Cranial Cruciate Disease

Cranial cruciate ligament (CCL) tears are a common cause of lameness in our canine patients. The cranial cruciate ligament in a dog is comparable to the anterior cruciate ligament or ACL that you read about people injuring. The cranial cruciate ligament is a major stabilizer to the canine stifle (knee). An intact ligament prevents instability to the knee. When a rupture of the cranial cruciate ligament occurs the stifle becomes unstable. This instability causes pain by putting excessive strain on the surrounding structures of the stifle mainly the joint capsule. In the canine species it appears to be more of a degenerative process where over time the ligament breaks down and eventually ruptures. An owner may report a rear leg lameness that waxes and wanes and then eventually does not get better when the ligament completely ruptures. Your veterinarian can do testing of the stifle along with radiographs to determine if a cranial cruciate ligament rupture has occurred.

During the past 20 years, numerous techniques have been utilized by veterinarians to reestablish stability to the CCL-deficient stifle. Most of these procedures use either a synthetic material, or a natural tendonous graft to replace the function of the CCL. Clinically, these procedures have given consistently good results in dogs weighing less than 40 pounds. However, in large and giant breeds, highly active dogs, or performance animals, the "standard" surgical techniques have not always returned the dogs to a near normal level of activity. In addition, the "standard" techniques still allow progression of arthritis to continue, because of the inability to completely replace the biomechanical function of the CCL.

A diagnosis is made upon eliciting forward motion of the tibia (cranial drawer sign). This is easy in acute, complete ruptures, but may be more subtle in chronic or partial tears. Mild sedation may be needed to allow muscle relaxation to elicit this drawer sign. In addition, radiographs (x-rays) help to determine if there are any arthritic changes or swelling in the joint.

Because of the shortcomings of these techniques, a new surgical technique was developed by Dr. Barclay Slocum in Eugene, Oregon several years ago. This technique is called a Tibial Plateau Leveling Osteotomy (TPLO), and has been performed in thousands of dogs (most weighing over 60 pounds), throughout the United States and around the world, with excellent results.

The TPLO is used to neutralize the instability in the stifle mainly what is called cranial tibial thrust. Due to the angle of the tibial plateau excessive strain is placed on the stifle when our patients bear weight. This strain is seen by the femur moving backward and the tibia moving forward when the cranial cruciate ligament is ruptured. This motion is called cranial tibial thrust. This unstable motion or cranial tibial thrust is due to the angle of the tibial plateau. The TPLO procedure 'levels' the tibial plateau, thereby eliminating the need for the cranial cruciate ligament as a restraint against cranial tibial thrust. In other words, rather than replacing the cable that broke in the first place, this procedure will level the surface and eliminate the need for the cable.

A TPLO effectively neutralizes the forces that cause the CCL to tear. Ongoing studies evaluating the long-term results of the procedure have demonstrated that patients undergoing a TPLO may recover quicker, return to normal function, and develop very little, if any, degenerative joint disease as compared to the "standard" surgical procedure. Instead of relying on synthetic ligaments or tendon grafts, the TPLO utilizes a proximal tibial osteotomy (bone cut) stabilized by a specially designed bone plate and screws to counteract the forces exerted across the stifle joint.

While the TPLO is not meant for every case of CCL disease, it certainly plays a role in the management of this disease in giant and athletic breeds of dogs. We continue to utilize both the TPLO and standard methods to stabilize the cruciate-deficient stifle in dogs and cats.Below are some pictures illustrating the before and after along with a schematic. Note the lines that are drawn showing the actual angle of the tibia plateau.

Healing takes about two months for the bone and slightly longer for the soft tissues. Strict confinement is mandatory during the healing process. Because the plateau leveling allows the joint pain to rapidly subside, the major problem during recovery is excessive patient activity prior to the completion of the bone healing. Most patients return to controlled activity in 2 months and full activity in 3 to 4 months.

Below are some pictures illustrating the before and after along with a schematic. Note the lines that are drawn showing the actual angle of the tibia plateau.