Two of our four sons have had to have an ACL repair from injury while playing sports. Their father had both ACLs repaired from different football injuries. Is there a genetic link or is it just the dumb luck of sports injuries?

You pose a good question. There may be a hereditary connection butresearchers haven’t addressed this topic directly. In a recent study from Australia, the results of 50 patients with revision ACL repairs are reported.

All 50 patients had the first ACL repair, which failed. A second (revision) operation was performed. Five of the 50 patients (10 per cent) had a failed revision surgery. The data collected from the patients showed that 16 of the 45 patients had a positive family history. That amounts to more than one-third (36 per cent) of the group.

Soft tissue such as muscles, ligaments, and fascia are made up of collagen fibers. The pattern of the collagen tissue as it forms each of these structures helps determine its strength. There are more than a dozen types of collagen fibers that determine how elastic the tissue is.

Variations in collagen length and elasticity are likely genetically determined. A positive family history of ACL injuries in your family may be the key factor here — more than luck! Participating in contact or collision sports also increases the chances of trauma and injury.