Cranial Cruciate Ligament Disease

Happy February everyone!  I figured that it was time to talk about one of the most common orthopedic issues in veterinary practice...Cruciate Ligament Tears!

Cranial cruciate ligament (CCL) disease is one of the most common and debilitating orthopedic diseases seen in dogs. The CCL (also called the anterior cruciate ligament or ACL) is an important ligament in the stifle (knee) of the dog that stabilizes the joint. Stretching and rupture of the ligament leads to instability in the stifle joint, which in turn leads to lameness, osteoarthritis and possible damage to the menisci (knee cartilages).

In human medicine, rupture of the anterior cruciate ligament (ACL) is a common sporting injury associated with overextension of the knee joint. While this is occasionally seen in dogs, (such as after jumping to catch a frisbee or rough play), the more typical presentation is a gradual onset of lameness that gets worse with exercise and over time. Often there is stretching or micro-tearing of the CCL over time leading to osteoarthritis and thickening of the joint, often already present by the time the pet first presents for lameness. As the damage progresses, it can lead to complete rupture of the CCL and injury to other structures such as the menisci (cartilages that cushion the joint).

While CCL tears have been linked to obesity, high carbohydrate diets, early spaying and neutering, and many other risk factors, fundamentally the underlying cause of canine CCL tear is biomechanical stress on the ligament. Humans also suffer from ACL tears, but the anatomy and mechanics of the human and canine knee (or stifle joint) are very different. In dogs, the weight bearing surface of the knee joint – the tibial plateau- slopes backwards. This leads to an inherent force within the knee whenever the limb is weight-bearing called the cranial tibial thrust. Once rupture has taken place, there is very little capacity for healing of the cranial cruciate ligament, partly due to poor blood supply to the ligament, and partly due to ongoing shear forces within the joint. Due to these factors, both stifle joints will eventually become affected in approximately 50-70% of patients with CCL disease.

Clinical signs for dogs with CCL tears can be variable. The dogs with a true traumatic injury to the CCL will present with acute onset of hind limb lameness, swelling, instability and pain on flexion and extension of the stifle, often with a palpable ‘clunk’ if meniscal injury is present. However, some patients may only exhibit lameness when first getting up in the morning. The lameness may subside with rest but recurs with activities like hiking or ball playing. However, other dogs have persistent, moderate to severe lameness. The degree of lameness is influenced by the amount of osteoarthritis, as well as the degree of tearing of the ligament and the meniscus, and may and may wax and wane for several months.

Almost all dogs with ACL problems will also show an altered sit posture. In many cases, dogs sit to the side, but in others they will slide their legs forward to sit on the tail base or pelvis rather than being centered over their tarsi (ankles).

Any dog suspected to be suffering from a CCL tear will require a thorough veterinary examination and often radiographs to determine the extent of the disease or injury and to determine the best treatment. Depending on the patient's lifestyle and the level of instability in the joint, surgery may be required to prevent rapid progression of arthritis, reduce pain and restore mobility. The most common methods of surgical repair are a TPLO (tibial plateau leveling osteotomy) or extracapsular stabilization procedure. In other cases, conservative management (assisted by an appropriate rehabilitation protocol) can be adequate to stabilize the joint and allow return to function.

Recently, stifle braces have become more widely available to assist in the management of dogs with CCL disease that not being managed by surgery. These can prevent some of the instability in the stifle that occurs during weight bearing, but can only be worn part of the day, so exercise would still need to be restricted.

Physiotherapy and rehabilitation are imperative to the success of either surgical or conservative management of cranial cruciate ligament disease. At Back on Track, we will work with you and your referring veterinarian to provide your pet with a tailored rehabilitation program, specific to your pet’s individual needs and goals.

Treatment ideally starts 5 -7 days after injury or surgery, but is beneficial at any point. Rehabilitation therapy may include manual therapy techniques such as massage and joint mobilizations, modalities such as heat and ice, LASER therapy, Acupuncture for pain relief, or the prescription of a custom stifle brace. Advice on appropriate bedding will be provided to ensure your pet is well supported.

Hydrotherapy, specifically underwater treadmill, also plays an important role in the rehabilitation program for patients with CCL disease. The buoyancy of the water means that strengthening can commence earlier while still protecting healing structures. This is ideally performed 2-3 times per week for best effects. Strengthening of the surrounding muscles is critical to help support the stifle, improve weight-bearing, and reduce pain as exercise increases.

A customized home exercise program allows you to continue therapy at home on a daily basis as well as addressing exercise restrictions specific to your pet’s stage of healing and your home environment. Regular reviews with your rehabilitation veterinarian are important to ensure your pet is progressing correctly and modify the home exercise plan accordingly.

Overall, the prognosis in most cases of CCL disease or injury is good once the stifle is stabilized adequately. Rehabilitation back to normal function can take from 3-6 months depending on severity and duration of injury and compliance with the rehabilitation program. As always, please feel free to contact Back on Track by phone or email to learn more about managing CCL disease in your pet.

Dr.G