Are Changes in Dynamic Knee Movement Control Related to Changes in Pain or Function in People With Knee Disorders? A Systematic Review and Meta-analysis.

OBJECTIVE: To study whether changes in dynamic knee valgus or varus were associated with changes in pain or function in people with knee disorders. DESIGN: Systematic review with meta-analysis. LITERATURE SEARCH: We searched the MEDLINE, Embase, CINAHL, SPORTDiscus, Cochrane Library, and Web of Science, from inception up to January 2023. STUDY SELECTION CRITERIA: We included randomized controlled trials investigating the effects of nonsurgical (including nonpharmacological) interventions for knee disorders on frontal and transverse plane knee and hip movements during functional tasks, which reported pain and/or function outcomes. DATA SYNTHESIS: The relationship between changes in kinematics and pain/function was analyzed using a 2-stage structural equation modeling approach. RESULTS: From 42 202 records, 48 trials met the eligibility criteria. For people with patellofemoral pain (25 trials, n = 894), there was moderate evidence that changes in the knee and hip movements were significantly correlated with changes in pain and function (r= -0.69 to 0.73), except for the knee transverse plane movements and for the relationship between hip transverse plane movement and function. For people with knee osteoarthritis (15 trials, n = 704) and anterior cruciate ligament injuries (8 trials, n = 198), the evidence was limited and uncertain. CONCLUSION: The relationship between changes in movement control and clinical outcomes was consistent in people with patellofemoral pain. For people with knee osteoarthritis or anterior cruciate ligament injuries, there was a paucity of evidence that precluded a proper evaluation of the relationship between dynamic knee movement control, and pain and function. J Orthop Sports Phys Ther 2023;53(7):1-14. Epub: 18 April 2023. doi:10.2519/jospt.2023.11628.

Indeed, Correlation Does Not Indicate Causation!

Author response to the JOSPT Letter to the Editor-in-Chief "Lower-Limb Kinematics and Clinical Outcomes: Correlation Does not Imply Causality" J Orthop Sports Phys Ther 2023;53(11):723-725. doi:10.2519/jospt.2023.0203-R.