Physical Activity Levels in Persons With Patellofemoral Pain: A Systematic Review and Meta-analysis

Context: Pain and symptoms of patellofemoral pain (PFP) are often exacerbated during daily activities, which may result in reduced overall physical activity levels.Objective: To summarize the evidence for physical activity levels among persons with PFP compared with pain-free controls.Data Sources: PubMed, Embase, CINHAL, Cochrane Library, and SPORTDiscus were searched from January 1, 2000 to February 22, 2024.Study Selection: Peer-reviewed studies published in English that measured physical activity subjectively or objectively in persons with PFP and pain-free controls.Study Design: Systematic review with meta-analysis.Level of Evidence: Level 1.Data Extraction: Standardized mean difference (SMD) with 95% CI are reported based on Hedges' g effect sizes.Results: From 23,745 records, 41 studies met the eligibility criteria. There was high-to-moderate-certainty evidence that persons with PFP reported higher physical activity levels compared with pain-free controls using the International Physical Activity Questionnaire (SMD, 0.27; 95% CI 0.03, 0.51), whereas lower physical activity levels compared with pain-free controls using the Tegner Activity Scale (SMD, -0.31; 95% CI -0.57, -0.04). There was low-to-moderate-certainty evidence that there was no group difference in physical activity levels using the Baecke Physical Activity Questionnaire (SMD, 0.17; 95% CI -0.09, 0.44) or self-reported sports participation duration (SMD, -0.46; 95% CI -0.98, 0.05). There was high-certainty evidence that runners with PFP reported shorter running distances compared with pain-free runners (SMD, -0.36, 95% CI -0.57, -0.14). No data pooling was possible for objectively measured physical activity levels due to device heterogeneity (ie, different algorithms used to quantify the intensity of physical activity).Conclusion: Self-reported physical activity levels among persons with PFP were inconsistent depending on the physical activity measurement tool used or which specific physical activity was measured. Clinicians should integrate multiple physical activity assessment tools to determine the extent to which PFP influences physical activity levels.Trial Registration: PROSPERO #CRD42022314598.