In my previous article, I discussed why so many dogs tear the cruciate ligament (the doggie ACL…). As I mentioned, it’s the most common orthopedic injury in dogs. As such, repairs of this injury are among the most common specialty surgeries performed in veterinary medicine. When I say specialty, I do mean that, ideally, these should be performed by a board-certified veterinary surgeon. This said, general practitioners can become quite adept at these procedures. However, this is usually in more remote regions where access to surgeons is limited. Luckily, we are surrounded by facilities on the South Shore where better skills are available.
There are three surgical procedures that are done for this injury. They vary in difficulty and early complication rates. However, should they remain complication free, they all have roughly the same prognosis for long-term success by the 6-month mark.
The first of these three is called a lateral suture. In this procedure, the knee is opened for removal of the damaged ligament and other tissue. This is followed by placement of a thick support suture through the bone on the outside of the knee. This suture, similar to tuna fishing line, holds the knee together in a similar fashion as the ligament used to while the surrounding joint capsule thickens to increase support. This is the least technical of the three procedures and, therefore, the least expensive. It also has the highest early failure rate due to the suture breaking if the dog is not kept quiet during the post-operative period.
The second is called a tibial tuberosity advancement or TTA. While this is the newer of the three procedures, it is still not the most popular or common one performed. With this surgery, the same damaged material is removed and then the tibia bone is cut just behind the lower ligament of the kneecap. A wedge is then placed into the cut and this slides the lower end of the femur forward to the flatter part of the tibia. This effectively prevents the instability that is created when the original ACL tears. While this has a lower early failure rate than the lateral suture, the failures can be fairly catastrophic when they happen with major fracturing of the bones that can require extensive repairs.
The last procedure is called a tibial plateau leveling osteotomy or TPLO. In this procedure, the surgeon uses x-rays and special measuring tools to determine the slope of the top of the tibia. After the same damaged tissue is cleaned out, the surgeon uses a specialized saw to make a circular cut just below the top of the tibia. This piece of bone is then rotated by the measured amount calculated during the x-rays. Like the TTA, this creates a flat surface and removes the instability of the knee joint. The bone fragments are then reattached using a titanium plate and screws. This strong metal implant creates a very solid repair with a much lower failure rate than the other two procedures.
Should this injury occur to your dog, your general practitioner should be able to counsel you on these three options as you discuss cost, prognosis, and the individual patient. The surgeon performing the procedures will help with the final decision.