Problem Patellas and the Performance Papillon

Written by Dr. Stanley Sohn
Email: pappwr@comcast.net  

Papillons competing in performance events need to be physically sound, just like any other athlete. Patellar luxation, a condition which can affect a dog's physical ability to compete is often seen in Papillons and other breeds, and is of concern to both breeders and those whose dogs compete in performance events.

The patella is a small, oval shaped bone located within the tendon of the muscle primarily responsible for extending the stifle (knee). Its job is to reduce friction on the tendon as the stifle bends. It slides up and down in a groove in the femur (thighbone). The tendon in which the patella is located attaches to the tibia (shinbone), which contracts as the muscle tightens, thus extending the stifle. The muscle and the tendon exert a straight line of force to accomplish this extension.

Patellar luxation is the term for the condition when the patella (kneecap) moves out of the groove it is suppose to slide in. Patellas in toy breeds and other small dogs usually luxate medially (to the inside), while the larger dogs patellas usually luxate laterally (to the outside). When the patella is not seated in its groove, the line of force is disrupted and the stifle cannot properly extend. It is easy to see how this condition can limit a dog's ability to ambulate properly, thus limiting its ability to participate in performance events.

Patella luxation is graded into four categories of severity: Grade I luxation means the patella normally slides in the groove, but with some pressure can be dislodged although it returns to the groove on its own; Grade II is where the patella can come out of the grove by itself, but also corrects itself; Grade III is where the patella comes out of the groove by itself, and does not correct itself but can be manipulated back into place; and Grade IV indicates the patella is always out of the groove and cannot be corrected manually.

My feelings about the cause of this condition and recommended treatments are a result of my personal experience in my veterinary practice. I strongly suggest that anyone whose Papillon is diagnosed with patellar luxation seek two or three different professional opinions before deciding to have their dog undergo corrective surgery.

I have found Grade I luxations almost never require corrective surgery. Most of these dogs live a long, normal life, and can successfully participate in performance events. Grade II luxations usually do fine without surgery. Most of the dogs never miss a step and can also compete in performance events. Dogs with Grade III and IV will usually have some problem walking. The problem usually manifests itself when the dog is running or walking normally, and then holds a leg up for a few steps before putting it back down. Even the majority of these dogs would not benefit from surgery. The primary indication for surgery is a dog that holds a leg up most of the time. If the dog walks normally most of the time, I would not consider surgery.

Patellar luxation generally does not seem to be painful for the dog, but rather a mechanical problem. When a patella is out of its groove, the line of force is out of alignment, which causes the inability to use the leg. Patellar luxation is usually a controversial condition, which is why I recommend seeking several opinions.

Unfortunately, the cause of patellar luxation is not yet known. There is no concrete evidence that the condition is genetic, and many feel it is a congenital condition. However, you have to wonder why so many toy breed dogs are affected. Personally, I would not breed a luxated dog nor repeat a breeding that produced luxation. We owe it to the breed to produce the healthiest Papillons we can, and doing our best to avoid patellar luxation is one of the ways to do that.