Characterization of Patellofemoral Pain in the U.S. Military, 2016-2022.

INTRODUCTION

Patellofemoral pain (PFP) is a common musculoskeletal condition and a leading cause of medical encounters in the U.S. Armed Forces. Despite its impact on readiness, little is known about its incidence and clinical correlates in active-duty service members (ADSMs).

MATERIALS AND

METHODS

We conducted a retrospective analysis of ADSMs from 2016 to 2022 using the Medical Assessment and Readiness System. PFP was identified using ICD-10 codes. Demographics, comorbidities, and service branch were extracted from administrative and clinical records. Chi-square tests and Poisson regression estimated unadjusted associations, while multivariable generalized linear models (GLMs) assessed adjusted risk ratios (aRRs) for PFP and its sequelae, including subsequent knee osteoarthritis.

RESULTS

Among 2,477,394 ADSMs, 85,023 (3.4%) had an initial PFP diagnosis, yielding an incidence rate of 0.94 per 100 person-years. The Army accounted for 47.0% of cases despite comprising 36.4% of the force. Female sex (aRR = 1.26, 95% confidence interval [CI]: 1.24-1.28), age 31-40 years (aRR = 1.32, 95% CI: 1.29-1.35), non-Hispanic Black race (aRR = 1.40, 95% CI: 1.38-1.43), vitamin D deficiency, hypertension, and hyperlipidemia were all independently associated with PFP. During follow-up, 4.4% of ADSMs with PFP developed knee osteoarthritis, compared with 0.9% without PFP, representing a 4-fold increased risk (aRR = 4.0; 95% CI: 3.9-4.1).

CONCLUSIONS

PFP disproportionately affects Army personnel, and strongly predicts knee osteoarthritis. These findings highlight the need for targeted prevention and early management strategies to mitigate long-term disability and preserve military readiness.