THE INFLUENCE OF INDIVIDUAL ANTHROPOMETRIC AND MECHANICAL VARIATIONS ON FUNCTIONAL INSTABILITY IN THE ACL-DEFICIENT KNEE

Individual variations in anatomy, structure and strength of the human knee and their effect on the functional instability of the knee was systematically examined in this 2D modeling study. The model included the tibiofemoral and the patellofemoral joint articulations, four ligaments, the medial capsule, and four muscle units surrounding the knee. Simulations were conducted to determine tibial anterior translation and internal joint loading at a single selected position during early stance phase of gait when the knee was under a peak external flexion moment. Incremental hamstring muscle forces were applied to the modeled ACL-deficient knee in order to examine the level of the hamstring muscle forces required to prevent abnormal tibial anterior translation. It was found that bony geometry of the knee joint, especially the slope of tibial plateau, strongly affected tibial translation and hamstring compensation in the ACL-deficient knee