Dr. Erica Periard, D.C.
According to Quatman and colleagues (2008), anterior cruciate ligament injuries are two to eight times more likely in females than males, but why is this? The answer comes down to hormones and gender difference in joint laxity. Hormones play a large role in our every day lives; this is especially true for women who have a monthly fluctuation of several different hormones. Hormones not only control a woman’s menstrual cycle, they control many different processes in the bodies of both men and women — including, but not limited to, things such as tendon, ligament, and muscle viability. Tendons and ligaments hold everything in a person’s body in place, including the spinal column. The goal in the field of upper cervical chiropractic is to help individuals hold their spinal alignment so that their bodies can heal properly. An individual’s ability to hold spinal alignment is likely affected by gender and hormonal fluctuations throughout the menstrual cycle and understanding the role that hormones play in the body could be a huge factor in helping patients hold their alignment longer.
The ligaments of the body can be complex to begin with. They have a different composition than muscle, making them more stable, but also slower to heal when damaged. Ligaments are made up of collagen fibers that are produced by fibroblasts, creating the strong and sturdy connective tissue that helps hold things in place in our bodies. “Ligaments often connect two bones together, particularly in the joints: Like strong, firmly attached straps or ropes, they stabilize the joint or hold the ends of two bones together. This ensures that the bones in the joint don’t twist too much or move too far apart and become dislocated” (National Library of Medicine, 2018). There are also ligaments that do not attach to bone, but are meant to hold organs in place, such as the uterus. In particular, the ligaments in the upper cervical spine play an important role in proprioception. This portion of the spine surrounds the brainstem, so when there are issues with the ligaments in this area, it can affect a person’s vestibular system, causing a wide arrange of symptoms from balance issues to vertigo. Maintaining stability of the ligaments in the upper neck will help promote longer holding times in patients. Longer holding times in patients will result in increased ligament strength and decreased symptomatology. The role hormones play in ligament stability is yet another important factor to consider in the equation of taking care of patients.
Having knowledge of a woman’s menstrual cycle and the fluctuation of hormones involved can help identify times of the month when women are prone to increased ligament laxity and, therefore, may not hold their spinal alignment as well. A woman’s menstrual cycle is defined by 4 distinct phases: menstruation, follicular, ovulation, and luteal. As stated previously, estrogen is the dominant hormone during the menstrual and follicular phases (days 1-14) and reaches its peak at the end of the follicular phase just prior to ovulation (Belanger et al., 2013). Upon ovulation, estrogen begins to drop off and giveaway to progesterone. While estrogen begins to pick up again towards the end of the cycle, progesterone remains the dominant hormone during the last half of the cycle (days 15-28) (Belanger et al., 2013). This fluctuation in hormones not only plays a large role reproductively, but play an intricate role in other bodily functions including the resilience of tendons, muscles, and ligaments.
Joint laxity can vary throughout the menstrual cycle due to hormonal changes. In a systematic review of literature done by Belanger, et al. in 2013, 21 studies were assessed including 68,758 total participants. Upon their review, the authors found that anterior cruciate ligament (ACL) injury risk is greater in the pre-ovulatory phase of the menstrual cycle. This means that several studies in this review of literature found that more women succumb to ACL injury during this time of the month. During the pre-ovulatory phase of the menstrual cycle, estrogen reaches its highest levels. Specifically, estrogen reaches its peak just prior to ovulation during the follicular phase of the menstrual cycle. It is important to understand the fluctuation of hormones throughout a woman’s menstrual cycle in order to further identify periods of increased joint laxity and prevention of injury.
Hormones bind to many receptors in different organs throughout the body, including ligaments. When estrogen, in particular, binds to these receptors, it decreases fibroblast production. Fibroblasts are cells that transform into connective tissue and prompt the body to secrete collagen particles which play a major role in keeping the body structurally sound (National Human Genome Research Institute, 2023). When estrogen binds to receptors in ligaments and decreases fibroblast production, ligaments naturally become weaker. With this being said, one can expect ligaments to be most vulnerable when estrogen reaches its peak during the menstrual cycle during days 1-14 (Belanger et al., 2013).
The effect of estrogen on human performance does not stop at ligaments, it plays a crucial role in other musculoskeletal functions, as well. Estrogen can affect a woman’s body in different ways. For example, estrogen levels which are too high can decrease athletic performance and cause women to be more prone to injury (due to the affect it has on fibroblast production in ligaments). On the contrary, too little estrogen can also negatively affect physical performance by leaving muscles and bones prone to weakness. Finding a balance in estrogen levels could be the key to avoiding injury and maintaining physical condition. In post- menopausal women, estrogen decreases significantly, which leads to a decrease in muscle mass.
Just 24 weeks of lowered estrogen can result in a 10 percent decrease in strength and 18 percent decrease in cross sectional areas of muscle (Chidi-Ogbolu et al., 2019).
