Health-related Outcomes following a Youth Sport-related Knee Injury.

PURPOSE: Active youth are vulnerable to knee injury and subsequent osteoarthritis. Improved understanding of the association between health-related outcomes and history of joint injury could inform osteoarthritis prevention strategies. The purpose of this historical cohort study is to examine the association between youth sport-related knee injury and various clinical, physiological, behavioral and functional health-related outcomes, 3-10 years post-injury.

METHODS: Participants included 100 individuals who experienced a youth sport-related knee injury 3-10 years earlier and 100 age, sex and sport-matched uninjured controls. Outcomes include; Knee injury and Osteoarthritis Outcome Score (KOOS), Intermittent and Constant Osteoarthritis Pain Score, body mass index (BMI), fat mass index (FMI), weekly physical activity, estimated aerobic capacity, hip and knee muscle strength, and dynamic balance. Baseline characteristics were described. Multivariable regression models (95%CI) were used to evaluate the association between injury history and each outcome, considering the influence of sex and time-since-injury.

RESULTS: Participant median age was 22 years (range 15-26) and 55% were female. The injured group demonstrated poorer KOOS sub-scale scores, more total and intermittent pain, higher BMI (1.8kg/m; 95%CI 0.9,2.6), higher FMI (1.1kg/m; 95%CI 0.5,1.6), weaker knee extensor (-0.18 NM/kg; 95%CI -0.33,-0.02) and flexor (-0.21 Nm/kg; 95%CI -0.30,-0.11) muscles, and poorer balance than controls. In the previously injured group, female sex was associated with poorer KOOS quality-of-life scores, knee flexor strength and greater FMI, while longer time-since-injury was associated with poorer KOOS symptoms scores, knee extensor strength and balance outcomes.

CONCLUSION: Youth that suffer a sport-related knee injury demonstrate on average more negative health-related outcomes consistent with future osteoarthritis compared to uninjured matched controls 3-10 years following injury. These negative outcomes differ by sex and time-since-injury.