Cruciate Ligament Rupture in Dogs: Why It Is Usually Not an Accident

In brief

There are five things you should know about cruciate ligament rupture. First, and this clears up the biggest misconception: in dogs, it is not an accident in most cases. The ligament does not tear because the dog landed badly; it tears because it was already damaged—the jump is simply the moment when an already weakened ligament finally gives way. Purely traumatic tears do happen, but they are the exception. Second: that is why the second knee is the real issue. Depending on the study, it also ruptures in 22 to 54 percent of dogs within the following months. Third: in roughly half to two thirds of affected dogs, inflammatory changes in the joint lining are already present at the time of the first diagnosis—so the knee had already changed. Fourth: the meniscus is often involved as well, and that has a major influence on pain and on the course of the disease. Fifth: rehabilitation after surgery is not an afterthought; it helps determine the outcome.

Cruciate ligament rupture is one of the most common causes of hind-limb lameness—and one of the topics where the everyday explanation and the scientific literature are furthest apart. This article explains what actually happens, why the other knee has to be part of the picture, and what a good treatment decision is based on.

Note: This article is general information and does not replace a veterinary examination. Which procedure suits your dog depends on size, age, activity level, knee angle and any additional findings.

👉 Everything about prevention and health: dog health basics at a glance

1. What the cruciate ligament does

In the knee joint (the stifle), the thighbone meets the shinbone—rounded condyles sitting on an almost flat tibial plateau, a connection that on its own would have hardly any stability. That stability comes almost entirely from ligaments, muscles and the menisci.

The cranial (front) cruciate ligament—the dog's counterpart to the human ACL—prevents the shinbone from sliding forward when the foot is placed on the ground, and it limits rotation of the joint. Dogs have a particular feature on top of that: the head of the shinbone slopes backward. With every step, this creates a force that pushes the shinbone forward—known as cranial tibial thrust. This is precisely the force the cruciate ligament withstands all the time. Remember the term: you are bound to hear it when a surgeon explains why she is recommending a particular procedure. So the ligament is not only working during peak loads but with every single step.

If it fails, the knee becomes unstable. The joint rubs, the joint lining becomes inflamed, and the remodeling toward osteoarthritis begins.

2. The accident myth

Almost every owner describes the same moment: the dog jumped, stopped abruptly or twisted while playing—and then the leg was gone. This explanation seems obvious, and in most cases it is wrong.

In the scientific literature, cruciate ligament rupture in dogs is mostly the result of degeneration of the ligament tissue that progresses over a longer period. The tissue gradually loses its capacity to bear load until a perfectly normal movement is enough to make it fail for good. A genuine, purely traumatic tear of a healthy ligament does occur, but it is the exception.

How clear this is can be seen in a finding in the joint itself: in about 51 to 67 percent of affected dogs, inflammatory changes in the joint lining are already present at the time of the first diagnosis. This suggests that in many dogs the knee was no longer healthy when the “accident” happened.

Some context belongs here so that this finding is not stretched too far: inflammation of the joint lining is part of the disease process and a strong indication that something has been going on in the joint for some time. On its own, however, it is not proof of any particular duration of prior damage—it also develops as a reaction to the instability itself. What it shows is that the knee had already changed by the time of diagnosis, not since when.

This also explains why many dogs had shown signs beforehand: brief lameness after getting up that went away again; sitting with one leg stuck out to the side; less enthusiasm for jumping. In hindsight, these can be the early signs of a partial tear—in many dogs the ligament does not tear all at once but in stages.

For you, this changes the most important question. Not: “How could this happen?” But: “What about the other knee?”

2.1 What this means for the time before

If the tear is the end of a process, then there is a phase in which this process is underway and nobody suspects anything yet. During this time something can still be changed—and it is regularly missed because the signs are so easy to explain away.

A dog that limps for a few steps after getting up and then walks it off has not necessarily just “slept funny.” A dog that has not wanted to jump into the car for a few weeks has not necessarily just “gotten lazier.” And a dog that sticks one leg out when sitting does not necessarily just have a quirk.

