Is Surgery Really Necessary for Dogs with Ruptured Cruciate Ligaments

In a recent article concerning an herbal product used for treatment of a dog with a ruptured cranial cruciate ligament (the equivalent of the “ACL” in humans), I stated, “Surgery is the treatment of choice for a ruptured cruciate ligament. Weight loss, physical therapy, and possibly medications are all helpful and important, but without surgery a large dog will have permanent instability in the knee and will develop progressive arthritis.” One of my regular readers challenged this statement and referred to evidence in humans suggesting that surgical therapy was no better than non-surgical therapy in treating this disease. This stimulated me to look into my assumption that surgery was superior to medical management for large dogs and see whether or not the evidence supports this claim.

Following the usual approach I take in evaluating a proposed therapy, I will look at the plausibility of the intervention first. A great deal has been written about the biomechanics of the canine knee and all the factors that may play a role in cruciate ligament ruptures (e.g. 1, 2, 3, 4, 5, 6, 7, 8). The bottom line of all this is that ruptures of the ligament are caused by multiple interacting factors including breed (and hence genetic influences), size, the structure of the canine knee, and activity. The various surgical procedures recommended for this disease are all rational and plausible based on a detailed understanding of the basic biomechanics of the disease.

There have also been many studies looking at the effect of various surgical procedures in animal models of the disease, usually laboratory dogs with ligaments that have been deliberately damaged. While this sort of model does not replicate all the features of naturally occurring disease, it can provide some clue as to whether the surgical therapies are likely to be effective. These sorts of studies, often used as models for arthritis in general, show clearly that severe joint disease and marked dysfunction results over time without surgical treatment of a ruptured cruciate ligament (e.g. 9, 10, 11, 12, 13, 14, 15)

There is extensive clinical research in humans concerning whether surgical repair of cruciate ligament rupture is necessary. I am quite skeptical of the applicability of this research to the same question in dogs since the biomechanics of the canine knee are quite different from those of the human knee. Also, conservative management for humans includes exercise restriction, physical therapy, and often immobilization of the knee with a brace, all of which are challenging and not often used in dogs with ruptured cruciate ligaments. However, the basic anatomy and pathophysiology of arthritis are quite similar, so research in humans may have some value in answering the question for dogs.

The results of clinical trials in humans are mixed. One Cochrane Review examining older surgical techniques found they were generally superior to conservative management. Some studies have found no advantage to surgical management, but these are not large or methodologically robust trials. It appears that both conservative and surgical management can have good outcomes, but the differences depend on the patient population (age, nature of injury, activity level, compliance with treatment, etc) and the specific therapy employed, so not incontrovertible conclusion can be made as to whether surgery or conservative management is superior overall.

There are a many studies looking at the outcome of surgical treatment of cruciate ruptures in dogs. Overall, they find good outcomes in the range of 70-80% or more of patients returning to normal or near normal function (e.g. 16, 17, 18, 19). Comparisons of different methods of surgical repair do not support the clear superiority of one method. However, there are few studies directly comparing surgical and non-surgical treatment in dogs. The best of these, published in 1984, compared outcomes of non-surgical treatment in dogs weighing more or less than 15kg (about 30lbs). For the dogs over 15kg, only 19% were normal (7%) or improved (12%)  years after their injury, and all had clear evidence of severe arthritis in the affected knee. For dogs weighing less than 15kg, almost 86% were normal (75%) or improved (11), and while all of these had evidence of moderate arthritis, it did not seem to affect the function of most of these dogs. Other less rigorous studies have the same general findings (20, Paatsama S: Ligament Injuries of the Canine Stifle Joint: A Clinical and Experimental Study. Master’s thesis, Helsinki, 1952) 

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.

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226 Responses to Is Surgery Really Necessary for Dogs with Ruptured Cruciate Ligaments

  1. skeptvet says:

    Unfortunately, there isn’t really any data to answer your question, so any answer, including mine, is just a “best guess.” My experience has been primarily with dogs either treated surgically or not treated at all (apart from anti-inflammatory medications for discomfort). Those not treated often compensate for long periods, they almost always develop pretty severe arthritis in those knees as the years go by, and they frequently develop complete ruptures eventually and stop using the leg. Though you should certainly make sure your dog isn’t overweight, and your might consider seeking out a physical therapy facility or specialist in your area, my “best guess” is that these things will happen to your dog sooner or later without surgery. I chose surgery for my own dog because in the absence of controlled research evidence my own experience still suggests it provides a better outcome. I’m open to the idea that isn’t true, but I just haven’t seen any compelling evidence saying so yet.

    Good luck!

  2. Victor says:

    This is only anecdotal, and related to a cat, but I’d like to offer a personal experience.

    My 10 year old DSH, overweight by about 3 lbs, tore her ACL while outdoors. I found her cowering next to my backyard fence while a neighborhood dog was standing over her and barking. I chased him off and found her hobbling with what looked like a severe dislocation of her knee joint (or what I would call a knee). I thought she had broken her hind leg in a fight and took her to my vet. On exam under anesthesia, the vet told me she had a torn ACL and offered that surgery was an option but that she may improve on her own. I decided on a conservative approach and kept her locked inside and tried to restrict her from jumping. That was easy, since she could not jump at all in her condition.

    Within 6 months she was walking normally and exploring the back yard again. Within a year she was able to jump over the fence again. She passed away about 5 years later, but had no sign of joint problems and the torn ACL seemed to have made a total functional recovery.

  3. skeptvet says:

    Cats are an entirely different issue as they re quite different from dogs anatomically as well as in raw size. And from your description, you may have been facing a deranged stifle rather than a torn ACL, which is a different entity altogether.

