I guess mine was the exception. No osteoarthritis, no ACL tear in other leg, no non steroidal drugs. Herbal supplements during her recovery and for about 1year after (she did not react well to Rimadyl or similar drugs). She was 6yo when she got injured and passed away 6 years later after having a stroke. The night before the stroke she ran her regular 2 miles with me, like she did every other night.
But she was very fit and slim before the injury, and I kept her just as fit and slim after she recovered. I expect that being as fit as she was supported her whole body during and after the injury. (and yes, it was a full ACL tear).