We have had two dogs tear their ACL on their back leg (at different times), one was a 25 pound cockapoo and the other was a 30+ pound cocker spaniel. My wife researched the different surgery options but found someone local (Christiansburg) that does laser therapy combined with rehab. It worked for both dogs, after a couple of weeks of therapy, they were both back to normal walking and running. The surgeries do work as others have said, just wanted to mention an alternate (and less expensive) option is out there.... 91