Anterior Cruciate Ligament Surgery

Anterior Cruciate Ligament Surgery

Just like football players, skiers, or athletes can injure or &blow out& their knee, active medium to large dogs can have the same injury when they play with other dogs, chase balls, or Frisbees. This injury involves tearing of a ligament within the knee that helps to stabilize the joint. The stifle joint (in layman's terms called the knee) of the dog is similar to a humans knee. The cranial cruciate ligament is located inside the joint and is responsible for maintaining a stable joint. One of the important functions of the ligament is to prevent backward sliding of the femur on the tibia bone (drawer motion). Frequently cruciate ligament rupture is a gradual process and not simply due to a single traumatic injury. A clinical sign of early cruciate disease includes stiffness or very mild lameness. As the disease advances and the ligament progressively tears, the lameness becomes more pronounced. Complete tears initially result in nonweight-bearing on the limb; it is unusual that the lameness will resolve in a large breed dog with no surgery. Rupture of the cruciate ligament in both knees is common. In fact, one out of three dogs will also develop a cruciate rupture of the opposite stifle.

ACL (Anterior Cruciate Ligament) surgery in dogs is a commonly done surgical procedure in veterinary practice. When the anterior cruciate ligament is torn or stretched, instead of moving like a hinge, the knee joint will actually make a sliding motion. This abnormal motion and instability creates trauma within the joint that leads to wearing of cartilage, increased synovial fluid production and inflammation. Eventually, DJD... degenerative joint disease... results.

A torn cruciate ligament can occur in any dog if just the right (or wrong!) forces impact the knee joint. Most commonly seen in larger breeds of dogs and in dogs that are overweight, the ACL surgical procedure does not actually repair the torn ligament but rather replaces the ligament with artificial material that takes over the function of the Anterior Cruciate Ligament. In the case presented below, nylon strands of 80 pound tensile strength are utilized to restabilize the knee (stifle) joint.

The veterinarian may tell the dog's owners that the dog has a torn Anterior Cruciate Ligament and one of the best ways to get him back to full function would be to do a surgical procedure where an artificial ligament is placed along the side of the knee joint; we don't try to fix the torn ligament because that particular one just won't heal properly. So we fool the knee into thinking that there is a ligament. After a few weeks of confinement, and then controlled activity, the fibrous connective tissue buildup along the artificial strands implanted along the knee joint stabilize the joint during activity. Then your dog can begin using the leg properly.

Q & A about Cruciate Ligament Rupture

What and where are the cruciate ligaments?

The word cruciate means "to cross over" or "form a cross." The cruciate ligaments are two bands of fibrous tissue located within each knee joint. They join the femur and tibia (the bones above and below the knee joint) together so that the knee works as a hinged joint. One ligament runs from the inside to the outside the knee joint and the other from the outside to the inside, crossing over each other in the middle. In the dog, the ligaments are called the cranial and caudal cruciate ligament. In dogs, the most common knee injury is a rupture of the cranial cruciate ligament. Humans have a similar anatomical structure to the knee, but the ligaments are called the anterior and posterior cruciate ligaments. Anterior cruciate ligament rupture is a common knee injury of athletes.

How is it diagnosed?

With traumatic cruciate rupture, the usual history is that the dog was running and suddenly stopped or cried out and was then unable to bear weight on the affected leg. Many pets will "toe touch" and place only a small amount of weight on the injured leg.

During the lameness examination, the veterinarian will try to demonstrate a particular movement, called a cranial or anterior drawer sign. This abnormal forward movement of the tibia (lower leg bone) in front of the femur (thigh bone) indicates laxity in the knee joint. It may be necessary to administer a sedative to relax the dog enough that the veterinarian can perform this test. Other diagnostic tests such as radiographs (x-rays) may also be necessary

Is an operation always necessary?

Dogs weighing less than 10 kg (22 lbs.) may heal without surgery, provided they have severe exercise restriction such as strict cage rest for six weeks. Dogs over 10 kg (22 lbs.) usually require surgery to stabilize the knee. Unfortunately, most dogs will eventually require surgery to correct this painful injury.

Is post-operative care difficult?

It is important that your dog have limited activity for six to eight weeks after surgery. Provided you are able to carry out your veterinarian's instructions, good function should return to the limb within three months. Unfortunately, regardless of the technique used to stabilize the joint, arthritis is likely to develop in the joint as your dog ages. Arthritis develops more slowly and to a lesser degree if the dog undergoes surgery. Weight control and nutritional supplements such as glucosamine / chondroitin may help delay the onset of arthritis in your pet. Many dogs will receive physical therapy after the surgery to speed recovery and reduce complications. Your veterinarian will discuss your pet's recommended post-operative care with you prior to surgery.

Is obesity such a problem?

Obesity or excess weight can predispose dogs to cruciate ligament rupture. If your dog is overweight, the post-surgical recovery time will be much longer. Obesity also greatly increases the risk of injury to the other knee, especially during the recuperation period. Weight loss is as important as surgery in ensuring rapid return to normal function, as well as being a preventive measure to help protect your dog against this debilitating injury.