  4. Nancy says:

    I was so grateful to see this article and all the discussions, very helpful! I am in the process of trying to figure out what to do for my 7 year old yellow Lab Lucy, who has been diagnosed with a torn cruciate ligament in her left hind leg. At first I thought it was arthritis, as she has terrible arthritis and elbow dysplasia in her two front legs. I took her to a canine PT who has been doing cold laser and massage tx with no appreciable improvement after about 5 treatments. I have a consult scheduled with a well-recommended surgeon in two weeks. But here is my dilemma–Lucy had a very serious reaction to a few doses of Rimadyl last fall, in which she sustained some liver damage. After a lot of hospital care, a special diet, meds and milk thistle supplements, her bloodwork normalized. However, her most recent bloodwork done in the vet visit where the cruciate tear was dx’d showed an elevation in one of the liver enzymes. She is back on supplements, but I am very worried about surgery, specifically the risk of anesthesia, with a compromised liver. Any thoughts? I certainly am going to discuss at length with the surgeon, but thought I would ask here as well. Thanks so much for all the information here!!

  5. skeptvet says:

    Of course, I can’t give you advice specific to Lucy since I am not her veterinarian. However, it is worthwhile to keep a few general things in mind:

    1. Liver enzyme elevations do not say anything about liver function. Depending on which specific enzymes are elevated, and how much, they can indicate inflammation of some kind in the liver or, often, in the GI tract, muscles, or other organs. However, even with severe elevations, the functioning of the liver (metabolizing drugs, for example) may be perfectly normal. Additional tests such as a serum bile acids, ultrasound, even biopsy, may be necessary to identify what is happing in the liver and whether it has any bearing at all on liver function.

    2. Anesthesia is a general term that encompasses the use of hundreds of different drugs. Some are metabolized by the liver and some aren’t. If there are concerns about liver function, it is possible to do anesthesia and surgery safely without using any drugs that involve the liver at all (though, as always, there are compromises made when one selects some drugs and not others). Liver enzyme elevations are certainly not a reason to avoid a surgery needed to correct a serious medical problem that is negatively affecting a dog’s quality of life, and they don’t necessarily indicate an increased risk, depending on the details of the situation. Obviously, if a drug was not tolerated in the past, that drug and others in the same class should likely be avoided, but it is certainly possible to do this and still have adequate anesthesia and pain control.

    I hope things work out well for you and for Lucy.

  6. Paula says:

    My 5 year old flat-coated retriever mix was just diagnosed with a partial ACL tear of his right knee. He also has severe hip dysplasia in his left knee which will probably require a hip replacement. He is not limping at all at this point and we only found out about the hip/knee because he started refusing to go up stairs two weeks ago and I asked for back, hip, and knee x-rays as a precaution. I would assume that we should fix the right ACL first and then the hip; however, with the likelihood that his left ACL may also go in the next year, I’m very hesitant at attempting two surgeries/rehabs knowing that a 3rd one may be coming up. Also with his being at least a partial flat-coat, restricting his exercise level will be difficult over a minimum of four to six months. Any suggestions?

  7. skeptvet says:

    No obvious right answer, as usual. My own dog had one bad hip and blew out the opposite cruciate. I had the TPLO done and the 8 weeks of recovery was a challenge (he was 75# and an active 6 years old), but then he went along just fine for another 10 years and never needed anything done about the bad hip. My own feeling is that delaying fixing the knee is only going to put more strain on the bad joints in the other leg, so the sooner you get it done the less chance there is of having two bum legs at the same time. The recovery is tough, but it is only 8 weeks out of his lifetime, so in the big picture it’s probably manageable. But of course you know your own dog and situation best.

    Good luck!

  8. Jen Smith says:

    Just got back from vacation and my 11.5 yr old chocolate lab torn his cruciate while I was gone. Do you have any information on surgery in older dogs? Other than some lipomas and light arthritis in both knees (the left one has been the bad one and of course the one that tore) his is extremely healthy. The vet was surprised at how good his hips are in fact and even said “wow that’s good for a young dog.” He had bloodwork done early this month due to some weight loss and lethargy (which has gone away with extra food, anti-inflammatories, and fish oil supplement) and again was noted as “couldn’t be any better even for a young dog.” Obviously no one else can make a choice for me, just wondering if there is any information about surgery in older dogs. Thank you!

  9. skeptvet says:

    I’m not aware of any research looking at outcomes with or without surgery specifically in older dogs. In general, health is really what’s important, not age. Older animals are sometimes at higher risk due to multiple health problems, not simply because they are older. If they are generally healthy, they are usually treated like any other patient.

  10. CJ says:

    Hi, I have a 13 year old aussie mix, Luna, who has already had tightrope surgery on her left back knee, and now may have torn her ACL on right. I’m future tripping a bit here, because the xray appointment isnt till Friday, but I went through the long long road of recovery with her 2 years ago with the first surgery…and not sure she can handle another long road of that at 13 years old. Nor can I find 4K to get her the surgery right now) I did get her weight down from 60lbs to 45, but I just want to know what you or other vets think of giving an older dog tightrope surgery (Or is TPLO a quicker healing) Of course I am still very much hoping she pulled a hip muscle, but she is walking like a duck so I fear its her knee…her stability looks totally wonky. Any input would be appreciated.

  11. skeptvet says:

    Of course, I can’t give you specific advice about your pet without seeing her in person. In general, if the problem is fixable and there are no specific conditions that make it impossible or excessively risky to try and fix it, age isn’t much of a factor. Of course, it can be a factor in that a couple of months of convalescence in an older pet that isn’t expected to live as long afterwards as a much younger animal would, is a factor for many owners, even if it doesn’t have much direct effect on the chances of success for the procedure. That is really a value judgment more than a medical issue, and so a personal decision we have to make for our pets as individuals. And finances are a frustrating but unavoidable factor ina ll these decisions.

    Good luck to you!

  12. tanya strout says:

    my eight year border collie seemed to hit her leg on the doggie door and yelped, then the limping began, dont know what to do.

