Knee pain in young sports players aged 6–15 years: a cross-sectional study in Japan

Background: Knee is the most commonly injured part of the body in young athletes. Knee pain in several studies have been seen to be more prevalent in active adolescents compared to inactive, although common in both groups. Nevertheless, few studies with large sample size have been published reporting the difference of the prevalence of knee pain for each sport among young sports players. This study investigated the point prevalence of knee pain among young sports players aged 6–15 years old according to age, sex, and sports discipline. Furthermore, this study investigated the association between knee pain and sports discipline among young sports players. Methods: A cross-sectional study was conducted using a self-reported questionnaire on young sports players aged 6–15 years from the Miyagi Amateur Sports Association. Multivariable logistic regression models were used to examine the association between knee pain and sports discipline and were adjusted for age, sex, body mass index (BMI), training days per week, and training hours per weekday and weekend. Results: A total of 7234 young sports players were included. The point prevalence of knee pain was 10.9%. Females (13.3%) had more knee pain than males (9.8%). Young, 13-year-old sports players had the highest prevalence of knee pain (19.1%). The multivariable analysis showed that the highest odds ratio [95% confidence interval] was observed for handball players (2.42 [1.01–5.81]). In addition, hand ball, mini-basketball (odds ratio 1.85; 95% CI 1.38–2.47), and basketball (odds ratio 1.66; 95% CI 1.23–2.26) were significantly associated with knee pain, compared with football. The lowest odds ratio was observed for swimming (0.34 [0.05–2.54]), followed by karate (odds ratio 0.38; 95% CI 0.16–0.89) and baseball (odds ratio 0.47; 95% CI 0.35–0.64). Conclusion: The prevalence of knee pain among young athletes differed according to age, sex, and sports discipline. Their parents and clinicians should recognize this information to manage knee pain among young sports players.