The effect of posterior tibial slope on knee stability after Ortholoc total knee arthroplasty.
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 degree 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 degree posterior slope knee were between the values for 0 degree and 7 degree 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 degree posterior slope are most likely to achieve normal stability in flexion and extension.
Whiteside
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DePaul Biomechanical Laboratory, Bridgeton, MO 63044.
Amador
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D001696:Biomechanical Phenomena; D002102:Cadaver; D006801:Humans; D007593:Joint Instability / Q000517:prevention & control; D007719:Knee Joint / Q000502:physiology*; D007720:Knee Prosthesis; D009068:Movement; D011474:Prosthesis Design; D013977:Tibia