Lower Extremity Strength Has Weak or No Associations With Clinical Outcomes in Individuals With Patellofemoral Pain: A Systematic Review With Evidence Gap Map and Meta-analysis

Abstract

OBJECTIVE: To evaluate the association between lower extremity strength and clinical outcomes (pain or self-reported function) in individuals with patellofemoral pain (PFP). DESIGN: Systematic review with meta-analysis. LITERATURE SEARCH: PubMed, Scopus, and SPORTDiscus, from inception to February 2024. STUDY SELECTION CRITERIA: Peer-reviewed studies published in English that evaluated the association of lower extremity strength with pain or self-reported function in individuals with PFP. DATA SYNTHESIS: We pooled correlation data across studies using a random-effects model and calculated pooled point estimates and 95% confidence interval (CI). We assessed the certainty of evidence and created an evidence gap map. RESULTS: From 29 786 records, 15 cross-sectional studies involving 652 individuals with PFP met the eligibility criteria. There was very low– to moderate-certainty evidence of no association between isometric hip abduction (r = 0.03; 95% CI: −0.14, 0.21; P = .706), hip extension (r = −0.11; 95% CI: −0.37, 0.16; P = .423), and hip external rotation (r = −0.06; 95% CI: −0.24, 0.11; P = .488) strength and severity of pain. There was low- to high-certainty evidence of a weak association between isometric hip abduction (r = 0.19; 95% CI: 0.02, 0.34; P = .029), hip extension (r = 0.37; 95% CI: 0.14, 0.56; P = .002), hip external rotation (r = 0.29; 95% CI: 0.11, 0.45; P = .002), and knee extension (r = 0.28; 95% CI: 0.18, 0.37; P<.0001) strength and self-reported function. CONCLUSION: Lower extremity strength had a weak or no association with clinical outcomes in individuals with PFP, with a wide range of evidence (very low– to moderate-certainty evidence). JOSPT Open 2024;2(3):179-193. Epub 20 May 2024. doi:10.2519/josptopen.2024.1137