The Epidemiology of Posttraumatic Osteoarthritis of the Knee in the United States: An Analysis of 948,853 Patients From 2000 to 2022.

Introduction: Posttraumatic osteoarthritis of the knee (PTOAK) is a known sequela of bony and soft-tissue articular knee injuries, although its historically reported prevalence is highly variable with no recent population-based studies.

Methods: The TriNetX/US Collaborative Network database was queried to identify adult patients diagnosed with a history of knee trauma using ICD-10-CM coding. Primary outcomes measured were yearly incidence proportion (IP), incidence rate (IR), and prevalence of knee osteoarthritis in the United States from 2000 to 2022. Chi square analyses were conducted to compare outcomes across categorical data. Regression modeling was performed to project PTOAK epidemiology to 2030. Statistical significance was held at P < 0.05 for all analyses.

Results: Nine hundred forty-eight thousand eight hundred fifty-three patients meeting criteria were identified. As of 2022, the IP of PTOAK was 5.93%, IR was 2.26 × 10 -4 cases/person-day, and prevalence was 21.1%. By strata in 2022, posttraumatic knee OA is most prevalent among the 54 to 59-year-old age group (50.9%), 60 to 64-year-old age group (50.3%), 50 to 54-year-old age group (49.7%), female patients (24.2%), and White patients (23.1%). Regression analyses revealed that the IP, IR, and prevalence of PTOAK have increased exponentially from 2000 to 2022. By 2030, the model predicts that the IP will further increase to 10.7% (95% PI = 9.79% to 11.7%), IR will be 3.79 × 10 -4 cases/person-day (95% PI = 3.28 × 10 -4 to 4.29 × 10 -4 ), and prevalence of PTOAK in the United States will be 40.6% (95% PI = 39.1% to 42.0%).

Discussion: These findings echo earlier, smaller scale studies but reveal an alarming rise in PTOAK prevalence, potentially doubling by 2030. The financial burden of knee OA treatment in the United States is already substantial, costing between $5.7 and $15 billion USD annually. This projected increase in prevalence could further increase healthcare expenditures by $1 to 3 billion by 2030. These results emphasize the need for additional research into factors contributing to PTOAK, evidence-based preventive public health interventions, and the development of multidisciplinary system-based care delivery optimization pathways.