Prognosis of Patellofemoral Pain: A Systematic Review With Evidence and Gap Map

OBJECTIVE: To appraise current prognostic factor literature for patellofemoral pain (PFP). DESIGN: Systematic review with evidence and gap map. LITERATURE SEARCH: PubMed, CINAHL complete, PEDro, Scopus, SPORTDiscus, Embase, Cochrane Database of Systematic Reviews, and Web of Science (inception to April 2024). STUDY SELECTION CRITERIA: Participants with symptoms consistent with PFP, and average age <45 years. Longitudinal cohort studies, and randomised controlled trials (RCTs) with a true ‘wait-and-see’ group, that measured at least one outcome variable at two time points and at least one potential prognostic factor at baseline. DATA SYNTHESIS: Prognostic factors were iteratively grouped relative to seven categories and mapped by population and follow up. RESULTS: Ten longitudinal cohort studies and 12 RCTs were included. The most frequently evaluated prognostic factors were sociodemographic (n = 21), anthropometric (n = 21), and symptoms/function (n = 19). Fewer studies evaluated biomechanics (n = 12), behavioral (n = 11), psychological (n = 6), and neurobiological (n = 4) factors. Most studies examined the general population (n = 13), with fewer studies in specific populations (adolescents, n = 4; military, n = 2; runners, n = 2; university athletes, n = 1). Most studies evaluated short-term (≤3 months; n = 9) or long-term (>1 year; n = 11) follow-up, with only 2 studies evaluating medium-term follow-up (3 months to 1 year). CONCLUSION: The evidence and gap map identified sociodemographic, anthropometric, and symptoms and function as the most examined prognostic factors for PFP. Neurobiological, psychological, biomechanical and behavioural factors are under-represented. Additional studies are needed to identify prognostic factors in specific populations with high incidence of PFP. A comprehensive understanding of prognostic factors may inform development and implementation of evidence-based interventions.