In dogs, as in people, the knee joint is a frequent site of injury. In fact, tearing (or “rupture,” as it’s technically called) of the cranial cruciate ligament (CCL) is the most common orthopaedic injury seen in dogs. It can be all too sudden or may even be a chronic degenerative injury of the anterior cruciate ligament that results in partial or complete instability of the knee joint. The good news is that there are a number of surgical procedures that can together with good post-operative care and rehabilitation, restore function to the ruptured ligament and return your dog to “active duty.” It is quite similar to the anterior cruciate ligament problems in humans, in which damage is often related to skiing, football, or other sports-related accidents.
The longer the time is between the injury and repair, the more likely the development of arthritis. Other concerns with waiting too long is because of the instability of the leg, this can then increase the risk of damage to the cartilage. The longer the dog doesn’t use their leg, the more the muscle wastage will occur. Look at it this way – for every one day of muscle loss (this begins from day one of the injury) it takes 3 days to rebuild. Even AFTER repair, studies show that the dog continues to lose muscle mass in their leg for a further 5 weeks.
But it doesn’t stop here, as there are more implications then just this – a secondary problem is damage that can be caused because of the increased weight placed on the other knee. A lot of dogs go on to get a cruciate ligament injury in the second knee within a year or two after surgery on the first.
So you have two choices. The first is to continue walking your dog with a standard lead. Here the dog will be carrying all their own body weight and causing further injury and unnecessary pain. Or, from day one of you noticing the injury, you can put them in one of our Spero harnesses.
The Spero harness is designed to help and support your dog by taking some of the weight off their legs. By attaching the dog harness to the human harness, you take some of the weight off your dog’s back legs. This in turn helps with walking and rebuilding the muscles a lot quicker as your dog can walk further whilst you give them support. Overall, the Spero harness helps rebuild the muscles quicker without putting excessive strain on the legs.
Understanding the cranial cruciate ligament (CCL)
A dog’s rear knee joint (or “stifle joint,” as it’s called in veterinary lingo) is a complex piece of bioengineering, no less so than its human counterpart. You can think of it as nature’s solution to the problem of connecting the femur, or thighbone, to the tibia, the large bone of the lower leg. A system of ligaments links the two bones so that they can function as a unit. A cushion of cartilage called the meniscus prevents the bottom of the femur from rubbing directly against the top, or plateau, of the tibia.
The CCL prevents the tibia from sliding forward, away from the femur, when a force is applied to the leg. If the dogs cruciate ligament is torn, the stability of the joint is compromised and lameness results, accompanied by pain. Left untreated, cruciate ligament can cause irreversible arthritis, which will eventually result in permanent damage to the joint, worsening pain, and lameness.
What’s the cause of cranial cruciate ligament (CCL) rupture?
There are two cruciate ligaments in the knee and they cross each other as they pass between the two main bones of the leg, the femur and tibia. If the knee is subjected to twisting when under load, a common injury is a tearing of the anterior cruciate ligament. The tear may be partial or complete and results in destabilization of the knee joint.
Cruciate ligament rupture can be chronic or acute in its origin. “A chronic rupture of the CCL is typically the end result of a number of degenerative changes to the stifle joint. Over time, these changes cause the CCL to fray or loosen, which will eventually lead to a partial or complete tearing of the ligament.”
Obesity and certain anatomical abnormalities of the leg or knee joint may predispose some dogs to CCL rupture. Chronic cruciate ligament rupture is more common than the acute variety. Trauma to the knee joint can result in injury, however that is not a common cause in dogs. Types of trauma include dogs that have stepped into a hole, become ensnared in a fence or jumped from a large height etc..
For example; An acute rupture usually results from a sudden, severe twisting of the joint as may happen, for example, if the dog steps in a hole while running or turns while its paw is fixed in position. This results in a sudden hyperextension and internal rotation of the leg. An acute cruciate ligament rupture can also occur when a dog jumps and the force exerted on the cruciate ligament is just too much for the ligament to bear.
Certain factors place a dog at increased risk of cruciate ligament rupture:
- Being of a large or giant breed, such as Rottweilers, Labrador Retrievers, and Golden Retrievers
- “Weekend warriors”, i.e. dogs who, like their owners, are sedentary most of the time, with intermittent periods of intense athletic activity, may be at increased risk, according to some studies.
Signs of a cruciate ligament rupture in a dog: what to look for
Often cruciate ligament rupture is a gradual process, resulting from chronic inflammation in the knee joint. Age-related changes, repetitive activities, poor conformation, obesity, and immune-mediated diseases are some of the more common causes. An immune-mediated disease is a condition where the body’s defence mechanism turns against itself and starts attacking the body, instead of protecting it.