Any one of these signs can be harmless. If they occur repeatedly or several appear together, that is the moment for an orthopedic examination—not the moment to keep watching.

What actually helps during this window is unspectacular and is listed in detail in Section 13: weight, steady fitness instead of peak loads, non-slip floors, avoiding abrupt stops and repeated jumping. None of this reliably prevents a tear. Together, however, these measures can delay the point at which it happens—and for a process that runs over a longer period, that is the realistic goal.

3. Why the second knee is the real issue

If a cruciate ligament does not tear because of an accident but because of a process, then that process often affects more than one side.

The numbers show exactly that. Depending on the study, the risk that the other cruciate ligament also ruptures is 22 to 54 percent within roughly six to seventeen months of diagnosis. In a longer-term analysis, the median “survival time” of the second cruciate ligament was about 947 days—a good two and a half years. And 4 to 10 percent of dogs already have findings in both knees when they are first brought to the clinic.

What is particularly revealing is what the risk is linked to. If the still-intact knee already showed marked joint effusion on X-rays, a tear on that side within a year was considerably more likely; something similar applies to pronounced bony outgrowths. In this analysis, by contrast, breed, age, weight, sex and knee angle were not significantly associated with the timing.

This is useful in practice: at the appointment, always have both knees examined and X-rayed, not just the lame one. The finding in the healthy knee is one of the most informative clues available—and it affects how you plan, whether you tackle your dog's weight and how you set up rehabilitation.

👉 Why weight is such an important lever: recognizing your dog's ideal weight

3.1 What can be done about the other knee

The figures in the previous section sound like fate. They are not quite—two of the factors involved can be influenced, and both belong in the period right after the first diagnosis.

Weight. Every kilogram acts with every step on a knee that is already under suspicion. This is one of the most important levers you have, and it costs nothing. The period of leash rest actually works in your favor here: energy requirements drop anyway, so the food ration needs to be adjusted—and if you do not adjust it, you can easily end up with a heavier dog at the end of rehab than at the start.

Muscle. While the operated leg is being spared, the opposite side carries more. That is unavoidable and, within limits, appropriate—it becomes a problem when the compensation patterns described in Section 11.1 persist. This is exactly what physical therapy works on, and exactly why it is not a measure for the operated knee alone.

What cannot be influenced, on the other hand, is predisposition—the angle of the tibial plateau, the breed, the quality of the ligament. So the goal is not to reliably prevent the second tear but to delay it and to be prepared if it comes.

And being prepared means, specifically: knowing the signs from Section 4 on the other side—above all the way the dog sits. A dog that suddenly sits crooked again after completing rehab is telling you something.

4. How to recognize it

An acute complete tear is impossible to miss: the dog suddenly stops putting weight on the leg entirely, or only touches down with its toes, holds the leg bent and does not want to sit down.

A partial tear is the real problem, because it is easily overlooked:

• Lameness that appears after rest or in the morning and “wears off” with walking
• Lameness after exercise that disappears again after one or two days
• The way the dog sits: the dog sits crooked and sticks the affected leg out to the side instead of tucking it under the body. This is one of the early signs that are easiest to observe in everyday life.
• Less enthusiasm for jumping, hesitation in front of the car, avoiding stairs
• Loss of thigh muscle compared with the other side—often visible after just a few weeks
• Thickening on the inner side of the knee

One point many people find surprising: many dogs with a cruciate ligament rupture keep eating and keep walking. The fact that a dog still comes along on walks is no argument against the diagnosis.

👉 Why pain in dogs is quiet: recognizing pain in dogs

5. Which dogs are affected

Cruciate ligament rupture is one of the most common orthopedic diagnoses; estimates of its frequency in the overall dog population range from about 0.6 to 2.6 percent, depending on the data source.

