Effect of a Concussion on Anterior Cruciate Ligament Injury Risk in a General Population

Recent studies indicate concussion increases risk of musculoskeletal injury in specific groups of patients. The purpose of this study was to determine the odds of anterior cruciate ligament (ACL) injury after concussion in a population-based cohort.

International Classification of Diseases, 9th and 10th Revision (ICD-9, ICD-10) codes relevant to the diagnosis and treatment of a concussion and ACL tear were utilized to search the Rochester Epidemiology Project (REP) between 2000 and 2017. A total of 1653 unique patients with acute, isolated ACL tears were identified. Medical records for cases were reviewed to confirm ACL tear diagnosis and to determine history of concussion within 3 years prior to the ACL injury. Cases were matched by age, sex, and REP availability date to patients without an ACL tear (1:3 match), resulting in 4959 controls. The medical records of the matched control patients were reviewed to determine history of concussion.

39 patients with a concussion suffered an ACL injury up to 3 years after the concussion. The rate of prior concussion was higher in ACL-injured cases (2.4%) compared to matched controls with no ACL injury (1.5%). This corresponds to an odds ratio of 1.6 (95% CI 1.1-2.4; p = 0.015).

Although activity level could not be assessed, there are increased odds of ACL injury after concussion in a general population. Based on the evidence of increased odds of musculoskeletal injury after concussion, standard clinical assessments should consider concussion symptom resolution as well as assessment of neuromuscular factors associated with risk of injuries.