Limited Evidence Suggests a Protective Association Between Oral Contraceptive Pill Use and Anterior Cruciate Ligament Injuries in Females: A Systematic Review

CONTEXT: Female athletes aged 14 to 18 years are at particular risk for anterior cruciate ligament (ACL) injuries. Hormonal factors are thought to predispose them to this injury. Oral contraceptive pills (OCPs) might reduce ACL injury risk, although the literature appears controversial. OBJECTIVE: To evaluate the association between OCP use and ACL injuries in women. The secondary objective was to determine the rates of ACL injuries in the pre- and postovulatory phases of the menstrual cycle in OCP and non-OCP (NOCP) users. DATA SOURCES: Searches were performed across 4 reference databases (PubMed, CINAHL, Embase, Cochrane), abstracts from 6 specialty societies, ClinicalTrials.gov, and reference lists of relevant papers. STUDY SELECTION: We included studies investigating the association between OCP use and ACL injuries in females of any age or the distribution of ACL injuries across the menstrual cycle in OCP and NOCP users. STUDY DESIGN: Systematic review. LEVEL OF EVIDENCE: Level 3. DATA EXTRACTION: Data regarding study design, population characteristics, OCP details, outcome definitions, analytic methods, and results were extracted from the included studies. The methodological quality of each study was assessed using the Newcastle-Ottawa scale. RESULTS: The search yielded 1305 citations, of which 7 retrospective observational studies met the inclusion criteria. Two large case-control studies with higher methodological quality suggested that OCP use may reduce the risk of sustaining an ACL injury. Five comparative studies examining injury distribution across the menstrual cycle in OCP and NOCP users had conflicting findings, were heterogeneous, and were limited by low methodological quality. CONCLUSION: The evidence suggests OCP use may reduce the risk of ACL injury; however, no conclusions can be drawn regarding differences in risk of ACL injuries between OCP and NOCP users across the menstrual cycle. Studies were limited by small sample sizes, heterogeneity, and methodological concerns.