LAUSR

Introduction Much injury literature has focused on successful return-to-sport in the two-years following traumatic knee injury. However, little is known regarding physical activity (PA) participation in the post-rehabilitation period (3–15 years later), which may be a stronger determinant of future health and risk of joint disease. Materials and methods A sub-sample of the Alberta Youth PrE-OA cohort wore a waist-mounted accelerometer device (ActiGraph wGT3X-BT) for 7 days. This cohort was comprised of individuals with a 3–15 year history of sport-related intra-articular knee injury and age, sex and sport-matched uninjured controls. Descriptive statistics [mean within-pair difference (95% CI)] were used to compare moderate-to-vigorous PA (MVPA) between pairs. Multivariable linear regression was used to explore the association between MVPA and Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales (scored/100), controlling for injury history. Results Seventy-six participants were recruited (38 injured and 38 matched-controls; 16–28 years; 63% female). Previously injured participants were a median of 8.2 years since injury and spent significantly less time in daily MVPA compared to matched-controls [−13 min (95% CI: −24 to –2)]. There was a significant association between MVPA and two of the KOOS subscales, sport and recreation (β=0.68, 95% CI: 0.1 to 1.3) and quality-of-life (QOL; β=0.89, 95% CI: 0.1 to 1.7) that was not modified by injury history. Conclusion Youth and young adults spend less time in MVPA 3–15 years after sustaining a traumatic knee injury compared to matched-controls. This may be partly explained by a perceived reduction in knee function related to sport and recreational activities (e.g. running/jumping) and QOL (e.g. lifestyle modification).