Facebook_off Twitter_off Pinterest Instagram_off Googleplus_off Youtube_off Emailnewsletter

Welcome to DogHeirs, Where Dogs Are Family! Log in or Sign Up


DogHeirs Tshirts

Anterior Cruciate Ligament (ACL) Injuries in Dogs: Symptoms and Diagnosis

Dhicon_thumb By DogHeirs Team | November 29, 2012 | Comments (5)

Part I: Symptoms and Diagonosis | Part II: Treatment and Management

Golden Retrievers are one breed prone to ACL injuries

Anterior Cruciate Ligament (ACL) injuries are one of the most common orthopedic injuries veterinarians see in dogs. The ligament is also known as the Cranial Cruciate Ligament (CCL) in animals. It connects the bone above the knee (the femur) with the bone below the knee (the tibia). Essentially, the ACL stabilizes the knee (or stifle) joint.

Canine's stifle or knee joint
Canine stifle or knee joint

It does not matter the size, breed, sex or age of the dog, all dogs can get an ACL injury. That said, studies have shows certain breeds are more prone to ACL injuries. These include: Labrador Retrievers, Poodles, Golden Retrievers, Bichon Frises, German Shepherd Dogs, and Rottweilers.

Other predispositions to ACL injury include:

  • Dogs who are overweight
  • Unfit dogs who engage in sudden strenuous, irregular activity (e.g. weekend warriors)
  • Male dogs neutered under five months old
  • Dogs with conformational abnormalities (e.g. lacking muscle tone and proper muscular skeletal development in their rear legs)
  • Approximately 30-40% of dogs who get one cranial cruciate ligament rupture will likely rupture the ligament in the opposite leg within two years of the first rupture.

An ACL injury is extremely painful and affected dogs experience pain while simply walking. A tear or rupture leads to joint swelling, pain and instability in the knee joint. If left untreated it will cause lameness in the affected rear leg and, ultimately, chronic irreversible degenerative joint changes. Damage to the ACL is a major cause of progressive osteoarthritis in the knee joint of dogs.

The good news is that there is a high success rate with surgeries performed to repair ACL injuries and that dogs who receive surgical treatment can resume regular activities after rehabilitation.



ACL injuries can be caused by many factors, although the exact reasons as to why it is so common in dogs is not completely understood. Continual biomechanical wear and tear eventually causes the ACL to break down until it reaches a point that the ligament tears completely. Simple activities such as walking, running and jumping, all cause wear and tear. Obesity, traumatic injuries or strenuous or repetitive activities can also cause the ACL to deteriorate.  

ACL injuries in dogs do not always occur during athletic activities. Some dogs will be making a simple movement like jumping off a couch or going down a stair when their ACL will tear or rupture. 

Most acute (sudden) ACL injuries in dogs occur during strenuous or exuberant activities, such as playing, chasing, roughhousing, running, hunting, jumping or engaging in other "doggie" fun. Sometimes a dog will simply stumble and when they get up they will have ruptured their ACL. Other times ACL injuries will develop slowly over time. This can be caused by genetic abnormalities that cause poor muscle tone or poor neuromuscular coordination. Obesity also contributes to chronic ligament damage because of the extra weight placed on the joints. 



There is no straightforward way to prevent ACL injuries in dogs. Keeping your dog healthy and in good physical condition is the best prevention, but by no means guarantees your dog will avoid tearing their ACL.

Well-conditioned dogs are better able to avoid injuries, because their joints and bones are protected from outside stressors by strong surrounding musculature. General rules of thumb are:

  • Keep dogs on high-quality diets at optimal weight
  • Give dogs regular, moderate exercise.
  • Dogs with conformational abnormalities in their rear legs may predispose them to ACL injuries. These dogs should not be bred and their activities monitored.
  • If a dog is inactive for a period of time, avoid suddenly getting dog to do sudden strenuous activity. (e.g. if they dog has been a couch potato all winter, avoid suddenly going out for a 2 hour play time at the beach in the summer). Instead, gradually work up /train your dog to have the endurance and muscles so they can enjoy more vigorous activities.



Often symptoms of ACL injuries are gradual and a dog will slowly become more lame as the ligament becomes more damaged. Other times, when there is a rupture or tear, there is no advanced warning signs. Nearly all dogs with tearing or damage to their cruciate ligament will have swelling that is felt on the front part of their knee.

Symptoms may include:

  • Lameness or weakness in one or both hind legs
  • Limping or reluctance to use one or both hind legs
  • Limping worsens with exercise and improves with rest
  • Abnormal posture, especially over the back and hip areas
  • Reluctance to get up, jump, run or go up and down stairs
  • Stiffness and difficulty getting up in morning
  • Sitting at an odd angle, with a hind leg slanted unusually off to one side
  • Swelling around the knee joint
  • Muscle atrophy in the affected limb



Veterinarians use a test called the cranial drawer test to check the cranial cruciate ligament for looseness. The test is called a drawer test because the movement of the femur in relation to the tibia is similar to pulling and pushing in the drawer of a cabinet. The affected knee is tested for palpable laxity or looseness, which is referred to as cranial drawer instability.

A drawer movement accompanies ACL injuries in canines
A drawer movement in the knee accompanies a ruptured ACL.

Secondarily, a radiograph (X-ray) will be taken to determine the extent of the ACL damage and the progression of the injury. X-rays also will likely reveal if there is any fluid or arthritis in the joint or if there are bone spurs or fragments. 

Partial ruptures are more difficult to diagnose. Dogs with partial ligament tears will usually have swelling of their knee and pain when their knee is completely extended.

