ACL Tears in School-Aged Children and Adolescents: Has There Been an Increased Incidence over the Last 20 Years?
Anterior cruciate ligament (ACL) tears are thought to be occurring with greater frequency in young patients. To our knowledge, no study has specifically shown there to be an increased incidence of ACL tears in children over time. The purpose of this study is to determine if the incidence of ACL tears has increased in this age group over the past 20 years. We also examined the trends in sex, age, and delay in surgery over the study period.
A retrospective review of an insurance company’s billing data within a large metropolitan network was performed for children and adolescents aged 6-18 years with ICD-9 codes for ACL tear and CPT code for ACL reconstruction from Jan 1994 - Dec 2013. Patients were included if they had at least 2 occurrences of ACL diagnosis codes on medical claims within 4 months apart, or at least 1 ACL procedure code during study period. Injury incidence was then calculated based on age and sex. Analysis included year-by-year total incidence, with break down by sex, and age. Delay in surgery was calculated by time between first ICD-9 code and CPT code. Poisson regression analysis was employed to look for significance of ACL injury rate trends. Logistic regression was employed to look for significant change in surgery rates. Linear regression was employed to look for significant change in delay in surgery.
Total patients enrolled in the insurance database within our study age range averaged 136,000 + 15,000/year. A total of 3303 ACL tears were identified. The overall rate averaged 121 + 19 per 100,000 person-years. The rate in males averaged 115 + 22 per 100,000 person-years. The rate in females averaged 128 + 24 per 100,000 person-years. All analyzed trends increased significantly over time except for the male 6-14 and 17-18 year old age groups. Based on logistic regression analysis, the overall incidence of ACL tears increased 2.3% per year. Males had an increase of 2.2% per year. Females had an increase of 2.5% per year. Females peaked at age 16 years with a rate of 392 ACL tears/100,000 person-years and males peaked at age 17 years with a rate of 422 ACL tears/100,000 person-years. The percent of ACL tears surgically reconstructed increased by 3% per year over the study period. The median delay in surgery was 28 days and decreased by 0.9% per year.
The incidence of ACL tears in young patients increased over the last 20 years. Both males and females had a large increase in incidence during high school years. The etiology of this is unknown; possible causes are increased sports participation and reaching skeletal maturity. This data will be helpful to target the most at-risk patients for ACL prevention programs.