Breeds affected more often than average include Labrador and Golden Retrievers, Rottweilers, Boxers, Newfoundlands, Bernese Mountain Dogs and Staffordshire types—but also small breeds such as the Miniature Poodle and the West Highland White Terrier, in which the tear often coincides with a dislocating kneecap.

Factors associated with a higher risk include excess weight, a steep tibial plateau angle, poor fitness combined with weekend peak loads—and a genetic component that is clearly evident in the affected breeds. In certain breeds, early neutering may also be associated with an additional increase in risk.

6. The meniscus: the underestimated player

The menisci are two crescent-shaped cartilage discs that sit as cushions between the thighbone and the shinbone. When the knee becomes unstable, the medial (inner) meniscus in particular is exposed to shear forces it was not built for—and it tears or gets crushed.

This matters for two reasons. Meniscal damage causes considerable pain, often more than the instability itself; an audible click when walking is typical. And it can also develop after successful surgery, when a meniscus that was initially intact fails later on—one of the most common reasons why a dog that has had surgery becomes lame again months later.

That is why the meniscus is assessed during every cruciate ligament surgery, and why renewed lameness after initial improvement should be checked promptly.

6.1 When to suspect meniscal damage

It can only be assessed inside the joint. But there are clues that raise suspicion and stand out in everyday life—and because missed meniscal damage is one of the most common reasons for persistent pain after surgery, they are worth knowing.

An audible or palpable click when walking, often with the first step after getting up. This is the classic sign, but it is far from present in every affected dog.

Pain that does not match the load. A dog that spares the leg much more than the instability alone would lead you to expect.

Lack of improvement. After surgery, weight-bearing normally increases step by step. If that does not happen, or if it reverses, it should be checked.

Renewed lameness after a good phase. The case from the previous section: a meniscus that was initially intact but fails later. This typically happens weeks to months after surgery, as activity increases.

What you can record: a video of your dog's gait and the date from which something changed. Both help more at the clinic than a description after the fact.

7. What else causes hind-limb lameness

Not every hind-limb lameness is a cruciate ligament rupture, and the alternatives point in completely different directions.

Patellar luxation. The kneecap slips out of its groove. Typical in small breeds: in the middle of running, the dog hops a few steps on three legs and then carries on normally. It often occurs together with a cruciate ligament rupture; it is thought that the misalignment places uneven load on the knee over the long term.

Hip dysplasia and hip osteoarthritis. Here the pain sits higher up, the dog has trouble getting up and shifts weight onto the front legs.

Disorders of the lumbar spine. They cause shifting or bilateral weakness, often with the paws dragging—a neurological rather than an orthopedic picture.

Bone cancer, especially in large breeds of middle to older age, with increasing lameness and pain over a section of bone.

Muscle and tendon injuries, as well as inflammation of the lumbar muscles.

They are told apart through examination, not through description—which is why a phone video of your dog's gait is valuable here as well.

8. What happens at the clinic

The diagnosis rests on three pillars.

The orthopedic examination checks two things. First, the range of motion: a knee with cruciate ligament damage or a meniscal problem often can no longer be bent fully, and this restricted flexion is considered a likely reason for the leg being stuck out crookedly when the dog sits. What you observe at home, the veterinarian checks specifically by hand. Second, stability—classically with the drawer test and the tibial compression test. Both only work when the muscles are relaxed, which is why they are repeated under sedation in tense or painful dogs. A negative test in an awake dog does not rule anything out, especially with partial tears.

X-rays do not show ligaments, but they show their consequences: joint effusion, bony outgrowths, the extent of osteoarthritis—and they provide the measurements for planning surgery. Both knees should be included.

Assessment of the inside of the joint takes place during surgery itself, by arthroscopy or by opening the joint. Only there can the ligament and meniscus truly be evaluated.

👉 What the necessary sedation involves: anesthesia in dogs

9. Surgery or not?

This question comes up almost every time, and the honest answer is: it depends—but less than many people hope.

