Evidence Update–Is Surgery Really Necessary for Dogs with Cruciate Ligament Ruptures?

A couple of years ago, I wrote about the question of whether or not surgery was better than medical management for dogs with cranial cruciate ligament (CCL) disease. Here was my conclusion at that time:

As is almost always the case, the evidence is not of the highest possible quality or unequivocal, but this does not exempt us from having to draw conclusions and make recommendations to our clients. My interpretation of the available evidence is that overall, cruciate ligament disease causes significant arthritis and loss of function when untreated. For most dogs under 15kg, conservative management (primarily restricted activity for 3-6 weeks, achieving and maintaining and appropriate body weight, and possibly physical therapy and pain medication) can achieve acceptable comfort and function. In larger dogs, significant arthritis is inevitable and dysfunction is extremely likely without surgical treatment. No single surgical technique is clearly superior, so the choice of specific surgery should be determined by the judgment of the individual surgeon and the needs of the owner.

A recent research article has added an important piece of evidence concerning this subject, and while supporting the value of surgery it does weaken somewhat the case against medical treatment for large dogs.

Wucherer, KL. Conzemius, MG. Evans, R. Wilke, VL. Short-term and long-term outcomes for overweight dogs with cranial cruciate ligament rupture treated surgically or nonsurgically. Journal of the American Veterinary Medical Association 2013;242(10):1364-72.

The authors interpretation of the results supports the argument that both surgical and nonsurgical treatment can be successful, even in overweight large-breed or giant-breed dogs, but that surgery appears to provide a better outcome.

Overweight dogs with CCLR treated via surgical and nonsurgical methods had better outcomes than dogs treated via nonsurgical methods alone. However, almost two-thirds of the dogs in the nonsurgical treatment group had a successful outcome…

Overall, I agree with their conclusion, though I would probably place less confidence in it than the authors do.

The Study
Forty overweight large-breed or giant-breed dogs with unilateral rupture of a CCL were recruited and randomized to either medical therapy alone (a weight loss program, individualized physical therapy, and daily use of a nonsteroidal anti-inflammatory medication) or medical therapy plus surgical therapy (TPLO). Outcomes were assessed at 6 weeks, 12 weeks, 24 weeks, and 52 weeks after the beginning of the study.

There was a high rate of drop out (5 digs by 6 weeks, 11 dogs by 24 weeks, and 17 dogs by 52 weeks). The majority of these dogs (11/17) dropped out due to CCL rupture in the opposite leg, and there was no overall difference in dropouts between the two groups (9 in surgical group and 8 in non-surgical group).

Both subjective outcome measures (surveys of owner perception of their dogs’ pain and lameness and pain scores generated by the investigators) and objective outcome measures (body weight, body fat, body condition scores, and several measures generated by force-plate analysis) were evaluated at the beginning of the study and in the dogs still participating at each follow-up point.

The Results
No adverse effects were reported for the weight loss diet, the NSAID therapy, or the physical therapy. A few minor complications associated with TPLO surgery were reported at rates consistent with those reported in other studies.

The weight loss program did result in decreases in body condition score and percent body fat for both groups, and there were no significant differences between the two groups. Interestingly, while total body weight did decline slightly for both groups, the decrease was not statistically significant for either, and there was no difference between the groups.

Subjective measures, both owner and investigator assessed, improved significantly for both groups. There were no differences between the groups in the subjective outcomes assessed by the investigators. The surgery group had significantly lower scores for pain severity and interference than the non-surgical group only at the 52-week evaluation. Some differences between the groups in visual analog pain scale assessment by owners were reported, but how many measures were assessed and which ones differed were not reported, and no statistical analysis of these differences was reported, so it is difficult to assess this outcome measure.

Of the several force-plate measures assessed (5 or 6 measures; it isn’t clear from the paper), only one differed between the groups, and this difference was significant only at two of the four assessment points (24 weeks and 52 weeks).

The investigators also created a composite measure of “successful outcome,” defined as achieving both a specific force-plate measure that was >85% that of a normal dog and a subjective, owner-assessed improvement in lameness and quality of life >/= 10%. The dogs in the surgical group had higher “successful outcome” scores at all assessment points, but this only reached statistical significance at 24-week evaluation.

Strengths of the Study
Overall, this was a well-designed study. The use of both subjective and objective outcome measures, random assignment of treatment, an aggressive and consistent medical therapy program, and partial standardization of surgical treatment all reduce the risk of bias, confounding, and other error in the study. The consistency of several reported variables (such as surgical complication rate) with those reported in other studies increases the confidence one can have in the results. And the attempt to verify compliance with the weight loss aspect of medical therapy is an important part of any study employing this therapeutic approach.

Limitations and Caveats
A significant limitation is the lack of blinding of owners or investigators to treatment group. While blinding would be difficult, and possibly unethical due to the need for a sham surgery component, the lack of blinding introduces significant risk of information bias, particularly in the subjective outcome measures.

There was some individualization of surgical procedure and physical therapy treatments employed, which means not all subjects had the same treatment. If some techniques used work better than others, or if the selection of technique to be used is associated with the likelihood of a good or bad outcome, this could generate an erroneous impression of the differences between the surgical and non-surgical treatment groups.

