Keele Research Repository

Objectives
To estimate the risk of clinically-diagnosed knee osteoarthritis (OA) after different types of knee injuries in young adults.

Methods
In a longitudinal cohort study based on population-based healthcare data from Skåne, Sweden, we included all persons aged 25-34 years in 1998-2007 (n=149,288) with and without diagnoses of knee injuries according to ICD-10. We estimated the hazard ratio of
future diagnosed knee OA in injured and uninjured persons using Cox regression, adjusted for potential confounders. We also explored the impact of type of injury (contusion, fracture, dislocation, meniscal tear, cartilage tear/other injury, collateral ligament tear, cruciate ligament tear, and injury to multiple structures) on diagnosed knee OA risk.

Results
We identified 5,247 persons (mean [SD] age 29.4 [2.9] years, 67% men) with a knee injury, and 142,825 persons (mean [SD] age 30.2 [3.0] years, 45% men) without. We found an adjusted hazard ratio of 5.7 (95%CI 5.0-6.6) for diagnosed knee OA in injured compared to uninjured persons during the first 11 years of follow-up and 2.7 (95%CI 2.3 – 3.1) during the following 8 years. The corresponding risk difference (RD) after 19 years of follow-up was 8.1% (95%CI 6.7%-9.4%). Cruciate ligament injury, meniscal tear, and fracture of the tibia plateau/patella were associated with greatest increase in risk (RD of 19.6% (95% CI 13.2%-25.9%), 10.5% (95%CI 6.4%-14.7%), and 6.6% (95%CI 1.1%-12.2%), respectively).

Conclusion
In young adults, knee injury increases the risk of future diagnosed knee OA about 6-fold with highest risks found after cruciate ligament injury, meniscal tear, and intraarticular fracture.