Objective To investigate the long-term (defined as ≥12 months) prognosis of knee pain and knee function in adults and adolescents with patellofemoral pain (PFP).

Design Systematic review with meta-analysis and meta-regressions.

Data sources MEDLINE, OVID, CENTRAL, Web of Science, OpenGrey, and International Patellofemoral Research Retreat abstract books.

Eligibility criteria for selecting studies Prospective studies of patients clinically diagnosed with PFP, aged <40 years, with a long-term follow-up (minimum of 12 months). Primary outcomes were self-reported pain intensity (worst, during activity, and usual) and function. Meta-analyses and meta-regressions were performed where appropriate. Narrative synthesis was performed for those not included in the metanalysis. Risk of bias was assessed using the Quality In Prognosis Studies (QUIPS) tool, and certainty of evidence using GRADE.

Results A total of 42 studies (n = 3,230) were included. At 12 months, meta-analysis indicated reduction in worst pain (SMD 1.36; 95% CI 0.85–1.86), pain during activity (SMD 1.36; 95% CI 0.61–2.11), and resting pain (SMD 0.91; 95% CI: 0.75- 1.08). No significant reduction was found for usual pain. We found improvement in self-reported function (investigated using the Anterior Knee Pain Scale (AKPS) MD 14.60; 95% CI 11.60–17.61), FIQ (MD 3.33; 95% CI: 2.46- 4.20) and the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) (MD –7.73; 95% CI: -10.36 to – 5.10). Extended follow-up (≥60 months) suggested more variable improvements. Meta-regression showed no association between age and 12-month function, while older age was modestly associated with greater improvement in activity-related pain at extended follow-up. Overall, a considerable proportion of participants continued to report persistent symptoms, and heterogeneity across studies was substantial. Certainty of evidence ranged from very low to moderate across outcomes investigated.

Conclusion Pain and self-reported function generally improve over time, particularly within the first 12 months. However, substantial heterogeneity and persistent symptoms in a considerable proportion of patients at extended follow-up indicate that recovery is not universal and trajectories are highly variable.

What is already known

Patellofemoral Pain (PFP) is a very common condition in both adolescents and adults.

Multiple treatments modalities exist, including patient education and exercise therapy.

People suffering from PFP request more knowledge on the long-term prognosis.

What are the new findings?

This systematic review and meta-analysis provide the most comprehensive synthesis to date of long-term outcomes (≥12 months) in adolescents and adults with patellofemoral pain.

Pain and self-reported knee function generally improve at the group level over time, particularly within the first 12 months.

Despite group-level improvement, a substantial proportion of individuals continue to report persistent symptoms, indicating that patellofemoral pain is often not fully self-limiting.

Long-term outcomes are highly heterogeneous, with different pain constructs demonstrating distinct trajectories across follow-up periods.

Meta-regression identified no consistent prognostic associations, suggesting that current study-level variables explain little of the variability in long-term outcomes.

How might this study affect research, practice or policy?

Clinicians should communicate that while improvement is common in patellofemoral pain, persistent symptoms are frequent, highlighting the need for realistic prognostic expectations and long-term management strategies.

Future research should prioritise harmonised outcome measures and long-term follow-up to better understand recovery trajectories and identify subgroups at risk of persistent symptoms.

The authors have declared no competing interest.

https://osf.io/wd4t3/overview

This study did not receive any funding

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The study used ONLY openly available human data that were originally published in peer-reviewed journals, open grey literature databases or openly available abstract books.

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All data produced in the present study are available upon reasonable request to the authors