What is cranial cruciate ligament rupture?

Canine cranial cruciate ligament rupture happens when cranial cruciate disease causes the cranial cruciate ligament (CCL), which is an important ligament in the knee joint, to degenerate overtime. This then leads to weakness, resulting in a rupture following strenuous exercise, such as running or jumping.

What are the symptoms of
cranial cruciate ligament rupture?

Your dog will display some clear symptoms of cranial cruciate ligament rupture, with the most common being:

  • Limping
  • Knee and hind limb lameness
  • Stiffness

They may come on suddenly, gradually or intermittently, and can affect one or both knees. If both knees are affected, you may find that your dog has difficulty getting up, or has an unusual gait when walking. Where dogs are severely affected, they may not be able to get up at all.

Other symptoms of cranial cruciate ligament rupture

Other symptoms include:

  • Pain in the knee joints
  • Difficulty jumping
  • Occasional ‘clicking’ or ‘popping’
  • A swollen knee

Where the ligament has frayed, your pet may find normal movement more difficult. This means that mechanical function has been affected, and this can result in lameness as well as pain.

This can be impounded by the shape of your dog’s tibia shin bone, which slopes backwards. As a result, the thigh bone (femur) can roll down the top of the shin bone every time your pet puts weight on the affected leg, causing significant issues if your dog is suffering from a CCL rupture.

Where this occurs, your dog may also suffer from damage, including crushing and tearing, to other parts of their knee joint, particularly the cartilage (menisci) that sit between the knee joint.

What causes cranial cruciate ligament rupture?

Cranial cruciate ligament disease is the main cause of cranial cruciate ligament rupture. That’s because, over time, it causes the ligament to slowly degenerate, and these progressive changes weaken the fibres that make it up.

Partial or total rupture is therefore more likely to happen when your dog is running, jumping or exercising enthusiastically.

The main cause is currently unknown, but genetic factors are believed to play a part, especially as some breeds are more likely to be affected than others. These include:

  • West Highland White Terriers
  • Labradors
  • Boxers
  • Newfoundlands
  • Rottweilers

Cranial Cruciate Ligament Rupture

Many dogs from these breeds will experience cranial cruciate ligament rupture in both knees, and usually early in their lives, particularly if cranial cruciate disease is prevalent through their bloodline.

But there are other factors that can influence the development of the disease, including:

  • Hormonal imbalance
  • Inflammatory conditions
  • Obesity

As the ligament starts to degenerate, your dog will also begin suffering from osteoarthritis, resulting in knee pain and lameness.

How is it diagnosed?

Diagnosis depends on whether the ligament is partially or completely ruptured.

Partial rupture

If your dog has suffered a partial cranial cruciate ligament rupture, or where the ligament has gradually degenerated, your vet will carry out veterinary diagnostic imaging, such as x-rays and MRI scans.

Complete rupture

If your dog’s cranial cruciate ligament has completely ruptured, it’s important that they’re referred to veterinary orthopaedics, who will examine your pet’s knee for cranial drawer motion. This involves the application of pressure to the thigh bone and tibia. This is where the thigh bone slides over the tibia, enabling your vet to positively diagnose a complete CCL rupture. 

Your vet may also carry out an x-ray to determine the extent of any arthritis within the knee joint, and may take a fluid sample from the knee to better enable them to find signs of inflammatory changes, including rheumatoid arthritis and infection.

Cranial cruciate ligament rupture treatment options

There are two types of treatment for cranial cruciate ligament rupture: non-surgical and surgical. Treatment depends on how severely the ligament is ruptured, and how big your dog is.

Non-surgical treatment

If your dog is small, it may be possible to treat them with body weight management, veterinary physiotherapy, a change in their exercise type and routine or anti-inflammatory medication.

Improvement can take a number of months to show, and their condition will have to be managed for the rest of their life. It’s therefore essential that you continue with any veterinary appointments, and follow any exercise regimes set out by your vet and your dog’s physiotherapist.

Cranial Cruciate Ligament Rupture

Surgical treatment

For larger dogs, there are a range of different surgical techniques including:

Cranial cruciate ligament replacement therapy

This includes:

  • Replacing the affected ligament – this is done with a graft or an artificial ligament
  • Local tissue transfer – this is where replacement tissues are placed in the same position as the affected ligament
  • Prosthetic ligament replacement – this is most often recommended for dogs whose ligament rupture has been caused by trauma, damage or injury
  • Fabello-tibial tuberosity sutures – this is where sutures are placed between the back of the thigh bone and the tunnel that sits at the top of the shin bone 
  • Where the need for the ligament is removed

Tibial plateau levelling osteotomy (TPLO)

This is where the top of the tibia is cut, and the bone is rotated until the angle has been changed and the usual slope formed by the bone no longer exists.

If both knees are affected, this surgery can be carried out on both joints at the same time. Once this maneuver is complete, your vet will fix the bone in place with screws and a bone plate.

Tibial tuberosity advancement (TTA)

This is where the top of the tibia is cut and moved forward, changing the direction of the thigh muscles, thereby preventing the thigh bone from rolling down the slope of the shin bone. The bones are then held in place with a bone plate and screws.

Cartilage surgery

Cartilage issues can be extremely painful and cause lameness, so it’s important that the damaged cartilage is removed. Your vet may carry this out through keyhole surgery, or by using a camera.

Cranial Cruciate Ligament Rupture

What’s the prognosis?

This depends on the treatment path:

CCL replacement therapy

The prognosis is uncertain. This could be partly due not having the strength of the original ligament, or that the replacement is often placed into the same area that held the affected ligament, resulting in new ligament degeneration.  


The restructured bone will heal more efficiently than the replaced ligament, providing a more robust outcome. This results in your dog having a more reliable recovery, and they will be able to use the affected limb(s) within one to three days.

As with any surgery, there is a low risk of complications, including infection and some mechanical issues, which can be caused by exercising before your pet has healed. However, for most dogs, their implants will stay in place for the rest of their lives without any issues.

How long is recovery?

While your dog will be able to use the affected limb within one to three days of their surgery, it’s essential that their exercise is restricted for the first few weeks. This allows the bones to heal and reduces the likelihood of complications.

After a few weeks, you can gradually increase your pet’s exercise, though this will need to take place while they’re on a lead. They may also need to undergo further physiotherapy or hydrotherapy.

If you need any further advice on cranial cruciate ligament rupture, please don’t hesitate to contact us or fill in our veterinary referral form.