Tibial plateau coverage in total knee arthroplasty.

Optimizing coverage of the resected tibial plateau is an important consideration in total knee arthroplasty. The tibial coverage of eight different tibial tray designs was examined in 35 resected tibial specimens. When no component overlap was permitted, the average tibial coverage of the different designs ranged from 76.4% to 80.8%. When the component was allowed slight overlap, a "surgical fit," the average coverage ranged from 78.5% to 85.5%. As a group, the six symmetric designs provided more coverage than the two asymmetric designs (p < 0.05). Areas of poor coverage were identified, and different tray geometries were compared. Asymmetric tibial components are thought to be more anatomic in nature and therefore cover the tibial plateau surface more completely than symmetric components. The results of this study do not support this, and in fact demonstrate that symmetric components can provide more coverage when compared with two asymmetric component designs.