In favor of surgery is the fact that unstable movement in the knee drives osteoarthritis forward and puts the meniscus at risk. For medium-sized and large dogs, it is therefore considered the standard, and experience shows faster and more complete recovery of function.

Conservative treatment, meaning without surgery, is used mainly in small and light dogs, in very old animals, when there are significant anesthetic risks, or when surgery is ruled out for other reasons. Conservative does not mean “wait and see”: it means an active program of consistent weight loss, controlled exercise over months, physical therapy and pain management.

What applies in both cases: osteoarthritis is to be expected. Surgery does not restore a healthy knee; it stabilizes it. If you know that beforehand, you will be less disappointed later.

👉 What osteoarthritis means and how to manage it: osteoarthritis in dogs

9.1 What the decision is based on

Because this weighing-up is rarely done in a structured way, here are the points that actually carry weight.

The dog's weight. One of the most important factors. The heavier the dog, the greater the forces in the knee and the more clearly experience favors surgery.

The meniscus findings. A damaged meniscus causes pain that often does not resolve with rest—and it can only be assessed and treated inside the joint.

The activity level. A young working dog places different demands on stability than a calm twelve-year-old.

The anesthetic risk. It is assessed through the pre-anesthetic workup and, in a healthy dog, is considerably lower than most people fear.

The findings in the other knee. The point from Section 3, and it is regularly forgotten. If the opposite side already shows changes, a second operation is considerably more likely—that belongs in the planning and in the cost calculation, not as a surprise six months later.

What you can realistically manage. Conservative treatment is not the easier route. It requires consistent exercise control, weight loss and physical therapy over months. If you cannot keep that up, your dog is better served by surgery—and conversely, even the best surgery achieves little if the aftercare does not happen.

What is not a good argument: that the dog is walking better after three weeks. Exactly that also happens with an unstable knee, because muscle and scar tissue partly compensate—while the osteoarthritis keeps progressing and the meniscus remains at risk.

10. Surgical procedures at a glance

Broadly, two principles can be distinguished, and the difference is easier to understand than the abbreviations suggest.

Procedures that replace the ligament. A suture or band outside the joint takes over the guiding function. Technically simpler, less expensive, and used mainly in light dogs. In heavy dogs, durability is limited.

Procedures that change the mechanics. Instead of replacing the ligament, the bone is repositioned so that cranial tibial thrust no longer occurs at all—the knee then no longer needs the cruciate ligament. There are two ways to get there, and they are often confused:

In TPLO, the joint surface of the head of the shinbone is freed with a circular cut and rotated until the backward slope is largely leveled; it is then fixed in place with a plate.

In TTA, the angle of the joint surface stays the same. Instead, the attachment of the patellar tendon on the shinbone is moved forward, so that the tendon pulls at a right angle to the joint surface, which neutralizes the thrust.

Both procedures are more complex and more expensive than ligament replacement, but they are considered the standard for medium-sized and large dogs.

Which procedure is right depends on size, weight, activity level, knee angle and additional findings. As a rule, the surgeon's experience matters more than the choice between two established procedures—feel free to ask about case numbers.

10.1 Questions worth asking before surgery

The statement in the previous section—the surgeon's experience matters more than the choice of procedure—can be translated into concrete questions.

How many of these procedures do you perform per year? This is not a rude question; it is the most telling one.

Why this procedure for my dog? A good answer mentions size, knee angle, activity level and findings—not “that's how we always do it.”

Will the meniscus be assessed, and how? By arthroscopy or by opening the joint—both are established, but it should happen.

What does pain management look like during and after the procedure?

When are the follow-up checks, and when is my dog cleared for what? A written plan for the first weeks is worth more than any verbal promise at discharge.

What does it cost in total—and what is included? It makes sense to ask for the total amount including the pre-anesthetic workup, anesthesia, implant, follow-up checks and X-rays. And to ask about the second knee, see Section 9.1.

