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. Gabby says:

    Hello. I have a 2 year old rescue boxer. I found out early that she had AS and wasn’t gaining weight (originally 49 lbs). She also has this weird dripping from her lady parts. I put her on a gluten free diet and she finally started to gain weight. Also probiotics and other natural supplements were given to her. The dripping has nearly stopped completely and she finally was 60 lbs. She also was seeing a chiropractor that has done really well for her. So her knee was always a concern where she would limp randomly for maybe a few hours and be fine. We were doing rehab but the knee always would act up and we couldnt do more until it settled. She was making so many improvements and I was so excited.

    8 months into having her her knee was acting different. She was limping more and it wasn’t the same. I took her into an orthopedic that took xrays and she completely blew out her ACL. The xrays also showed how much degeneration she had in her knees already at 2 years old. This further supports a theory that she was raised in a mill, malnourished, an over vaccinated. Also an accident early on with being hit by a car or jumping out of a moving one with her AS.

    I’m stuck on what to do because I’ve heard to rehab it and do the TPLO. As a chiropractic student I understand the biomechanics and complexity of it. If I do the surgery I plan to ice, use the Assisi Loop, tape, and rehab the crap out of it.

    In her case I’m confused on what to do. I realize no one can tell me what to do but I appreciate opinions since it’s a big decision. Based on your clinical experience and knowledge what would you suggest? Do you know of any studies with dogs with AS or anything for that matter?

    Tootsie Roll is an active, caring and amazing dog that I just want to make the right decision for her. I’d like to make her a therapy dog because she’s wonderful and brings so much joy. She’d be perfect in an office setting. She’s been through a lot and I’ve had her for 10 months now.

    I appreciate your advice and time!

  2. skeptvet says:

    To begin with, I am not sure what you are referring to in saying “she had AS,” so I can’t comment on that. What condition are you referring to?

    Otherwise, you probably won’t be surprised, if you have seen much of my blog, to see that I have a rather different approach than you do to healthcare generally, so I’m not sure how useful my perspective will be. I don’t mean any of this personally, but there are a lot of assumptions and beliefs implied in your comment that I simply think are unproven or untrue, and it’s hard to give my advice on TPLO without starting by pointing out what I see as misconceptions or false assumptions.

    I put her on a gluten free diet and she finally started to gain weight. Also probiotics and other natural supplements were given to her. The dripping has nearly stopped completely and she finally was 60 lbs.

    The fact that her condition improved while you were doing these things is not, of course, evidence that these things worked. That is, after all, why we need science and why anecdotes and testimonials are unreliable. There is no reason to believe a gluten free diet has any value other than for the tiny subset of Irish Setters with true gluten intolerance. And the majority of supplements have never been tested to determine what if any value they have. Anecdotes alone, don’t suffice. I’m not sure what the DC was treating her for, but the only thing chiro has ever been shown to have reasonable value for is back pain in humans, so there is no evidence it is useful in dogs, and certainly not for knee problems.

    he xrays also showed how much degeneration she had in her knees already at 2 years old. This further supports a theory that she was raised in a mill, malnourished, an over vaccinated.

    There is absolutely no relationship between vaccination and degenerative joint disease so this is simply untrue. There is a relationship between hip and elbow dysplasia and excessive calories and calcium in growing large-breed puppies, but apart from the effect of obesity in overfed dogs, there is no known relationship between nutrition and cruciate ligament diseases, so this too is just a hypothesis or belief, not a fact. Genetic factors, age at neutering, trauma, some medications (e.g. fluoroquinolone antibiotics) raise the risk of some joint problems, but your are simply stating your beliefs as if they were facts, and the evidence doesn’t support them.

    If I do the surgery I plan to ice, use the Assisi Loop, tape, and rehab the crap out of it.

    Physical therapy and icing have reasonably good evidence to support them in humans, so while there is zero evidence in dogs it is a reasonable thing to do. PEMF devices like the Assisi loop are, again, not supported by very good evidence, though probably harmless.

    As far as the TPLO itself, as I’ve said in this article and in the comments, the evidence clearly shows surgery is effective in most dogs. What we don’t know is if non-surgical treatments are as good (braces, PT, etc). For this young a dog with existing degenerative joint disease, my experience suggests she is going to be crippled quite early without surgery, but again there are no studies comparing surgery with non-surgical alternatives so that is just an opinion.

    Good luck!

  3. art malernee dvm says:

    Human cruciate surgery is not what its cracked up to be for humans.

    The last three friends of mine did not get surgery so I suspect most cruciates are treated medically in human medicine but I do not have that data.

