medial Pivot fixed-bearing prosthesis reportedly improve kinematics compared with TKAs using fixed-bearings, clinical improvements have not been reported. We asked whether the clinical and radiographic outcomes, ranges of motion of the knee, patient satisfaction, and complication rates would be better in knees with a Medial Pivot fixed-bearing prosthesis than in those with a PFC Sigma mobile-bearing prosthesis. We compared the results of 92 patients who had a Medial Pivot fixed-bearing prosthesis implanted in one knee and a PFC Sigma mobile-bearing prosthesis implanted in the other. There were 85 women and seven men with a mean age of 69.5 years (range, 55-81 years). The minimum followup was 2 years (mean, 2.6 years; range, 2-3 years). The patients were assessed clinically and radiographically using the rating systems of the Hospital for Special Surgery and the Knee Society at 3 months, 1 year, and annually thereafter. Contrary to expectations, we found worse early clinical outcomes, smaller ranges of knee motion, less patient satisfaction, and a higher complication rate for the Medial Pivot fixed-bearing prosthesis than for the PFC Sigma mobile-bearing prosthesis.


METHODS
Level I, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
Kim
Young-Hoo
YH
The Joint Replacement Center of Korea, Ewha Womens University DongDaeMun Hospital, 70, ChongRo 6-Ga, ChongRo-Gu, Seoul, 110-783, Korea. younghookim@ewha.ac.kr
Yoon
Sung-Hwan
SH
Kim
Jun-Shik
JS
D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D007720:Knee Prosthesis / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000503:physiopathology / Q000601:surgery; D010147:Pain Measurement; D011446:Prospective Studies; D011474:Prosthesis Design; D016459:Prosthesis-Related Infections / Q000453:epidemiology / Q000601:surgery; D016059:Range of Motion, Articular; D020127:Recovery of Function; D016896:Treatment Outcome