Twelve different tibial components were compared for fixation. The
components included compartmental, anteriorly joined, posterior-cruciate
retaining, and one-place with one, two, or three fixation posts;
all-plastic or with a metal tray. The apparatus applied compressive load
with anterior-posterior force, rotational torque, or varus-valgus moment.
The relative deflections, both compressive and distractive, were measured
between the component and the bone. The least deflections occurred with
one-piece metal-tray components with one or two posts and with one-piece
plastic components with a post on each side. Compartmental components
deflected the most.