In memories of all immobile dogs that were not given a second chance

What is Ruptured ACL or CCL?

Let’s look at the anatomy of a canine knee joint. The way the stifle (or knee) in a dog is situated, there is a major ligament located on the anterior of the knee that plays the role of providing stability to the knee joint.  It achieves this stability by attaching to the anterior of the joint, stabilizing the femur on the tibia.  In dogs this ligament is known as the cranial (also sometimes referred to as canine) cruciate ligament, or CCL. There is also a ligament located on the posterior of the knee known as the caudal cruciate ligament which provides secondary support to the joint.


The human knee also has ligaments with anterior and posterior attachments that provide stability.  In humans they are named for these attachment points and known as the Anterior Cruciate Ligament, or ACL, and the Posterior Cruciate Ligament, or PCL. As far as dogs are concerned, the specific acronym used makes very little difference.

Anterior Cruciate Ligament (ACL) injuries are one of the most common orthopedic injuries veterinarians see in dogs. The ligament is also known as the Cranial Cruciate Ligament (CCL) in animals. It connects the bone above the knee (the femur) with the bone below the knee (the tibia). Essentially, the ACL stabilizes the knee (or stifle) joint. It does not matter the size, breed, sex or age of the dog, all dogs can get an ACL injury. That said, studies have shows certain breeds are more prone to ACL injuries. These include: Labrador Retrievers, Poodles, Golden Retrievers, Bichon Frises, German Shepherd Dogs, and Rottweilers.

An ACL injury is extremely painful and affected dogs experience pain while simply walking. A tear or rupture leads to joint swelling, pain and instability in the knee joint. If left untreated it will cause lameness in the affected rear leg and, ultimately, chronic irreversible degenerative joint changes. Damage to the ACL is a major cause of progressive osteoarthritis in the knee joint of dogs.


Professor of Orthopedic Surgery & Director of Surgical Service

Diplomate of the American Academy of Pain Management, is a a founder and past-president of the International Veterinary Academy of Pain Management.

Janet B. Van Dyke, DVM
Diplomate American College of Veterinary Sports Medicine and Rehabilitation, CCRT, CEO

Ludovica Dragone, DVM, CCRP
Vice President of VEPRA, Veterinary European of Physical Therapy and Rehabilitation Association.

Andrea L. Henderson, DVM, CCRT, CCRP
Resident, Canine Sports Medicine and Rehabilitation

Steven M.Fox, MS, DVM, MBA, PhD
President Securos. Inc

What causes ruptured of the ACL or CCL in Dogs and are there certain breeds at risk?

Anterior Cruciate Ligament (ACL) injuries can be caused by many factors, although the exact reasons as to why it is so common in dogs is not completely understood. Continual biomechanical wear and tear eventually causes the Anterior Cruciate Ligament (ACL) to break down until it reaches a point that the ligament tears completely. Simple activities such as walking, running and jumping, all cause wear and tear. Obesity, traumatic injuries or strenuous or repetitive activities can also cause the Anterior Cruciate Ligament (ACL) to deteriorate.

Anterior Cruciate Ligament (ACL) injuries in dogs do not always occur during athletic activities. Some dogs will be making a simple movement like jumping off a couch or going down a stair when their Anterior Cruciate Ligament (ACL) will tear or rupture.

Most acute (sudden) Anterior Cruciate Ligament (ACL) injuries in dogs occur during strenuous or exuberant activities, such as playing, chasing, roughhousing, running, hunting, jumping or engaging in other “doggie” fun. Sometimes a dog will simply stumble and when they get up they will have ruptured their Anterior Cruciate Ligament (ACL) . Other times Anterior Cruciate Ligament (ACL) injuries will develop slowly over time. This can be caused by genetic abnormalities that cause poor muscle tone or poor neuromuscular coordination. Obesity also contributes to chronic ligament damage because of the extra weight placed on the joints.

Signs and Symptoms of Cranial Cruciate Ligament (CCL) in Dogs.

Often symptoms of ACL injuries are gradual and a dog will slowly become more lame as the ligament becomes more damaged. Other times, when there is a rupture or tear, there is no advanced warning signs. Nearly all dogs with tearing or damage to their cruciate ligament will have swelling that is felt on the front part of their knee.

Symptoms may include:

  • Lameness or weakness in one or both hind legs
  • Limping or reluctance to use one or both hind legs
  • Limping worsens with exercise and improves with rest
  • Abnormal posture, especially over the back and hip areas
  • Reluctance to get up, jump, run or go up and down stairs
  • Stiffness and difficulty getting up in morning
  • Sitting at an odd angle, with a hind leg slanted unusually off to one side
  • Swelling around the knee joint
  • Muscle atrophy in the affected limb

Anterior Cruciate Ligament (ACL) – The importance of a proper diagnosis process

Diagnosis in dogs with complete rupture of the CCL is usually based on examination by an experienced orthopaedic surgeon, with demonstration of laxity of the joint by specific manipulations of the knee. In dogs with partial tears or early degeneration of the ligament, other tests may be necessary, including radiography (x-rays) or MRI scans. To be of maximum benefit, radiographs must be of optimal quality. In most dogs, exploratory surgery or arthroscopy (keyhole surgery) is used to confirm the diagnosis, and to investigate for possible cartilage tears or other problems.

The importance of Rehabilitation and Physiotherapy for Dogs diagnosed with Anterior Cruciate Ligament (ACL)

Cranial cruciate ligament disease may be treated either conservatively or surgically.  The decision to treat your dogs cranial cruciate ligament disease with conservative or surgical management will very much depend on the stability of the stifle joint (knee) and severity of clinical signs. Stability can be assessed by your primary care vet.

