As you consider ligament injury treatment options, bear in mind that there is a lot of poorly-supported opinion presented as though it were fact on the various vets' websites and in their offices. Anyone who looks into canine ligament injury treatment will find there is no shortage of statements from surgery advocates making claims about the surgery they sell. Asked for evidence to back up their opinions, surgeons point to flawed Class III & IV studies full of outrageously sloppy thinking which would be laughed at by anyone familiar with scientific method and the accepted norms of medical research. This sort of thing is often what you see referred to as supposedly providing proof of a surgery's superiority. These 'proofs' are not proof to anyone who understands what scientific medical studies really involve and what methodological flaws are not acceptable in research. Unfortunately most of us just trust that the vet knows best, and don't question the basis of his opinion.

The sad truth is that evidence-based medicine is not the standard in veterinary treatment. While surgery of one kind or another is many vets' first choice for treatment of ligament injury, this preference is not supported by real evidence indicating that any surgery leads to a superior outcome.  Unfortunately, the preference for surgical treatment is often supported by the profitability of the procedure, not its efficacy.

Human docs and vets often 'spin' the facts when they talk with patients/clients. They misrepresent the prognosis, the potential for complications and failure of treatments, the options available, etc. This is done because they believe that they know best and when they discuss treatment options with you their intention is to convince you to accept the treatment option they prefer. It is a rare doc who thinks you are the right person to make your own medical treatment decisions. Most are not trying to present you with the unvarnished facts. They are 'spinning' the facts to make their preferred treatment look best to you. It's wise to bear this in mind in your interactions with vets and other docs. When you discuss with a surgeon whether surgery is appropriate, remember that his goal is to convince you to agree to the surgery he recommends. He is an advocate for his surgery, not a disinterested person providing an informed opinion. His opinion may be heavily influenced by the fact that he is in business to make money.  His intention is to sell you on the surgery, not to inform you with a balanced presentation. He will emphasize some facts and fail to mention others. He may really believe that what he is selling is best, but that doesn't mean he is right.   

"Max, you say there is no research to support the TPLO surgeons' claims, but the surgeon we saw says there are lots of peer-reviewed published articles that show TPLO to be great. And I see these articles on the net when I do searches for TPLO info. How do you respond to that?"

The TPLO articles you have seen are what are referred to in research as "Class III" and "Class IV" studies. These are very different from what we usually think of as medical research. We expect that in a medical research study there are rigorous controls on the way a study is organized and conducted.  These controls function to exclude bias and error. That kind of study is a Class I or perhaps a Class II study. In Class III & IV studies, what you see is basically the article's author reporting his opinions concerning his own experience with treatment. In theory the opinions of docs who have experience with a procedure should be valuable, but the value of these opinions falls into question when the authors of the articles are making large profits doing the type of procedure they are reporting on. In reading research articles, the first question to ask is: "Que bono?" which is Latin for "Who benefits?" When considering any statement or claim, this question should be uppermost in your mind. Does the author of an article have a reason to favor a particular way of addressing a question?; A personal interest in the interpretation of the results? Does he/she see things from a point of view that is other than uninvolved and disinterested in whether the procedure being considered is shown to be advantageous or otherwise? When the answer is that the article was written by someone who profits a great deal from the procedure his 'research' concerns, and he has published a Class III or Class IV study, I think it is clear that there is little or no value in it for obvious reasons.

As an analogy to describe the nature of Class III & IV studies, consider this--- Someone might write: "I have driven Ford cars and Chevy cars and all the foreign-makers' cars, and I tell you I am sure that Chevy makes the best cars. I've compared their features and there is no doubt Chevy is superior." If I believe he is a man who knows cars, this opinion of his might influence me. But if he owns a Chevy dealership, that is going to seriously effect the value of his stated opinion. The Class III & IV studies on TPLO written by TPLO surgeons are similar to a car dealer saying his brand is best. The lack of objective perspective is much the same. The self-interest is the same. The difference is only that the surgeon writes his opinion in medical jargon. 

"...Most studies in orthopaedics are retrospective case-control studies in which the surgeons simply report their experience with a procedure and bias is uncontrolled. ...Retrospective studies have some value, but of all study types they are the most susceptible to misinterpretation. They are the easiest to perform, but they are also the most prone to study error. History has shown that many drugs, treatments, and surgeries initially thought to have benefit on the basis of retrospective studies are later shown to be beneficial mostly or entirely from a placebo effect. ..." ---Bruce Moseley, MD