To determine the association between selected biomechanical variables and risk of patellofemoral pain (PFP) in males and females.
US Service Academies.
Four thousand five hundred forty-three cadets (1727 females and 2816 males).
Assessment of risk factors:
Three-dimensional biomechanics during a jump-landing task, lower-extremity strength, Q-angle, and navicular drop.
Main outcome measures:
Cadets were monitored for diagnosis of PFP during their enrollment in a service academy. Three-dimensional hip and knee kinematic data were determined at initial contact (IC) and at 50% of the stance phase of the jump-landing task. Logistic regression analyses were performed for each risk factor variable in males and females (P < 0.05).
Less than 10 degrees of hip abduction at IC [odds ratio (OR) = 1.86, P = 0.03] and greater than 10 degrees of knee internal rotation at 50% of the stance phase (OR = 1.71, P = 0.02) increased the risk of PFP in females. Greater than 20 degrees of knee flexion at IC (OR = 0.47, P < 0.01) and between 0 and 5 degrees of hip external rotation at 50% of the stance phase (OR = 0.52, P = 0.04) decreased the risk of PFP in males. No other variables were associated with risk of developing PFP (P > 0.05).
The results suggest males and females have differing kinematic risk factor profiles for the development of PFP.
To most effectively reduce the risk of developing PFP, the risk factor variables specific to males (decreased knee flexion and increased hip external rotation) and females (decreased hip abduction and increased knee internal rotation) should be addressed in injury prevention programs.