Patellar Luxation

The patella (knee cap) is a movable bone located over the knee that connects the muscles of the thigh to the lower leg. When the patella functions correctly, your dog can use the leg well.

Patellar luxation is a dislocation of the knee cap most often seen in small breed dogs.

Luxation of the patella can be a congenital problem (something the animal is born with) or acquired as a result of injury or trauma.

One or both knees may be affected.

A fall or twisting injury may aggravate an already existing condition.

Symptoms Of Patellar Luxation:

With patellar luxation, your dog may occasionally hold the leg up while running, but then spontaneously start using it again. This happens as the knee cap pops in and out of place. Your dog may give out a short cry or yelp when this happens.

Your dog may have a bow-legged stance and be reluctant to run or jump.

As time progresses, the joint may begin to develop degenerative (arthritic) changes as a result of the movement of the patella.

Diagnosis Of Patellar Luxation:

Diagnosis involves a physical examination for your dog.

The movement of the patella is usually easily palpable and not difficult to diagnose.

Radiographs (x-rays) of your dog's knee may be necessary to rule out degenerative changes in the joint, which can result from long-standing patellar luxations.

Treatment Of Patellar Luxation:

Treatment is usually surgical correction, which is much more successful if accomplished before degenerative joint changes occur.

Surgical procedures recommended may include:

• Imbrication, which is the procedure of tightening the joint capsule. 
• Trochleoplasty, which involves creating a deeper groove for the kneecap to sit in.
• Tibial tuberosity transposition, which is a procedure in which the end of the tibia (the bone below the knee joint) is surgically moved back into proper alignment.
• Osteotomy, which involves removing part of a bone to realign the joint.  This may involve removing part of the femur (the bone above the knee joint) or part of the tibia (the bone below the knee joint).

If surgery is not an alternative due to arthritic changes within the knee joint or for other reasons, your dog's veterinarian may be able to offer pain medication and medications designed to help improve joint health to make your dog more comfortable.

These may include non-steroidal anti-inflammatory medications, such as Rimadyl, Etogesic, and Deramaxx.

Other medications recommended may be supplements which include glucosamine and/or chondroitin.