My dog ruptured what?? – Torn Cruciate Ligaments
The most common cause of sudden lameness in dogs is a torn cruciate ligament – so chances are, you know of someone, whose dog who has had a “cruciate”. Several ligaments tie together the 6 bones of the stifle (knee) joint and its surrounding muscle. Cruciate ligaments are the 2 primary ligaments of the stifle joint that cross inside the joint to keep the tibia (shin bone) from moving out from under the femur (thigh bone). In walking, the femur and tibia work together to flex and extend correctly.
A cruciate ligament injury is extremely painful because if the ligament is torn, the bones no longer work together. This puts strain on the entire joint, can cause bone to rub on bone, and quickly causes swelling due to bone friction. If left untreated, arthritis sets in swiftly due to the inflammation and constant strain on the joint. Initially, dogs with complete cruciate ligament tears walk 3 legged, although some with partial tears will put moderate amounts of weight on the affected leg. The sharpness of the pain may lessen but the ligament does not heal with time, so the pain continues. Gradually, the cushioning cartilage wears from the bone grind. As the joint continues to degenerate, bone spurs can form- developing further pain, arthritis, and decreased flexibility. Initial diagnosis of a cruciate tear can be very difficult as the painful dogs are often tense and their muscle strength overrides the subtle changes in the joint on initial exam. If they continue to limp during medical treatment, a recheck with sedation and radiographs are required to look for early signs of arthritis already occurring.
How does the ligament tear occur? The two most common types of patients with cruciate ligament injuries are the young athletic dogs and large breed dogs who are older and often overweight. The young dogs often rough house or race around the yard – a turn on the dime can cause a twisting action that injures the ligament. Larger breeds tend to have a higher genetic risk of cruciate ligament tears and when these dogs are overweight, the daily strain on their joints stretches the ligament to the point of a partial tear. Once there is a partial tear, it only takes a step down off the furniture to put enough pressure on the ligament to tear it completely. The full tear then leads to the non-weight bearing lameness. Dogs that tear their ligament due to strain from obesity often tear the second ligament within a year of injuring the first side. The degeneration of the joint will continue and cause increasing amounts of pain over time, although, with strict cage rest, some smaller animals under 35 pounds can scar over the joint to gain stability. However, in most animals, the only hope of slowing the degeneration of the joint and therefore relieving the pain is orthopedic surgery. There are 3 major types of surgical repair recommended and an orthopedic surgeon will choose the best method for your pet based on the damage to the joint, and whether the anatomical structure of your pet’s leg is what led to the injury in the first place. Surgical recovery time depends on the amount of damage within the joint and the overall condition of the pet, but can range from 8-16 weeks. Physical therapy and rehabilitation, as with humans, will improve comfort levels and reduce recovery time. Rehab can include home exercises directed by the veterinarian, underwater treadmills, swimming, cold laser therapy, and other methods just as in human medicine.
For our patients with severe chronic damage to the joint or who are not good surgical candidates, arthritis treatment is essential. Work with your veterinarian to create a plan that involves multiple types of treatment such as nutraceuticals, therapeutic diets, anti-inflammatories, cold laser therapy and physical therapy. I often find that while the damage is irreversible, I can ease these pets pain significantly by combining such therapies. These therapies are so helpful even if your pet is limping from another cause. So, if your dog is limping, call your veterinarian – remember the cruciate and how important it is to your pet’s comfort!