  13. Janice says:

    I have a very big yorkie, she weighs 19lbs. She is overweight and I have her on dental food from the vet. I feed her the recommended amount as per guidelines. She gets one small milkbone in the morning and that is it. I can’t understand why she is that big. She is not fat but solid. I brought her to the vet as she was hobbling for a couple of months now and doc said she needs cruciate surgery. Her back inner knee is the issue. I have to bring her to a specialized vet out of town an the surgery will cost $1000+. Can you suggest an alternative to surgery, thanks

  14. skeptvet says:

    Well, of course as this article discusses, physical therapy and wieght loss might be an appropriate alternative to surgery for your pet, though this is not something I can counsel you on directly. You might consider discussing the alternatives with your veterinarian, or if he/she seems unresponsive consider a second opinion.

    Good luck.

  15. skeptvet says:

    You should take her to see a local veterinarian.

  16. Mary says:

    I have a toy poodle who was always flying down a steep set of stairs and he came up limping. I took him to one vet they didn’t do xrays and said to do the conservative route with being on total lockdown except to be out to go potty. So I took him to another vet yesterday and they did xrays and said he blew out his cruciate and was the worse he has seen but was boggled by the fact my dog never showed a sign of pain. He said to stop the kenneling since he is holding his own leg up but no stairs and wont be walking for a very long time. He said he needs surgery but I cant afford it either so Im letting him out of his kennel got him on Deramax (sp) and have him on natural drops called ‘joint resolution’ after I read reviews on them.
    Its crazy though he really doesn’t seem in any pain. When I got him home and he was free from the kennel he ran to his toys and wanted to play! He stretches his legs and even uses his bad one to scratch his belly. Should I have seen the xrays or is this normal? Except for him holding up his back leg you wouldn’t know anything is wrong with him… never has he made a sound of pain since this and for him to have a full blown cruciate and basically doesn’t have a knee anymore how can he be pain free? I have been massaging his legs when he was kenneled and doing a lot of praying. Am I a bad mom cause I cant get him the surgery they say he needs? When I told him I cant afford it he said to just do what Im doing now except kenneling him.

  17. skeptvet says:

    The thing about pain is that we can’t ask our pets about it, we can only guess based on outward sigsn. Different individuals have different temperments, and they may express pain in different ways. I’ve seen dogs with enormous wounds and open fractures wagging their tails and acting perfectly happy. That doesn’t mean they weren’t in pain. And when pain is acute (for example, someone steps on their tail), they will often cry out. But when it’s been going on for a while (like arthritis, or like a ruptured cruciate, which is often partially torn and then may not completely rupture for months or years), they often won’t act noticeably painful. Again, this doesn’t mean they aren’t in pain. A good rule of thumb is to treat our pets for pain whenever they have a condition that people report to be painful when they have it. And there is no reason for a dog to refuse to use his leg except that it hurts to use it!

    As for surgery, if it’s not affordable then all you can do is manage any discomofrt and follow the medical treatment advice you get from your veterinarian. Rest, anti=inflammatory medications, eventually physical therapy, weight loss, and such approaches can be helpful, though as you can see from the article it isn’t entirely clear if they are as effective at restoring function as surgery.

    Good luck!

  18. marlene says:

    My 7 month old lab has been diagnosed with elbow dysplaysia. I cannot affort the 5,000 surgery not knowing if it is going to be needed in the other leg at some point or is it going to be fixed permanentely. what are some other alternatives that could be successful?

  19. skeptvet says:

    Unfortunately, there arent well-supported therapies for this disease. Most people agree maintaining a healthy weight, regular moderate activity (no forced or ocassional but intense activities,etc), and pain control as needed are reasonable. Other than that, there is a laundry list of unproven therapies . Fish oils may have some potential benefit for arthritis and joint inflammation, but the evidence is weak. Glucosamine likely does nothing. Injectable products such as adequan may help, but the evidence is weak. Stem cell therapy is promising but experimental, and still quite expensive. Physical therapy (expecially underwater treadmill) is likely helpful, thougb unproven and expensive. Acupuncture is probably a placebo. Homeopathy is certainly a placebo. And so on….

    It’s a regular and frsutrating problem in veterinary medicine that finances limit what we can do, and understandably this leads us to grasp at straws. Most of the time, there’s no way to know if those straws have any real values since they haven’t been tested properly, and we’re very susceptible to seeing what we expect or want to see.

    Good luck!

  20. marlene says:

    If it was your dog and money was not an option would you do the surgery? Arthritis has not set in. My surgeon will do both for the 5,000 and will take payments. I am worried about the recovery since i have 2 small dogs so my household is crazy with a lab puppy. Heart broken I am considering finding a way to make my dog well

  21. v.t. says:

    Marlene, I’m not speaking for Skeptvet, but have you sought a second opinion? Sometimes a second opinion or specialist opinion can result in different cost options.

    The fact your vet is willing to take payments is a plus. You would be doing the same if you took a loan, CareCredit, etc, so payment options allowed by the vet are definitely worth consideration.

    Depending on the severity, surgery might provide a better option than waiting until it might be necessary anyway (or less successful later on).

    Crating is useful in recovery, helps limit the dog’s activity level when required, and strict supervision during phases of activty will be necessary. Your vet can explain the details, risks vs benefits with you.

  22. natalie says:

    I had a Lab mix that blew his rt cruciate. I was told the only option was the TPLO. The surgeon had great credentials, so i paid almost $4000 fix his leg. This poor dog was in horrible pain after the surgery. I did his recoup as i was told restricting his activity, crating etc. This was very hard as this dog was extremely active. Months after his surgery he hiked his leg up. It was almost a year before he stopped it. The surgeon said that everything had gone well & that he would be ok. One year later he torn the opposite leg. They did the tplo on the left leg. He was never right. I heard a popping noise & was told that they had to go back in & remove the miniscus. they did that & he still was lame. Once again they had to operate & remove the screws that loosened up & he was now reacting to. This poor dog was in so much pain. As time went on he was able to play but his legs were never stable & he suffered with a lot of arthritis. Every time it would rain he was in pain. He was on adequan & other supplements but still hurt.
    I had spent $12000 & my boy was still hurting. So what I’m i stating here. TPLO is not a miracle surgery. You are breaking a bone to fix a ligament!! We need another alternative surgery for big dogs.
    If your dog is small consider other type surgeries & Prolotherapy. I now have a 2yr 110 pd dog that blew her cruciate when her brother pulled her leg sideways (as they were running.) I’m looking into other options. Do your homework & reserve the TPLO as a last resort.

