Bridging the Gap: A Systematic Evidence and Gap Map of Risk Factors and Preventive Strategies for Patellofemoral Pain

Abstract

OBJECTIVE: To systematically review, map, and appraise the existing prospective evidence on risk factors for, and preventive strategies against, the development of patellofemoral pain (PFP), and to identify key gaps.DESIGN: Systematic Evidence and Gap Map (EGM).LITERATURE SEARCH: Nine electronic databases (PubMed, CINAHL, PEDro, Scopus, SPORTDiscus, Embase, Cochrane, Web of Science, CENTRAL) were searched from inception to the end of March 2024.STUDY SELECTION CRITERIA: Published prospective observational studies and randomized controlled trials (RCTs) investigating the development of PFP in individuals without baseline PFP were included. Studies of other knee conditions, older adults (mean age >45), or retrospective designs were excluded.DATA SYNTHESIS: Evidence was mapped across the following domains: sociodemographic, neurobiological, anthropometric, psychological, biomechanical, and behavioural.RESULTS: From 57,897 identified records, 36 studies were included: 24 prospective observational studies and 12 RCTs. Most studies focused on biomechanical risk factors (n = 22), with limited exploration of psychological (n = 1), behavioural (n = 2), and neurobiological (n = 1) domains. Preventive interventions involved orthoses (n = 4), exercise (n = 3), bracing (n = 2), gait retraining (1), stretching (1), or running intensity/volume modification. Non-biomechanical strategies such as education or graded exposure were rarely tested. Risk of bias was low to moderate for most prospective observational studies and moderate to high for most RCTs.CONCLUSION: This evidence and gap map reveals an over-reliance on biomechanical perspectives within the context of PFP risk factor research, with limited attention to psychosocial, behavioural, and load-related risk factors. Preventive trials are few, often low in quality, and narrowly focused. Addressing these evidence gaps is essential for developing effective, multifactorial prevention strategies for PFP.