Familial Predisposition to Anterior Cruciate Ligament Injury in Australian Rules Footballers

Background: A community athlete with an anterior cruciate ligament (ACL) injury is 2.5 times more likely to have a family history of ACL injury than an athlete without an ACL injury. The prevalence of family history and its relationship to ACL injury has not been investigated in elite athletes playing a high-risk sport such as Australian rules football. Purpose/Hypothesis: The purpose of this study was to determine whether there is an association between primary ACL injury and family history in professional male and female Australian Football League (AFL) players. It was hypothesized that players with a history of ACL injury would have greater rates of family history. Study Design: Case-control study; Level of evidence, 3. Methods: All AFL players in the state of Victoria, Australia, were invited to complete a survey querying about their history of ACL injury and whether they had any immediate family members with a history of ACL injury. ACL injury history was compared in those with and without a family history of ACL injury according to sex. Results: Completed surveys were obtained from 615 out of a possible 672 (91.5%) AFL players, of whom 410 were men and 205 were women. Of players with a history of ACL injury, family history was reported in 47% of male players (15 of 32) and 32% of female players (7 of 22). Male players with an ACL injury history were 3.19 times (95% CI, 1.55-6.76; P < .003) more likely to have a positive family history compared with those without ACL injury, and female players with an ACL injury history were 1.7 times (95% CI, 0.66-4.5; P = .2) more likely to report a family history than those without. Conclusion: A strong association was observed between family history and primary ACL injury history in male Australian rules football players. The same association was not statistically significant in female players.