The biggest limitation of the study was probably the high dropout rate. In general, dropout rates greater than about 20% are considered to severely compromise the data, and the overall dropout rate was 42.5% in this study. Though the number of dropouts were evenly distributed between the two groups, this does not mean the dropouts did not introduce bias into the results. If those patients who dropped out, most because they developed a second CCL rupture in their other leg, differed in terms of their underlying disease or response to treatment from the subjects who stayed in the study, this could have significantly altered the findings.

Also, as the authors themselves point out, the dropouts caused a significant loss of power in the study (though no power analysis is presented in the report), and this could lead to a failure to detect a difference between the groups. Overall, the dropouts significantly weaken the confidence we can place in these results.

Bottom Line
This study does provide some support for the contention that overweight, large-breed or giant-breed dogs have better long-term outcomes when treated with both surgery and non-surgical therapy rather than with non-surgical therapy alone. However, the limitations in these data are great enough that the case for preferring surgical intervention is not strong. The non-surgically treated patients had overall very good outcomes that, at most time points and by most measures, did not differ significantly from the patients who received surgical treatment. Additional evidence would be required to make a strong statement that overall surgery is superior to aggressive medical therapy.

While it is reasonable to tell dog owners that there is some evidence their pets will benefit more from having surgery than not having it, we must also inform them that most dogs will have a good long-term outcome even without surgery. And it is important to emphasize that even with surgery, aggressive management of weight and physical therapy are important elements of  comprehensive and successful treatment. For those owners who cannot afford surgery, or those patients who are not good candidates, there are still effective therapies that can be offered.

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68 Responses to Evidence Update–Is Surgery Really Necessary for Dogs with Cruciate Ligament Ruptures?

  1. zbr says:

    While a financial bias may be present, it is offensive to claim that all vets care about is money.

    I’m not in the field, I do live with dogs. Lucy, maybe you need to find a new Vet. I have had the privilege of knowing wonderful Vets in my lifetime. Are they infallible? I think that is only reserved for the Pope :). I have had and seen worse in the human medical field!

    Skepvet, because the extracapsular procedure “loosens” over time on larger dogs (over 50lbs). What about that procedure and a brace? They use this in human acl procedures. What would your thoughts be on this?

  2. skeptvet says:

    I don’t have any specific opinion on the idea of extracapsular repair+brace other than that it needs to be evaluated in clinical trials, ideally in direct comparison with TPLO and other methods. It seems plausible, bu many things do that don’t actually work in reality.

  3. zbr says:

    Ah, reality, stickler. Thank you for quick the answer.

  4. Sandi Centoni says:

    I have a 9 yr. old female boxer with a right rear TPLO. She was diagnosed about with this condition about a year ago.
    She’s had 2 Cancer Surgery’s in the past year on her right front ankle area for this reason and due to her age I really don’t want to put her out again so soon.
    My question is, **Will a fitted brace help her out instead of the Surgery??
    I’ve taken weight off of her and do walk her twice a day for about 20 minutes for each walk so as not to overdue the strain on the rear leg.
    I’d appreciate your advice.

  5. skeptvet says:

    Unfortunately, the bottom line is no one knows because no research has been done comparing various types on non-surgical treatment and surgery. Extrapolation from human medicine is particularly difficulty in this area because the anatomy is so very different, so we really can’t predict outcomes on non-surgical treatment. I would just keep a close eye on your dog’s comfort and function. If she is clearly avoiding putting weight on the leg, that probably indicates it is uncomfortable or unstable, and at some point I would consider surgery. If she seems to be supporting her weight normally on the affected leg, then there’s probably no urgent reason to have surgery done.

    Good luck!

  6. Pat Carden says:

    My 14 year old Border Collie (26kg/57lb) has just been diagnosed with cruciate ligament disease in the right back leg and possibly developing in the left back leg. I am trying to make the decision re surgery considering his age and other age related problems i.e arthritis, failing sight and hearing. He would be happy if he could enjoy his walks, as a result of surgery, but taking 2-3 months of rehab to achieve this when life has become so short is making the decision very difficult. Is conservative management the better option? Or is surgery always the better option regardless?

  7. skeptvet says:

    As you can see from this article, there really is no simple answer to your question. We know surgery is effective for most dogs. We don’t know if some kind of medical management (and there are many different non-surgical treatments offered) works as well or better or does not work at all. And, as you point out, each individual patient has circumstances that affect the decision and the balancing of risks and benefits. I would try to have a detailed discussion with your vet about your options, and unfortunately you will have o make the best choice you can without perfect information.

    Good luck!