A note from practice: the most expensive procedure is not automatically the right one, and the cheapest is not automatically the worse one. In a dog weighing six kilograms, ligament replacement may be exactly right, whereas in a Rottweiler it reaches its limits.

11. After surgery, rehab makes the difference

This is where the outcome is made or lost, and this is the part that is in your own hands.

The first six to twelve weeks are strict: leash only, even in the yard, no jumping, no stairs, no play with other dogs, non-slip floors, a ramp into the car. The most common mistake is not a lack of care but being cleared too early, because the dog already seems fit again. He seems fit before he is.

At the same time, pure rest is wrong. A controlled build-up—short, slow leash walks according to plan, physical therapy, targeted muscle exercises and later often an underwater treadmill—is part of the treatment.

With the underwater treadmill, however, the timing is not negotiable: it only becomes an option once the wound has fully healed and the surgeon has given the go-ahead—after a bone cut, often considerably later than after suture removal. If water gets into a wound that has not yet closed, there is a risk of infection around the plate and screws, and that is far harder to treat than the original problem. So do not book hydrotherapy on your own in the first week. Muscle is the knee's active stabilization; without it, the outcome falls short of what is possible.

The mind needs a substitute: nose work, search games and calm shaping keep a dog occupied without loading the knee. Otherwise, an under-stimulated dog on leash rest can easily become exactly the dog that takes off at the first off-leash run.

👉 Why abrupt stops strain the knee: ball games with dogs—myths and facts

11.1 What physical therapy actually does

“Physical therapy” sounds like an extra for particularly dedicated owners. With this procedure, it is part of the treatment, and it is worth understanding what it works on.

Building up the thigh muscles. This is the actual goal. Muscle is the knee's active stabilization—surgery restores the passive stabilization, the active one has to be brought back. Muscle loss begins before surgery, because the dog is sparing the leg, and it continues after surgery as long as the leg bears little weight.

Restoring even weight-bearing. After weeks of sparing the leg, dogs develop ingrained compensation patterns—they shift weight onto the front legs and onto the other hind leg. That puts extra load on precisely the knee that Section 3 is about. These patterns often do not resolve on their own once the pain is gone.

Mobility in the joint. A knee that has not been fully bent for weeks loses range of motion. It is easier to recover that sooner rather than later.

The therapist will show you what you can contribute yourself—usually a few simple exercises for home that take a few minutes a day and can account for a large part of the effect. The appointments at the clinic steer and correct; the work happens in between.

And a note on timing: the start is cleared by the surgeon, not chosen by you. This applies especially to anything involving water, for the reason given in the previous section.

12. Six to twelve weeks of leash rest—how to make it work

The previous section says that this is where the outcome is made or lost. Because this is the part that actually breaks down in everyday life, here is concretely how to see it through.

12.1 Preparing your home—before surgery

Whatever is not in place on the day your dog comes home usually never gets put in place. Non-slip runners on every route your dog takes daily. Block off stairs, do not just forbid them. Make the sofa inaccessible or put a sturdy ramp in front of it. Get a ramp for the car and practice beforehand—a dog that is supposed to see it for the first time after surgery often will not use it.

And a resting spot on the floor, with enough padding, in the room where the family spends its time. A dog lying alone in the kitchen gets up frequently.

12.2 Mental work replaces physical exercise

The statement from Section 11 deserves a closer look, because it decides between success and failure: an under-stimulated dog on leash rest can easily become exactly the dog that takes off at the first off-leash run.

What works and does not load the knee: scattering food over a blanket or a snuffle mat. Search games while lying down—hide something while the dog waits, then lead him to it. Chews that take time. Calm handling training, which is needed for the checkups anyway. And cues that require no movement: chin rest, nose to hand, giving a paw while lying down.

What does not work: tricks that require standing up on the hind legs, spinning or alternating sit positions. And anything that creates excitement, even if the dog is lying down while doing it—a dog trembling with anticipation can easily jump up as soon as something moves.