The video below summarizes symptoms and diagnosis of ACL injuries.


Next - Part II:  ACL Injuries in Dogs: Treatment and Management

Copyright 2015 DogHeirs. All Rights Reserved.

View more articles in: Musculoskeletal Diseases and Injuries

You may also like

Canine Hip Dysplasia: Symptoms, Diagnosis, Treatment and Prevention

Hip dysplasia is one of the most common skeletal diseases in dogs and affects millions of dogs worldwide. As the disease progresses, a dog's hip joints degenerate, causing increased pain and mobility issues for the dog. If left untreated, a dog will eventually be unable to use his/her hind legs and suffer extreme pain. However, the vast majority of dogs with hip dysplasia can lead full and active lives if the disease is diagnosed early...
Read more

Canine Lyme Disease: Symptoms, Treatment and Prevention

Lyme disease is one of the most common tick-transmitted diseases in the world. Lyme disease is caused by a bacterium (borrelia burgdorferi) that is commonly transmitted to animal hosts by ticks. Deer ticks, Western black-legged ticks, Taiga ticks and Sheep ticks (Castor Bean ticks) are the most common vector ticks for Lyme disease. These ticks and other kinds also carry different blood-born diseases such as Rocky mountain spotted fever, anaplasmosis, canine ehrlichiosis etc. Basically, a...
Read more

How to trim your dog's nails and why long toe nails are harmful to your dog’s health (VIDEO)

One of the key ways to maintain your dog’s general health is to cut his/her nails regularly. Bridget Wessel is a foster for Italian Greyhound Rescue and teaches canine agility. She explains why cutting your dog's nails is so important in maintaining joint and bone health and shares some tips on how to properly trim your dog’s nails. Some dogs hate nail trimming, others merely tolerate it, almost none like it. Some dogs need tranquillizers...
Read more

Anterior Cruciate Ligament (ACL) Injuries in Dogs: Treatment and Management

Part I: Symptoms and Diagonosis | Part II: Treatment and Management Canine ACL tears are debilitating to a dog. Oftentimes, full tears to a dog's ACL will require surgical repair to avoid severe, progressive osteoarthritis. Surgical repairs to ACL tears have a high success rate (usually around 95% for all the procedures), but as with all surgical procedures there is always risks involved. For partial tears, non-surgical treatment may be the better, less invasive option,...
Read more

Sweet, adoptable Pit Bull saved from euthanasia needs help to get second chance

Tessa arrived at a local county animal shelter in Northern California after she was found as a stray. The friendly and sweet 2-year-old Pit Bull mix appeared to have recently given birth to a litter of puppies but none were found with her when she was picked up. Tessa was never claimed, so she underwent a behavioral evaluation and passed with flying colors. Well-behaved and very gentle, Tessa quickly became a favorite of volunteers. "She...
Read more

Comments on this Article

I had never heard of Ortocanis before, but my amstaff tore her CCL recently and I'm looking into alternative treatment options with the help of my vet. I'm going to ask her and see if she knows anything else about the Ortocanis support products, from what I've seen online they look like a reputable company that makes high quality products.
Wow glad to see someone else has been successful with the Ortocanis products! We bought a hip brace from them last year and we were super impressed with the quality and results.. It's a really great online store and above all, the products are worth every cent. Hopefully our lab doesn't ever tear her ACL but if she does or it happens to anyone else that I know, I'll be sure to tell them about it!
My dog tore her ACL last year. We decided not to go with the really expensive surgery, I wanted to avoid putting her under all of that stress and possible complications, especially being 10 years old at the time. Our vet also suggested using a dog knee brace and I looked into the dynamic brace but the price was way out of reach for us. We found an online store called Ortocanis (www.ortocanis.com) that manufactures their own neoprene knee brace for dogs for less than $50! I was a little skeptical but I read a lot of the positive reviews they had and checked with my vet who said they were a reputable company. The Ortocanis knee brace worked wonders for us, and there was no other brace that we found with the same quality at a better price.
If you think your dog may have an ACL injury definitely talk to your vet - if you are looking for a brace as an alternative or as therapy before/after surgery you NEED to check out the A-TraC Dynamic Brace by Dr. Joel Spatt!! Fantastic product at a terrific price and to top it off the people that work there REALLY care about what they are doing - I made a mistake in my measurements on my order and they not only caught it but they also stopped the order from going out and contacted me to confirm my order and saved me (and my injured dog) a lot of aggrivation and money in return/exchange fees!! I am so impressed I just had to sign up for a couple of the larger message boards to tell people what a great experience I had. When I have official news of my dogs improvements after using the brace you'd better believe I will be back to let everyone know. Go to woundwear.com and check them out! I know I made the best decision for my dog by choosing the A-TraC Dynamic brace by Dr Spatt at woundwear.com - they have videos on YouTube as well.
As someone who is facing this with her 2 year old lab, get pet insurance. The surgery is costly - $2500 plus AND the knowledge that 30-40% end up having to have the other side done...wheesh..it's a good thing I love my bugger of a dog. Not all dogs who have an ACL injury were older or weekend warriors. My dog went to the dog park for running or swimming every day (unless storming out) and is fit as a fiddle (now a broken fiddle :(..)
» View all comments

Add Your Comment!

Log in to leave a comment or Create an account

Spring Sale on T-Shirts

Must See

Follow DogHeirs

Also find us on: DogHeirs on Twitter DogHeirs on Pinterest DogHeirs on Instagram DogHeirs on Google+

Copyright 2015 DogHeirs