Home » Diseases » In dogs » Rupture of the cruciate ligament (cruciate ligament tear in the knee joint)

Rupture of the cruciate ligament (cruciate ligament tear in the knee joint) in Dogs

Occurrence: common
Location of disease: Legs

Author: Dr. med. vet. Gisa Löwe | Last modified: 17.02.2026

When to visit the vet?

Non-urgent see a veterinarian within 2–3 days

If the condition worsens / symptoms persist, consult a veterinarian.

Definition

A ruptureA rupture is a tear or break in an organ or tissue. It can be caused by trauma, illness, or overextension, and often requires medical intervention. of the cruciate ligament, also known as a cruciate ligament tear, is a common orthopedic injury in dogs in which one of the cruciate ligaments in the knee joint tears or is completely severed.

The most important facts at a glance

A cruciate ligament tear in a dog’s knee joint is a common injury that can be caused either by sudden traumatic movements or by chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. degeneration of the ligament tissue. Active dogs are particularly at risk, as abrupt twisting or turning during play or sport can lead to a tear. Certain dog breeds, such as the Labrador Retriever and the German Shepherd, have an increased risk due to the anatomyAnatomy is the scientific study of the structure of living things. It deals with the construction and organization of organisms, including their systems, organs, and tissues. of their knee. Symptoms of a cruciate ligament tear include Pain, lameness, and Difficulty lying down and rising. DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is made through a clinical examination and tests such as the drawer test, supported by imaging such as X-rayX-ray is an imaging technique that uses X-rays to create images of the inside of the body. It is often used to diagnose bone fractures, lung diseases, and other conditions. or MRI.

Treatment depends on the severity of the injury and can be surgical or conservative. Surgical procedures such as tibial plateau leveling osteotomyAn osteotomy is a surgical procedure in which a bone is cut or removed to correct alignment or improve a deformed bone structure. (TPLO) aim to restore joint stability, followed by a rehabilitation phase. Conservative treatments include pain management and controlled exercise. The prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. is good with early treatment, although full recovery can take several months.

Preventive measures can reduce the risk of a cruciate ligament tear. These include maintaining a healthy weight and avoiding abrupt strain during sporting activities. Research focuses on genetic factors, the role of anatomyAnatomy is the scientific study of the structure of living things. It deals with the construction and organization of organisms, including their systems, organs, and tissues., and improving treatment and preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. strategies.

Causes

A dog’s knee joint, also known as the stifle joint, is a complex joint made up mainly of bones, ligaments, tendons, and cartilage. The cruciate ligaments, consisting of the cranialCranial refers to a position that is closer to the head or towards the head of an animal. In veterinary medicine, the term is used to describe the location of structures or diseases in relation to the head. and caudalCaudal refers to a position closer to the tail or posterior end of the body. In human medicine, the term is used to indicate the direction "downward" in relation to the body's longitudinal axis. cruciate ligament, are crucial for stabilizing the knee joint by controlling the movement of the femurFemur is the technical term for the thigh bone. It connects the hip joint to the knee joint and plays a central role in supporting body weight and movement. on the tibiaThe tibia, also known as the shinbone, is the larger of the two bones in the lower leg. It bears the weight of the body and is connected to the knee joint at the top and the ankle joint at the bottom.. They prevent excessive forward and backward movement of the bones and stabilize the leg during movement.

A cruciate ligament tear can be caused by various factors. One of the most common causes is a sudden traumatic injury triggered by abrupt twisting or turning of the knee while running or jumping. This is common in active dogs, especially during sporting activities or play.

Another factor can be chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. degeneration of the ligament tissue, which often occurs in older dogs or certain breeds with a genetic predispositionA predisposition is an innate inclination or susceptibility of an organism to certain diseases or conditions. In dogs and cats, there may be a genetic predisposition to certain conditions such as hip dysplasia or certain heart diseases.. This degeneration causes the ligament to weaken over time and eventually ruptureA rupture is a tear or break in an organ or tissue. It can be caused by trauma, illness, or overextension, and often requires medical intervention.. Overweight can also increase the risk of a cruciate ligament tear because it puts additional pressure on the knee joint.

There is also evidence that knee anatomyAnatomy is the scientific study of the structure of living things. It deals with the construction and organization of organisms, including their systems, organs, and tissues. plays a role in certain breeds, such as the Labrador Retriever or German Shepherd, as these breeds have a steeper tibial plateau angle, which increases the risk of ruptureA rupture is a tear or break in an organ or tissue. It can be caused by trauma, illness, or overextension, and often requires medical intervention..