    The vet surgeons promote dogs need surgery when human knees would not because they do not walk on two legs and are not included in the RCT link above.
    I’m not sure what they think of the need for cruciate surgery for this subset of dogs below.

    There was just a study published in human medicine that showed no benefit for special costly rehab after artificial knee replacement. Sometimes the best treatment is no treatment.

  4. Kelly says:

    To the vets trying to build an empire, out of their practice, by performing unnecessary surgeries turn my stomach. They know these fur kids mean the world to us.

    My 8 yr old GSD has pannus, among other issues that were over looked during visits. Not once did my vet tell me this based on numerous eye exams, at least once a month. I adamantly demanded an eye specialist ASAP. Glad I did because she has pannus and it was pretty bad in one eye and starting in the other eye. She’s now on Tacrolimus drops to save her sight. Again, the same vet, my girl had nasty female infection loaded with hard to treat rods. The vet treated her with 2 rounds of a ridiculously expensive antibiotic ($200+ for the RX) before deciding to give her another 2 weeks of antibiotics…Cipro, which is free at most pharmacies. So, 4 weeks of treatment and I being a first time pet owner, God forbid your vet tell the owner that she needed to slim her girl down, stay on a long course of Cipro and the infection would clear up. After the 3rd visit, my vet suggested surgery…for WHAT? Per the vet, to open the area more. Hey, here’s an idea, tell me my dog is fat, which we already knew and were working on daily, i.e. smaller meals, 3-4 mile walks, etc. I finally decided to get a 2nd opinion. New vet takes a look, cultures it and yes, it’s a horrible rod infection. Instrutions we’re given to keep reducing her weight. She was dropping it nicely and that hourglass waist returned . After losing all the weight and 9 months of Cipro, that nasty infection is gone. I also warned my hubby if he fed her any more Nutter Butter cookies he was sleeping on the back patio until he stopped.

    Why do you suppose this vet allowed my girl to go through so much crap to clear up a vulva infection? I get it, it was a seriously strong strain. However, the new vet stated she needed longer antibiotic treatment, weight loss and $35 later, I was thrilled I found a vet that was concerned about helping me heal my girl without breaking my bank account.

    She now has a torn ACL with severe degenerative joint disease. We’re freaking out of course, she’s my service dog, warns and prepares me before I have a big seizure. She’s currently on Novox to reduce the inflammation. Oh, probably a good idea to mention my GSD loved catching frisbee’s. She herded them like cattle. Yes, I feel 100% to blame for her bad knee. I noticed the separation one day and took her to her very first vet. They placed her on Metacam and stated she could return back to her frisbee playing after a week of rest. I’m not flat out accusing them but I personally felt like they were patiently waiting for that right knee ACL to blow out. This vet also felt it was detrimental to remove benign growths that are typical with GSD’s. Three surgeries to remove those AND they returned. I could not leave the old vets office without pulling out my debit card and getting robbed $400 per visit. So, with severe Degenerative Joint Disease already in play, is surgery really the best option? I’m worried her quality of life, her spunk and her refusal to remember she’s 8 years old not 8 months will add to this issue. She’s a softy and gets her feelings hurt easily. Is surgery really the best thing for my GSD? The degeneration is already pretty bad would ACL surgery worsen it?

    I’m not trying to bash any vets nor will I give vet or clinic names. I just wished our first vet would’ve shared some great preventative info. They informed me if I take the frisbees away from her now, it would cause severe depression and would shorten her lifespan.

    Sorry for the rambling… I’m also crying while typing this and my girl is licking my tears away. She’s such a good girl. She’s happy, I never leave home without her. We are peas and carrots and attached to each other 24/7. She’s quite stiff upon standing and I’m not comfortable nor will I allow her to jump up in bed with me or up on the couch. She’s compensating with her good leg and we’d like to keep that left knee from blowing out. No issues with left leg and her hips are perfect.

    Any thoughts on having surgery to repair the ACL with the severity of the degeneration she currently has?

  5. L says:

    @ Kelly

    I just want you to know I am sorry for your dilemma. In the end it’s a judgement call, no one can predict the future, what the outcome will be if you do this or that or don’t.

    My dog recently had cataract surgery (at great expense) I was told there was a 90% success rate. Well, my dog is having some complications (2 weeks post-op)
    I am still hoping for a positive outcome but it is very stressful.
    I wish you the best, I know how hard it is.

