Cruciate ligament injury in dogs

A cruciate ligament injury (also known as a cruciate ligament rupture) is one of the most common causes of sudden hind leg lameness in dogs. It affects the knee joint and can be very painful, often making it difficult for dogs to bear weight on the affected leg.

Because diagnosis, treatment, and rehabilitation can be costly, taking out lifetime dog insurance early in your dog’s life can help with the cost of care if this condition develops.

What is cruciate ligament injury in dogs?

A cruciate ligament injury in dogs occurs when one or both of the cruciate ligaments inside the knee joint are damaged or torn. These ligaments sit in the middle of the knee and help stabilise the joint during movement. When they’re damaged, the knee becomes unstable, and the lower leg can shift abnormally in relation to the thigh bone (femur), leading to pain, inflammation, and lameness.

In many cases, the ligament weakens gradually over time due to small repeated injuries before eventually tearing. Less commonly, a sudden traumatic injury can cause an acute rupture.

Causes of cruciate ligament injury in dogs

Most cruciate ligament injuries develop over time due to a combination of degenerative, biomechanical (how the joint is moved and used), and inflammatory changes rather than a single incident. Common contributing factors include:

• Gradual wear and tear on the ligament
• Repeated minor strain or micro-injuries
• Excess body weight placing stress on the joints
• High-impact or twisting movements
• Underlying joint instability or poor conformation

In some cases, a sudden movement such as landing awkwardly or turning sharply can trigger a rupture in an already weakened ligament.

Commonly affected breeds

Any dog can suffer a cruciate ligament injury, but it can be more common in certain breeds, including:

• Labrador Retrievers
• Golden Retrievers
• Rottweilers
• Newfoundlands
• Staffordshire Bull Terriers

Smaller breeds can also be affected, particularly if they’re overweight or inactive, although the condition is more common in medium to large dogs. Larger and heavier dogs tend to be at higher risk due to increased strain on the knee joint.

Types of cruciate ligament injury

Cruciate ligament injuries can range from partial tears, where the ligament is damaged but still partly intact, to complete ruptures, where it fully tears and the knee becomes unstable. In some dogs, both knees can be affected, either at the same time or with the second knee developing problems later on.

Symptoms of cruciate ligament injury in dogs

Signs often appear suddenly and may include:

• Sudden lameness in one hind leg
• Holding the affected leg up
• Swelling around the knee joint
• Stiffness or difficulty bearing weight
• Sitting more often to relieve pressure on the leg
• Reluctance to exercise or move normally

Some dogs may seem slightly better after rest, but the lameness often returns.

What to do if your dog shows signs of cruciate ligament injury

If your dog suddenly becomes lame or is struggling to put weight on a back leg, contact your vet as soon as possible. They’ll assess your dog’s movement, examine the knee joint, and may recommend imaging such as X-rays to confirm the diagnosis and rule out other causes. Early diagnosis is important to prevent further joint damage and begin appropriate treatment.

What age could you expect cruciate ligament injury in your dog?

Cruciate ligament injuries can occur at any age, but they’re most commonly seen in adult and middle-aged dogs.

Gradual degeneration of the ligament often develops over time, meaning symptoms may appear as dogs get older, particularly in those with additional risk factors such as excess weight or high activity levels.

How to manage cruciate ligament injury in dogs

How it’s managed depends on things such as how severe the injury is and whether surgery is needed. In most cases, recovery takes time and involves a structured rehab plan. Management options may include:

• Strict rest during the initial healing phase
• Controlled, gradual exercise plan
• Weight management to reduce joint strain
• Pain relief and anti-inflammatory medication prescribed by a vet
• Physiotherapy and hydrotherapy to rebuild strength and mobility
• Use of ramps, non-slip flooring, and supportive bedding at home

Rehabilitation is typically gradual, with activity slowly increased under the guidance of a vet.

Does pet insurance cover cruciate ligament injury?

Cruciate ligament injuries are often covered by pet insurance, but it depends on your policy and when the condition first develops.

Agria offers lifetime pet insurance, which means conditions like cruciate ligament injury can be covered as long as the policy was taken out before any signs or symptoms appear and is renewed each year. This is why it’s important to insure your dog early, before any health issues develop.

To make sure your cover suits your dog’s needs, always check the policy wording carefully. You can also ask your insurer what is and isn’t covered before taking out a policy, especially if cruciate ligament injury is a particular concern.

Cruciate ligament injury treatment options

Treatment for a cruciate ligament injury generally depends on the severity of the injury, the size of the dog, and their overall health.

Surgical treatment

Surgery is commonly recommended, especially for medium to large dogs, to help stabilise the knee and improve their long-term mobility. This may involve arthroscopy (keyhole surgery) to assess the joint and remove damaged tissue or debris. Other options include TPLO (tibial plateau levelling osteotomy) to stabilise the knee, or alternative stabilisation techniques depending on the individual case and your dog’s needs.

Non-surgical treatment

In some cases, particularly for smaller dogs or partial tears, non-surgical management may include things like:

• Strict rest and restricted activity
• Pain relief medication
• Controlled rehabilitation exercises
• Physiotherapy and hydrotherapy support

When to speak to a vet

You should contact your vet immediately if your dog suddenly develops lameness, is unable to bear weight on a back leg, or shows signs of pain or swelling around the knee.

Even if symptoms appear mild or improve with rest, it’s still important to have your dog assessed, as untreated cruciate ligament injuries can worsen and lead to long-term joint damage and arthritis.