Where Sex Matters for Perioperative and Postoperative Anterior Cruciate Ligament Reconstruction Outcomes: A Systematic Review of MOON Literature

BACKGROUND: Females are 2 to 8 times more likely than males to sustain an initial anterior cruciate ligament (ACL) tear. However, after ACL reconstruction (ACLR), it remains less certain how males and females differ in other ACLR-related outcomes. PURPOSE: To summarize Multicenter Orthopaedic Outcomes Network (MOON) studies reporting on ACLR-related outcome differences between sexes. STUDY DESIGN: Systematic review; Level of evidence, 3. METHODS: A systematic literature review based on PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines was conducted utilizing the Embase, MEDLINE, and Cochrane Library databases. Studies were included if they analyzed the MOON knee cohort and reported sex-specific outcomes for perioperative or postoperative primary ACLR outcomes. RESULTS: This review included 28 studies. Six of 6 studies (100%) found no difference between sexes for graft tear at 2 and 6 years of follow-up. Three of 3 studies (100%) found no difference between sexes for contralateral native ACL tear at 2 and 6 years of follow-up. Six of 6 studies (100%) found that female sex correlated with worse Marx activity scores at 2, 6, and 10 years of follow-up. Three of 5 studies (60%) found female sex correlated with worse International Knee Documentation Committee (IKDC) scores at 6 and 10 years of follow-up. CONCLUSION: There was 100% agreement on the following: sex is not associated with differences in graft tear or contralateral native ACL tear at 2 and 6 postoperative years; female sex is associated with worse Marx activity scores at 2, 6, and 10 years; and female sex is associated with worse return-to-play percentages at 2 and 7 years. There was 60% agreement that female sex is associated with worse IKDC scores at 2 and 6 years.