    PS: My regular vet has been very helpful in helping navigate as to how to proceed.
    There are some good vets out there that really care 🙂

  6. Ann Vaughn says:

    What age are most dogs normally diagnosed with the cranial cruciate ligament disease? We have a male lab, 14 months old, who started limping after a fall up the stairs. He gimps out of the crate or after he’s been laying down for a while, it only started the day after his fall, which at this point we’re about 3 weeks out. Our vet says he has this condition, that the fall was nothing, and essentially said wait for him to completely tear it or the ligament to weaken and he goes lame and have the surgery. He’s not obese, he’s about 75 pounds, we played fetch normally about 20-30 minutes a day broken up into sections, and he’s had walks most days since he was 9 months old or so and we worked up gradually to about 2 miles a day until this episode. Is there something our vet isn’t considering?

  7. skeptvet says:

    Most dogs with cruciate ligament disease are middle-aged, but it can happen at any age. Unfortunately, I can’t really give advice for specific patients online, so I would suggest getting a second opinion or consulting a rehabilitation specialist for more ideas.

    Good luck!

  8. Anne Onymous says:

    Skeptvet, I had an eye opener reading your blog. I didn’t realize that animal medicine didn’t have too much research behind it. My dog is scheduled for a TPLO partly because of your blog to be frank. To the lay person the op seems horrific and perverse. Because you have been clear about what is fact and what is opinion I have felt able to overcome my aversion to surgery. Thank you for your blog!

    My vet is sold on TPLO rather than extra capsular despite mutt being 16lbs because he thinks that the x-ray will show a steep tibial angle. At least he has a reason he can explain to me. There are a hell of a lot of opinions on the web without facts which seem pretty short of reasons to be plausible too.

    So my next thought is after surgery. Is there any evidence for physiotherapy etc after surgery, hydrotherapy or anything else that helps restore normal function? I ask because it’s very expensive and if it will help I’m in, if it will just make me feel better, I’m out!

  9. skeptvet says:

    Unfortunately, there aren’t many studies of specific physical therapy methods in animals. While it is certainly a soundly evidence-based intervention in human medicine, it is quite new to vet med, so there hasn’t been the time to run the kinds of studies we would like. I think it is reasonable to consider and may well be helpful, but it is mostly anecdotal at this point.

    Good luck!

  10. art malernee dvm says:

    it’s very expensive and if it will help I’m in, if it will just make me feel better, I’m out!>>>

    the specialist practice I refer to has a glass underwater treadmill they show off to vets during our required by law CE. They put a greyhound in it. Looks really cool. To take the dog for a walk around the block might work just as well. So I ask for prospective randomized studies. Good luck finding them.

  11. art malernee dvm says:

    Unfortunately, there aren’t many studies of specific physical therapy methods in animals. While it is certainly a soundly evidence-based intervention in human medicine, it is quite new to vet med,>>>>

    The doctors want to take knees to rehab. I. Say no no no.
    see randomized study.

  12. Elle W. says:


    I am hoping you can help me. My cockapoo is 15 years old and she has a fully torn cruciate ligament in her right hind knee. We could manage the cost of lateral suture surgery, but because of her age and health, I have serious reservations. She never had any health issues until she was 14 years old, but for a year now she’s had no thyroid function and she cannot tolerate thyroxine. This means she is several pounds overweight despite decreased portions of her diet dog food. She also has pronounced liver inflammation and we give her Denamarin daily. On top of that, she has arthritis and disc issues in her spine, so we give her Adequan shots twice a week, and her exercise is very limited, which also contributes to her extra weight. We give her Glycoflex, fish oil, and Duralactin tablets daily and have done so for about 3 years now. Do you have any advice or information about how we should proceed with treatment? I want her to have the care she needs, but I don’t want to put her through a difficult post-surgical recovery, and I am concerned about the risks during surgery (even though she does have a strong heart).

    Any reply would be greatly appreciated.

    Thank you.

  13. skeptvet says:

    As you can see from your own description of the situation, every individual has their own unique set of issues and needs, and there is no way to make a universal recommendation that fits everybody. I can’t ethically or responsibly give medical advice for particular patients online because that requires an established relationship between vet and pet owner. I would encourage you to talk with your vet about all the important issues you have raised, or to consult with specialists in surgery or in rehabilitation (the veterinary version of Physical therapy) to get a better sense of your options and what might be best for your dog.

    Good luck!

