ACL Injuries in Women

The FIFA women’s world cup has just wrapped up in Australia and New Zealand where the women’s game continues to grow and challenge the status quo that football is a men’s game. Along with the rise in popularity in women’s football, there has been a significant rise in anterior cruciate ligament (ACL) injuries among the elites. Since January 2022, there have been 195 reported ACL injuries in women in the top tier league around the world

I resonate strongly with the game and have been playing it for more than 10 years where I have had my fair share of highs and lows. In my time in club football, where I played for Singapore’s Home United Women’s Team and Arion FC, my teams easily had more than 2 ladies tearing their ACLs each season. I have torn my ACL once while playing football, and another time while climbing in the past 7 years. My journey with this injury is still ongoing as I’m waiting for my third knee operation and I truly understand the pain of ACL rehabilitation – physically, psychologically and emotionally. You did your math right, I only tore my ACL twice, but I had to go for a 2 stage ACL reconstruction this time. ACL injuries might appear as momentary setbacks, but their ripple effects can reverberate through an athlete’s career trajectory.

Did you know that women are 2 to 8 times more likely to tear their ACL than men? In recent times, there has been an increase in participation in women’s sport. Not only do women tear their ACL more than men in football, the incidence of women having ACL injuries as compared to men is 3.5 times greater in basketball too.

Understanding the reasons for ACL injuries helps lay the foundation for interventions that can aid in prevention. There are various ways we can break it down, but I’ve chosen to keep this simple. Let’s look at it in 4 different aspects.

1. Anatomy

   • Women generally have wider hips, which increases the q angle. Also known as knocked knees.

• However, gender anatomical differences have not shown a direct correlation with increased risk of ACL injuries. Griffin et al, 2000

• In simple terms, just because women have these risk factors does not mean they are at higher risk of having ACL injuries.

• Biomechanics

  1. This has shown to be more responsible in why ACL injuries occur instead of focusing solely on anatomy.

  2. Women demonstrated decreased Hamstring-to-Quadriceps peak torque ratio (Hewett et al, 2006)

  3. Research shows that female athletes take significantly longer to generate maximum hamstring torque during isokinetic testing than males. The muscle recruitment order in some female athletes was markedly different, and the quadriceps was recruited initially in response to anterior tibia translation instead of the hamstrings for initial knee stabilisation (Journal of Orthopaedics, 2016 – link as above).

  4. Increased knee valgus in dynamic movements during landing, pivoting and changing directions also puts women at a higher risk as there is more stress placed on the ACL. This dynamic knee valgus may also be influenced by the inappropriate muscle contractions of hip abductors and adductors. (Ford et al, 2005)

  5. Knee Valgus in dynamic movements

• Hormones

  1. Currently, there has been more research regarding the women’s menstrual cycle influence in performance and injuries.

  2. In women with normal menstrual cycle, knee laxity increased from 4.7 ± 0.8mm in the follicular phases compared to 5.3 ± 0.7mm in the ovulatory phase, which is proposed to explain increased knee injury risk given that a 1.3mm increase in knee displacement increases ACL injury risk four-fold. (Myer et. al, 2008)

  3. However, there is a lack of research to support whether this increases the risk of injury. If you are keen to learn more about menstrual health literacy, you can give themenstrual.circle on Instagram a follow, she’s a fellow Singaporean PhD Candidate in Ireland researching female athlete physiology!

• External influences

A) This might be more football specific but footwear and gear that’s been made with men as the norm.

• Women move and run in a different way to men and yet the length of studs on boots are designed around male movement and traction, which increases the risk of women getting their boots stuck in the surface and an injury (ACL or otherwise) being caused.

B) Playing Surface

• In our local context, this probably extends to the men as well. The fact that our fields in Singapore are largely synthetic (aka Turf), has an influence on ACL injuries too. Turf has shown to produce a higher torque on the ACL as compared to grass, this is because grass deforms as needed and hence does not result in a threshold torque value that stresses the ACL. (Mansfield, 2014)

Despite the current research that has been done on why women are more at risk of ACL injuries, not much has been done to look into preventing it solely in women. As women’s sports flourish, it’s crucial to channel resources into researching ACL injuries, enabling targeted rehabilitation.

However, I will acknowledge that there have been various injury prevention programs such as FIFA 11+, the KNEE Program for Netball (done in Australia) and https://poweruptoplay.org/ (based in the UK). I strongly believe that there’s still more to be done in ACL injury prevention in women's sports. My purpose in writing this article was to not only shed some light on the gender disparity in ACL injury but to help you understand why it is so prevalent.

In my interactions with fellow athletes, I have learned that the shared struggle of navigating ACL injuries highlights the importance of fostering a supportive community. So, if you are a female athlete who has or had an ACL injury, I would like you to know that you aren’t alone in this and that every small win counts. Don’t be too hard on yourself, focus on what you can control and all your feelings towards the injury are valid.

References:

• The female ACL: Why is it more prone to injury?. (2016). Journal Of Orthopaedics, 13(2), A1-A4. doi: 10.1016/s0972-978x(16)00023-4

• Ford, K. R., Myer, G. D., Toms, H. E., & Hewett, T. E. (2005). Gender differences in the kinematics of unanticipated cutting in young athletes. Med Sci Sports Exerc, 37(1), 124-129.

• Hewett, T. E., Myer, G. D., & Ford, K. R. (2006). Anterior cruciate ligament injuries in female athletes part 1, mechanisms and risk factors. The American journal of sports medicine, 34(2), 299-311.

• Mansfield, M., & Bucinell, R. (2016). Effects of Playing Surface and Shoe Type on ACL Tears in Soccer Players. American Journal Of Engineering And Applied Sciences, 9(4), 1150-1157. doi: 10.3844/ajeassp.2016.1150.1157

• Myer, G, D, Ford, K, R , Paterno, M, V, Nick, T, G, & Hewett, T, E. The effects of generalized joint laxity on risk of anterior cruciate ligament injury in young female athletes. American Journal of Sports Medicine. 36: 1073–1080. 2008