Symptoms

Very common symptoms:

Common symptoms:

A cruciate ligament tear in dogs often presents as sudden lameness of the affected leg. The dog may no longer be able to stand on or bear weight on the injured leg. In some cases, the dog may only be able to move the leg in pain and hold it in an unusual position.

Another common symptom is swelling of the knee joint. The swelling is caused by fluid buildup in the joint due to the body’s inflammatory response to the injury. This can be accompanied by pain, which the dog may try to relieve by Licking or biting the affected area.

In chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. cases where the ruptureA rupture is a tear or break in an organ or tissue. It can be caused by trauma, illness, or overextension, and often requires medical intervention. develops gradually, the dog may show a gradual decline in mobility and reduced willingness to be active or increased Stiffness after rest periods.

Diagnosis

DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. of a cruciate ligament tear usually begins with a thorough clinical examination by a veterinarian. The veterinarian will observe the dog’s gait and manually examine the affected knee joint for signs of instability, pain, or Swelling.

An important diagnostic test is the so-called drawer test, in which the veterinarian moves the dog’s leg in a specific position to assess the movement of the tibiaThe tibia, also known as the shinbone, is the larger of the two bones in the lower leg. It bears the weight of the body and is connected to the knee joint at the top and the ankle joint at the bottom. relative to the femurFemur is the technical term for the thigh bone. It connects the hip joint to the knee joint and plays a central role in supporting body weight and movement.. An unnatural forward movement often indicates a ruptureA rupture is a tear or break in an organ or tissue. It can be caused by trauma, illness, or overextension, and often requires medical intervention. of the cranialCranial refers to a position that is closer to the head or towards the head of an animal. In veterinary medicine, the term is used to describe the location of structures or diseases in relation to the head. cruciate ligament.

In addition to the clinical examination, imaging procedures such as X-rays can be used to support the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients.. X-rays can show changes in the joint space, signs of arthritisArthritis is an inflammation of the joints that can cause pain, swelling, stiffness, and limited mobility. There are many forms of arthritis, including rheumatoid arthritis and osteoarthritis., or other bony abnormalities associated with a cruciate ligament tear. In some cases, magnetic resonance imaging (MRI)Magnetic resonance imaging is an imaging technique that uses strong magnetic fields and radio waves to create detailed images of the inside of the body. It is used in veterinary medicine to diagnose diseases of the brain, spine, and other organs. may be required to obtain a more detailed view of the soft tissues in the knee joint.

Therapy

Treatment for a cruciate ligament tear depends on the severity of the injury and the dog’s overall health. In most cases, surgery is required to restore stability to the knee joint. There are various surgical techniques, including tibial plateau leveling osteotomyAn osteotomy is a surgical procedure in which a bone is cut or removed to correct alignment or improve a deformed bone structure. (TPLO) and tibial tuberosity advancement (TTA), which aim to change the biomechanics of the knee joint and reduce strain on the torn ligament.

After surgery, a rehabilitation phase follows, which may include physiotherapyVeterinary physiotherapy encompasses a range of treatment methods aimed at improving the mobility and well-being of animals through exercise, massage, and other manual techniques. measures such as controlled exercise, massages, and training on an underwater treadmill. These measures are intended to support the dog’s recovery, maintain muscle massIn pathology, the term "mass" is used to describe an abnormal lump or growth in the body. A mass can form in the skin or subcutaneous tissue, or even inside the body. The causes can be benign (not cancer) or malignant (cancer)., and improve joint mobility.

In less severe cases, or if surgery is not an option, conservative treatment may be considered. This includes pain management, an anti-inflammatory drugAnti-inflammatory drugs are medications or substances that help reduce or prevent inflammatory responses in the body. They can be divided into nonsteroidal anti-inflammatory drugs (NSAIDs) and steroidal anti-inflammatory drugs (e.g., corticosteroids)., and a controlled exercise plan to minimize stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. on the joint and relieve symptoms.

Prognosis and follow-up care

The prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. for dogs with a cruciate ligament tear is generally good, especially with early and appropriate treatment. Dogs that undergo surgical repair usually show a significant improvement in stability and function of the affected leg. However, full recovery can take several months, and following aftercare instructions is crucial to the success of treatment.

In dogs treated conservatively, the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. can vary depending on the severity of the injury and the owner’s ability to monitor and control the dog’s activity. Some dogs may face some limitation in mobility and an increased susceptibility to arthritisArthritis is an inflammation of the joints that can cause pain, swelling, stiffness, and limited mobility. There are many forms of arthritis, including rheumatoid arthritis and osteoarthritis. in the affected joint.

Prevention

PreventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. of a cruciate ligament tear in dogs focuses on minimizing risk factors that can lead to ruptureA rupture is a tear or break in an organ or tissue. It can be caused by trauma, illness, or overextension, and often requires medical intervention.. This includes maintaining a healthy weight to reduce stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. on the joints. Regular exercise and a balanced training program can strengthen the dog’s muscles and support knee joint stability.

