Oral contraceptives provide protection against anterior cruciate ligament tears: a national database study of 165,748 female patients

Objective: Anterior cruciate ligament (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 determine the potentially protective effects of oral contraceptive pills (OCPs) on ACL tears. 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 29,888) were compared to a control group of females undergoing surgery for an ACL tear, but not on OCPs. Chi-squared testing was used to assess for significant differences in the rate of ACL reconstruction 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 was a total of 569 (0.69%) ACL reconstructions 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 reconstructions, whereas, in the OCP group, this same age group only accounted for 13.33%. Among all age groups, the odds ratios for experiencing an ACL reconstruction while on OCP was 0.82 (chi(2) = 0.001, 95% CI 0.72-0.92) compared to not using OCP. This protective effect was driven primarily by the 15-19 age group (odds ratio 0.37 (chi(2) < 0.001, 95% CI 0.27-0.50)). The number need to treat for OCP usage in the 15-19 age group was six patients. Conclusions: OCPs have a protective effect on ACL tear, especially in the 15-19 age group, which exhibited a 63% reduction in the rate of tear. Consideration should be given to prescribing OCPs to younger athletes, after careful assessment of the risks of these commonly prescribed medications.