12.3 The most dangerous moment comes later

The first week is not the problem; weeks four to six are. The dog feels good again, uses the leg, wants more—and the people around him relax, because things seem to be going well.

This is exactly the phase in which the incidents happen: the jump off the sofa in an unsupervised moment, the doorbell, the neighbor's dog at the garden fence, slipping on the hallway floor. Any one of these can jeopardize a bone cut that has not yet fully healed.

The most effective precaution is therefore to keep the safeguards in place until your dog is cleared—even and especially when they seem excessive. Clearance is based on findings, not on impressions.

12.4 When to get in touch

Your dog should go back to the clinic if there is swelling, redness or discharge at the wound, if weight-bearing suddenly gets noticeably worse after an incident, if a new click appears in the knee—and if he seems to be suffering despite pain medication. Renewed lameness after initial improvement is the case from Section 6 and should be checked promptly, not waited out.

13. What you can do at home

Keep your dog lean. With this condition, that is one of the most important levers—for the operated knee and even more so for the other one.

Watch how your dog sits. A dog that sticks one hind leg out to the side when sitting often has a knee problem. This is easy to observe in everyday life and is almost always overlooked.

Avoid peak loads. Abrupt stops, turning at full speed and repeated jumping are exactly the movements that can overwhelm a previously damaged ligament—throwing a ball combines all three.

Provide non-slip floors. Laminate and tile force constant balancing and can increase the risk.

Build fitness steadily instead of weekend hikes after five quiet days.

Take brief lameness seriously, even when it goes away on its own. That is exactly the window in which something can still be changed.

13.1 What prevention can—and cannot—achieve

The points above make sense and are worthwhile. Still, one statement belongs here that is otherwise easily skimmed over: there is no sure way to prevent cruciate ligament rupture.

The reason is in Section 5. Important influencing factors are body structure—such as the angle of the tibial plateau—breed and ligament quality. None of these can be influenced. A lean, well-conditioned Labrador with a steep knee angle can get a cruciate ligament rupture, and then it is not necessarily because someone did something wrong.

What the measures achieve is something different, and still very valuable: they can shift the probability and often the timing. For a process that runs over a longer period, that is exactly the realistic goal—and in the case of the second knee from Section 3, time gained can make the difference between two surgeries and one.

And the point that matters for owners: if you did everything right and still face this diagnosis, you did not miss anything. When it comes to this condition, the question of blame leads in the wrong direction—the useful question is the one about the other knee.

14. Limits of the evidence

The figures on the second knee come from different studies with different follow-up periods and populations—hence the wide range of 22 to 54 percent. They also mostly involve dogs from surgical referral centers, which is a selected group.

The statement that degeneration predominates is well supported, but it is a statement about the majority. The purely traumatic tear of a healthy ligament exists—it is just rare, and the everyday explanation greatly overestimates it.

When it comes to comparing surgical procedures, the evidence is more difficult than the debate about them would suggest: many studies are small, unblinded case series with differing criteria for success. There is no well-supported ranking.

And the same applies to the rehabilitation recommendations as to osteoarthritis: they are based on biomechanics and clinical experience, not on randomized comparisons of individual protocols.

On the structure of the evidence as a whole: the statements on degeneration and on the risk to the opposite side rest on observational studies of dogs presented because of a cruciate ligament rupture—that is, on a preselected group. These figures are not suitable for estimating frequency in the overall population, but they are suitable for the question “What can I expect after a diagnosis?”, because they represent exactly this group.

To this day there is no large randomized study comparing the surgical procedures that would justify a clear ranking. The recommendations are based on case series, experience and biomechanical reasoning—which is why this article does not call any procedure the best.

👉 Primary care veterinarian, board-certified specialist or referral hospital: When does my dog need to see a specialist?

