One of the most common reasons that a dog takes a trip to our surgery department is for lameness or limping on one of their rear legs. While there are always other conditions or diseases to rule out, a torn CrCL (cranial cruciate ligament) is the most common cause. Here, our Little Rock, Arkansas vets explain.
The Anatomy of a Dog’s Knee
The function of the cranial cruciate ligament in dogs is to prevent the tibia from shifting forward as the knee goes through a range of motion. The leg/knee will lose stability if the ligament tears or ruptures, allowing the bones to freely move back and forth. This, in turn, can cause pain, inflammation, injury to the meniscus (fibrous cartilage between the surface of the joint), and arthritis.
Symptoms of a Ruptured Cranial Cruciate Ligament
Symptoms of a ruptured CCL include:
- Lameness/limping on the affected leg
- When the dog sits, they may hold the affected leg out to one side.
- Vocalizing in pain
- Difficulty rising
- Muscle atrophy (muscle wasting) in the affected leg
- Decreased activity level
Causes of a Cranial Cruciate Tear
A cruciate ligament tear can happen acutely or result from several micro-tears over a period of time. In dogs, the tear most often occurs as a result of a series of micro-tears vs a single traumatic event, which is the primary cause of the ligament tearing in humans. The tear, or rupture, can be partial or complete, although partial tears will progress to a full tear over time. It can occur as a result of exercise (dog catches frisbee and lands wrong), a dog being overweight (obesity puts extra strain on the knee and ligament), age, and breed disposition. Large breed dogs, in general, are most commonly seen for this injury, although we do occasionally treat smaller breed dogs as well. Newfoundlands and Labrador retrievers are especially genetically predisposed to CrCL disease.
Treatment for CCL Rupture
At AVES, the preferred method of treatment for a cruciate ligament tear is a tibial plateau leveling osteotomy (commonly known as a TPLO). With the TPLO, we see few long-term complications and observe significant improvement in 85-90% of our patients. Arthritis still has the potential to progress in patients who undergo surgery but is expected to be slower than in patients who do not receive the procedure.
Rather than repairing the torn ligament itself, the TPLO changes the biomechanics of the knee so that it functions without the CrCL and has more stability. The surgery itself involves making a circular cut at the top of the tibia and rotating the tibial plateau to change its angle. These changes are secured with a stainless-steel plate and screws while the bones heal. After the bones have successfully healed, the plate and screws are no longer needed but are not removed unless a rare complication occurs.
What to Expect if Your Pet Has a TPLO
Owners who elect for their pet to have a TPLO performed can expect the following:
- An initial consultation/appointment with the surgeon to evaluate and confirm a torn CrCL and confirm that surgery is the next course of action.
- Owners will be requested to withhold food after midnight the night before the procedure. They will be asked to drop their pet off with our surgery department on the morning of the surgery.
- A full physical exam, along with necessary lab work, will be performed to ensure that your pet meets the safety criteria to undergo anesthesia.
- A courtesy call will be given to the owner before and after surgery to notify the start of the surgery and discuss how the pet is doing afterward.
- Patients will be kept comfortable with pain medications and will be provided twenty-four-hour care by a veterinarian and a team of technicians.
- Patients will stay overnight and be discharged the following day, barring any unforeseen complications.
- Both a doctor and a technician will go over the procedure, and the home-care, at the time of discharge. Patients will be required to adhere to strict kennel rest for six weeks (leash-walked bathroom breaks only), followed by supervised time out of the kennel on a carpeted service only for the next two weeks. The final stage of recovery will involve gradually increasing walks over the next several weeks. No unattended activity, running, or jumping is permitted until follow-up radiographs have confirmed that the bones have healed.