If your dog has ruptured its cruciate ligament, you’re not alone! I know that a very high percentage of readers will have experience of this condition because this is the reason the majority of my clients visit me! It is one of the most common causes of lameness in the canine world. About 1.4 billion is spent each year on medical and surgical management of cruciate ligament disease in dogs, so I felt it was worth a discussion.
Firstly, don’t be ashamed to not know what the cruciate ligament is! We all hear about famous footballers injuring their cruciate so most people are aware that in a human the cruciate ligament is in our knee. But where is the dog’s knee? The knee is, of course, in your dogs back leg… you’d be surprised to hear how many people think their knee is in their front leg- no judgement here, it’s confusing!

The cranial cruciate ligament plays a very important role in stabilising your dog’s knee. It is a small, but strong ligament that attaches the femur (thigh bone) to the tibia (shin bone), preventing excessive movement of the tibia in relation to the femur. It also helps to prevent the knee joint from over-extending or rotating. Hopefully the image below will help this to make this clear (the cranial cruciate ligament is marked in red). To put it simply, it prevents excessive movement in the joint. And excessive movement results in pain, inflammation and eventually arthritis. So it is fair to say that the cruciate ligament is very important.


People often think that this problem is seen following a fall or injury, which results in a traumatic rupture of the ligament, but actually only about 20% of cruciate ligament ruptures are as a result of trauma. In the majority of dogs, the ligament ruptures following long term degeneration, which leads to the fibers within the ligament weakening over time. The dog will gradually become lame and painful even before the ligament has completely ruptured. So this is why we often refer to it as cruciate ligament “disease” as opposed to “injury”.
Unfortunately, nobody is 100% sure what causes this disease process, but it does seem that genetic factors play a massive role. Cruciate ligament disease is most commonly seen in Labradors, Boxers, West Highland Terriers, Newfoundlands and Rottweilers. No breed is safe though! I see plenty of crossbreeds that are affected by this disease too! In fact, two of my three Terrier crossbreed dogs had/have cruciate ligament disease. Another massive predisposing factor is obesity, another reason your vet is so strict with your dogs weight checks! Some dogs may also have conformational abnormalities, hormonal imbalances or certain inflammatory conditions of the joint, which can predispose them to cruciate ligament disease.


So how will you know if your dog has cruciate ligament disease? The most obvious sign is lameness, which can be sudden in onset or can gradually come on over a prolonged period of time. Usually by the time we notice lameness the disease process is quite advanced. In fact, even at the earliest stage of detection, osteoarthritis is normally already present in the knee. The ligament will have started to fray away causing a cascade of events, which leads to pain, swelling and inflammation. Rupture of the ligament leads to decreased nerve signaling to associated muscles, which leads to decreased muscle activation, further joint instability and inevitable muscle weakness of the associated leg.
There are some earlier indicators that something may not be right within the joint. One thing I notice a lot with these dogs is they often don’t sit symmetrically. They tend to sit unevenly or to one side. Owners often notice that their dog sits funny or untidily, or sometimes its not very obvious and we only spot it in the consult. Some owners will report an unusual gait or a change in the way they move, they may be reluctant to walk or tire more easily, or stop jumping into the car or onto furniture. Some dogs are very stoic, and won’t have any sign of pain until things have progressed quite far, and others are very dramatic and may even refuse to move at all! (Did someone say Bichon Frise?!).

Your vet will usually have a fair idea from examination if cruciate ligament disease is suspected, but they will also usually need to take Xray’s to have a good look at the joint and to check for other problems, and this gives them a good opportunity to examine your dogs knee under general anaesthesia and determine how much instability might be present.
Once your dog has been diagnosed with CCL disease, you will be presented with options. Depending on many factors (your dogs size, age, general health, level of joint instability and financial factors), your dog will either be treated surgically or non-surgically.
In my own opinion, dogs who are treated surgically seem to have the best possible outcome long term. However, this does not mean that surgery is your only option. There are so many reasons your dog may not be a suitable candidate for surgery and your vet will discuss all of these with you. In fact, there are often many reasons why your dog would be an excellent candidate for non-surgical management too! Generally, smaller dogs do better with conservative treatment. Older and quieter dogs are better candidates; because lets face it they aren’t going to be running a marathon any time soon. But if you have a medium-large breed, young and otherwise healthy dog then your vet will most likely be recommending the surgical approach. The surgery is not cheap, so if finance is an issue then discuss conservative management with your vet as well.
I’m not going to get into the surgical treatment of this condition because it’s not my area, but the aim of surgery is usually to provide stabilisation or to alter the geometry of the knee joint in such a way that there is no longer a need for the cruciate ligament. There are several techniques, and your vet will decide which one is best for your dog. It is not uncommon for your vet to refer you to a specialist orthopaedic surgeon for this procedure.

So, where does physio come in? Whether your dog has had surgery or is being treated conservatively, rehabilitation is so important in your pet’s recovery.
In the early stages post injury or post surgery, physio treatment can help to provide pain relief, reduce inflammation, encourage healing and relieve any muscle tension that will have developed as a result of the injury. Treatment will also help to prevent further muscle tension. It is important to maintain or improve the joints range of motion and to carefully encourage early use of the leg.
Muscle weakness will have developed following decreased weight bearing of the affected leg. Rehabilitation will be aimed at strengthening and rebuilding muscle mass, while ensuring that the dog is not doing too much too soon! Adequate healing time is very important. The hamstring and quadriceps groups of muscles are very important for joint flexion and extension so we focus on these a lot.
Compensatory patterns often develop in your dogs movement- they tend to shift more weight than normal forwards, increasing strain on their front legs. Abnormal movement patterns need to be corrected before they become a habit, as they can lead to more problems in the future and further weakening of the affected leg.


Rehabilitation is also important in providing osteoarthritis management going forward, as the majority of dogs will be affected.
Physiotherapy can include the use of a range of electrotherapy modalities, which can have numerous benefits to your dog throughout the various stages of healing, and for the management of osteoarthritis going forward. Massage therapy, hot/cold therapy, gentle stretching and other forms of manual therapy are also hugely beneficial. All dogs are prescribed a home exercise programme as a lot of the important work is carried out at home.
The bad news is that 30-50% of dogs affected by cruciate ligament disease will eventually injure the ligament in the opposite leg. But the good news is that their rehabilitation programme will be aimed at preventing this from happening, so with physiotherapy treatment we hope to greatly reduce this risk.

Limerick Canine Physiotherapy Zelda

I hope that this has provided a clear explanation of what happens when your dog suffers from cruciate ligament disease! It can be a nerve wrecking time if your dog has been affected, but whatever road you go down treatment wise the outcome is likely to be very good if you do your research and get reputable, professional treatment. Please don’t be afraid to email with any questions you might have.
Keep checking in for future posts on various conditions here or other interesting topics, I will try my best to keep them coming as quickly as I can. If you don’t already, follow Limerick Canine Physiotherapy on Instagram, I’ll be getting ideas there over the next couple of weeks on what conditions you guys are interested in hearing about.



My name is Karen Kennedy and I am a Veterinary Physiotherapist situated in Limerick City. I have been working with animals for almost 20 years now, first as a veterinary nurse, before combining this work with canine rehabilitation. I have a Post-Graduate Diploma in Veterinary Physiotherapy and a Certificate in Small Animal Hydrotherapy. I live on the outskirts of Limerick City with my family and my two dogs- Toby and Ted, who could probably do with benefiting from having a Vet Physio in the house more than they do! I have spent the last few years travelling between Galway, Limerick and Cork offering physiotherapy clinics, but you can now find me at Treaty Veterinary Clinic in Limerick.