Cruciate Ligaments
Dr. Todd B. Friedland, DVM

It is my pleasure to write this article for chocolatepeanut.com. I have been a general small animal practitioner for 36 years. During that time, I have developed a great understanding not only for veterinary medicine, but the all important relationship between people and their pets. Hopefully you will learn many important tidbits from this and future articles that will enable you to enjoy your pet for many years to come.

Facing the prospect of your dog having a major operation can be a very emotional time for the family. One of the most common major operations performed thousands of times each year is the surgical repair of a very special ligament in your dog's knee. This ligament is known as the cruciate ligament. Many of you have pets or even relatives that have had surgery on this part of the knee and know just how necessary the surgery is in order to return an injured knee back to normal function. Here's a brief look at this common ailment.

Zoey, a chocolate labrador, recovering from anterior cruciate (ACL) surgery in 1999. She was 9 years old and very active.

A ligament is a tough, fibrous tissue connecting two bones together. In the knee, or stifle, there is a system of support comprised of eight ligaments. All are vulnerable to injury, with some injuries more serious than others. Two of the ligaments, the cruciate (crossing) ligaments, are located inside the knee joint capsule. If one or both of these ligaments rupture or tear, the knee joint is allowed to move in an abnormal, unstable fashion, causing severe pain. The anterior cruciate ligament is the more important of the two in the dog. When the rupture occurs, the femur, or thigh bone, is allowed to slide and rub over the tibia, or shin bone. If left damaged, arthritis will develop and dogs often lose the use of the affected leg due to the pain of the arthritis. In order to restore stability to the knee, as well as relieve pain and prevent severe, debilitating arthritis, surgical repair is necessary as soon after the injury as possible. Successful surgery should return the knee joint to normal, or at least near normal function.

The diagnosis of a torn cruciate ligament is most often made by considering the history of your dog's lameness, a thorough physical examination, and most often examination of the affected knee when your dog is under heavy sedation or anesthesia. Your veterinarian knows several knee manipulations that can help diagnose the ailment. Occasionally, radiographs are taken to aid in the diagnosis, and rule out a broken bone. If it is determined that the ligament is torn, surgery will be recommended. Depending upon the severity of the injury, and the technique your doctor uses for repair, recovery can be expected in 6 to 12 weeks. During that period, your pet must not be allowed to run free whereupon it could injure the repaired leg, or even another leg.

The cause of anterior ligament tear are not completely understood. Certainly, trauma to the knee can result in torn ligaments. More often, however, the ligaments seem to tear spontaneously, and in many dogs, the ligament in the other leg follows suit within a 6-18 month period. This suggests that there is a natural or spontaneous weakening of the ligament as some dogs get older. The injury is most common in overweight, middle-aged dogs. We rarely see this injury in the cat. We are less apt to operate on a cat as well. They seem to develop less problems without surgery that dogs do.


Dr. Todd Friedland graduated from Cornell University in 1972. During his first six years as a veterinarian, he worked and studied under some of the most respected veterinarians in the Long Island, New York area. He fulfilled his childhood desire to live in a small New England town when he purchased the North Windham Animal Hospital in January of 1978. He has built the former 4-room country practice into a well-respected, high-quality, 3-doctor hospital, providing the best in veterinary medical advancements, client service, sophisticated medical and surgical skills, and community involvement. He is a member of the American Veterinary Medical Association, Connecticut Veterinary Medical Association, and Connecticut Academy of Veterinarians.

"I have grown to enjoy all aspects of pet care, but my special interests now lie in getting you off to the right start with your puppy and kitten through early and proper counseling and spending that extra time with pets as they get older. Geriatric medicine is one of my greatest pleasures."

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