  23. skeptvet says:

    While it’s always sad when a procedure doesn’t go well for a particular dog, it’s improtant to remember that such stories don’t tell us whether or not the procedure is right for someone else’s pet. Studies show the kinds of complications you saw in your pet happen in about 5% of dogs getting TPLO surgery. While it’s important to recognize the procedure has risks, it would be a shame to have the other 95% of dogs not get surgery due to this risk. My own dog had TPLO surgery when he was 6 years old and was comfortable on that leg until he passed at 16. Such stories, good or bad, just aren’t the way to make these decisions.

  24. Bob says:

    My 12+ mixed breed just tore her ACL (confirmed by vet visit). In addition to surgery or doing nothing, another option I’ve discovered is a brace. There are numerous ones on the market, but the leader seems to be the A-Trac from Wound Wear. Any comments about these?

  25. skeptvet says:

    I am not aware of any controlled research on the use of these, so all we have is anecdote and opinion. I’ve heard both positive and negative stories, so really I think it’s a roll of the dice.

  26. dfg says:

    I have a 2-yr old lab that has been diagnosed with bilateral DJD. We saw 3 vets on this over a month and a half. X-Rays were taken of his knees and hips. The draw test was done, twice, failed both times. They have differing opinions about how much arthritis exists in the knees now, from “advanced bone-on-bone” to “nothing in the joint space, no bone-on-bone, some osteocytes outside”. One said his right hip was fine, the left was iffy. Another said that they’re both fine. The third said that left hip was fine and the right one was iffy. They all agreed surgery was indicated, 2 said TPLO and 1 said it doesn’t matter, ex-cap is just as good. Regarding CM, the ortho surgeon said that his current condition was the result of CM (which was not true, his current condition was the result of “do nothing”). This made me wonder if he understood what CM meant, to me anyway (ref: I tried to explain it to him and he dismissed it. Another vet who advocated TPLO did not know what TTA was. I believe this vet to be well meaning, didn’t know ortho, and was just recommending what ortho colleagues were saying. We did not get an opinion of CM from the first vet, because we were too shell shocked to even know what to ask. However, that vet did say that the fibrosis response is what stabilizes the joint in ALL surgeries. The others said that the fibrosis would build up over time and render the joint immobile and painful.. Was this the same fibrosis he was counting on post-TPLO? Regardless, this fibrosis sounds like pretty strong stuff if it can overpower a dog’s quads. One vet said that my dog’s future was bleak no matter what. The others said that TPLO would give him a great future while no surgery a very bleak future. Two of them said there would be arthritis in his future, one said none (but only if TPLO). One vet didn’t say how long TPLO recovery/rehab would be, the ortho surgeon vet said 3-4 months, another said that it’s typically 6-9 months with the last wrinkles working their way out after about a year, at which point I would say it was worth it. That last one sounded most reasonable given everything else I’ve heard.

    So what did I decide to do? It’s still early, only about 6 weeks from the point of the injury that brought me to the vet. In the meantime, we took a default course of CM as described in tiggerpoz. The symptoms that brought him to the vet in the first place were gone inside a week (no rimadyl used after day 4). Symptoms he had prior to this, symptoms which I didn’t even recognize, like sitting on his hip all the time, getting up “like an old man”, reluctance to jump, would not just “stand around”, and gimpy for a few steps after rising have all gone! He’s better now than he was a year ago ! I simply cannot ignore this obvious progress and send him into surgery. I’m not very religious, but this is almost like God saying “look, I’m fixing this for him”. I have to agree with max tiggerpoz that I at least owe him (or God) a chance to fix this, and I don’t care if that means I have to carefully watch and restrain him for 6 more months. I’ll do it for a year if I can avoid TPLO ! Facing the consequences of bilateral TPLOS is, IMO, far, far more daunting, especially considering the pain I’d be putting my dog through and the possibility of coming out worse than he went in.

    Decision by the numbers…
    I’ve heard it said that 85% of TPLO surgeries end up being “successful”. I infer that to mean that 15% are not, they are some kind of failure. If that’s so, and my dog needs two of them, then the chances that at least one of them will fail is about 30%, or about 1/3. After all, a dog with only one successfully TPLO’d knee isn’t going to be an active dog as promised. That’s 1/3, or like playing Russian roulette with 2 loaded chambers. Gulp ! More numbers…. My dog is 2, and this breed lives to be about 12. That means he has about 10 years left, the last 2 probably being inactive for reasons that have to do with plain-ole old age. That leaves about 8 active years (hopefully). If 2 of those years are spent recouperating from surgery and in rehab, well, that’s a lot ! Two years may not seem like much to you and me, but to him, it’s a big part of his life. It’s certainly something to think about. One last angle on the numbers… The ortho surgeon vet said that in TPLO, they change the angle by about 5 degrees in order to redirect 100% of the force from the femur straight down into the tibia. IOW, there’s a small portion (5 degrees worth) of the force in the horizontal direction pre-TPLO. I’m no vet, but I know trig, and that portion can be found by getting the sin of 5 degrees. The sin of 5 is 0.087. That means that TPLO redirects about 8.7% of the force. For an 80 pound dog, standing on 2 hind legs, that’s (80/2)*(sin(5))=3.48 pounds. IOW, the TPLO advocates, who rely on the fibrosis to hold the joint together in every other way claim that it cannot withstand 3.48 pounds in this rare and short lived case of a dog standing on his hinds? Wasn’t this the same fibrosis which they said would render the joint immobile because it was so strong? What’s going on here?

