My dog, Alfie, a Black Labrador retriever mix, can’t tell me how much pain he is in, but I’ve known him since he was nine months old and he’s tough: a good dog, a trooper. About a month ago, he snapped his CCL, the cranial cruciate ligament in his leg (named ACL in humans) and after some research I feel like this is actually the end of months of pain. Vets now think that CCL injuries are progressive: picture the ligament being like a rope that frays with wear over years of heavy activity – like sprinting and jumping – and, then, finally snaps. Alfie is what some vets call an “athlete” and he’s now nearing retirement. From time to time over the past few years, he has taken to periods of limping, has been slow to get up after strenuous exercise and needed to rest, so this school of thought makes sense to me.