ABSTRACT
Increases to the posterior tibial slope can lead to an anterior shift in tibial resting
position. However, the effect of this shift on anterior cruciate ligament (ACL) strain
has not been investigated sufficiently. This study examined the relationship between
increased tibial slope and ACL strain, as well as the subsequent kinematics of the
tibiofemoral joint. We hypothesized increases in slope would shift the tibia anterior
relative to the femur and increase ACL strain. Anterior cruciate ligament strain measurements
and tibiofemoral kinematics were compared for 5 intact and experimental knees subject
to anterior opening wedge osteotomy. Combinations of both compressive and AP loading
were applied. As slope increased, the resting position of the tibia shifted anteriorly,
external tibial rotation increased, and tibial translation remained unchanged. Contrary
to our hypothesis, ACL strain decreased. The clinical implication of these findings
is that alterations to the posterior tibial slope should not increase strain in the
ACL.