    These numbers don’t bode well for surgery, TPLO specifically. And the varied professional opinions of the xrays, the prognoses and the rest are disconcerting. The lack of good head-to-head studies, pitting ex-cap against TPLO against TTA against CM is abysmal, especially after this stuff has been out for as long as it has and the data must certainly be attainable. In the pharma industry, drug companies fund scientific trials and studies all the time, boasting the results in their sales pitches. And that’s fine. But why isn’t the TPLO vendor (Slocum is it?) funding a study like this? If things were as good as they claim, then a study like this would be a wise investment. Just more questions that make me skeptical.

    In the meantime, the dog is doing fine and I’m going to give him his shot at CM. If he does well, then that’s that. If he gets bad some years from now, and TKR is more available and better studied, then maybe I’ll go with that, getting rid of the arthritis and restoring function in one fell swoop. They do it with canine hips all the time now. But I can’t throw him to the TPLO surgeons given the current way it’s being presented and justified. Where’s the beef? And if there’s bone, fat, and gristle in that don’t leave that part out.

    Sorry if I came across angry. I, like all the others reading this, just want to do what’s best for our beloved dogs. And that’s so tough to glean.

  27. skeptvet says:

    As you can see from my article, I don’t think the answer is clearcut, so I don’t have a particular agenda here. My own dog had a TPLO at 6yrs old, recovered perfectly in 8 weeks, and was comfortable on the leg until he died at 16, but all that proves is that can happen, not how likely it is to happen. In any case, I don’t think your choice is at all unreasonable. However, I did want to point out a few minor problems with some of your reasoning, just for the sake of clarity.

    I’ve heard it said that 85% of TPLO surgeries end up being “successful”. I infer that to mean that 15% are not, they are some kind of failure. If that’s so, and my dog needs two of them, then the chances that at least one of them will fail is about 30%, or about 1/3. After all, a dog with only one successfully TPLO’d knee isn’t going to be an active dog as promised. That’s 1/3, or like playing Russian roulette with 2 loaded chambers. Gulp ! More numbers…. My dog is 2, and this breed lives to be about 12. That means he has about 10 years left, the last 2 probably being inactive for reasons that have to do with plain-ole old age. That leaves about 8 active years (hopefully). If 2 of those years are spent recouperating from surgery and in rehab, well, that’s a lot !

    I’m not sure where the outcomes statistics come from. They resemble one study which found a rate of “minor complications” of 15% and “serious complications” (requiring plate reoval or other additional surgery) of 5%. This is quite different from saying the procedure is unsuccessful 15% of the time. Minor complications were defined as superficial wound infections that resolved with antibiotics, local irritation at the surgery site, and other factors which didn’t affect overall comfort and function. The most recent study reporsted good function and quality of life in 90-97% of dogs, so it is likely the outcomes are a lot better than you have heard.

    As for the idea of spending 2 years in recover, I’m not sure where than comes from. Most dogs with a TPLO are comfortable within a week and fully functional within 2-3 months. And even if one surgery is less than fully successful, many dogs have excellent comfort and function with only one repair. My own dog had a congenital hip abnormality ont he sode opposite the TPLO (which is likley why he ruptured his CCL in the first place, shifting weight away from the hip). He was active and happy before the CCL ruptures, and fine for 10 years after the TPLO despite having imperfect function in the other leg.

    All of this is just to say that while the superiority of surgery over CM is not proven, you have painted a rather gloomier picture of surgery than seems justified by the data.

    On a minor statistical point, which doesn’t really affect your argument, if there were a 15% chance of a poor outcome for each surgery, this does not mean exactly a 30% probablility of one or the other of the two failing. The additive rule applies to mutually exclusive events only. Technically, the probability of either surgery failing is P=(.15+.15)-(.15x.15); 27.8%. And of course the probability of both failing is P=.15X.15=2.25%. We could also debate whether the chances of failure are truly independant since some causes of failure (characteristics of the dog, or of the surgeon if the same does both procedures) may mean the probabilities are not actually independant.

    Good luck with your pet!

  28. Art says:

    But why isn’t the TPLO vendor (Slocum is it?) funding a study like this? >>> he died a few years ago.

  29. dfg says:

    Thanks for the reply ! (Really, I’m info hungry on this topic)

    The 15% was from a survey (if I recall) asking owners if it was worth it. I’m sure serious complications were part of that. But I also expect another piece of that had to do with permanent levels of pain. There was a study on this that pointed to about 30%. The article = “Use of an owner questionaire to evaluate long-term surgical outcome and chronic pain after cranial cruciate ligament repair in dogs: 153 cases (2004-2006)” by Sari H. Molsa (and others). Of course, it does not subtract from that number the permanent pain that would have been realized without surgery. Still.

    The larger question is why we are debating these stats at all? The lack of serious and formal study of this is almost suspicious. The only morsel I’ve found in that space is which seems to indicate no difference in terms of return to function. The sample size is small, but the breed is right on (for me anyway). I got that link from an article written by a colleague of yours… Dr. Hines is skeptical of surgery.

    CM is somewhat of a “garbage term” (tiggerpoz pointed this out). It’s ill defined to the point where the ortho surgeon who saw my dog implied that doing nothing = CM. Others equate it to a successful course realized by small dogs. Others think of it as alternative medicine. Few think of it as what is prescribed by tiggerpoz. Clarification of a specific CM prescription is needed before it can be discussed. Yes, good studies on the outcome of that are lacking (earlier discussion with tiggerpoz). But that’s true of all of the options, leaving us pet owners scratching our heads and surfing the web.

