We written many blog posts on ACL injuries as they continue to be a risk to our youth and amateur athletes in Boulder County.  Thankfully, evidence shows we are able to screen athletes at risk for future injury as well as reduce their risk through Physical Therapy strength, balance, and conditioning programs.  Another group at risk of future ACL injury are those athletes who return to sport after surgery and Physical Therapy.  A percentage of these athletes are at risk for re injuring their knee, but they are also at risk for injury to their uninvolved knee.

A recent study in The American Journal of Sports Medicine documented the incidence of second ACL injuries either to the involved or uninvolved knee after the athlete returned to sports (Schilaty et al. 2017).  The authors followed over 1000 athletes over a ten year period to determine the number of 2nd ACL tears.  They reported 66 (6%) of repeat ACL injuries with a surprising 67% occurring on the opposite side.  A few factors including graft type, reconstruction vs. conservative care, and an athlete’s sex were correlated with this 2nd injury.  Allografts were associated with higher re injury risk compared to ACL autografts with patellar tendon autografts having the lowest risk of re injury.  The highest risk of re injury was found in females younger than 20 years old.  This study highlights the importance of completing a full course of post operative Physical Therapy after ACL surgery as well as delaying return to sport until 9-12 months.