Abstract
The bisurface knee (KU-type) is an artificial knee joint which has a unique ball and socket joint in the midposterior portion of the tibiof emoral joint. The joint has two surfaces, one for weight-bearing and the other for flexion kinematics. The joint was developed in 1989 in cooperation between Kyoto University and Kyocera Corp. for the purpose of allowing deep flexion after TKA. Between 1990 and 2005, Bisurface knees were implanted for 874 knees in Tamatsukuri Koseinenkin Hospital. Knee joint scores averaged 50 points before surgery, 76 points 4 weeks postoperatively, and 83 points one year after surgery. The percentage of knees with a flexion range more than 130 degrees before surgery was 66% and that score rose to 84% after surgery. The knees that can not flex more than 143 degrees before surgery may obtain a better flexion range after TKA.
