By Nan Talleno

PHILADELPHIA (CBS) – Canine patella luxation is not uncommon in both large and small dogs (sometimes seen in cats as well) but needs to be evaluated by your veterinarian as to which level your dog is experiencing.

The patella is a small bone known as the kneecap. It protects the knee joint and guides the action of the quadriceps muscle in the lower leg. Due to trauma to the leg or a physical malformation, the patella groove may become much too shallow. If the patella jumps out of the groove or luxates sideways, it causes the leg to lock. The affected leg will be extended out to the back and, for a time, the dog is unable to flex it back into the normal standing position.

This usually happens after the affected dog runs or sprints. The dog may yelp or whine while running or shortly after. It can cause varying degrees of pain dependent upon the level of intensity. It can also cause severe pain, arthritis and lameness.

Smaller breeds can be most susceptible, such as the Chihuahua, the Toy Poodle, the Pekinese, Pomeranian, Lhaso Apso, Boston Bull, the Pug, the Dachsund, etc. But it’s certainly not limited to breed, size or age.

Natural supplements may also help the condition but if your dog displays any signs of discomfort or pain, have him/her examined by your vet.