Oral Contraceptives Provide Protection against Anterior Cruciate Ligament Tears: A National Database Study of 165,748 Female Patients

Abstract

Objectives: ACL tears are more prevalent in females than males. One of the factors responsible for this may be the variation in levels of estrogen and progesterone. The purpose of this study was to query a large nationwide database to determine the potentially protective effects of oral contraceptive pills (OCPs) on ACL tears. We hypothesized that females taking OCPs would exhibit ACL tears at lower rates than a matched population of patients not taking OCPs. Methods: The PearlDiver database (www.pearldiverinc.com, Fort Wayne, IN) was queried for all OCP users amongst females aged 15-49. Female experiencing an ACL tear and undergoing surgery (CPT 29888) were compared to a control group of females undergoing surgery for an ACL tear, but not on OCPs. Patients were matched by age and Charlson comorbidity score. Chi-squared testing was used to assess for significant differences in the rate of ACL tears for the OCP and non-OCP users, according to age groups broken down into age intervals of 5 years. Results: There were a total 82,874 patients in both the OCP and non-OCP groups. There were a total of 569 (0.69%) ACL tears in the non-OCP group and 465 (0.56%) in the OCP group (p<0.001). In the non-OCP group, patients aged 15-19 accounted for 29.35% of all ACL tears, whereas, in the OCP group, this same age group only accounted for 13.33% of ACL tears. Among all age groups, the odds ratios for experiencing an ACL tear while on OCP was 0.82 (χ2=0.001, 95% CI 0.72-0.92) (Figure 1) compared to not using OCP. This protective effect was driven primarily by the 15-19 age group (odds ratio 0.37 (χ2<0.001, 95% CI 0.27-0.50)). Conclusion: This investigation utilizing a large national database found that usage of OCPs was associated with an 18% decrease in the risk of ACL tear when compared to a matched population of patients with ACL tears not taking OCPs. These findings were in line with smaller studies which demonstrated similar results. Additionally, it was shown that OCPs were most protective in the 15-19 year old age group, with a 63% reduction in tears in this group. Ongoing randomized trials in patients without ACL tear could help to demonstrate further clinical evidence for OCP usage as a way to modify risk factors for ACL tear. While clinical evidence is limited, there should be strong consideration for OCP usage in elite high school and college aged athletes, especially those who are at risk of ACL tear.