The Tibial Plateau Leveling Osteotomy (TPLO) was a surgery first developed almost 30 years ago by Dr. Barclay Slocum. In the decades since, it has proven to be a reliable and consistent treatment for injuries to the cranial cruciate ligament in dogs (ACL in people). Cranial cruciate ligament (CCL) injury is the most common orthopedic problem recognized in dogs, and the TPLO is probably the most commonly performed orthopedic surgery in dogs. Read on to learn how the surgery works, and why we are glad to offer this great procedure at AMSC.
What is the job of the Cranial Cruciate Ligament?
The CCL is responsible for keeping the tibia (shin bone) from sliding forward relative to the femur (thigh bone).
The resulting motion allowed after tearing of the CCL is called “cranial tibial thrust” and is an important component of your veterinarian diagnosing a CCL tear.
The TPLO Concept
When the TPLO was developed in the mid-1980s, the prevailing surgical techniques were focused on replacing the torn CCL, either with a suture passed around the outside of the knee to tighten the joint back up again (extra-capsular or lateral fabellar suture method), or replacement of the ligament with a living or donor graft. The grafting procedure (still the standard of care in humans) was not consistently successful due to the length of time required for these surgeries to recover (dogs don’t appreciate extended convalescence!).
The lateral suture method, while still a viable option and in use today, poorly addresses the major forces placed on the knee joint by medium and especially large-breed dogs, and could fail at any time in a dog’s life due to suture breakage or slippage within the tissues.
When a dog has torn its CCL, the “cranial tibial thrust” is made even more pronounced by the angle present at the top of the tibia. This is called the tibial plateau angle (TPA), and is demonstrated in the graphic below. Essentially the TPLO is a circular cut in the tibia, followed by a rotation of that cut segment of bone to “level out” the tibial plateau and eliminate the “cranial tibial thrust”.
The result is a knee joint that is “stable” in all weight bearing positions that a dog uses, without having to replace the ligament and risk suture breakage or “re-tearing” of the same ligament.
Once the tibia has been cut and rotated, a bone plate and screws are used to stabilize the area for a healing process that usually takes about 8 weeks.
The Bottom Line: What are the Results?
The TPLO is one of the most consistently successful surgeries in veterinary medicine. Well over 90% of patients who undergo the surgery return to normal enough function that you can’t tell they ever had a torn CCL. Even among the remaining 10%, the vast majority of these patients are still greatly improved, but may retain some level of lameness. While we know that arthritis will continue to progress following any CCL tear with or without surgery, its rate of worsening is slowed dramatically with a TPLO. You can expect your dog to return to completely normal activity about 12 weeks after a TPLO…..with no restrictions!
Choosing a Surgeon
The TPLO is a fantastic surgery for dogs with a CCL tear, but as with any major procedure experience, proper training, and the surroundings matter. If you are going to invest the time and money necessary for a TPLO procedure, you want it to be done in the best manner possible. At AMSC we offer the ultimate combination of experience, training, and a world class surgical facility. We encourage you to take our virtual tour or stop in to see AMSC, and appreciate just how well your pet will be cared for during his or her stay.