Along with dietary and lifestyle changes, hormone replacement therapy and oral contraceptives may help to balance estrogen levels. According to Herzberg and colleagues 2017, oral contraceptives may offer up to a 20 percent reduction in risk of anterior cruciate ligament injury and overall reduction of risk in other soft tissue injuries. In an analysis of 840 post- menopausal women, muscle cross sectional area and grip strength were greater in the estrogen replacement therapy group at the end of the study (Chidi-Ogbolu, 2019). In another study, groups who practiced exercise as well as hormone replacement therapy for one year had significantly greater muscle cross sectional area, vertical jump height, and knee extension torque. The group who did not exercise but received hormone replacement therapy had smaller differences, but still increased compared to the control group. While hormone replacement and oral contraceptives may be beneficial in balancing hormone levels, it is important to note they also have their risks associated with them that should also be considered. Risk associated with these supplemental hormones include, but are not limited to, an enhanced risk of cervical cancer, hepatocellular carcinoma, and intrahepatic cholangiocarcinoma (Kamani, 2022). Unfortunately, there are many different varieties of hormonal supplements on the market, so the lines are very blurry as to which may cause an increased cancer risk and the other effects they will have on the body.
In addition to hormonal fluctuations contributing to joint laxity, there are gender differences as well. As mentioned above, anterior cruciate ligament injuries are more common in females, but how do males and females compare? In a study performed by Quatman and colleagues (2008), pre and post pubertal females had overall increased joint laxity than males; however, pre-puberty, males and females experience relatively equal amounts of ligament sprains with differences happening after the age of twelve. The evaluative measurement used to assess joint mobility was the Beighton and Horan Joint Mobility Index (BHJMI). Females had overall higher BHJMI mean scores than males. Post-pubertal females had higher BHJMI scores than pre-pubertal females, supporting the fact that hormones definitely play a role in joint laxity. Males had no significant change in BHJMI scores pre and post puberty. In a study performed by Lovering and Romani in 2005, subjects with higher testosterone throughout various stages of the menstrual cycle showed greater anterior cruciate ligament stiffness than those with lower testosterone. The ACL is an estrogen/progesterone responsive tissue, but it is still unclear if it is androgen responsive, even after this study, because it is likely the higher levels of testosterone are simply balancing out the circulating estrogen levels thereby reducing the binding capacity of estrogen to the ACL. Conclusively, we do not know the entire role that testosterone plays in ligament laxity, but we know that it is not as strong of a player as estrogen or progesterone. Information like this is crucial to understanding the dynamic complexity when it comes to athletes and patients.
By understanding the role hormones and gender differences play in ligament laxity, upper cervical chiropractors can help individuals hold their spinal alignment longer. We now know there are several different factors to consider when caring for patients when it comes to optimal holding times. First, we should consider the gender of the patient as this will play a role in overall ligament laxity. Second, when working with females under chiropractic care, it may be beneficial to document where they are at in their cycle or plan appointments around phases of the cycle when ligaments are less likely to have increased laxity. Third, we might consider if the patient is on an oral contraceptive or hormone replacement therapy. Lastly, weighing the pros and cons of oral contraceptives with the patient and considering hormone replacement therapy for post menopausal women who may be struggling with maintaining muscle, ligament, or bone health would be beneficial. It is important for professionals and patients to understand the large role that hormones play in the body; by increasing one’s knowledge on this subject, doctors can care for patients more effectively and patients will further reap the benefits of continued health and healing.
References
Belanger, L., Burt, D., Callaghan, J., Clifton, S., & Gleberzon, B. J. (2013). Anterior cruciate ligament laxity related to the menstrual cycle: an updated systematic review of the literature. The Journal of the Canadian Chiropractic Association, 57(1), 76–86.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3581006/
Chidi-Ogbolu, N., & Baar, K. (2019). Effect of estrogen on musculoskeletal performance and injury risk. Frontiers in Physiology, 9. https://doi.org/10.3389/fphys.2018.01834
Heitz, N., Eisenman, P., Beck, C., & Walker, J. (1999). Hormonal changes throughout the menstrual cycle and increased anterior cruciate ligament laxity in females. Journal of Athletic Training, 34(2), 144–149.
Herzberg, S. D., Motu’apuaka, M. L., Lambert, W., Fu, R., Brady, J., & Guise, J.-M. (2017). The effect of menstrual cycle and contraceptives on ACL injuries and laxity: A systematic review and meta-analysis. Orthopaedic Journal of Sports Medicine, 5(7), 232596711771878. https://doi.org/10.1177/2325967117718781
Kamani, M., Akgor, U., & Gültekin, M. (2022). Review of the literature on combined oral contraceptives and cancer. Ecancermedicalscience, 16, 14-16. https://doi.org/10.3332/ecancer.2022.1416
Lovering, R., & Romani, W. (2005, July 1). Effect of testosterone on the female anterior cruciate ligament. American journal of physiology. Regulatory, integrative and comparative physiology. https://pubmed.ncbi.nlm.nih.gov/15790748/National Human Genome Research Institute. (2023). Fibroblast. Genome.gov. https://www.genome.gov/genetics-glossary/Fibroblast#:~:text=A%20fibroblast%20is%20a%20type,the%20structural%20framework%20of%20tissues.
National Institute of Health. (2018). What are ligaments? [NBK525790].
https://www.ncbi.nlm.nih.gov/books/NBK525790/
Quatman, C. E., Ford, K. R., Myer, G. D., Paterno, M. V., & Hewett, T. E. (2008). The effects of gender and pubertal status on generalized joint laxity in Young Athletes. Journal of Science and Medicine in Sport, 11(3), 257–263. https://doi.org/10.1016/j.jsams.2007.05.005