The effect of posterior tibial slope on knee stability after ortholoc total knee arthroplasty

Abstract

The effect of posterior tibial slope was evaluated in a rotationally unconstrained anterior cruciate ligament-sacrificing total knee replacement (Ortholoc, Dow Corning Wright, Arlington, TN). Sloping the surface 7° posteriorly loosened the knee to varus—valgus and anterior—posterior stress in flexion. Eliminating posterior slope improved varus—valgus stability in flexion but slightly increased anterior—posterior laxity in extension. Values for the 3° posterior slope knee were between the values for 0° and 7° sloped surfaces, but not significantly different statistically from either. Total knee replacement designs with a posterior tibial slope are likely to promote anterior—posterior and varus—valgus laxity in flexion, and those with no posterior slope or 3° posterior slope are most likely to achieve normal stability in flexion and extension.