Luxating Patella (Floating Kneecap)

Luxating patella, also known as floating kneecaps, generally affects small and toy dog breeds. Normally your dog will not have had a traumatic prior injury and enjoys an active lifestyle. Often luxating patella will happen out of the blue. One day, he will suddenly pick up a back leg or yelp and cry for “no discernible reason.” He may be able to put his leg back down and resume running or play with no further problems. Huh? What may have happened is his kneecap popped out place and popped back into position again.

The kneecap sits at the distal end of the femur. It helps the quadriceps muscles flow across the joint between the thigh and lower leg so your dog has mobility of his entire leg and shin. It moves up and down in a groove with patella ridges holding the kneecap in place. As long as these ridges are deep, the kneecap is only able to move up and down. Some dogs have flatter patella ridges. This means the kneecap doesn’t sit as snuggly in its groove and can pop out medially (to the inside) or laterally (to the outside, as pictured above).

As previously stated, many small or toy dog breeds have a genetic predisposition to developing luxating patella, including (but not limited to): miniature or toy Poodles, Maltese, Jack Russell Terriers, Yorkies, Pomeranians, Pekingese, Chihuahuas, Papillions and Boston Terriers. Short-legged dogs (think Basset Hounds or Dachshunds) aren’t genetically prone, but their short femurs can allow the kneecap to change the angle it sits in the ridges, meaning a short-legged breed can develop luxating patella. Larger breeds tend to not experience the condition as they have the deep grooves that keep the patella in place. However, larger dogs are prone to hip problems, namely hip dysplasia, which is a condition in which the hip sits out of place and can cause a secondary condition of luxating patella to occur.

Feline lovers, take heed as well. Cats can also experience luxating patella. Thankfully, the situation is much less severe in felines. Cats are smaller and lighter in body weight than dogs and have much more flexible joints. A cat’s body simply moves differently than a dog’s. You may never even realize your cat has a luxating patella, most cats with a significant issue won’t show any symptoms; he may not even ever limp!

There are four levels of severity of luxating patella:

Grade 1 is very mild: a kneecap pops out of place and pops right back into place. (You may be able to manually pop it in and out of place yourself.)

Grade 2 had a kneecap popping out of place, but doesn’t pop back in immediately or sometimes requires manual manipulation to pop it back in.

Grade 3 has the kneecap sitting out of position most of the time. You can manually put the kneecap back in place and it should stay in place temporarily.

Grade 4 is the most severe: the kneecap is always out of place and can’t be positioned back where it should be.

In puppies, his patella can pop out and pop back in with ease and he may not even be caused any pain. As he ages, he will gradually not want to put weight on his leg until his kneecap pops back into place which may cause him temporary flashes of pain and will otherwise appear fine. As his cartilage continues to wear down from the frequent “traveling” of his kneecap, the bone-to-bone contact becomes more and more painful for him.

If your dog is experiencing any symptoms, no matter how mild and no matter what grade your veterinarian has diagnosed him with, taking a proactive approach from the beginning can prevent future surgery,  joint degeneration and save him from a diminished quality of life.

Your first course of action will be to help your dog maintain a healthy body weight. Any extra pounds will only put a bigger burden on his knees. Your dog at his optimal body weight will mean your dog is full of lean muscles which, in turn, will limit the stress he places on his joints. It may sound counteractive, but maintaining exercise is important. Keeping up his muscle tone can help him form a cage around his patella which will keep it in place. The more toned your dog is (from top to bottom), the more stable his kneecap will be. Building muscle is the single most important thing you can do for your dog. (Yes, you want your dog to become a canine body-builder.) Once your dog is a mass of muscle, you’ll want to provide him with oral joint support supplements or glycosaminoglycans (GAGs). These GAGs will help the cartilage of the knee to maintain their integrity and improve their fluidity. Adequan is an injectable joint support supplement. This helps dogs to prevent premature arthritis by slowing down joint degeneration and improves fluid production (which is what you’re trying to do). Chiropractic or acupuncture (for canines) can also help with his luxating patella, if those are avenues you want to explore. In fact, there are many chiropractic manipulations that you can help your dog perform to keep his knees and hips in alignment. Diet-wise, an anti-inflammatory, carb-free (or at least very low in carbs) will reduce joint inflammation for your dog. As always, consult with your veterinarian for specifics and to figure out the best course of action for your dog.

Your vet may recommend surgery first off, regardless of your dog’s severity. Unfortunately, there remains every possibility that, despite your best efforts, your dog may require surgery anyway. Be aware that your dog doesn’t necessarily need surgery (provided you’re not ignoring his symptoms without any kind of intervention) until he is at least stage 3. Surgical intervention will focus on deepening the trochlear wedge (if your dog has flat joints, the surgeon will cut a deeper V to hold the kneecap in place) or tightening down the joint capsule. Feel free to explore all non-surgical options before you opt for surgery. Surgery carries a risk due to anesthesia and/or infection, plus the surgery itself is aimed at a dog’s moving part that is weight-bearing. Therefore, if surgery goes wrong, your dog may have an even worse quality of life. If your surgeon puts a pin in your dog’s joint, the pin may still be able to move, requiring more surgeries or an abscess (seroma) can form at the site of the pin and can require draining or surgical removal. After surgery, your dog should not run or jump for about two months to allow the repair to stabilize. This can cause your dog a tremendous amount of stress because he’s a dog and he wants to be outside playing. Sometimes repair of the kneecap can set off other problems in other bones or joints. Even worse, about 10% of dogs do not show any improvement after surgery. They continue to be in pain.

It’s a tough decision, but only you and your veterinarian together can determine the best course of action for your dog and your family. Just know that there are a multitude of less invasive actions to try first. If these actions are successful, there may not even be a need for surgery! If the surgery is successful, it can give your dog a new lease on life but this type of surgery is by no means a guarantee and carries a lot of risks.  I wish your dog a lifetime of healthy knees!

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2 thoughts on “Luxating Patella (Floating Kneecap)

  1. Pingback: Luxating Patella (Floating Kneecap) | LITTLER DOGS

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