    Regarding TPLO outcomes, yes, I’ve heard success stories too. And my wife heard a nightmare story where a dog was in so much residual, long term pain after two TPLOs (in series, not parallel) that it started biting people and had to be put down :-(. Since there were no complications and the dog could eventually use her legs to a near normal level, I have to wonder if this case was in some way deemed a success, by the surgeon anyway. Is there a criteria for that?

    Here’s are three new questions I was hoping you could respond to…

    1) Where, exactly, is the fibrosis/scar that I hear so much about? I think of scar as something on tissue, like on the skin or on an organ. What part(s) of the stifle realizes the scarring and/or fibrosis? The joint capsule? Surrounding ligaments? New growth between the bones? Something else? I’m trying to understand the mechanics.

    2) How tough is the fibrous/scar? I know it’s holding my ankle together quite well. But there’s no tibial slope in my ankle. Can/does this fibrous scar withstand reasonable levels of stress imposed by non-athletic dogs who just go on walks, maybe run and play with other dogs for brief periods? Or is it doomed to failure over the long term?

    3) Where does TKR stand at this time. I know what the vendor (BioMedix is it?) says, but what’s your view? One possible course for us may be to move in that direction years from now if my dog falls into a real bad way and tkr is more available and “tweeked”.

    One last nit, regarding the stats, you’re right, left leg OR right leg ~= 30. But if you add in the possibility of both failing, then it’s 30. I was considering both failing an overall failure too.

  30. skeptvet says:

    The key point here, I think, is the absence of adequate studies you highlight. Head-to-head comparisons of clearly defined alternatives with appropriate, clinically meaningful outcomes and proper design would be ideal. That said, we have to make decisions on the basis of the evidence we have, not the evidence we would like to have. The current evidence has to be used to draw conclusions, but we have to recognize those conclusions are etremely tentative due to the poor quality of the evidence. Hopefully, that will change at some point.

    As for the biomechanical questions you ask, I’m afraid you’re well past my level of expertise since I am not an orthopedic surgeon. I’ve never even seen a TKR, and it’s not a real option for my clients, so I know next to nothing about it.

  31. dfg says:

    I agree, we have to make decisions on the evidence we have, however fuzzy it is. The problem has to do with ascertaining even this fuzzy evidence. You have to admit that there’s a certain element of conflict of interest when asking the tplo surgeon if your dog needs a tplo. So where does a poor dog owner go? The “evidence I want” is, I would agree, irrelevant. I suppose its a human failing to filter evidence where a bias is involved. That knife cuts both ways though. I’ve yet to hear about bad surgical outcomes from vets who I’m sure have seen them.

    Also, what does “success” and “failure” really mean? I’m sure you’ll agree that outcomes aren’t terrific or terrible (although those are the only two mentioned to me by 2 of the 3 vets I saw). They’re terrific or terrible or anything in between. I suspect mediocre outcomes, of many different shades, are the norm. If this is like most things in nature, the probable outcomes lie on a bell curve. Practical people will look at the middle of that curve, understand what that means, and make that their expectation when making a decision. And I suppose somewhere on that curve a vertical line should be placed separating ‘failure’ and ‘success’, the different players involved pushing that line left or right to stake out their turf.

    In the meantime, I feel like I’m living an experiment. I can’t deny what I’m witnessing first hand, how much he has improved over these past 2 months, even to a point that was superior to what he was up to a year before the injury. When I consider the target of an 85% return to normal function post-surgery, where “normal” is the pre-surgery level, I’m already over 100%. But I don’t have a crystal ball that shows me what’s ahead.

    There’s an old adage… “For every opinion, evidence can be found to support it”. It looks like that’s true here. And there is no referee rating the evidence. Maybe that in itself says something.

  32. skeptvet says:

    Well, I think conflict of itnerest is tricky. Are all surgeons auomatically disqualified from having trustworthy opinions about whether or not to have surgery? For that matter, should we always view any therapeutic recommendation from a doctor with suspicion because their job is to provide therapy? Certainly, we all view every situation through the lens of our own beliefs and desires. Clients frequently take a skeptical view of procedures that are frightening or expensive for reasons which probably have little to do with their objective merits. I agree that surgeons are inclined to view surgery favorably (as they should since who would want a surgeon who offerred a treatment they believed to be worthless?). But I’m not sure we can afford to write off their expertise or advice, especially given that we aren’t likely to get research into surgical procedures by people who aren’t surgeons since by definition they aren’t able to perform it.

    As for outcomes, we always have to decide how to classify them for analysis. A binary outcome is not inherently more or less reasonable than a continuous outcome. If the goal is “adequate comfort/function as perceived by the owner,” then a binary outcome may be appropriate, and this would be classified as “success” or “failure.” To generate a Bell curve, you would need a continuous outcome variable. What would this be? Would your create a numercial scale from 0 (can’t walk) to 10 (agility champion) and then look for distribution with different treatments? Would this necessarily give owners the clear guidance they want? Would the subjectivity in the middle lead to potential misclassification?

    What I’m saying is that if we are asking the question “Is therapy A superior to therapy B?” we need to have an outcome measure that is as objective, unambiguous, and relevant to the goals of owners as possible. The fact that some continuous outcomes might fall on a distribution doesn’t necessarily mean these are better outcomes to use than “success” or “failure.”

  33. dfg says:

    Considering surgeon bias is (IMO) merely a factor in the process, certainly not a criteria for writing them off. Unfortunately, the ortho experts and the surgeons are usually the same people, and they are the only place dog owners are sent for advise. Indeed, Ron Hines DVM indicates that in some states at least, general vets are required to refer these ccl patients to ortho specialists. (ref: which points to,referralsTBVME.htm). An independent, ortho specialist who is not a surgeon or affiliated with group(s) that do surgery, would be a great place to go, if they existed. But I can’t find anyone like that. Or, of course, a good study would be just as good. No luck there.

