Multi-plane, multi-joint analysis of limb support moments with gender comparison and analysis of sagittal plane tibiofemoral shear during a rapid deceleration task: Implications for non-contact anterior cruciate ligament injury
Podraza, Jeffery T.
MetadataShow full item record
Injury of the anterior cruciate ligament (ACL) within the knee joint is a common occurrence among all age groups. Females have a 2-10 times greater rate of ACL injury versus males. Non-contact rapid deceleration movements are considered the most common source of injury which occurs most often with the knee near full extension. ACL strain is thought to result from excessive anterior tibial translation and or a valgus collapse. There is a dearth of literature that investigates the non-contact mechanism of ACL injury from the perspective of it being a multi-planar, multi-joint occurrence. The three analyses presented utilized kinematic and kinetic measures of a lunge deceleration movement to identify the effect of the hip knee and ankle moments of force on the overall limb support moment (LSM) and to determine the presence of gender differences within this LSM model. Additionally, the tibiofemoral shear load generated by the deceleration maneuver was calculated via a sagittal plane knee model. Twenty subjects, (10 male, 10 female), performed deceleration trials landing within the ranges of 0 - 25, 25 - 50 and 50 - 75 degrees of knee flexion. Repeated measures ANOVA was used to compare LSMs and the contribution of individual joint moments at initial contact (IC) and IC through 50 ms after. Tibiofemoral shear loads based on a sagittal plane knee model where compared across the three landing conditions at IC and at their peak. A multivariate ANOVA was used to assess for gender differences within the limb support and individual moment data across conditions and assessed time frames. Significant limb support moment differences were noted in all three planes. Sagittal plane support increased while frontal plane support decreased with increased knee flexion at landing. Transverse plane support was considered unsupportive. Sagittal plane limb support was generated predominately by the knee while the hip is responsible for the majority of frontal plane and transverse plane limb support. Gender differences were noted predominantly at IC. Female frontal plane limb support was less than males due to an unsupportive net hip adductor moment when landing initially. In the sagittal plane female limb support was greater than males at IC due to a greater magnitude hip extensor contribution as well as a larger ankle extensor moment. In the transverse plane female support was greater than males only at IC in the 0-25 degree condition. Although females generated greater resistance to lower limb collapse in the sagittal plane, the differences in hip and ankle moments suggested they landed with less shock absorption initially. This lack of shock absorption and the presence of a net hip adductor moment, which implies a greater potential for frontal plane limb collapse, may be an explanation as to why females injure their ACL more often than males. Overall shear load was found to increase as knee flexion increased. This is contrary to the understanding that ACL injury occurs with the knee near full extension. The contribution to the overall shear in the 0-25 degree condition is dominated by the patellar tendon contribution. However, a small joint reaction force shear contribution mitigates the dominant patellar tendon contribution thereby lowering the overall shear with the knee near full extension. Overall the present data brings into question the applicability of a strict sagittal plane mechanism of injury while implicating a diminished capacity for shock absorption and a large frontal plane hip adductor moment as possible reasons for injury gender disparity.