Ic. Burgess et al., DEVELOPMENT OF A 6 STATION KNEE WEAR SIMULATOR AND PRELIMINARY WEAR RESULTS, Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine, 211(1), 1997, pp. 37-47
In order to assess the wear performance of different designs of total
knee replacements (TKR), a six station multi-axis knee simulator has b
een designed, built and commissioned. The most important features of a
knee simulator are representative angles of flexion-extension synchro
nized with a dynamically applied load, and a combination of rolling an
d sliding motion. The simulator typically applies flexion-extension of
0-65 degrees, anterior-posterior translation of up to 15, a dynamic l
oad of up to 5.0 kN, and operates at 1.0 Hz. The loads and motions are
applied using computer controlled servohydraulic actuators and hence
their profiles are easily modified. A preliminary wear test has been c
onducted using a Kinemax (Howmedica, United Kingdom) TKR. The test was
conducted in 30 per cent bovine serum which was changed every 150 000
cycles, at which time the bearing surfaces were examined and the UHMW
PE tibial component was weighed. Over eight million cycles, a tibial w
ear rate of 2.62 mg/10(6) cycles was measured. The mild wear observed
was characterized by burnishing and slight scratching in the anterior-
posterior direction. These observations are broadly in line with both
in vitro and ex vivo studies reported in the literature for this type
of prosthesis. Delamination wear sometimes observed in vivo was not se
en.