We read on vets' websites and hear from them in their offices that the surgery they recommend is the best treatment for our dogs' ligament injuries. We assume there must be a solid foundation supporting vets' treatment recommendations-- But is there?

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 claims, they 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 that your dog should have surgery. 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 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. When they discuss treatment options with you their intention is to convince you to accept the treatment option they prefer. 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 an objective expert providing an informed opinion. His intention is to sell you on the surgery, not to provide 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.   

     "...Medical history is littered with once-popular procedures that subsequently proved ineffective or dangerous. ..."         

----------A quote from Consumer Reports 'On Health'


"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 question to be always asking yourself about the claims and statements being made is: "Cui bono?" which is Latin for "Who Benefits?" When considering any statement, this question should be uppermost in your mind. Does the author of an article have a personal interest in the matter? Does he/she see things from a point of view that is other than disinterested? Does he 'have a dog in this fight'? 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 affect 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 

Here are clips from an article published in the professional journal 'Veterinary Surgery'

Applications of Evidence-Based Medicine:

Cranial Cruciate Ligament Injury Repair in the Dog



Objective-—To evaluate the literature reporting surgical interventions pertaining to canine cranial cruciate ligament (CCL) injury using an evidence-based medicine paradigm. 

Study Design— Systematic literature review.

Methods---- An on-line bibliographic search through Medline, PubMed, Veterinary Information Network, and Commonwealth Agricultural Bureau Abstracts was performed during August 2004. Two hundred and forty resources of information were identified. Studies were compared and evaluated with regard to study design (retrospective, prospective, randomization), surgical technique, short- and long-term follow-up, and evidence classification.

Results----Twenty-eight resources qualified to assist with evidence classification. No class I or class II studies were present, 5 studies were categorized as a class III and 23 studies were categorized as a class IV. Seventeen studies were retrospectively designed and 11 studies were prospectively designed. Proposed results ranged from a wide variety of subjective findings including clinical impression, radiographic analysis, synovial fluid analysis, gross pathology, and histopathology. Objective results, although infrequent, included force plate analysis and cadaveric biomechanical testing.

Conclusions—- At this time, the application of evidence-based medicine in analyzing the current available evidence suggests that there is not a single surgical procedure that has enough data to recommend that it can consistently return dogs to normal function after CCL injury. The requirement for assessing and categorizing the available evidence becomes increasingly important as more data becomes available and the quality of research improves.

Clinical Relevance---- An evidence-based medicine paradigm did not provide sufficient evidence favoring 1 surgical technique for management of canine CCL injury.

Copyright 2005 by The American College of Veterinary Surgeons
[from the 'discussion' section of the article:]
"...Our review found no class I or class II studies. This finding is problematic as it is from these classes which the clinician can make the best informed choice about a given therapy under the evidence-based medicine paradigm. Unfortunately, in our review most investigations were retrospective comparison case reviews and non-randomized prospective comparison case series. These studies fall into class III and class IV and provide the weakest information from which to make treatment recommendations. Furthermore, the evidence or results produced from these investigations varied dramatically pertaining to clinical applicability and the use of diagnostic or therapeutic interventions. Thus, the use of evidence-based medicine in answering the current question yielded very little data to support any single procedure. Unfortunately, clinical practice has and will continue to be guided by this datum in the absence of more robust research and reliable evidence. In reviewing the evidence currently available, there is no single surgical procedure that has enough data to suggest a potential for long-term success in terms of return to normal function, prevention of OA [Osteo Arthritis], or any claim of superiority to other surgical techniques. ..."