Patellar Luxation
What is Patellar Luxation?
The patella, or kneecap, is part of the stifle joint (knee). Patellar luxation occurs when the kneecap slides or pops out of place from the femoral groove when the knee flexes, causing the dislocation. Medial patellar luxation is the most common type seen in toy breed dogs and should be considered an inherited disease except in cases of luxation resulting from trauma.
Clinical Signs:
The clinical signs for patellar luxation vary depending on the extent of the disease, and mild cases often remain asymptomatic. Luxation can occur on one or both knees, and the dislocation can be either medial or lateral (moving towards the inner or outer aspect of the knee, respectively).
The most common sign is an intermittent “skipping” lameness when one hindlimb is suddenly lifted for a few “skips,” and then the dog resumes walking normally after kicking or shaking the limb. Patellar luxation is graded 0-4, with 0 being normal and 4 being the most severe. Grades 3 and 4 are usually candidates for surgical correction.
Treatment:
While most Cavaliers with patellar luxation will have mild symptoms that only need conservative management (i.e., joint supplements, low impact exercise, limiting jumping, and maintaining a lean body condition), more severe cases will benefit from surgical correction.
In more severe cases, as patellar luxation progresses, the patella dislocates more easily and frequently — persistently rubbing on the knee joint cartilage and leading to arthritis. The strain from the patella dislocating can also predispose dogs to other orthopedic knee conditions, such as cranial cruciate ligament rupture.
Your veterinarian may recommend surgery if your dog has more advanced patellar luxation or persistent lameness. If you choose to move forward with an operation, there are a few different surgical approaches, and your veterinarian will help determine which is best for your dog.
More Information:
- Orthopedic Foundation for Animals (OFA): https://ofa.org/diseases/patellar-luxation/
- American College of Veterinary Surgeons: https://www.acvs.org/small-animal/patellar-luxations/