If you blow your left ACL, you are at higher risk to blow your right ACL.
These are my theories:
- Pre-disposing factors for ACL injury remain the same, such as, female (anatomic alignment, neuromuscular imbalance, hormonal fluctuation), anyone (narrow tunnel for ACL/PCL, narrow intercondylar notch, poor ratio of hamstring strength to quadriceps strength, initial joint laxity, poor sports technique)
- Under-rehabilitation of the "good". The focus is on getting the quad & hamstring strength returned in the bad leg, and improving proprioception on the bad leg, that the "good" leg is often ignored.
- Overcompensation putting more forces on the "good". Such as landing a jump with more weight on the uninjured limb. Fear of re-injury causes one to use the "good" one more often. Maybe some kind of interaction with fatigue caused by brace and change in mechanics?
For the ones in the business, am I heading down the right path? At first I thought it was all about overcompensation, but now I'm thinking under-rehabilitation of the contralateral leg may be an even larger factor.
Interesting tidbit: It appears ACL injuries occur significantly more frequently in the left leg.