I have had 2 dogs with torn CCL, one dog tore both back legs. The first dog had the "fishing line" surgical repair (the cheaper one) and the first leg healed ok, but not 100% and the 2nd leg did not heal and we had to put her down (she was 12 when she had the 2nd surgery). This was A LOOOOOOOOOOOONG time ago so they may have changed and/or perfected the technique since then.
My 2nd dog was 150 pounds, the only option we had with him was the TPLO since he was too big to support weight on that leg with the other surgery. He healed magnificently and never showed any pain or arthritis from the surgery. We had x-rays taken about 3 years later for another issue and the knee showed minimal arthritis. Your vet probably wants to rush into surgery to prevent/reduce inflammation and arthritis from the bone rubbing together. Since you run with your corgi I would recommend a TPLO. It is more expensive but it is also more of a sure thing if you follow the recovery directions. My dog walked out of surgery on all four feet with no limp the day after surgery. You can equate the TPLO surgery to a healing after a broken leg.....its essentially the same thing, so as long as you give the bone time to heal and keep up on the pain meds for the first 2 weeks or so they will be fine. My dog seemed more bothered by the fact that he couldn't run and play than by any pain he may have been feeling.
I went through a torn ACL with Seanna just last year. I went with surgery, as Seanna is very active also, and if you run with Dakota, then that is the route I would take. I also have a rescue dog, Jackson, that tore his approximately a year before I got him, and I could have had the surgery done but opted for conservative management instead- for different reasons.
The surgery is the best way to fix the tear. Without the ligament, the bones are free to move as they please, causing much arthritis. I had Seanna's surgery done two weeks after the tear, and she had already started to form arthritis. Now, the surgery won't prevent arthritis from forming-it still will- it just won't be as bad later in life. The two surgeries called extracapsular repairs are temporary fixes while the scar tissue is formed, then the scar tissue is what stabilizes the leg for the rest of their life. (These are called "fishing line" or the tightrope procedures). The "gold standard" of repair is the TPLO. What type of surgery you opt for depends on your financial status, how active your dog is, the angle of the bones and what weight your dog is. The extracapsular repair is the cheapest, and the fishing line is the cheaper of the two surgeries. The cost of all repairs depends on where you live. I found a vet to do the fishing line for $500 about 45 minutes away from where I live, but opted to go with a surgeon here in town that did it for $1200. The tightrope procedure was going to be $2000, the TPLO $3000. As far as all managements of the tear go, all are painful and rehab after is time consuming. Your dog will have no activity for approximately 12 weeks, and must do physical therapy exercises three times a day. I also chose to go to hydrotherapy after surgery for a month, and that helped a lot. We went 3 times a week at $40 a session.
So the choices are really up to you, and what your vet recommends. I would recommend the surgery. Jackson never had his repaired, and is lame quite frequently. We give him Previcoxx, and that helps with the pain, but Seanna hasn't limped at all since early spring when we started running her hard. She is VERY active, and has done extremely well. You can contact me at any time if I can answer any more question for you!
There are two types of extracapsular. One is where they take line (used to be fishing line...no kidding) and the other is a newer procedure called the "tightrope" procedure. Seanna had the one with the fishing line- and since she was active he put two lines around her knee-equaling 80 pounds of tension. (40 each). The tightrope is a braided material, and is essentially the same concept- just a little more sturdy material. I didn't go with that one because it was a relatively new material, and there were studies that suggested the infection rate was higher because bacteria could attach easier to the braids. Jill Usher, a member here too, had her corgi Jake done with this method and had great success with no complications. My vet (who I love and trust) stated that for a dog under 30 pounds (max weight) the extracapsular is a more than adequate repair. I would have gone with the TPLO but I have this thing for bones--I'm an RN in an Emergency Room and can't stand broken bones--it totally grosses me out. So the thought of them cutting her little legs just wasn't something I could do. Plus the husband would have killed me if I'd spent that much money on one leg. He was mad enough I didn't go with the vet that was only $500. I don't know if they told you this, but once one goes, the odds are very good that the other leg will go too within 1.5 years. Seanna is still going strong though, and the other leg is solid.
The hydrotherapy is essentially just a big tub of water with a treadmill underneath that they can walk on or swim in. I have pictures and I think a video on my site of her at some of her sessions. It was expensive, but the rehab doctor gave us many different exercises to do than the surgeon did. The science is that the resistance of the water helps strengthen the muscles in both legs while providing the bouyency of the water so not all weight is placed on the rehab leg. Seanna hated it at first, even with all the noms, but finally got to the point where she just had the attitude of "alright, let's get this over with". I really believe it helped alot. They had her walking for 30 minutes at a time in the water, and by the end she was going at a pretty good pace--plus she lost weight. They had her doing weaves, balance board, laser therapy, going up and down blocks, plus gave me at home exercises to do.
How are you keeping her confined? It's crucial there are no sudden bursts of exercise (frapping is a no-no), no jumping, no running, no stairs. I went to PetSmart and bought a round puppy pen, put a bed in there, and that's where she stayed the whole 14 weeks. She really did very well. There's pictures of that on my site too...send me a request and I'll approve you...