Computed tomography analysis of proximal tibial coverage.

Researchers of this study used computed tomographic studies of the proximal tibia for patients undergoing total knee arthroplasty to determine basic morphologic data of size, shape, and area of varying levels from the articular surface. Five off-the-shelf tibial component shapes (4 symmetric, 1 asymmetric) were templated to determine the fit of the components at the various resection levels. Seventy-two knees were assessed at 2-mm, 68 at 5-mm, 40 at 8-mm, and 17 at 11-mm resection levels. Significant differences in fit and percentage of total area of coverage were identified. Fit was significantly better for asymmetric as compared with the symmetric components (p = 0.001) at all levels of resection. Fit was significantly worse for each component as the resection depth increased. This information can serve as a bridge to clinical and laboratory data in identifying the importance of tibial component fit to the overall performance of a total knee arthroplasty design.