Changes in Hip and Knee Strength Are Not Associated With Improved Clinical Outcomes After Rehabilitation in Individuals With Patellofemoral Pain: A Critically Appraised Topic

Abstract

Clinical Scenario: Patellofemoral pain (PFP) is a widespread knee disorder encountered in clinical practice. Clinicians have often focused on strengthening hip and knee musculature to improve pain and disability, which are the ultimate clinical goals of PFP treatment. However, PFP literature has shown improvement in pain and disability without concurrent changes in lower-extremity strength after rehabilitation. Although some researchers have achieved a significant increase in strength after rehabilitation in PFP cohorts, there was no association with improved pain and disability. The inconsistent improvements in strength and the lack of association with clinical outcomes call for a critical appraisal of the available evidence to better understand the association between changes in hip and knee strength and improved clinical outcomes in individuals with PFP. Clinical Question: Are changes in hip and knee strength associated with improved pain and disability after rehabilitation in individuals with PFP? Summary of Key Findings: Four studies met the inclusion criteria and were included in the appraisal. Following rehabilitation, one study achieved strength improvements in knee extension. One study achieved strength improvements in knee extension, but not in hip external rotation and hip abduction. Two studies did not achieve strength improvements in hip external rotation, hip abduction, hip extension, or knee extension. All included studies achieved improvements in pain or disability after rehabilitation. None of the studies found a significant association between changes in hip and knee strength (either improved or not) and improved pain and disability. Clinical Bottom Line: There is consistent evidence that changes in hip and knee strength are not associated with improved clinical outcomes after rehabilitation in adults with PFP. Strength of Recommendation: Collectively, the body of evidence included is to answer the clinical question aligns with the strength of recommendation of B based on the Strength of Recommendation Taxonomy.