Background: Anterior cruciate ligament (ACL) injuries are a critical health care issue for the young sporting population with over 100,000 injuries occurring annually in the US alone. Of the 4000 papers published on ACL injuries over the last 15 years only 3% deal with prevention of injury. Recognising at-risk groups is an essential part of preventing ACL injuries and reducing the injury rate. Some studies have suggested that there may be a family predisposition to ACL injuries. In addition ACL injuries in siblings are commonly observed in the clinic. One, possibly genetic, factor contributing to the pathogenisis of sibling injuries may be narrow femoral intercondylar notches, which are well recognized as predisposing to ACL injury. Purpose: This study aimed to compare intercondylar notch width size between injured and uninjured control siblings. It was hypothesised that siblings with ACL injuries would have significantly narrower notches compared to those without and that shared narrow notches would be more common in the injured compared to the control sibling pairs. Methods: 12 ACL injured participants from a physiotherapy cohort of 72 and their 12 injured siblings took part in this study together with 24 uninjured siblings matched for activity level, age, gender, and family composition. Intercondylar radiographs using the LePrade view were taken of all 48 paticipants. The anterior and posterior notch width indices were calculated. by an assessor blind to the grouping of the subjects. Using ANOVA and Chi-square analyses, the size and the number of narrow notches in sibling pairs, were compared between groups. Results: The average anterior notch width index was .18 in ACL injured and .24 in uninjured siblings (p < .001). The posterior notch width index was .26 in injured to .30 in uninjured siblings (p = 0.006). Sixty percent of injured sibling pairs shared a narrow notch, while no uninjured sibling pairs did so (p = .003). Conclusion(s): This study showed that siblings (and often sibling pairs) with ACL injuries do have significantly narrower notches than those without. This could partly explain the prevalence of ACL injuries in siblings. However other predisposing factors may also be involved. Implications: This study suggests that if one sibling in a family has a ruptured ACL, other siblings may be at-risk. The role of physiotherapists should involve advice to such siblings on notch width assessment as well as education re participating in safer sports and in injury prevention programs, which are shown to reduce the rate of ACL injuries in young sports people.
2015 World Confederation for Physical Therapy (WCPT) Congress, Singapore 1-4 May 2015