I might be wrong here but both Sophie and Abbie injured themselves in the exact same way your describing and I cant recall the name of the injury. Both injured the opposite leg with in a year. At the time my vet said this injury used to be treated only with surgery but now he could treat it with a shot serries of Adequan. They each got 4 to 6 shots 2weeks apart at $50. a shot, totalling $200 to $300. Sophie's brother also had this problem but they used a different vet and had surgury.(cost a fortune)All dogs healed wonderfully. My records dont say the name of the injury but it was a torn something in the hind leg. They would run around the yard yet limp in the house and seem afraid of stairs.Vet said they werent in pain just afraid to use the leg. I can call on Monday to find out the name, maybe it was something else, it just sounds like the same thing.Either way good luck.