15. Conclusion

In dogs, cruciate ligament rupture is usually not an accident but the end of a process—in roughly half to two thirds of affected dogs, the joint lining already shows inflammatory changes at the first diagnosis. This explains the early signs that many owners recognize in hindsight: the brief lameness after getting up, the leg stuck out crookedly when sitting. And it explains the real consequence: if a process lies behind it, the second knee is not a matter of chance but of probability—between 22 and 54 percent, depending on the study. If you have both knees examined at the first appointment, tackle your dog's weight and take rehab seriously, you are therefore not just working on the leg that happens to be lame.

👉 What matters when choosing: what makes a good veterinarian

If you take only one thing from this article: at the appointment, have both knees examined and X-rayed. The finding in the apparently healthy knee is one of the most informative clues available about what lies ahead for the two of you over the next one to two years—and with the sedation that is needed anyway, it costs hardly anything extra.

Key takeaways on cruciate ligament rupture in dogs

It is usually not purely an accidental injury. The tear is predominantly the end of a progressive degeneration—the jump is the moment of failure, not the cause. Purely traumatic tears do exist; they are the exception.

The knee had already changed by the time of diagnosis. In about 51 to 67 percent of affected dogs, inflammatory changes in the joint lining are already present at the first diagnosis—a strong indication of a process that has been going on for some time, but not a measure of how long.

That is why the second knee is the real issue. Depending on the study, it ruptures in 22 to 54 percent of dogs within roughly six to seventeen months; in a longer-term analysis, the median time to the second tear was about 947 days.

The finding in the healthy knee says more than breed or weight. Marked joint effusion on X-rays was associated with a considerably increased risk—breed, age, weight and knee angle, by contrast, were not significant. That is why both knees should always be X-rayed.

The way a dog sits is an easily observed early sign. A dog that sticks one hind leg out to the side when sitting often has a knee problem—this is easy to see in everyday life and is almost always overlooked.

The meniscus has a major influence on pain and the course of the disease—and it can still fail even after successful surgery. Renewed lameness after initial improvement should therefore be checked promptly.

Surgery does not restore a healthy knee; it stabilizes it. Osteoarthritis is to be expected in both cases—if you know that beforehand, you will be less disappointed later.

Conservative does not mean wait and see, but an active program of weight loss, controlled exercise over months, physical therapy and pain management.

The most common mistake after surgery is being cleared too early. The dog seems fit before he is—clearance is based on findings, not on impressions.

References

• Muir, P. et al. (2011): Contralateral Cruciate Survival in Dogs with Unilateral Non-Contact Cranial Cruciate Ligament Rupture. PLOS ONE 6(10): e25331. https://doi.org/10.1371/journal.pone.0025331 (median survival time of the contralateral cruciate ligament 947 days; risk of rupture on the opposite side reported in the literature as 22–54 % within 6 to 17 months of diagnosis; inflammatory changes in the joint lining in 51–67 % of dogs already at the time of first diagnosis)
• Chuang, C., Ramaker, M. A., Kaur, S., Csomos, R. A., Kroner, K. T., Bleedorn, J. A., Schaefer, S. L. & Muir, P. (2014): Radiographic Risk Factors for Contralateral Rupture in Dogs with Unilateral Cranial Cruciate Ligament Rupture. PLOS ONE 9(9): e106389. https://doi.org/10.1371/journal.pone.0106389 (odds ratio for rupture of the opposite side with marked effusion in the contralateral knee 13.4 after one year and 11.4 after two years; with pronounced bony outgrowths 9.9 after one year; breed, age, weight, sex and knee angle not significantly associated with timing)
• Comerford, E., Smith, K. & Hayashi, K. (2011): Update on the aetiopathogenesis of canine cranial cruciate ligament disease. Veterinary and Comparative Orthopaedics and Traumatology 24(2): 91–98. https://doi.org/10.3415/VCOT-10-04-0055 (cruciate ligament rupture in dogs mostly the result of progressive degeneration of the ligament tissue; acute traumatic rupture possible, but the exception)

Frequently asked questions about cruciate ligament rupture in dogs

The questions asked most often in the exam room