The title quote belongs to my therapist. In PT we’ve been focusing intensely on strengthening the gluts–never gets old.
It’s all about getting the butt in shape so it will pull your body into better alignment and prevent further injury.
The butt is easier than you think to whip into shape, at least for the knee-supportive-strengthening purposes. Start with stairs and sitting/standing–two activities will do multiple times throughout the day. Since so much of rehab is a head game, and retraining your thinking about how your muscles work, get yourself to think that using your butt muscles is the ONLY way to pull yourself up from a seat and up a flight of stairs. So squeeze, pull and repeat. Try to consciously think about it for one whole day. If your butt isn’t sore by the end of the day, then try harder 
It sounds simple, but you want to focus on retraining your “head,” which will trickle into every exercise, movement and sport you do.
A long, but informational video on Glute Strengthening and Theory from Posture Exercises blog.
Hi, I’ve been reading your blog for about a week now. I just tore my ACL and have been documenting my progress as well. Thanks for starting this blog, it has helped me tremendously in getting in the right state of mind for my upcoming surgery.