One of the most serious consequences of a primary anterior cruciate ligament (ACL) injury is the substantially high risk of sustaining yet another ACL injury, in both the ipsilateral and the contralateral knee. In a meta-analysis from 2016, Wiggins et al53 concluded that an athlete who returns to play after an ACL injury has a 20% chance of sustaining a new ACL injury, with the contralateral knee being slightly more susceptible than the ipsilateral knee.