It is also important to watch out for sudden and excessive strain, especially in dogs that take part in sporting activities. Owners should ensure the dog warms up before intense activity and does not make abrupt changes of direction or jumps without adequate preparation.

For breeds with a genetic predispositionA predisposition is an innate inclination or susceptibility of an organism to certain diseases or conditions. In dogs and cats, there may be a genetic predisposition to certain conditions such as hip dysplasia or certain heart diseases. to cruciate ligament tears, it may be useful to have regular veterinary check-ups to detect and treat early signs of joint problems. Working with a veterinarian to develop an individualized joint-health plan can help reduce the risk of injury.

Outlook on current research

Research into cruciate ligament ruptureA rupture is a tear or break in an organ or tissue. It can be caused by trauma, illness, or overextension, and often requires medical intervention. in dogs aims to better understand the underlying causes and the best treatment methods. One of the main questions being investigated is why certain dog breeds are more prone to cruciate ligament tears than others. Genetic factors are suspected to play a role, which is why some studies focus on identifying specific genes that could increase risk.

Another important aspect of research is the development and improvement of surgical techniques for treating cruciate ligament tears. There are various surgical methods, such as tibial plateau leveling osteotomyAn osteotomy is a surgical procedure in which a bone is cut or removed to correct alignment or improve a deformed bone structure. (TPLO) or tibial tuberosity advancement (TTA), which aim to restore knee stability. Researchers are working to refine these techniques and develop new procedures that are more effective and less invasive.

In addition, non-surgical treatment methods are also being researched. PhysiotherapyVeterinary physiotherapy encompasses a range of treatment methods aimed at improving the mobility and well-being of animals through exercise, massage, and other manual techniques., weight management, and the use of orthopedic aids are areas being studied intensively. The goal is to develop alternative treatment strategies that support the healing process and can improve the quality of life of affected dogs, especially when surgery is not possible.

An emerging area of research is regenerative medicine, which looks at the use of stem cells and other biological therapies to promote healing of cruciate ligament tears. InitialInitial means beginning or at the start. In medicine, it can refer to the first symptoms of a disease or the first phase of a treatment process. studies show promising results, and intensive work is underway to make these therapies safer and more effective.

Finally, research also focuses on preventive measures to avoid cruciate ligament tears. This includes nutrition studies examining the impact of diet and supplements on joint health, as well as research into optimal exercise and physical activity to minimize the risk of injury.

Frequently asked questions (FAQs)

What is an ACL tear in dogs?

A cruciate ligament tear is a knee injury in which one of the ligaments that stabilize the knee partially or completely tears. This leads to Pain and instability in the affected leg.

What symptoms does a dog with an ACL tear show?

Typical symptoms include lameness, difficulty getting up or jumping, Swelling around the knee, and a changed gait. In severe cases, the affected leg may not bear any weight at all.

Which breeds are particularly at risk for an ACL tear?

Large dog breeds such as Labrador Retrievers, Golden Retrievers, Rottweilers, and German Shepherds are more commonly affected. However, some smaller breeds can also be prone.

How is an ACL tear diagnosed?

Diagnosis is usually made through a clinical examination in which the veterinarian checks the affected leg for stability and pain. X-rays or an MRI can be used to confirm the diagnosis.

What treatment options are available for an ACL tear in dogs?

Treatment can be conservative or surgical. Conservative measures include rest, pain medication, and physiotherapy, while surgical options such as TPLO or TTA aim to stabilize the knee surgically.

How long does healing take after ACL surgery in dogs?

Healing time varies depending on the treatment method and the dog’s individual response. In general, dogs need about 8 to 12 weeks for full recovery after surgery, with the first weeks being especially important for rest and rehabilitation.

Can an ACL tear in dogs heal without surgery?

In some cases, especially in small dogs or partial ruptures, non-surgical treatment can be successful. However, surgical stabilization is often the preferred method to achieve long-term results.

What are the risks of ACL surgery in dogs?

As with any surgery, there are risks such as infections, Bleeding, or complications from anesthesia. Specific to cruciate ligament surgery, problems with plate or screw fixation can also occur.

Are there ways to prevent an ACL tear in dogs?

Preventive measures include maintaining a healthy weight, regular controlled exercise, and avoiding abrupt jumps or twisting movements. A balanced diet that supports joint health can also be helpful.

Can dogs walk normally again after an ACL tear?

Yes, many dogs can walk normally again and return to activities after successful treatment. The prognosis is especially good if the tear is detected early and treated appropriately.