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knee deep: petplan pet insurance explains luxating patellas

  • Dr. Kim
  • Posted by Dr. Kim Smyth on
    Staff Veterinarian and Pet Health Writer of Petplan


Knee injuries are common in both big and small dogs. While large dogs may tend towards injuries to the ligaments in the knee, the most common knee ailment I see in small and toy breed dogs is called patellar luxation. In this condition, the patella (knee cap) slides in and out of place, causing lameness.

Anatomy of a normal knee
Much like ourselves, our dog’s knees are made up of the meeting of the large bone of the upper leg (the femur) with the bone of the lower leg (the tibia). The patella, or knee cap, sits nicely in a groove in the middle of the lower end of the femur, where it can slide easily up and down as the knee bends.

The most common sign of a luxating patella is intermittent lameness. Affected dogs will seem to have a temporary hitch in their gait that resolves quickly with no treatment. Often, I will find luxating patellas on a routine annual physical exam and mention it to the owners who had no idea! The intermittent lameness results from the knee cap temporarily slipping out of the groove in the femur. The knee cap will shift to one side (usually to the inside of the knee in small dogs) and cause discomfort before slipping right back into its normal position in the middle of the knee.

Luxating patellas are graded based on their severity as follows:

Grade 1: The patella slides out of joint when manually manipulated, but will slide right back into place on its own.
Grade 2: The patella slides out of joint when manually manipulated and stays there.
Grade 3: The patella remains out of joint, but can be put back into place manually.
Grade 4: The patella remains out of joint and cannot be manually replaced.

In all grades of luxating patella, the knee joint becomes more prone to degenerative joint disease over time. Treatment of this condition depends on the grade of disease. Dogs with Grade 1 disease generally do not require surgery, though from time to time, they may need anti-inflammatories to ease discomfort. Dogs with Grade 2 disease may benefit from surgery - generally this decision is made on a case by case basis. Dogs with Grade 3 or 4 patellar luxations need surgery to repair their conformation and prevent further joint damage and pain.

If you have noticed a hitch in your dog’s get-a-long, make sure your veterinarian checks her knees. If patellar luxation is found in one or both knees, talk to your veterinarian about your treatment options.  Unlike some other pet insurance providers, Petplan pet insurance can cover treatment for luxating patellas. Often, symptomatic treatment of discomfort is all that is needed, but if surgery is required, you may be referred to an orthopedic specialist. Don’t despair if your precious pet needs surgery; within six to eight weeks, your pup’s knees will be as good as new.  

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Posted by Sarah King
on January 13 2014 15:00

I took my 3 year old Chi for his annual booster and health check today. They told me his knees pop, and explained about luxating patellas. Would I be able to get insurance now or would it be classed as a pre existing condition? Not sure if they made a note of it as he hasn't been xrayed or anything, just said I might like to see a specialist to discuss possible surgery. I should qualify for PDSA help if I register with a different vets who are part of it, but they might not help either if they notice it on the initial consultation. So normal insurance would be my first choice providing it wouldn't be classed as a pre existing condition. Please help!

Posted by Darcy Saunders
on September 14 2011 19:10

Our cat, Boo, was diagnosed with bilateral luxating patella when he was only 1 1/2 years old. He required surgery on both knees. It was a lengthy process (one surgery in June, the second in October), but Boo was a trooper! PetPlan picked up a large portion of the cost, which was a huge, huge relief.

Posted by jeannie prouty
on September 11 2011 11:39

My 1 year old puppy had patellar luxation in both knees and we were refered to a orthopedic specialist. Petplan covered the surgery and rehab and even sent get well cards to the patient. Thank you Petplan!

Posted by Kurt Kraft
on September 08 2011 20:19

Dr. Smyth, thanks for the information. My Amstaf has been limping for the past few weeks when we are walking slowly. When she gets into her trot she looks fine. I also noticed every time she gets up from a rest position she limps. Can this be possible be patellar luxation.

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