answer:Not sure why he told you to wait 9 months unless it’s a partial tear. A (fully) torn ACL does not heal on it’s own, and time only increases the arthritic changes in the joint. Whether to repair the tear will be a judgment call on your part. A 13yo GSD doesn’t realistically have a whole lot of years left, but it really depends on his quality of life. There are several surgical techniques available, although my personal choice for an older animal would probably be an extracapsular repair (as opposed to some of the more dramatic techniques). It’s less expensive, less invasive, and though it doesn’t tend to last as long, that’s probably not an issue in this case. (We primarily use the TPLO technique, or excap for small dogs.)