Purpose: Previous research has provided evidence of a hereditary predisposition for anterior cruciate ligament (ACL) injury. The purpose of this study was to evaluate the association between ancestral population genetics and risk of non-contact ACL injuries.
Methods: Blood samples were collected from 177 individuals with a history of non-contact ACL injury and 556 non-injured control individuals for analysis of the genetic material through the use of a panel of 48 INDELs ancestry genetic markers from three ancestral origins.
Results: Among patients with non-contact ACL injury, 82% were male and 18% were female. In the control group, 78% were male, and 22% were female. The mean age of the non-contact ACL injury group was 31.7 years (± 10.2), and the control group was 33.8 years (± 13.2). The individual genetic contribution from INDELs of each ancestral origin varied considerably: ranging between 1.5-94.8% contribution for INDELs of African origin (mean of 21.4% of INDELs); between 2 and 96.1% contribution for INDELs of European origin (mean of 66.7% of INDELs); and between 1.3-96.4% contribution for INDELs of Amerindian origin (mean of 11.7% of INDELs). When comparing paired subjects from the non-contact ACL and control groups, the genetic analysis showed that the European ancestry score was higher in the non-contact ACL group than control group (0.70 ± 0.21 vs 0.63 ± 0.22 respectively, p < 0.001), whereas African ancestry scores (ACL group 0.18 ± 0.18 vs control group 0.24 ± 0.21, p < 0.001) and Amerindian ancestry scores (ACL group 0.11 ± 0.09 vs control group 0.12 ± 0.10, n.s.) were lower among the non-contact ACL group than in controls.
Conclusion: European INDELs markers were found to represent a potential genetic predisposition for non-contact ACL injuries when compared to African and Amerindian INDELs. This study has the potential to correlate a measurable and distinct genetic marker with risk of a non-contact ACL injury. Thus, it increases knowledge base and volume of molecular and genetical factors associated with this pathology. Furthermore, this study provides guidance and evidence for the development of genetic risk-screening panels for non-contact ACL injury.
Level of evidence: Level III Diagnostic Study.