Bad Knees From Bad Genes: The Impact of Genetic Factors on ACL Injuries
Written by Daria Beniakoff
Edited by Mckenna Ma
May 2, 2021
Edited by Mckenna Ma
May 2, 2021
Do your genes contribute to the likelihood of you getting injured? Anterior cruciate ligament (ACL) ruptures are a tear of a ligament in the knee joint are common injuries in contact sports. From a review of previous studies, risk factors of an ACL injury are the bone structure, alignment, and looseness of the knee joint. These factors vary from person to person as inherited genetic differences contribute to the variation in anatomical structure of knees.
A 2020 study published in the British Journal of Sports Medicine looked at the lifetime genetic risk contribution to getting an ACL rupture. The study followed the health care data of more than 88,000 twins from the Swedish Twin Registry for incidence of ACL injuries over a 30 year period. The researchers used a twin study because twins share their genes, 100% for identical twins and 50% for fraternal twins, which allows for a better estimate of the impact of genes versus the environment. They collected data on the
number of ACL ruptures and used a statistical model for twin studies to calculate the overall heritability for ACL injuries. The study reported a heritability of 0.67 for ACL injuries, which indicates that genetic factors have a large contribution to incidence of injury. Identical twins also had a higher risk ratio for injury than fraternal twins. The study’s findings imply that having a sibling who has had an ACL rupture would mean you have a 20% to 140% higher risk for getting an ACL rupture. The study concluded that their results support some risk factors for ACL injuries as being highly heritable and the findings support other research studies on ACL risk factors and heritability.
The study’s findings may have important new implications for injury prevention in sports medicine. Clinicians could consider inherited risk factors for ACL injuries into their injury prevention and treatment practices for a more individualized approach. Since ACL injuries are most common in contact sports, athletes with a family history of ACL injuries could receive counseling for the increased risk and implement preventative strategies to avoid injuries. This study provides new considerations for sports medicine, although more research needs to be done in how to best incorporate heritability into injury prevention.