There is a paucity of information on the influence of patient sex on outcomes following ACL reconstructions (ACLR). Previous studies have demonstrated that females have worse outcomes with regards to instrumented laxity, revision rate, Lysholm score, Tegner activity score, and are less likely to return to sport. However, other measures have been shown to be similar between male and female patients. The purpose of this study was to perform a systematic review and meta-analysis comparing outcomes after ACL reconstructions with regard to sex.
A systematic review and meta-analysis were conducted using PubMed, PubMed Central, Embase, Cochrane Library, and OVID (inception – April 2020) according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. Outcomes including functional tests, re-rupture rates, re-operative rates, post-operative range of motion, post-operative stability, return-to-sport rates, and International Knee Documentation Committee (IKDC) scores were recorded and analyzed.
Studies that reported post-operative IKDC scores, re-rupture rates, and revisions rates were included in the meta-analysis. For IKDC scores, there were 7 studies included with 2022 males and 1402 females. We found that males had a statistically significant higher IKDC post-operative score (MD = 3.02; 95% CI = [1.19, 4.84]; I2 = 66%). Seven studies (14,543 males and 5,306 females) reported the rate of ACL revision. Our results show that there was no significant difference between males and females with regards to revisions (OR = 0.85; 95% CI = [0.45, 1.60]; I2=94%). For the re-rupture rate, there were 7 studies with 19,370 males and 14,747 females. We found that males were significantly more likely to suffer a graft re-rupture than their female counterparts (OR=1.35; 95% CI = [1.22, 1.50], I2 = 0%). Males also reported a 17% higher return-to-sport (RTS) rate than females (59.82% compared to 42.89%); however, no formal statistical analysis was able to be done due to the variability in reporting techniques between papers.
To our knowledge, this is the most recent and comprehensive study focused on the role of a patient’s sex on ACLR outcomes. Males and females showed similar outcomes with regards to rate of revision surgery. However, males were found to have higher post-operative IKDC scores and higher re-rupture rates. Males also showed almost a 17% higher incidence of returning to sport; however, the variability in reporting RTS rates following ACLR by sex prevents us from being able to perform a statistical analysis on these results. More studies are needed that focus directly on the effect of sex, combined with other co-variables such as age, graft used, or level of sport, to increase the breadth of knowledge on sex specific outcomes following ACL reconstructions.