The standardized testing method for tibial trays, proposed by the International Standards Organizations (ISO), was evaluated. Two components were analyzed, the Kinematic and the Kinemax, one with a known history of failure by fracture and one that does not have such a record, respectively. Finite element analysis was used to calculate stresses in the two tibial tray designs subjected to the conditions proposed in the ISO test. The analyses suggest that the ISO test is unrealistic and that it exaggerates the stresses on the tibial baseplate. Using a load of 2000 N, the test cannot differentiate between tibial trays that are known to fail in vivo and trays that give successful clinical performance.
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|Published - 1 Dec 1998