Sports Medicine Research: In the Lab & In the Field: Oral Contraceptive Use May Help Prevent ACL Injury (Sports Med Res)
Wednesday, January 14, 2015

Oral Contraceptive Use May Help Prevent ACL Injury

Is the use of oral contraceptive associated with operatively treated anterior cruciate ligament injury?: A case-control study from the Danish Knee Ligament Reconstruction Registry.

Rahr-Wagner L, Thillemann TM, Mehnert F, Pedersen AB, and Lind M. Am J Sports Med. 2014; 42:2897-2906.
           
Take Home Message: Women who take oral contraceptives are less likely to sustain an anterior cruciate ligament (ACL) injury than women who do not.

A woman is 2 to 9 times more likely to have an ACL injury than a man, especially in the athletic population. A better understanding of the factors that place women at a higher risk, would allow clinicians to implement more effective preventative measures against ACL injury. Previous literature has shown that collagen synthesis is inhibited when estrogen levels are increased; therefore, Rahr-Wagner and colleagues completed a case-control study to assess the impact of oral contraceptive use on the odds of sustaining an operatively treated ACL injury among women in a national registry. The authors used the Danish Ligament Reconstruction Register and Danish Prescription Registry to identify 4497 women who underwent ACL surgery. Over 8,800 age-matched controls, who had no history of ACL injury, were selected from the Danish Civil Registration System. The authors used the Danish Prescription Registry to determine if the selected individuals used oral contraceptives. Selected individuals were divided into those who ever used oral contraceptives or never used. Among those who ever used oral contraceptives the authors evaluated new users, recent users (took oral contraceptives but stopped), and long-term users. Approximately, 45% percent of the group with an ACL injury used OC compared with ~48% of the control group. After adjusting for important factors (for example, obesity) the authors found that individuals who used oral contraceptives were 11 to 20% less likely to sustain an ACL injury than those who did not take oral contraceptives. These findings were similar for recent users and long-term users. The number of new users were similar between those with and without an ACL injury. Interestingly, using an oral contraceptive for 1 to 4 years may be protective but using an oral contraceptive for more than 4 years did not alter the likelihood of sustaining an ACL injury.

Overall, the authors found that oral contraceptive use has a protective effect against ACL injury. However, one must be cautious before trying to use an oral contraceptive to prevent ACL injuries among women. The two major issues surrounding this data is completeness of information and an inability to assess a patient’s activity level. One major strength of this study was using various Danish registries to develop a large data set; however, patients who did not undergo ACL surgery were omitted in this study. Furthermore, the researchers were unable to determine who was physically active – let alone who was participating in sports. Ultimately, this study indicates that the next step should probably be a randomized clinical trial to test if oral contraceptives can reduce the risk of ACL injuries. In the meantime, clinicians may benefit from using this information more from a diagnostic than preventative perspective. For example, clinicians may ask patients about oral contraceptive use and want to use more ACL diagnostic tests when evaluating knee injuries among athletes who do not use oral contraceptives, as they are at a higher risk. Furthermore, if a patient asks about whether oral contraceptives may help prevent an ACL injury we can use this study to explain that there is some evidence to support this concept but it is unclear if it will hold up in future studies with female athletes.

Questions for Discussion: Do you currently make note of oral contraceptive use during preseason athlete screening? If so, how do you feel this has impacted your ability to prevent, diagnose and treat injuries if at all?

Written by: Kyle Harris
Reviewed by:  Jeffrey Driban

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Rahr-Wagner, L., Thillemann, T., Mehnert, F., Pedersen, A., & Lind, M. (2014). Is the Use of Oral Contraceptives Associated With Operatively Treated Anterior Cruciate Ligament Injury?: A Case-Control Study From the Danish Knee Ligament Reconstruction Registry The American Journal of Sports Medicine, 42 (12), 2897-2905 DOI: 10.1177/0363546514557240

4 comments:

Kaitlyn Grossman ATC said...

In pre-participation forms, I do ask whether athletes are currently taking oral contraceptives. I use the information in conjunction with menstrual history in the past year. I can admit to never thinking oral contraceptives could prevent ACL injuries. I always associate it more with stress fracture prevention. I think it is interesting that there was some evidence to show it may prevent ACL injury. If there was more substantial numbers and this study was repeated several times in several populations, I could possibly see the recommendation for the use of contraceptives. Although, I think it is important to take into account that there was no difference in individuals who have been taking contraceptives for over 4 years. I wonder how applicable this would be depending on the patient population you are working with. Interesting thought. I wonder if there were any other side effects or abnormal findings that could have been caused by the use of the contraceptives. Also, I think its important to weigh the ethical issue. Some girls are against contraceptives, and we have to be cautious of what recommendations we are making as clinicians.

Kyle said...

Kaitlyn,

You bring up some very interesting thoughts and comments. I could not agree more with your comment about wanting to see the study results reproduced. I also would be interested in the side effects as you pointed out. I believe that since the information was retrospectively collected from a registry the information was not as readily available and thus was not addressed in the article. This again shows why reproducing the results in additional studies would be ideal. I also think your comment on the ethical questions surrounding this topic are spot on. Often as clinicians we are anxious to find ways to help our athletes but we should always be vigilant to temper this with maintaining a patient-based approach. While we see trends in treatment options on paper, each individual athlete and or patient is exactly that, an individual. Again, great comment! Thank you!

Jennifer Joseph said...

I find this topic to be very interesting right now. Our PPEs ask each athlete about the regularity of their menstrual cycle as well as if they use OC regularly. I wonder how recommendations for OC use would change depending upon the patient population you are working with. Would young high school female athletes benefit from taking OC compared to college athletes? I think we also have to take into consideration the age each athlete began menstruating as well as weight, as these are 2 internal variables that play a huge role on hormone production. An idea for a future study would include testing patient's knee laxity throughout the month and correlating findings to the monthly cycle.
- Jennifer Joseph

Jeffrey Driban said...

Hi Jennifer: You may be interested in Sandra Shultz's paper that evaluated knee laxity throughout the mentrual cycle and how they relate to other changes (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3371148/).
Your point about the potential benefits of OC among high school or college athletes is a great one and a good study that will hopefully get done.

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