My dog had a suspected partial ccl tear on her right knee; then more recently sustained a minor injury to her left knee. We healed both without surgery, but each one took about 5 months of no running just leash walks; then leash walks incorporating hills, then starting her off slowly with a little jogging, then running on leash with me.
We also did some cavaletti exercises as this is one of the activities our surgeon recommended:
Along w/ some massage, passive range of motion exercises, stairs on leash, sits & downs & spins (but all of this as she was ready in the healing process). Did allot of training to exercise her mind and tire her out that way.
Also put her on an omega fatty acid and joint supplement.