Effects of A-P translation and rotation on the wear of UHMWPE in a total knee joint simulator

We developed a three-channel total knee joint simulator and studied the eff ect of tibial anterior-posterior translation and internal/external rotation on the wear of polyethylene tibial inserts in total knee replacements (Ana tomic Graduated Component knees). The wear rate was the lowest in experimen t (Exp.) 1, without translation and rotational [1.74 mg/million (mg/Mc) cyc les]. In Exp. 2, with +/-5 degrees tibial rotation added, the wear rate inc reased to 10.6 mg/Mc. In Exp. 3, with rotation and -12 mm tibial translatio n added, the wear rate was 15.1 mg/Mc, whereas in Exp. 4, with rotation and +12 mm tibial translation, the wear rate was 18.7 mg/Mc. Internal/external rotation and anterior-posterior translation added a 6- to 11-fold increase in the wear rates of tibial knee inserts. The shapes of the tibial wear tr acks were rectangular and the area of the track increased when rotation and translation were added. (C) 2000 John Wiley & Sons, Inc. J Biomed Mater Re s 54: 400-406, 2001.