My Cocker Spaniel Cooper had TPLO surgery last
fall. Yesterday he started holding up his other
leg–the one he did not have surgery on.

Could he have torn the crutiate ligament in his good leg?
How common is that? He is resting in his
crate and we only take him out to go to the
bathroom then back into his crate. He will be 7 in
January. We will take him to the vet after the weekend.

Martha
Ottawa, On Canada

First, the basics. The cruciate ligament is located in the knee. It holds the joint stable during motion. Dogs commonly damage or tear a cruciate ligament during activities such as jumping or running. Risk factors include long legs and obesity.

When a dog tears his cruciate ligament, he generally refuses to put weight on the affected leg. This leads to the typical symptom of a dog with a cruciate ligament injury–a dog holding one rear leg up, and walking on only three legs.

There are several treatments for cruciate ligament injury. The currently accepted gold standard (best treatment) is a surgery known as TPLO.

Now, finally, to answer your question. Dogs that have injured one cruciate ligament have an increased likelihood of injuring the other one. The main reason for this is that after suffering a cruciate ligament injury dogs transfer extra weight to the good leg. This stresses the leg, and increases the risk of injury to the knee.

Unfortunately, I have known several dogs who have incurred bilateral cruciate ligament tears during their lifetimes. The good news is that, with bilateral TPLO surgery, most of these dogs go on to lead relatively normal lives. The bad news is that the surgeries are expensive and painful for both the dog and the person caring for the dog.