Huh, we had two newfs that tore thier cruitate ligaments. One we knew imediately, she was simply walking and slipped on a piece of ice and lifed her leg right away, had to be corrected with surgery. The other one also tore the cruitate ligament, but he would walk fine for about 10-15 minutes, then became lame, surgery agan! Now, we have an older newf that has always had a on and off limp since he was a pup, the vets cannot find anything. If she needs surgery,you MUST follow the rehabilitaion instructions to the letter, if you do, they make a full recovery. Just our experiences, good luck