  14. Nirvashnie says:


    I have a 15kg Boston Terrier, possible partial cruciate ligament tear, limping 90% of the time. Conservative treatment was not sustainable as he became aggressive to the other dog. I have also tried the pemtosulphate injections. Will a Brace and rimadyl help or is surgery the only option
    What is the post operation results and does he need stabilization and rest as he is unlikely to do that

  15. skeptvet says:

    As you can see from this article, there is not clear answer to your questions. Surgery is often very successful, but nothing is without some risk. Braces are largely untested, so it is not known if they help or not. I would consult a surgeon for details about the specific procedure they recommend and the recovery.
    Good luck!

  16. art malernee says: not sure if they will measure the 1/3 no surgery cases. I signed up .

  17. Roni says:

    My dog is a very active Yorkshire terrier, 7 years old. She is still running and jumping and sometimes runs on 3 legs. She has had an X-ray and I’m told she has torn ligaments in her knee. Vet had recommended surgery.
    I really don’t know what to do

  18. skeptvet says:

    Unfortunately, I can’t give individual medical advice, but if you feel like you aren’t clear about your options or why the vet is recommending surgery, I would strongly suggest a local second opinion or a consult with a board-certified surgical specialist.

    Good luck!

  19. art malernee says:

    been reading behind paywalls boarded vet discussions about cruciate surgery recommendations for cats and small dogs. Anyone got acess to the recent article in JFMS showed cats do well with conservative therapy or surgery ( both groups were equally ambulatory by 6 weeks whatever surgery was done) but conservatively treated cats with CCLD experienced less chronic pain at long-term follow-up than surgically treated cats. Interesting review article–there are also others but this is the most recent… would be nice to show this to clients along with the human RCTs if the cat study was blinded well.

  20. art MALERNEE says:

    here is the article. I will try and look on the free website that is trying to free up medical articles from paywalls.

    Boge GS, Engdahl K, Moldal ER, Bergström A. Cranial cruciate ligament disease in cats: an epidemiological retrospective study of 50 cats (2011-2016). J Feline Med Surg. 2020 Apr;22(4):277-284. doi: 10.1177/1098612X19837436. Epub 2019 Mar 21. PMID: 30896333.

  21. ARTUR W MALERNEE dvm says:

    this is really cool. I found a randomize study in pets treating cruciates with surgery or not. The pets that got no surgery did better. found the study free on sci-fi.

  22. ARTUR W MALERNEE dvm says:

    my bad the study is not really a rct. they did divide the cases up between surgery or treated with no surgery but not a true RCT . only true RCT i know of is the human one.

  23. skeptvet says:

    Interesting study. Of course, the vast majority of cruciate surgery takes place in dogs, and the disease and biomechanics are quite different, so it would be great to have this study done in dogs.

  24. ARTUR W MALERNEE dvm says:

    easy pesi would be to look at bilateral cruciate cases that come in where the owner can only afford to have a tplo done on one leg. At 7000 dollars a leg i bet alot of owners of bilateral cruciate rupture are going to try surgery on just one leg first rather then do them both at the same time. You could even cut left or right leg at a flip of a coin and put a skin incision on the unoperated leg to avoid the placebo effect of a expensive surgery and offer to do the second surgery at no cost if the tplo operated leg did better than the placebo unoperated leg with just a surgical scar.
    The neurology departments at the vet schools get a lot of bilateral cases because the referring vets think they are some unknown neurological problem. The neurology department then sends them to orthopedics for bilateral surgery and the vet who referred the case who does cruciate surgery in the office feels like a idiot.

  25. art malernee dvm says:

    check this new tplo alternative cruciate surgery out
    Canine Cruciate Center of New England | The TPLO Alternative (
    The QLF (MFLS) surgical procedure is based on proven scientific principles and our typical clients are educated forward-thinking individuals in the Boston area often in professions such as the human medical field (physicians, nurses, chiropractors, etc.) and engineering.

    The bio-synthetic union just gets stronger and stronger over time. QLF (MFLS) surgery re-stabilizes and reinforces mother nature’s anatomy and in essence mother nature returns the favor by reinforcing our implanted synthetic ligaments over time.

    The science behind QLF (MFLS) surgery that calls for distributing or sharing the load among multiple filaments placed strategically to provide stability to the stifle joint throughout its entire range of motion also provides a built-in safeguard against the failure of the surgical procedure as a whole. By not relying on a single filament to carry the entire load (hence a single point of failure should the filament slacken, loosen or break) multifilament load sharing (MFLS) requires multiple points of structural failure before complete failure of the surgical repair is ever a possibility.
    Sent from Mail for Windows

  26. Pingback: Evidence Update: Is Surgery Necessary for Dogs with Cranial Cruciate Ligament Rupture? |

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