My 11 yr. old cairn had to have both knees done as he tore the ACL when he was 2 yrs. old and then the other one 8 months later. I took him in for his annual check up two days ago. The vet who did both surgeries is on vacation so a different one saw him. She said one of his knees felt "bubbly" and asked if he was having any problems. I said no, everything has been fine. Now I am a bit worred since I felt the knee and it does seem bubbly. He has not had any problems leg- wise since the surgeries. At the time I did not think to ask if the repair will last his lifetime. Anybody know? If your dog has had ACL repair has it ever felt bubbly? Does the surgery ever need to be done again? If it is not holding up is it a gradual process or sudden?