Had to get my old lurcher Jack PTS on monday, he had taken a knock a month ago to his knee when lamping a rabbit, he brought it back across two fields one being plough, then jumped a wooden fence dropping it at my feet, I could see he was sore as he came back, he was holding one leg.... a few trips to the vets, antiinflams, antibiotics, numerous xrays at first the vet suspected the dog had jarred his hock, but we later found he'd taken a knock to his knee and developed a lump that was growing and had triggered bone cancer... I had to make the decision to get him PTS, I was totally devastate