TY - JOUR
T1 - How Do Hip Exercises Improve Pain in Individuals with Patellofemoral Pain? Secondary Mediation Analysis of Strength and Psychological Factors as Mechanisms
AU - Holden, Sinead
AU - Matthews, Mark
AU - Rathleff, Michael Skovdal
AU - Kasza, Jessica
AU - FOHX GROUP
AU - Vicenzino, Bill
AU - Claus, Andrew
AU - Nee, Robert
AU - Crossley, Kay M.
N1 - Funding Information:
Ethical approval for this study was granted by the University of Queensland Medical Research Ethics Committee (2013000981) and the ethics committee in the North Denmark Region (N-20140022). This study was supported by the National Health and Medical Research Council (reference 631717) and Vionic Group LLC. The funders of the study had no role in the design and conduct of the study; the collection, management, analysis, and interpretation of the data; or the preparation, review, and approval of the manuscript. The authors certify that they have no affiliations with or financial involvement in any organization or entity with a direct financial interest in the subject matter or materials discussed in the article.
Funding Information:
1Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark. 2Center for General Practice at Aalborg University, Department of Clinical Medicine, Aalborg University, Aalborg, Denmark. 3School of Health and Rehabilitation Sciences, The University of Queensland, St Lucia, Australia. 4Sport and Exercise Sciences Research, Ulster University, Newtownabbey, United Kingdom. 5Department of Physiotherapy and Occupational Therapy, Aalborg University Hospital, Aalborg, Denmark. 6School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia. aEqual contribution as first author. bFOHX Group members: Andrew Claus, Tess Cramond Pain and Research Centre, Royal Brisbane and Women’s Hospital, Herston, Australia and School of Health and Rehabilitation Sciences, Faculty of Health and Behavioural Sciences, The University of Queensland, St Lucia, Australia; Robert Nee, Department of Physical Therapy, Samuel Merritt University, Oakland, CA; Kay M. Crossley, La Trobe Sport and Exercise Medicine Research Centre, School of Allied Health, Human Services and Sport, La Trobe University, Bundoora, Australia. Ethical approval for this study was granted by the University of Queensland Medical Research Ethics Committee (2013000981) and the ethics committee in the North Denmark Region (N-20140022). This study was supported by the National Health and Medical Research Council (reference 631717) and Vionic Group LLC. The funders of the study had no role in the design and conduct of the study; the collection, management, analysis, and interpretation of the data; or the preparation, review, and approval of the manuscript. The authors certify that they have no affiliations with or financial involvement in any organization or entity with a direct financial interest in the subject matter or materials discussed in the article. Address correspondence to Professor Bill Vicenzino, School of Health and Rehabilitation Sciences, Level 3, Therapies Annexe (84A), The University of Queensland, St Lucia, QLD 4072 Australia. E-mail: [email protected] U Copyright 2021 JOSPT ®, Inc
Publisher Copyright:
Copyright © 2021 JOSPT®, Inc
PY - 2021/12
Y1 - 2021/12
N2 - OBJECTIVE: To determine whether the effect of hip exercise on patellofemoral pain is mediated through changes in hip muscle strength or psychological factors. DESIGN: Secondary mediation analysis of a randomized clinical trial, in which 218 participants with patellofemoral pain were randomly assigned to receive foot orthoses or hip exercises. METHODS: Pain (Knee injury and Osteoarthritis Outcome Score pain subscale) and number of pain-free squats at 12 weeks were the outcomes for this mediation analysis, as they are pathognomonic of patellofemoral pain. Hip strength dynamometry (abduction, adduction, and external rotation) and psychological characteristics (pain catastrophizing, kinesiophobia, and anxiety) measured at 6 weeks were considered as potential mediators. We used mediation analysis to decompose the total effect of treatment on the outcome into (1) the “indirect effect” (ie, the portion acting through the mediator) and (2) the “direct effect.” RESULTS: The effect of hip exercise on pain and squats was not mediated by any of the strength or psychological mediators analyzed. All indirect effects were small and showed wide 95% confidence intervals (CIs) that contained zero (eg, for pain-free squats: abduction strength, -0.13; 95% CI: -0.49, 0.23; Tampa Scale of Kinesiophobia, -0.17; 95% CI: -0.64, 0.30). CONCLUSION: Hip strength improved after hip exercise, yet strength did not mediate improvements in pain and pain-free squats, and alternative psychological mediators were not implicated.
AB - OBJECTIVE: To determine whether the effect of hip exercise on patellofemoral pain is mediated through changes in hip muscle strength or psychological factors. DESIGN: Secondary mediation analysis of a randomized clinical trial, in which 218 participants with patellofemoral pain were randomly assigned to receive foot orthoses or hip exercises. METHODS: Pain (Knee injury and Osteoarthritis Outcome Score pain subscale) and number of pain-free squats at 12 weeks were the outcomes for this mediation analysis, as they are pathognomonic of patellofemoral pain. Hip strength dynamometry (abduction, adduction, and external rotation) and psychological characteristics (pain catastrophizing, kinesiophobia, and anxiety) measured at 6 weeks were considered as potential mediators. We used mediation analysis to decompose the total effect of treatment on the outcome into (1) the “indirect effect” (ie, the portion acting through the mediator) and (2) the “direct effect.” RESULTS: The effect of hip exercise on pain and squats was not mediated by any of the strength or psychological mediators analyzed. All indirect effects were small and showed wide 95% confidence intervals (CIs) that contained zero (eg, for pain-free squats: abduction strength, -0.13; 95% CI: -0.49, 0.23; Tampa Scale of Kinesiophobia, -0.17; 95% CI: -0.64, 0.30). CONCLUSION: Hip strength improved after hip exercise, yet strength did not mediate improvements in pain and pain-free squats, and alternative psychological mediators were not implicated.
KW - Anterior knee pain
KW - Causal mechanism
KW - Exercise
KW - Muscle strength
KW - Resistance training
UR - http://www.scopus.com/inward/record.url?scp=85121739015&partnerID=8YFLogxK
U2 - 10.2519/jospt.2021.10674
DO - 10.2519/jospt.2021.10674
M3 - Article
C2 - 34847699
AN - SCOPUS:85121739015
SN - 0190-6011
VL - 51
SP - 602
EP - 610
JO - Journal of Orthopaedic and Sports Physical Therapy
JF - Journal of Orthopaedic and Sports Physical Therapy
IS - 12
ER -