“When a dog comes into the veterinary teaching hospital with knee problems, I tell my students: it’s a CCL rupture until proven otherwise,” says Dr. Trina Bailey. “CCL stands for cranial cruciate ligament, and it’s a common and expensive problem in dogs. Pet owners in the United States spend more than 2-billion dollars a year in CCL-related treatments.”
Dr. Bailey is an assistant professor and surgeon at UPEI’s Atlantic Veterinary College. She’s working with Dr. Laurie McDuffee to develop stem-cell-based therapies to repair and even regrow damaged ligaments in dogs.
“The CCL is an important ligament inside the knee,” explains Dr. Bailey. “It’s important, because it holds together the two main bones of the leg—the femur and tibia—and prevents them from sliding apart during movement.”
Dr. Bailey says the CCL’s tendency to rupture is due to several factors. In younger dogs, the rupture often occurs because of a trauma to the knee. In older dogs, it’s often caused by a combination of minor trauma and natural degeneration over time.
No matter what the cause, Dr. Bailey says it’s a painful experience.
“To which I can attest first-hand,” she says. “The equivalent ligament in humans is the anterior cruciate ligament, or ACL. A few years ago, as I hopped from rock to rock while hiking at Peggy’s Cove, I heard a popping sound, and felt immediate pain in my knee. I knew right away I’d damaged my ACL.”
In humans, the most common treatment is a surgery that uses the hamstring tendon as a graft to replace the ACL. In dogs, it is much more complicated.
“A lot of that is because of the many different sizes of dog. It just isn’t a practical surgical option,” says Dr. Bailey. “The most common treatment now is a surgery called the tibial plateau-leveling osteotomy. We reshape the end of the tibia, to make it less likely to slip out of alignment with the femur. It works, but the dog almost always develops arthritis. There has to be a better way.”
Dr. Bailey and Dr. McDuffee are experimenting with injecting stem cells into damaged or deteriorated ligaments, to see whether it’s possible to not just stop the rupture from becoming worse, but to even regrow the ligament.
“There are veterinary surgeons who currently provide this service, but there has never been research to confirm it’s actually doing any good,” says Dr. Bailey. “If we can explain what’s happening and refine the techniques, it would mean a much higher quality of life for our companion animals.”