Tears of the anterior cruciate ligament (ACL) are one of the most common orthopedic injuries in the dog. The anterior (or front) ligament is one of two major stabilizers of the knee joint. The posterior ligament is rarely injured. The ACL prevents the tibia from thrusting forward during the weightbearing phase together with the hamstrings and quadriceps muscles. The ligament can either tear completely or partially. Partial ligament tears commonly lead to mild, longterm lameness, whereas a complete tear normally leads to a complete nonweightbearing lameness. These injuries may improve for short periods of time only to return after the dog is allowed to have unrestricted exercise.
The TPLO procedure has revolutionized the way veterinary orthopedic surgeons treat this problem. It was designed by a veterinary surgeon named Barclay Slocum in the late 1970’s. Since then it has helped suffering dogs go back to normal activity and is the most popular surgical technique in treating the ACL deficient knee. The principal behind this technique is in reconfiguring the biomechanics of the joint preventing anterior displacement or thrust. This anterior tibial thrust is the reason that this condition is painful. Repeated anterior thrust leads to continued damage to the joint and eventually secondary arthritis sets in.
The TPLO procedure is used whenever there has been damage to the cruciate ligament. It is indicated in partial or complete ruptures. In fact the surgery has better results in partially ruptured cruciates. It has been traditionally used in dog’s over 40 lbs of weight. However, we have been using this technique more frequently in smaller sized dogs (as small as 11 pounds) and have found excellent results as well. The implants used during the surgery have become smaller to serve the needs of these patients. MVS surgeons have been performing TPLO surgeries for over 10 years and have a combined 30 years of experience with this technique. While there are countless other techniques available, the TPLO surgery provides the best longterm results in our opinion.
Generally the rupture of the cruciate ligament occurs in the young active dog. However, there is a small percentage of older patients that injure this ligament. These provide a different dilemma in that surgery and anesthesia have to be discussed thoroughly to decide which is the best option for your pet.
Unlike the human knee, the canine tibia slopes backwards where it meets the knee. This results in a force called Cranial Tibial Thrust when weightbearing.