  8. Brette says:

    We agonized (and I stress the agonized) over whether to have the procedure done as recommended by our vet (who we believe is an excellent veterinarian) for our 8 year old husky, who would have required 2 separate procedures (bilateral). Part of the difficulty in making a decision was wading through the mountain of anecdotal and clinically unsupported material that turns up in search results. Ultimately we were able to find a published study indicating (at least at that time) there was no clinical evidence supporting a finding that surgery provided a better outcome vs. conservative management, and decided that the recovery time (which with two procedures would have meant a year of significant limitation) weighed in favor of conservative management providing a better quality of life for our pet given her anticipated lifespan. Did we make the right decision? Unfortunately there’s no real way to know on an individualized basis since you you only get to make that decision one way or the other, but I can say that it would have been extremely helpful to have had the benefit of this blog at the time we were weighing our options. Thank you for this site, which does an excellent job of providing fact based information to assist in making critical choices about the care and well being of cherished members of our family.

  9. skeptvet says:

    Thanks for the comment. I hope the site will be useful to you now that you’ve found it!

  10. Emanuela Leabu says:

    I need help ! My dog is a 7 years old Maltese and she weights 5.4 lb . She s not an eater so she s pretty skinny . .She was diagnosed with ccl and surgery was recommended. She has good days and bad days. She was limping for a few days and then she was back to normal Most of the articles reffer to big dogs and the weight being a problem. We definitely don t have that problem 🙂 my question is : how soon should she get the surgery ? What’s the downside of not doing the surgery ? She already had knee surgery in both legs ( pattela) and i m really not looking forward in putting her through that pain again but in the same time I want the best for her

  11. skeptvet says:

    As always, these are really questions you should be asking your vet. If you feel like you can’t get clear, adequate answers, then a second opinion is a good idea. In general, surgery isn’t always necessary for small dogs, but every individual is unique and the circumstances of the case make a big difference, so no one can give you reliable advice online.

    Good luck!

  12. Merrill Fox says:

    Hi Skeptvet
    I Have a very fit active working(sheep) border collie who is nearly 10. He briefly caught his hind leg whilst jumping from the sheep pens. He was carrying the leg and I put him away. He seemed sound the next day but I kept him on the lead as a precaution. After a couple more days I decided he looked fine and let him collect a few sheep in a tiny paddock, but that was a mistake. He was carrying the leg again. The vet has ex-rayed and examined the leg and diagnosed a damaged cruciate ligament. The joint is free of arthritic change and there is only a small amount of unwanted movement. The treatment recommended is the tta. He was examined a week ago. I have done some online research and question whether surgery is necessary. With or without surgery I realise that his return to full recovery might be months rather than weeks and am well aware that very careful lead exercise and cage confinement is the way to go. So far anyway he is fine with this. At the moment he is walking on the injured leg without being lame other than the first few strides after coming out of his cage. He is having 3 short walks a day, just ambling and sniffing. As a consequence his food ration is also drastically reduced to avoid him becoming overweight but he has graciously accepted his lot poor lad! Later on I intend to take him to hydrotherapy. Now my question, is he able to make a full recovery with this conservative management or is the proposed surgery the only way?

  13. skeptvet says:

    Obviously, I can’t give advice about specific pets online since they are not under my care. Dogs with cruciate injuries have been reported to recover with no treatment, various medical treatments, and various surgical treatments. The problem is we can’t yet predict how any individual dogs is going to do with each of these options. It is not unreasonable to try medical rather than surgical treatment in some cases, depending on the details of that case, but the answer to the general question of “Is surgery necessary?” is still uncertain.

    Good luck!

  14. Merrill Fox says:

    Thanks, will post back in 6 months or so to update you

  15. Madison says:

    My dog had the TPLO surgery this past week. I read everything I could find on cruciate surgery, had two medical consultations, and in the end decided I would trust the veterinary surgical specialist. Sometimes you just have to trust your instincts.

  16. art malernee dvm says:

    Sometimes you just have to trust your instincts.>>>>
    the problem with surgeon trust is when you are a hammer everything looks like a nail. Even after surgeons saw this randomized study (below) a head of a surgery association has stood up and said to the press the joint surgery should still be done. I wonder if the ocd shoulder joint surgeries I have done on dogs the last 40 years did any good.

  17. Debra Hope says:

    I have a 21 mo. f. Newfoundland who ruptured her ccl. Her vet has recommended TPLO, she is 111lbs and is good for her frame. Her breader is suggesting the surgery that uses the cord, I don’t remember the name, and is saying this has nothing to do with genetics. My girl did slip when running but the vet said it just helped what was already happening and the TPLO is the best way to go. Any ideas?

  18. skeptvet says:

    Sorry you’re having to deal with this. I’m not surprised that your breeder doesn’t want to believe there is a genetic component to CCL disease, but unfortunately, that’s just not correct. There are other risk factors as well, but it happens in certain breeds more than others partially because of genetic differences between breeds.

    As for which procedure to use, there isn’t very good data comparing the TPLO and the tightrope procedure. One low-quality study was done by the owner of the patent on the tightrope procedure, but otherwise there isn’t much research to compare them. Subjectively, most surgeons I have talked to who do CCL procedures (I don’t), feel like the tightrope is less reliable, and it seems to have gone somewhat out of fashion. As always, I would find a surgeon you trust and get their opinion, and I wouldn’t take the breeder’s opinion very seriously since breeders often have very strong opinions about medical subjects without the training or expertise to really have informed opinions. I would give the surgeon’s opinion more weight.

    Good luck!

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