Dog Knees

Q. My dog was walking on three legs, and the vet diagnosed it as a “luxated patella.” What is that, and is there any alternative to surgery?

A. The patella is the proper name for the kneecap. In dogs, the knee is the first joint down from the body on the back legs, and when the patella is “luxated,” that means it slips out of position. In humans the problem is sometimes referred to as a “trick knee,” but it’s no treat to walk on, that’s for sure.

Luxated patellas are not uncommon in small dogs, and not unheard of in big ones, either. (Occasionally they show up in cats as well.) Mild luxation is often found by a veterinarian during a wellness exam, although more severe problems are often discovered exactly the way your dog's was: The pet carries the affected leg so as not to put pressure on the joint, or cries out when walking or running. The problem is not a misstep or twisted knee, though; it’s the result of a deformity of the joint.

Veterinarians rate the severity of the luxation based on the age of onset and the joint’s ability to slip back into a normal position. Typically, when the problem shows up early, it’s more severe and more likely to be addressed with surgery. Luxated patella is thought to be hereditary, which unfortunately means that once it's been diagnosed in one knee, your dog is likely to have problems with the other knee as well.

For dogs with mild luxation, whose kneecaps go in and out of a normal position, the condition may be able to be handled with rest, strict weight control (keep your dog at or slightly below normal weight) and pain management. Dogs with more severe cases will likely need surgery on one or possibly both knees. Your veterinarian will go over surgical options with you, or may refer you to a board-certified veterinary surgeon. In severe cases, surgery is needed to help the pet live a normal, active and happy life.

One further point: Because of the hereditary issue, it’s important that you have your pet spayed or neutered (if you haven’t done so already) to keep this condition from being passed on.