Cruciate ligament injury in dogs

Content by Emma Chandley BVetMed PGCertSAS MRCVS

A cruciate ligament injury in dogs refers to the damage of one of the important stabilising ligaments within the knee joint (called the stifle). The cranial cruciate ligament helps keep the joint stable when a dog walks, runs or turns. When this ligament becomes stretched, partially torn or completely ruptured, the joint becomes unstable and painful.

Unlike many human sports injuries, cruciate ligament problems in dogs often develop gradually. In lots of cases, the ligament weakens over time before it eventually tears (rather than failing as the result of a single traumatic event). Once the ligament is damaged, inflammation and joint instability can lead to arthritis developing in the joint if it’s not appropriately managed.

Cruciate ligament disease is one of the most common orthopaedic conditions seen in dogs. It can affect pets of many different ages and breeds. Early recognition and veterinary assessment are important to help manage pain and protect long-term joint health.

• The cranial cruciate ligament stabilises the knee (stifle) joint in dogs
• Damage may involve stretching, partial tearing or complete rupture of the ligament
• The condition causes hindlimb lameness and joint pain
• It may develop gradually due to ligament degeneration rather than a sudden injury
• Without treatment, joint instability can lead to arthritis and long-term mobility problems

Cruciate ligament injuries can occur for lots of different reasons. In many dogs the ligament gradually weakens over time before eventually tearing. This degeneration can be influenced by factors such as genetics, joint conformation, body weight and overall activity level – as well as the type of activities the dog is doing day to day. 

Sudden injuries can still occur during activities that involve twisting or rapid turning, such as chasing a ball or jumping. However, even in these cases where an acute injury has occurred, the ligament is often already weakened beforehand.

Other contributing factors may include obesity, poor muscle support around the joint, or abnormal alignment of the hind limbs. In some dogs, inflammation within the joint may also play a role in weakening the ligament structure over time.

Cruciate ligament disease can occur in any breed of dog, but some dogs appear to be at higher risk. Medium-to-large breeds are more commonly affected, particularly:

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

Smaller breeds are certainly not immune, and vets regularly diagnose cruciate ligament injuries in dogs of many different sizes. Body condition can also play a role, as excess weight places additional strain on the joints and ligaments. Maintaining a healthy body weight and good muscle condition can therefore be an important part of supporting long-term joint health in any breed.

In milder or partial cruciate ligament injuries (often referred to as grade 1 or grade 2), the ligament is stretched or only partially torn. Clinical signs can be very subtle at first. Common symptoms may include intermittent lameness in one of the hind legs, stiffness after rest, reluctance to jump or climb stairs, or reduced enthusiasm for exercise. Some dogs may appear comfortable at rest but begin limping after activity.

Owners may also notice their dog sitting with the affected leg held slightly out to the side, or they may report difficulty rising from a lying position. These early signs should always be assessed by a vet, as early intervention can help slow the progression of the condition.

Diagnosis

Diagnosis of the condition starts with a clinical examination by your vet. Your vet will assess the dog’s gait and examine the knee joint for swelling, pain and instability. Specific orthopaedic tests can help detect abnormal movement within the joint.

In some cases sedation may be required to allow a full examination, especially if the dog is in a lot of pain. X-rays are often taken to assess the joint and rule out other causes of lameness, although ligament damage itself may not always be directly visible on radiographs.

Treatment options for partial cruciate ligament injuries vary depending on the severity of symptoms, the dog’s size and their activity level. In some dogs, particularly smaller or less active pets, conservative management may be advised.

This can include strict exercise restriction, weight management, anti-inflammatory medication and physiotherapy. Controlled rehabilitation exercises and hydrotherapy can help strengthen the surrounding muscles and improve joint stability.

In larger or more active dogs, surgery may still be recommended to stabilise the joint and reduce the risk of further damage. Your vet will discuss the most appropriate options based on the individual case.

Prognosis

The prognosis is often very good in these cases. Many dogs with partial cruciate ligament injuries respond well to appropriate management, particularly when the condition is recognised early.

However, there’s always a risk that a partial tear may progress to a complete rupture over time. So it’s very important to monitor closely and have regular check ups with your vet. 

Long-term joint health is usually improved when weight is carefully controlled and exercise is managed appropriately. Some degree of arthritis may still develop within the joint, but many dogs can return to a comfortable and active lifestyle.

A grade 3 injury refers to a complete rupture of the cruciate ligament. In these cases the knee joint becomes unstable and dogs often develop sudden and more severe lameness. 

Affected dogs may hold the leg up completely when walking (non weight bearing) or place very little weight on it. The knee joint may appear swollen and painful, and some dogs show obvious pain and discomfort when attempting to stand or move.

Over time the instability in the joint can lead to progressive arthritis and muscle loss in the affected limb if the injury isn’t treated.

Diagnosis

Vets diagnose a complete cruciate ligament rupture through a combination of clinical examination and imaging. Orthopaedic tests can demonstrate abnormal forward movement of the tibia relative to the femur, which is characteristic of cruciate rupture.

X-rays are usually recommended to assess joint changes and to rule out other orthopaedic problems and help plan treatment. In some cases, advanced imaging or referral to an orthopaedic specialist may be advised.

For most dogs with a complete cruciate ligament rupture, surgery is the recommended treatment. The aim is to stabilise the knee joint and reduce ongoing damage within the joint. Several surgical techniques may be used, including procedures such as TPLO (tibial plateau levelling osteotomy) or TTA (tibial tuberosity advancement). In some cases a lateral suture method may be used. These operations change the biomechanics of the joint, so that stability is restored even without the damaged ligament.

Post-operative care is extremely important. Your vet will give you a detailed plan which usually includes several weeks of restricted exercise followed by a structured rehabilitation programme. Physiotherapy and hydrotherapy are often recommended to support recovery.

To learn how water-based rehabilitation aids recovery, listen to our podcast episode with Dr Julia Mewes: Injury recovery for dogs: Hydrotherapy & mobility.

Prognosis

With appropriate surgical treatment and rehabilitation, many dogs recover really well and are able to return to normal activity levels. Recovery times can vary, but most dogs begin to show significant improvement within a few months.

Arthritis can still develop over time, but stabilising the joint helps to reduce further damage and improves long-term comfort and mobility.

“Cruciate ligament injuries are one of the most common orthopaedic problems we see in dogs, and it can be so worrying for owners when they first notice their dog limping. The good news is that with the right treatment and rehabilitation, many dogs go on to make an excellent recovery. My own dog has had cruciate surgery in both knees, and she still enjoys her walks and is very comfortable. 

“One of the most important factors we can influence and manage is body weight. Keeping your dog at a healthy weight significantly reduces the strain placed on their joints and can make a real difference both in recovery from cruciate ligament injury and long-term joint health.

“If you notice persistent limping or stiffness in your dog, it is always worth having it checked by your vet early. Addressing the problem sooner rather than later can help improve the outcome.”

Emma Chandley – BVetMed PGCertSAS MRCVS 

Tell us about your dog’s cruciate ligament injury when you get a quote for Lifetime Plus insurance and we’ll see if we can cover them*. If we accept, we cover vet fees for cruciate ligament injury up to £2,000.

You must tell us about all the conditions they’ve had in the last two years – including those which need ongoing treatment, monitoring or check-ups. This way we can offer the exact level of cover for your dog’s individual needs.

Find out more about our dog insurance for pre-existing medical conditions.