    Personally, I’m not skeptical because of fear or because the surgeries are expensive. I’m skeptical because of the serious lack of good evidence supporting the surgical recommendations. I find this to be puzzling, especially given the amount of raw data that must exist on this, the amount of time some of these procedures have been available, and the expectation that I have that surgical recommendations should be based on hard evidence. Another point of skepticism comes from the number and variety of new surgeries being invented to treat this problem. You don’t see churn like that in the hip space where a good fix exists (thr). Also, the 3 vets we saw had significantly different interpretations of my dog’s x-rays (arthritis in the knees and state of the hips), plus significantly different prognoses (see my original post). Finally, I was told that after a brief period of improvement (a week or tw0), I would see the state of my dog get progressively worse as I reintroduced him to activity. That hasn’t happened. In fact, symptoms he had up to a year prior are diminishing.

    Yes, bell curves based on subjective evaluations of unmeasurable variables aren’t very good. But its infinitely better than what we have (almost nothing). In lieu of anything like this, it’s either a faith, as opposed to evidence, based decision. Or its a matter of trying to make sense of this myself while observing (experimenting with) my dog.

    I think I have to disagree on the point that a good study on this is not possible except by experts. This is more of a matter of data gathering and number crunching than anything clinical. The later is easy, I could do that. The former, getting records from a broad spectrum of vet offices and gathering up the observations of even general vets and pet owners in terms of how good or bad things appear clinically over the years, is where the real work is. But that does not require any special ortho skills.

    My main concern regarding my dog now isn’t so much if he can return to normal function. He appears to be well on the way to that given the default CM course I’ve taken. I believe we’ve still got months to go (I may be too cautious, but I don’t care). But so far, so good. My main concern is if he can maintain that. Does the fibrosis “fix” stand up over time? There have been some studies (few, and weak, but some) which seem to indicate that in the short term, there’s little difference between the options when it comes to return to function . But what about 3-5-7-+ years out? Is tplo a superior fix in the long run?

    It has been suggested that properly executed CM (many months of carefully monitored rest->rehab) can result in the same long term outcome as conventional ex-cap procedures ( The fibrosis mechanism is cultivated in both options as a long term solution, the difference being in the temporary stability offered by ex-cap. I agree, there is no good evidence for this either (I’m getting used to that). But if function and symptoms of pain are a measure of stability, I can see for myself that indeed, my dog’s knees appear to be stable, at least for the 20-30 minutes walks we now take, some 2 months out from the point of injury (apparently not a severe injury as he quickly returned quickly to function). Is there a flaw in my reasoning?

  34. skeptvet says:

    The evidence is no better for CM than for surgery, yet you seem less skeptical of CM, which led me to suggest that you have a desire to avoid the cost/risk/discomfort etc associated with surgery. There’s nothing wrong or unreasonable about that, I was just pointing out that just as surgeons tend to think of surgery readily as a ptoential option, the rest of us have biases and inclincations of our own. In any case, while I agree good studies could be done by anyone with an appropriate understanding of both the nature of the problem and the techniques abvailable to address it, the reality is that as you say these folks are almost all surgeons in veterinary medicine.

    I think you may underestimate how difficult it is to design and conduct a good study. The paucity of such studies is not due to any”suspicious” motives but to the cost, the difficulty in creating a design that controls for bias, confounding, and other sources of error, the willingness of cleitns to participate, and many other factors. Good research is hard and expensive, which is the main reason why there isn’t more of it in veterinary medicine generally.

    As for what will happen to your dog, I agree the existing evidence doesn’t help us much in predicting that. And frankly, whatever happens doesn’t validate either approach. My dog did well for 10 year with surgery, yours may do well for as long without, but neither tells us anything about the relative emrits of surgery and CM. That’s why we need better studies, despite all the barriers to conducting them.

  35. Art says:

    Indeed, Ron Hines DVM indicates that in some states at least, general vets are required to refer these ccl patients to ortho specialists. (ref: which points to,referralsTBVME.htm). An independent, ortho specialist who is not a surgeon or affiliated with group(s) that do surgery, would be a great place to go, if they existed. But I can’t find anyone like that.>>>>>

    Slocum, the vet who “invented” tplo was not a specialist.
    Art Malernee Dvm

  36. dfg says:


    Agreed, the evidence is no better for CM. But its a far, far less invasive, painful or risky course which has a fair chance of working. I think tiggerpoz had a point earlier when he/she/they said it can’t hurt to try this non-surgical approach for all the reasons you stated (cost/risk/discomfort). If the results are good, then wouldn’t that be the preferred course? If not, then there’s always surgery, and the rest/rehab of CM wouldn’t be a bad thing to have done in the meantime. IOW, it’s not an either-or. It can be a “do one or both”.

    In my readings, one vet pointed out a patient perception that choosing surgery designed to fix a problem is a better course than not having the surgery. If my dog does poorly, and he’s in bad shape 3-4 years from now, everyone will think that the CM course was a poor choice, he should have had the tplos. If he had the surgery right after the injury, and he ends up in bad shape 3-4 years from now, the belief would be that he’d be worse off if he hadn’t had the surgery. No one will think that the CM course would/could be a better choice than tplo (except perhaps in cases of morbid surgical complications). It’s another perceptual bias I guess, one worth adding to the discussion.

    My wife, who works in the medical profession, sees back surgeries performed every day on people to correct problems where the long term outcomes of many of these procedures is statistically no better than doing nothing (putting the risk, recovery, pain and expense factors aside). But the surgeries go on. Veterinary medicine is not the only place where skepticism has a home. And patients want surgery as opposed to not, probably influenced in part by the bias I mentioned.

    I actually do understand how tough it can be to put together a real good study for something like this. I actually wouldn’t expect anything that robust for something like this given the subjectivity in evaluating results. The 2005 Iowa State University study on this would be something more realistic ( It’s not a great study, the sample size is small, only one breed was examined, the state of the meniscus was a variable unaccounted for, etc… but this sort of study appears to be a lot better than what’s out there now.

