Evidence-based framework of the causes and consequences of patellofemoral pain: Shifting from single factors to a web of determinants

Patellofemoral pain (PFP) is a common and persistent musculoskeletal condition. Despite its multifactorial nature, existing studies have focused primarily on isolated contributors, limiting our understanding of how multiple biological, biomechanical, behavioral, and psychological determinants could interact to drive symptom onset. We propose a hypothesis-driven framework in which PFP emerges from a dynamic “web of determinants”, rather than from a single causal impairment. The framework proposes that risk profiles may vary by sex and converge toward increased patellofemoral joint stress and PFP. Males at risk of developing PFP may more commonly present with reduced knee extensor strength and limited knee flexion during functional tasks, whereas females may present a broader profile involving greater hip adduction and reduced knee extensor and hip abductor strength. We also hypothesize that, once PFP develops, secondary consequences such as reduced physical activity, deconditioning, altered pain processing, and psychological distress may reinforce symptom persistence through reciprocal feedback loops and may contribute to a downstream pathway toward patellofemoral osteoarthritis that requires longitudinal validation. The novelty of this framework lies not in recognizing that PFP is multifactorial, but in organizing this multifactoriality into a PFP-specific, longitudinal, and testable conceptual model. This perspective may help stimulate future research on interacting risk patterns and support more precise prevention and management strategies.