The cranial cruciate ligament (CCL) stabilizes the knee by preventing rotation and forward movement (thrust) of the tibia, or shinbone, relative to the femur, or larger bone in the upper leg. The ligament is stranded, like a cable, so that damage can occur in the form of "fraying" of some of the strands (partial rupture) or complete rupture of the entire ligament. The resulting instability produces pain, inflammation and damage to other tissues in the knee joint, including the meniscus, or cartilage shock absorber.Ongoing inflammation causes arthritis and chronic pain in the joint.
For most dogs, surgical repair is necessary to eliminate pain and the progression of arthritis in a joint with a damaged cruciate ligament. There are several options for surgical repair, depending on the dog (size, age, temperament and activity level), and the extent of the damage to the structures in the knee.
Tibial Plateau Leveling Osteotomy is a surgical procedure in which the top of the shinbone just below the knee is cut and rotated so that the surface of the joint is more level and less sloped. This corrects the instability that is the result of the ruptured CCL. This procedure is generally recommended for young, large breed dogs and specific breeds (Newfoundlands, boxers and Akitas) with partially ruptured CCLs. This technique protects the remaining strands of the CCL, which provides additional stability. It also protects the meniscus by redistributing the forces in the joint more evenly. Potential post-operative concerns with the TPLO procedure include weakening of the plate/screw apparatus used to hold the newly realigned joint surface in the proper position until the bone has healed (approximately 8 weeks post-op.) Keeping a large, young dog restricted for that period of time may be a challenge.
Another approach to stabilizing the knee after the cruciate ligament is damaged is called the lateral suture technique. This involves the placement of a very strong suture around the back of the top of the knee and through the shinbone just below the knee. This prevents the rotation and forward instability (tibial thrust) that results when the CCL is ruptured. This technique may be recommended for small dogs or older, less active dogs. Post- operative concerns specific to this surgery include breaking of the stabilizing suture material. Restricting off leash activity will help to prevent this problem.
Another technique designed to prevent forward tibial thrust and rotation is called the Tightrope procedure. This procedure is similar to the lateral suture with a couple of important differences. First, the material used to stabilize the joint is not a suture, but tape-like material similar to Kevlar. This FiberTape® is secured, passed through the femur through a bone tunnel above the joint, then redirected and passed through a bone tunnel through the tibia, below the joint. This technique is stronger than the basic lateral suture and is suited to larger, younger dogs with a complete CCL rupture. One post-operative concern specific to this surgery is that the synthetic material used to stabilize the joint may be more prone to infection than traditional suture material. Also, despite the fact that this procedure could be considered "minimally invasive" compared to TPLO, it may be more painful immediately after surgery for some dogs. Joint infusion of pain medication at the time of surgery helps improve patient comfort.
There are other surgical procedures used to address cranial cruciate ligament disease in the dog. At the Dougherty Veterinary Clinics, our focus is providing the most appropriate therapy for your dog, considering both dog and owner lifestyle. We are dedicated to providing comprehensive post-operative care both short term and long term, including appropriate pain control, follow up exams and x-rays, and recommendations for physical therapy. Our surgical team enjoys the role our clinic plays as a regional referral center for the treatment of cranial cruciate ligament disease.