Either sex and any age or breed of dog can be affected but evidence suggests that younger, more active large breeds of dogs may be more likely candidates for a cruciate ligament rupture.
The signs and symptoms of cruciate ligament rupture in dogs vary depending on whether the rupture is acute or chronic, partial or complete. In the case of an acute cruciate ligament rupture, circumstances and your dog’s behaviour will usually tell you that there’s a problem. Lameness may be subtle and only evident when the dog is engaged in vigorous activity; in the case of a complete rupture of the ligament, the dog may be unable to bear any weight on the affected limb.
Your vet can make a definitive diagnosis of cruciate ligament rupture by palpation (physical manipulation) of the affected limb, x-ray, and range-of-motion examination. She or he will also make sure to rule out other possible causes of lameness, such as fractures, tendon rupture, as well as a number of other orthopaedic conditions.
Treatments for cruciate ligament rupture in a dog: Surgical and non-surgical options
Surgery to stabilize the knee joint is the best option for treatment. When the joint is unstable for a period of time, arthritic changes will begin that cannot be reversed. Some small dogs will respond to conservative treatment, such as rest and non-steroidal antiinflammatory medication for 6-8 weeks, although the risk of developing degenerative joint disease is higher. Our Quincys mobility harness has proved to help dogs who suffer from a cruciate injury by the walker taking some of the weight, allowing the dog to walk further, which aids in building up or retaining muscle.
In the case of small dogs (under 20 lbs.), a non-surgical approach is sometimes sufficient. Vets may recommend conservative management for these dogs for roughly one month period, with surgery reserved for those who have not improved. If the dog is kept completely inactive during that time, enough scar tissue may be produced within the joint to provide adequate stabilization. However, surgery is recommended for all dogs weighing more than 20 lbs.
The two most common surgical procedures are the TPLO and the TTA:
TPLO, or Tibial Plateau Levelling Osteotomy, is a procedure in which the top of the tibia — which ordinarily is sloped sharply downward, is levelled. This prevents the femur, which is normally held in place by the now-torn cruciate ligament, from sliding downward and forward. Without that sliding, the knee joint is stabilized even though the cruciate ligament is still torn. A metal bone plate is attached with screws to allow healing.
TTA, or Tibial Tuberosity Advancement, is a procedure in which a portion of the tibia is cut, thrust forward, and fixed in place with a metal plate and screws. The result is that the downward-forward force of the femur is now opposed by the repositioned upper portion of the tibia.
Other surgical procedures
Both TPLO and TTA are extracapsular surgical techniques. This means that the surgeon does not have to go inside the knee joint, or capsule itself. With intracapsular techniques, the surgeon stabilizes the knee by going inside the capsule and replacing the ruptured cruciate ligament with a graft of either synthetic material or with tissue taken from elsewhere in the dog’s body. There are a number of intracapsular procedures referred to as “Over-the-top,” “Under-and-over,” as well as arthroscopic procedures.
In the case of smaller dogs, another surgical option, called lateral imbrication, which involves the use of sutures to stabilize a ruptured cruciate ligament, may provide good results.
After surgery, activity is restricted to leash walking for a minimum of 6-8 weeks. Supervised rehabilitation of the knee should start within 2-3 days and should include a regime of passive range of motion, balance exercises, and walks on leash.
Which surgical procedure is right for my dog?
The number and variety of procedures for the surgical treatment of CCL rupture can present the dog owner with a difficult choice. How do you know what the correct procedure is for your dog?
Which procedure is best is a matter that even experienced veterinary surgeons disagree about. However, some generalizations are possible:
- TPLO is a more surgically challenging procedure than TTA and has a longer “learning curve” for the surgeon;
- In medium to large or very active dogs, both TPLO and TTA are preferable to intracapsular procedures;
- If the slope of the tibial plateau is excessive, TPLO is preferable;
- TTA is a more recently developed procedure than TPLO, and so has less of a long-term `track record;’
- TPLO and TTA are more expensive than lateral imbrication;
- Which procedure a surgeon recommends is usually a matter of the surgeon’s professional experience, training, and personal preference.
A question that sometimes comes up is; will the cruciate ligament in the other leg rupture also?
Overweight dogs are more prone to cruciate ligament tears, so a weight loss program is recommended for overweight dogs. In some cases, there may be degenerative changes in the ligaments that predispose them to injury, resulting in partial tears that can progress with time to full tears, so there is a chance that the opposite knee joint may have a similar type injury in the future. The underlying reason for these degenerative changes is not fully understood.