    Yep, better studies would be great. 1000% agreement on that. The veterinary community may have an opportunity to help in this area by making available records of patients for statistical analysis (the identities of the patients being protected as well as practical/possible).

    The point is that a non-specialist is required to make a referral, not treat on his/her own. It makes one wonder about the possibility of referrals being made by vets would prefer to try something like CM, but dares not.

  37. v.t. says:

    dfg, there’s also the possibility that referrals are done because the primary vet does not have the surgical experience (i.e., new techniques), equipment etc – which then is rather incumbent for the benefit of the patient to be referred to a specialist.

  38. dfg says:


    Absolutely. There are all sorts of possibilities. Our general vet took x-rays and did the drawer test. If a vet can’t do that, or read the x-rays, then yes, make a referral. But some general vets can and do make diagnoses based on these tests.

    But I frown to think that a vet may have to make a referral because they fear for their job or license if they don’t. Just as the surgical options were described to me by the vet, the CM option should be presented too. And if CM is the owner’s choice, I see no need to send them to a surgeon for that.

  39. Art says:

    The point is that a non-specialist is required to make a referral, not treat on his/her own. It makes one wonder about the possibility of referrals >>>>

    My plea is that more Veterinarians get involved with their State Boards. Attend the public meetings,ask questions,make some input.
    The “word” around Texas is there is a group of surgeons expressing their opinion to the state board that some surgeries should be restricted to only boarded surgeons. The exact circumstances I don’t have, whether it was in expert opinion on cases in front of the board or in written suggestions. I think a GP can do brain surgery in his practice — if he chooses. No one would choose to – but their license says they “can”. Am I wrong?
    Art Malernee Dvm Fla Lic 1820

  40. v.t. says:

    Art, I don’t know – I wouldn’t want my GP to perform brain surgery on me. I would want the specialist who has the latest state of the art equipment, latest effective techniques, has attended the most and latest and greatest conferences and expanded his/her knowledge and practice skills, has a great deal of experience under his/her belt and sufficient knowledge to know what he’s doing over his colleague, the GP. But, that’s just me.

  41. dfg says:


    But what if the GP said “Let’s see if your body can heal this problem on its own before going to surgery. It may not work but there’s a chance, I’ve seen it work before. If you’re willing to try, and put in the effort, we can work together to develop a plan on how to approach this.”.

    In that situation, the referral to a surgeon would not be necessary.

  42. v.t. says:

    Correct, but Art was saying something altogether different – that GPs could do brain surgery if they chose to because they have a medical license, not whether or not a referral would be required (which it would be if said GP wished to keep his medical license and avoid potential malpractice 🙂

  43. Eaglebeard says:

    Hi thanks for the help , our Rottie had her cruciate ligament done at age 3 in her right leg and now 5 yrs later the left is looking to be the same way we will not be doing surgery on the left as we feel the rest of her body will not cope , but the original surgery worked great and she never had any probs with it. £3000 well spent.

  44. Lisa Subers says:

    I am hoping you can help me with a surgery decision on my 14lb Bishon/Yorkie mix. Teddy tore his ACL, right hind, playing tennis ball in the back yard. Initially, he could
    not put any weight on it. We did the wait and see, coupled with anti inflammatory medicine. He is 70% better…but he does not put full body weight on it, and when he sits he keeps his knee straight. It has been 3 months since the injury, activity levels are much better. The Vet is suggesting Cruciate level 1 surgery, using an artificial tendon. My concern is Teddy is hyper-active, and seems mostly recovered. He has never been crated, and the recovery period concerns us. Can you provide any direction considering the circumstances? Is surgery really necessary at this point?.

  45. skeptvet says:

    I can’t give you specific advice about your pet since I’m not his doctor. My experience suggests that once the initial trauma and inflammation subside, dogs compensate so that their lameness isn’t as noticeable, but the joint does not become any more functional. I still think young active dogs do better with surgery, but the point of this aticle was that there is no definitive research evidence to prove it.

    Good Luck!

  46. Art Malernee Dvm says:

    Why does a “14lb Bishon/Yorkie “weigh 14 lbs?

  47. Eric says:

    I have a spayed 4 year old yellow retriever, Sasha, just diagnosed with a possible tear or rupture of the cranial cruciate ligament. The vet prescribed Carporfen to use for inflammation. She is overweight, 92 lbs. but has lost a few pounds recently. We are cutting down on the volume of food she gets. We are taking her to a Holistic Vet Center next week in hopes that there is something that can be done vs. surgery. Any thoughts regarding this approach?

  48. skeptvet says:

    As always, I can’t give any specific advice about Sasha without being her veterinarian.

    I’m afraid that “holistic” is generally a code word for the use of all kinds of therapies not supported by any real evidence, and many that are complete nonsense. The danger of that sort of approach is the primary reason this blog exists. While there is some genuine uncertainty about whether surgery or medical management is better for these cases, and while achieving and maintaining a healthy weight is absolutely one of the most important things you can do, I fear a “holistic” vet will steer you towatds a lot of useless waste of money and time: homeopathy, acupuncgture, chiropractic, and supplements galore. Since most of these dogs appear to improve with time no matter what we do, I don’t doubt these treatments will look like they are working, but I do doubt they actually will be.

    My advice is to always ask for the evidence behind whatever is recommended, and if it’s all anecdote be skeptical.

    Good luck!

  49. Sioban says:

    Do u recommend prolotherapy for torn cruciate.? My poodle mix is 22 lbs. Her regular vet referred me to ortho surgeon who suggested PTLO surgery. However, other vet in her regular vets office suggests prolotherapy. If we do try prolotherapy and it fails does it complicate a future PTLO operation?

  50. skeptvet says:

    Here is my discussion of prolotherapy, which will hopefully give some useful information.

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