Available Treatment by Veterinarian here in Singapore

Platelet rich plasma therapy (PRP) has been used with success to treat arthritis in joints, muscle, tendon and ligament damage. In this process, the blood is drawn from the patient and then centrifuged to concentrate the platelets as well as remove the majority of white and red blood cells. Then, the plasma is injected back into the patient at the site of the injury. Its injection may be peppered along the site of the injury to maximize its beneficial effects.

Stem cells have also been researched in conjunction with new tissue generation. Just as in PRP therapy, stem cells bring growth factors to the site of the injury. However, within 24 hours of injection as many as 95% of the stem cells have already died. Given that stem cell treatments cost $3,000 on average per treatment, PRP seems to be the better alternative for experimental nonsurgical treatment for canines. At this point in time, neither PRP nor stem cell treatment will guarantee that your dog will never require surgery. Long-term case studies will be required to understand the benefits of PRP and how long they can be expected to last.

Conservative Management – If you’re considering non-surgical options for your dog’s torn cruciate ligament, most likely you have a reason. It could be you cannot afford the very expensive surgery or you’re looking for a more conservative approach for an older dog. It may also be you are trying to learn as much as can about this condition and want to make the best decision for your pal.

The subject of surgery in torn cruciate ligaments seems to be a subject of controversy. One thing is for sure: when the ligament is torn, the knee is unstable and the bones are subject to an abnormal range of motion. This leads to a cascading effect, where the bones and the meniscus cartilage are subject to wear and tear which lead to degenerative changes. When the meniscus is affected, parts of it may need to be removed or repaired. Bone spurs, which develop in deteriorating joints, may start to form as early as 1 to 3 weeks after the rupture. A swelling just on the inside of the knee, known as a “medial buttress,” may be a sign that arthritis has set in, in cases where the tear is old. Surgery, appears to slows down degeneration, but it’s unfortunate that the degenerative changes cannot be reversed once started.

Non-surgical management consists of exercise restriction, anti-inflammatory medications, physical therapy and weight loss. These therapies can be effective in very small animals such as cats and dogs weighing less than 15 pounds, although these animals will develop some arthritis, they may regain almost normal function. Additionally, dogs that have ruptured the cruciate ligament on one side are more likely to tear the ligament in the other knee. So whether you are opting a surgical or non-surgical approach, rehabilitation is crucial.

Rehabilitation Aims

The aim of rehabilitation is to restore knee range of motion and improve patellar stability by reinforcing the quadriceps.

Besides training the quadriceps muscle, stretching of the Hamstring muscle and articular retinaculum should be included in the rehabilitation program one month after trauma. Patient-education should be part of the therapy as well. The patient should receive home exercises which he/she should regularly do.

Whilst your dog already has existing CCL disease or luxating patella and is being managed conservatively, there is a risk of “flare ups” or exacerbation of clinical signs following trauma or inappropriate exercise. At this stage, the aims would be to control the inflammation and surrounding muscle spasm. It is also important to encourage careful limb use and prevent muscle atrophy. The soft tissues also need to be maintained. If your dog responds positively to the conservative rehabilitation programme the aims can be adjusted to include the above with greater limb loading, further limb strengthening and increased cardiovascular fitness. Restricted walking between prescribed exercise times is advised to ensure the knee isn’t overloaded alongside the specific controlled rehabilitation exercises.

Rehabilitation Options

Ice (Cryo) therapy, compression, massage and stretches are initially employed to reduce any swelling and pain and to care for the soft tissues. Specific strengthening exercises are then added as is hydrotherapy in the pool or in the underwater treadmill. Advice for caring for your dog at home and how to avoid any factors that might aggravate the condition such as slippery floors, jumping up and in and out of things will be advised by your physiotherapist. Gradual introduction of off lead exercise will then be advised and activities that stimulate core stability. Many dogs require on-going rehabilitation to prevent further problems and to maintain limb strength. This on going form of rehabilitation quite often is carried out in the water.

Should your dog deteriorate at any point during a conservative management programme it is important you contact your chartered physiotherapist so an appointment with your orthopaedic clinician can be arranged. Conservative rehabilitation is not suitable for all dogs, some require surgical intervention to address cranial cruciate ligament disease therefore it is important your dog is reassessed to evaluate stifle stability as soon as you have concerns.

TimelinePhysiotherapy AimsRehabilitation Therapy options
Week 0 to 4Reduce inflammation
  • Electrotherapy – Laser
 Reduce muscular guarding
  • Electrotherapy – laser
  • Soft tissue massage
  • Heat therapy
 Improve core stability
  • Home exercise program
 Increase strength
  • Home exercise program
  • Neuromuscular electrical stimulation
  • Hydrotherapy
  • Under Water Treadmill
 Increase sensation and awareness of body position
  • Home exercise program
 Maintain soft tissue length and flexibility
  • Home exercise program – passive movements and stretches
 Management at home
  • Exercise restriction
  • Advice regarding flooring,
  • Advice regarding walking with a mobility aid e.g. harness and sling if required
Week 4 to 6Continue as above
  • Progression of home exercise program to challenge balance, body awareness and strength
  • Advice on maintaining restricted exercise when dog feeling better
  • Advice on maintaining controlled exercise when dog feeling better
Week 6 to 12Increase exercise tolerance
  • Increase exercise level, considering land and water based options.
 Continue to increase core stability
  • Home exercise program considering land and water based exercises
Week 12 onwardsReturn to full function
  • Progress to off lead exercise and previous exercise level