Female Athletes are Underrepresented in Anterior Cruciate Ligament Reconstruction Rehabilitation Studies: A Systematic Review.

Purpose: To systematically review the representation of female athletes in the current primary literature available on rehabilitation following anterior cruciate ligament reconstruction (ACLR).

Methods: A systematic review was conducted using PubMed to provide a comprehensive analysis of female representation in ACLR postop rehabilitation protocols. PRISMA guidelines were followed. Studies were analyzed based on nine factors: study population, athletic caliber, menstrual status, research theme, journal impact factor, sample size of male and female participants, time to return to sport (RTS), and graft failure rate. Population categories included males-only, females-only, mixed-sex, and male vs. female comparisons. Athletic caliber had six tiers. Menstrual status was categorized as natural, hormonal contraception, irregularities, mixed, or unclassified. Research themes were health-focused, performance-focused, or combined. Study impact was assessed via journal impact factor.

Results: Thirty-three studies were included. Females comprised 3031/6798 (44.6%) of ACLR participants. No female-only studies were found; male-only studies accounted for 3/33 (9%), mixed-sex for 25/33 (69.7%), male vs. female sub-analysis for 3/33 (9%), and male vs. female features for 2/33 (6%). No studies investigated outcomes for the highest athletic levels. Menstrual status was not considered. No studies focused on performance outcomes; 25/33 (69.7%) had a health research focus. Females were underrepresented in studies evaluating RTS timeline and graft failure rate.

Conclusion: Females face a 2-8 times higher risk of ACL injury but are underrepresented in ACLR postop rehabilitation studies, with only 44.6% participation compared to 55.4% for males. In nine studies, females comprised 30% or less of participants. Even studies including female athletes at near-equal rates failed to address menstrual status or sex hormones on injury and rehabilitation.

Level of evidence: Level IV, Systematic Review of Level I - IV studies.