Cruciate Ligament Surgery in Dogs

A torn Anterior Cruciate Ligament (more properly termed a Cranial Cruciate Ligament for the canine patient) can be an athletic injury in the dog, but is more often the result of a degenerative process.

You think your dog has an ACL tear? Has he been limping on his rear leg? In veterinary medicine, we consider cruciate injury part of a larger disease process of the knee(stifle) joint. Once the cruciate ligament is damaged, the knee joint begins a process of degenerative joint disease and osteoarthritis formation. It is the instability of the joint that cause the rapid onset of arthritis. Early surgical intervention can be a significant part of prevention of severe arthritis formation. Dogs less than 25 pounds can sometimes have adequate recovery without surgery.

There is a long list of things that can cause a dog to limp on a rear leg and the first step in the process is a thorough exam by a veterinarian. I have been surprised how incredibly lame a dog can be with a broken toenail or a lacerated pad. I have also found bone tumors on xrays that I was not expecting in very young dogs. A complete physical exam and xrays (radiographs) are critical to an accurate diagnosis.

When considering surgery, there are many different techniques and options. The reason for all the different techniques, is that none of the procedures is a perfect replacement for a natural cruciate ligament. To briefly explain some of the procedures and terms you may come across, it is best to think of them in three basic groups:

Intracapsular repair: Passing a replacement ligament “inside” the joint capsule to run in the most similar anatomic position as the original cruciate ligament. This is usually done with a strap of fascial tissue from a muscle surrounding the joint, but the problem is that the body recognizes that the new ligament does not belong in the joint and the ligament is broken down and stretches. Newer techniques have been developed to solve the problem in different ways.


Extracapsular repair – This is a method that involves transposing muscles or placing a suture that runs along the same plane as the cruciate ligament but is “outside” the joint so as not to cause further inflammation inside the joint. There are a broad range of suture techniques and some debate about the exact points of placement of the sutures, but all these techniques rely on the formation of a thick band of fibrosis on the lateral (outside edge) of the joint to protect the knee from instability. Most all the sutures fail eventually, but if we can keep the knee stable for 8 weeks, we allow time for fibrosis that will protect the knee for a lifetime.

Osteotomies – These are procedures where the tibia (shin bone) is cut with a saw and repositioned to prevent cranial tibia thrust (a bucking action that occurs on flexing an unstable joint.) The tibial plateau leveling osteotomies (TPLO,CBLO) have been quite successful and probably are the best option for your dog if he has a “steep tibial plateau.” The tibial tuberosity advancement procedure has had greater results in recent years as it has been refined and may be recommended depending upon the anatomy of your dog’s patella (knee cap) among other considerations.

All surgeries can have complications and some active dogs can be very rough on a surgical repair. It is important to be very careful to avoid post surgical infections and physical therapy is a big part of recovery. The success of the surgery is half dependent on the surgery and half dependent on the postoperative care.  Aftercare is very important in all surgeries, but very active dogs with an osteotomy and a bone plate can fracture their leg and cause a catastrophic failure if allowed to run free after surgery.

A few take-home points to remember are:

  • Cruciate ligament injury in a dog is a disease process and can affect the opposite leg 50% of the time.
  • Management of osteoarthritis is very important including weight loss, physical therapy, appropriate exercise, nutritional support and medications.
  • Pain medication will be necessary after surgery and probably periodically in the future.
  • Omega 3 Fatty acids and Glucosamine/Chondroitin supplements also are likely beneficial.

Dr. Jeff Smith is happy to answer any questions you may have by phone consultation or in person. He performs cruciate ligament surgeries as well as many other soft tissue and orthopedic surgeries.

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We are committed to providing compassionate and effective care to help you, and your pet live your best lives together. You can call us at (434) 836-2499 or visit us at 280 Piney Forest Rd., Danville, VA 24540.