Longitudinal Changes in Adiposity after a Youth Sport‐Related Knee Injury: Informing Post‐Traumatic Osteoarthritis Prevention

OBJECTIVE: Youth who experience a sport-related knee injury have elevated odds of overweight or obesity in 3-10 years, compounding their risk for post-traumatic osteoarthritis (PTOA). To inform prevention strategies, this study compared patterns of adiposity change between youth with a sport-related knee injury and uninjured youth in the 2-year period following injury. METHODS: This was a primary analysis of the Alberta Youth Prevention of Early Osteoarthritis Cohort (PrEOA) prospective cohort study. Fat mass (FM; bioelectrical impedance) of 186 youth (106 injured, 80 uninjured, 62% female, mean age 16±2 years) was assessed at baseline (≤4-months from injury) and 6-, 12-, 18-, and 24-month follow-ups. Linear mixed models examined the association between knee injury and FM change over time after adjusting for confounders. Missing data was addressed with multiple imputation. RESULTS: The injured and uninjured groups did not experience differences in FM gain over the 24-month follow-up (0.1 kg, 95%CI: -0.6, 0.9), and minimal to no between group differences in FM were observed at any time point (6-months: 0.9, 95%CI: -0.2 to 2.0; 12-months: 0.7, 95%CI: -0.4 to 1.9; 18-months: -0.1, 95%CI: -1.4 to 1.1; 24-months -0.9 95%CI: -2.3 to 0.6) or between individuals with ACL tear injuries versus other knee injuries, or female versus male sex. CONCLUSIONS: Adiposity gains of youth with a sport-related knee injury over the initial 2-years post-injury may not differ from uninjured youth. Due to similar adiposity gains, the initial post-injury period is a potential window of opportunity to prevent future overweight and obesity, and knee PTOA.