To Fix or Not to Fix: Cranial Cruciate Ligament
Austin Fetner, DVM
Dogs frequently engage in high-performance recreational activities, endurance sports, and agility competitions, so it’s not uncommon for pet owners to notice sudden lameness or weakness in their pet’s hind limbs, knee swelling, stiffness, or even clicking sounds as they walk. If a pet begins to limp or favor one leg over the other, they may have ruptured or torn the cranial cruciate ligament (CCL).
The CCL can be compared to the anterior cruciate ligament (ACL) in humans. While the CCL in canines performs a similar function to the ACL, a canine’s anatomy is slightly different. The ACL is the thin connective tissue in the middle of the knee. The CCL structure in canines stabilizes the knee joint. If we think about human versus canine functional anatomy, humans are straight legged, while dogs always have their knees flexed when standing, load-bearing their weight, thus making them more susceptible to injury. Patients with a confirmed torn or ruptured CCL typically suffer extreme pain. Confirmation can be done by a physical exam, radiographs, MRI, and an arthroscope inspection to determine the extent.
CCL injuries are one of the most commonly diagnosed orthopedic problems in canines. Pet owners sometimes ask what would happen if they did not address a torn or ruptured CCL. Depending on the severity of the injury, a patient with a torn or ruptured CCL that is left untreated or treated conservatively (non-surgical) will likely limp to avoid putting weight on the leg because of the pain and discomfort. In most cases, surgery is not always necessary. Small, healthy dogs below 30 lbs, may consider conservative treatments to ease the patient’s pain before considering invasive surgery. Some conservative treatments, such as progressive resistance bands or leg braces can be bought over-the-counter while others are customized as an orthotic therapeutic support. Other conservative treatments are rest with anti-inflammatory medications, acupuncture, supplements (Turmeric & Glucosamine), and aquatic therapy (swimming). Considerations need to be made for canines over 30 lbs since there can be consequences to conservative treatments. First, long-standing tears lead to degenerative joint disease (DJD) which is a gradual deterioration of the articular cartilage. Second, fibrosis alone is not enough to provide good function. Scar tissue builds up around the medial joint capsule instead of the collateral ligament. Third, the DJD coupled with fibrosis leads to decreased mobility. Fourth, a disused leg leads to muscle loss, which leads to weight gain. Weight gain allows instability in the knee and the spine. The answer then becomes, yes, it is possible for canines to live with a torn or ruptured CCL, and it may be the only option when pet owners do not have the financial means to afford surgery. However, from a functional point of view, a ruptured or torn CCL is the beginning of a cascade of deterioration in other parts of the body, including, the joints, the muscles, and ultimately becomes a serious condition that hinders a pet’s mobility.