Do females with patellofemoral pain have abnormal hip and knee kinematics during gait?

Our objective was to test the hypothesis that females with patellofemoral pain (PFP) have increased hip adduction, hip medial rotation, and knee valgus (medial collapse) during the stance phase of gait. Twenty subjects with PFP and 20 pain-free subjects participated. Subjects underwent three-dimensional motion analysis during free speed and fast speed walking. Hip frontal and transverse plane angles and knee frontal plane angles were calculated at two time points (peak knee extensor moment [PkMOM], and maximum knee extension/hyperextension angle [MxExt]) and averaged over three trials. Within each walking task, Student's t-tests compared group differences in all variables. A post hoc analysis was performed, which compared a subgroup of four PFP subjects (those whose pain level was above 30/100) to pain-free subjects. Initially, there were no group differences during free speed walking. During fast speed walking, subjects with PFP had less hip adduction at PkMOM and greater hip adduction at MxExt. The subgroup of PFP subjects had greater hip adduction at PkMOM and greater knee valgus at MxExt during free speed walking and greater hip adduction and knee valgus at MxExt during fast speed walking. During low-level tasks, frontal plane components of medial collapse were present at the hip and knee in a subgroup of PFP subjects with higher pain levels. Symptom behavior may be important in identifying individuals with medial collapse movement impairments.