A biomechanical analysis of patellofemoral stress syndrome.

THIS STUDY WAS CONDUCTED IN ORDER TO: a) investigate the relationship of selected anthropometric, strength, and kinematic variables to the incidence of patellofemoral stress syndrome in high school female athletes; and b) develop a predictive equation to screen individuals who may be predisposed to patellofemoral stress syndrome. Twenty-nine subjects were analyzed across nine dependent variables: two anthropometric measures, one strength measure, and six kinematic measures. Heavy subjects and those with a larger static quadriceps angle (Q-angle) were more likely to have patellofemoral stress syndrome. Leg strength did not seem to be a factor. Also, a variable of gait, the time from foot contact to the time when the minimum dynamic Q-angle occurred, was significantly slower in the subjects with patellofemoral stress syndrome. Furthermore, a predictive equation, which we created using discriminant analysis, was 89% accurate in predicting which subjects would or would not have patellofemoral stress syndrome. The equation uses an individual's weight, pelvic width, and static Q-angle. We conclude that, through proper screening, individuals susceptible to patellofemoral stress syndrome may be identified prior to their becoming symptomatic, and that, through identifying causal variables, corrective procedures may be introduced in order to prevent patellofemoral stress syndrome from hindering an individual's physical activity.