It is widely accepted that your sport of choice, surface you play on and even your shoes can contribute to your risk of an anterior cruciate ligament (ACL) tear. But is your risk of rupturing your ACL also influenced by your genetics? A new study answers that question.
Throughout the years, research has helped us narrow down the risk factors for suffering an ACL tear. Weak and tight muscle structures definitely play a role. We know that strength and conditioning, especially proper training of the core and lower body, can help reduce the likelihood of tearing your ACL.
But a new study published in the British Journal of Sport Medicine has added a brand new risk factor: genetics. The research team drilled into data from the Swedish National Patient Register and the Swedish Twin Register to see how many fraternal twins and identical twins had suffered diagnosed ACL tears. The study included data from 88,414 twins aged 17 and up.
Karin Magnusson, a researcher and expert in twin studies in orthopedics at Lund University, said the chance to study injuries in fraternal and identical twins let the team to draw some conclusions about heredity and genetics.
“Identical twins have totally identical genes, while fraternal twins, like other siblings, share half of their genes with each other. We can estimate heritability by studying how often cruciate ligament injury occurs in both twins in a set, that is, we compare the ‘double’ prevalence in identical and fraternal twins. This way we can draw conclusions about the importance of heredity and environment.”
“Our results show that genes appear to contribute more than we thought. To put it very simply, we can say that out of all cruciate ligament injuries, 69 per cent can be explained by genetics. This should not be interpreted to mean an individual’s risk of suffering the injury is 69 per cent, rather that it is significant in terms of the wider population. Heredity is easier to understand when compared with other illnesses or conditions. The genetic risk of suffering from cancer is 33 per cent, for example. This means that 33 per cent of variation within the population in terms of causes of all cancer cases is due to genetic variation, while the rest is due to other factors ¬- such as environment or lifestyle,” explains Magnusson.
They found that there was equal risk for both women and men. The researchers think their findings my be important in terms of more effectively preventing this kind of injury.
“In the past, genetic factors have not been taken into account when working to prevent anterior cruciate ligament injury, for example among athletes. This study does not provide us with an answer as to whether heredity entails anatomical or physiological conditions that could affect the risk of a cruciate ligament injury. However, if we know that there are many cases of this injury within a family, then it is worth being extra cautious and doing more preventive training, such as landing after jumping when playing handball, and so on,” says Martin Englund, professor at Lund University, physician at Skåne University Hospital and one of the researchers behind the study.
Good equipment and good training can help minimize many of the risks of an ACL tear. I don’t think we’ve come up with an effective training system or any equipment for dealing with genetics, however. The person who does stands to be pretty famous – and probably very rich!
Keep the faith and keep after it!
Journal Reference – Karin Magnusson, Aleksandra Turkiewicz, Velocity Hughes, Richard Frobell, Martin Englund. High genetic contribution to anterior cruciate ligament rupture: Heritability ~69%. British Journal of Sports Medicine, 2020; bjsports-2020-102392 DOI: 10.1136/bjsports-2020-102392