The Effects of Movement Pattern Modification on Lower Extremity Kinematics and Pain in Women With Patellofemoral Pain

STUDY DESIGN: Controlled laboratory study. OBJECTIVES: To compare hip and knee kinematics and pain during a single-limb squat between 3 movement conditions (usual, exaggerated dynamic knee valgus, corrected dynamic knee valgus) in women with patellofemoral pain. BACKGROUND: Altered kinematics (increased hip adduction, hip medial rotation, knee abduction, and knee lateral rotation, collectively termed dynamic knee valgus) have been proposed to contribute to patellofemoral pain; however, cross-sectional study designs prevent interpreting a causal link between kinematics and pain. METHODS: The study sample included 20 women with patellofemoral pain, who demonstrated observable dynamic knee valgus. Participants performed single-limb squats under usual, exaggerated, and corrected movement conditions. Pain during each condition was assessed using a 0-to- 100-mm visual analog scale. Hip and knee frontal and transverse plane angles at peak knee flexion and pain levels were compared using repeated-measures 1-way analyses of variance. Pearson correlation coefficients were used to determine within-condition associations between kinematic variables and pain. RESULTS: In the exaggerated compared to the usual condition, increases were detected in hip medial rotation (mean +/- SD difference, 5.8 degrees +/- 3.2 degrees; P<.001), knee lateral rotation (5.5 degrees +/- 4.9 degrees, P<.001), and pain (8.5 +/- 10.8 mm, P=.007). In the corrected compared to the usual condition, decreases were detected in hip adduction (mean +/- SD difference, 3.5 degrees +/- 3.7 degrees; P=.001) and knee lateral rotation (1.6 degrees +/- 2.8 degrees, P=.06); however, average pain was not decreased (1.2 +/- 14.8 mm, P=1.0). Pain was correlated with knee lateral rotation in the usual (r=-0.47, P=.04) and exaggerated (r=-0.49, P=.03) conditions. In the corrected condition, pain was correlated with hip medial rotation (r=0.44, P=.05) and knee adduction (r=0.52, P=.02). CONCLUSION: Avoiding dynamic knee valgus may be an important component of rehabilitation programs in women with patellofemoral pain, as this movement pattern is associated with increased pain. J Ort hop Sports Phys Ther 2012;42(12):1017-1024, Epub 5 September 2012. doi:10.2519/jospt.2012.4231