"Doc", said the lady, I don't know what's wrong. One minute he was runnig around like normal. The next minute, he yelped and has been holding up that back leg since. He didn't fall or run into anything. He was just doing his normal running. I thought he just strained it, but it has been three days, and he still is not using it." I looked at 'Poppet'. The Terrier mix was indeed not using one of his rear legs. He would run around on three legs, then stop and look at us.

"Okay, Poppet", I said, "let's see what's going on with you. Let's put Poppet up on the table." We got Poppet on the table. I had the owner hold Poppet on his side so that I could examine the leg he had been holding up. As I got to his knee, he started squirming. When I pushed on his knee I could feel his keecap slide. I finished examining the rest of the leg and then checked the other leg.

"Poppet has a ruptured cruciate ligament", I said to the owner. "A what?" asked the owner. "A ruptured cruciate ligament", I repeated. "It is like the athelete who tears his ACL. That stands for anterior cruciate ligament. It is the ligament that keeps the bottom portion of the knee, the tibia, from sliding too far forward under the top part of the knee, the femur." "I did not even know dogs had ACLs", said the owner. "Yes, they do," I said. "They have pretty much the same ligaments that we do. Anterior cruciate ligaments are usually torn by a stress to the ligament, such as a twisting motion at the knee or hyperextension of the knee. We see a lof of this type of injury from dogs doing things like playing frisbee. Injuries usually happen pretty acutely; they suddenly hurt their leg and start holding it up. The treatment for it is surgery." "What does surgery involve, Doc"? "There are several metods of repairing torn anterior cruciate ligaments. One of the most common methods is using suture material to stabilize the joint. It keeps the bones centered so that the tibia does not silde too far forward". "Will he be in a cast when he goes home?" "I generally put them in a bandage for at least a week or two, and excerise is restricted over the next couple of months." "Okay, let's do it" the owner said.

We scheduled Poppet for the surgery. He went through the surgery fine, and at his first week's recheck, he was starting to bear a little weight on the affected leg. The following week he was using it more. At his one month visit, he was bearing full weight on the leg, and Poppet graduated to short leash walks. We gradually started increasing the amount of excercise that Poppet could do after the second month. At a visit a few months after the surgery, he was walking around like normal.

As mentioned before there are several methods that can be used to repair torn anterior cruciate ligaments. Aside from the use of suture material, some veterinarians use a surgical technique that involves moving a portion of the bone with the muscles still attached to act as a stabilizing structure. Some surgeons like to use this technique with big dogs. Another technique involves using part of the patellar tendon, the tendon that holds the kneecap in place, to perform the functions of the anterior cruciate ligament. All of the surgery techniques work.

Not all sudden injuries to the leg are ruptured carnial ligaments. Sometimes it is just a strain. If so, it usually gets better within a couple of days. Have the pet examined if an injury to the leg does not improve within a couple of days. A positive diagnosis can be made if the veterinarian can get a "drawer sign", that excessive movement in the knee. Sometimes he drawer sign cannot be elicited. The pet may be so sore that he tenses up his muscles too much to get any kind of movement. This is especially true of the bigger dods. If the veterinarian thinks that that is the case, he/she may suggest examining the pet while it is under anesthesia. With the pet relaxed, the veterinarian has an easier time testing the strength of the knee. The veterinarian may also suggest radiographs to see if any other abnormailties may be present. If there is a lot of arthritis in the knee, the benefits of surgery decrease; the knee may still be painful just because of the arthritis.

If you have an active dog be prepared for all kinds of mishaps. If one of those mishaps happens to be a ruptured cranial cruciate ligament, take comfort in the fact that there is a treatment for it.

Dr. Cox practices at Hufford Animal Hospital, a small animal practice in Pasadena, Maryland. She is a graduate of the University of Missouri, Columbia.