Effect of the tibial anterior translation to the kinetics of a patellofemoral joint

Abstract

Kinetics of the patellofemoral joint is important for analyzing the knee joint or a whole lower limb, because it effects the moment arm length of quadriceps around a knee joint. However, there have been little data about the patellofemoral kinetics, especially during deep knee flexion. Therefore we performed a simulation with changing the anterior-posterior position of a tibia, considering a large femoral roll back at deep knee flexion. The model was 2D on a sagittal plane. Tibia was settled as referring literature, and moved anterior by 5mm. As a result, patellofemoral joint dislocated at deep flexion with 15mm of tibial anterior translation. Moreover, although patellofemoral contact force reduced by the tibial anterior translation, patella tendon force did not change very much except just before the lift off. It indicated that patella would work as a lever arm of quadriceps regardless of the tibial anterior translation.