Patella Luxation in Yorkshire Terriers

Having an animal that has joint problems can be very distressing for both the owner and the animal. Most people have heard of hip dysplasia, especially in dogs and some may have heard of elbow dysplasia, however, this Pets4Homes Article discusses another part of the dog, the kneecap.

One of the common dog breeds to have kneecap problems is the Yorkshire Terrier, so the article is predominantly about that breed and sizes like it. The condition they can commonly get in the kneecap is called patella luxation. This disease does affect other breeds, and it is not exclusive to Yorkshire Terriers, so please take a read.

What is patella luxation?

Although luxation sounds like a mixture of luxury and vacation, it is far from a holiday for the affected dog. The patella is a small bone (also known as a kneecap) that sits in a groove between the tibia and femur (exactly where your own knee would be). In a normal knee, this bone would slide up and down in the groove as the dog's movement would naturally make it work properly.

If a dog has patella luxation, much like Yorkshire Terriers can get, the bone slips out of the groove to one side. As you can imagine this is very uncomfortable for the animal. Luxation can also be thought of as a dislocated bone. Although this article predominantly deals with Yorkshire Terriers and other dog breeds, cats can also be affected.

What other breeds can get patella luxation?

Although Yorkshire Terriers are commonly seen for this disease, there are other breeds of dogs where research seems to suggest the condition could be genetic. There is no correlation between which leg is affected either, as both the left and right legs are at risk. Other breeds that can be affected are:

• Poodles
• Staffordshire bull terriers
• Labrador retrievers

The reason behind it happening is often not clear-cut – however, it is thought that some deformity to the area is the main cause. In some cases, the bones such as the femur are so deformed, they are actually bowed. One thing is certain, that the groove the patella is supposed to slide into, is not aligned correctly, causing it to slip out of that groove and luxation is the result.

What are the signs of patella luxation?

You would think that if the patella bone dislocated, the dog would stumble and fall over, or not be able to walk at all. In reality, the patella will still move in the knee joint, but if it has dislocated, it won’t move freely. So, the signs are variable sometimes owners notice it and other times owners believe it is just a way dog walks.

If the patella is dislocating as the dog walks – that is moving out of the groove that it is supposed to be in, it can cause the dog to almost 'skip' as they walk. When the knee returns to a certain position, the patella bone realigns and goes back into the groove. This process keeps going with the bone dislocating and then relocating.

How is patella luxation diagnosed?

If patella luxation is suspected, a vet will fully examine the knee area which may show some muscle wastage, although this is uncommon. During the examination, the vet can manipulate the knee and if the patella is not stable, they may even be able to push it out of the groove with very little effort. There are times when a dog visits with patella luxation, and the bone is permanently out of the groove and to one side – the vet will grade this on a system between 1 and 4, with the biggest problem being number 4.

Two confirm the diagnosis, the vets may take some x-rays often from different angles, this will show whether there is a luxation and also deformities in any bones. If osteoarthritis is found it can also be managed.

What is the treatment?

There are various ways of treating patella luxation. In Yorkshire Terriers, because they are small dog breed, they can benefit from having their exercise restricted, and you make sure that they are their ideal weight. Like any joint problem, if the dog is overweight, regardless of the breed, more strain is put on the joint, so increasing the problems within it.

Dogs that do not have a severe luxation, and the grading system is 1 or 2, may also benefit from hydrotherapy. If the problem is severe, they may need surgery to correct it. According to the type of luxation, is how the veterinary surgeon will treat the problem. It may be a realignment of the bone, making the groove deeper so the patella sits inside it better, or even changing the shape of the femur, so the patella fits snugly.

What after-care will wear dog need?

Like any surgery, your dog will need to recover fully, and for joint surgery especially around the knees, restricted exercise until everything heals is very wise. Painkillers are also a must following surgery. Your vets will advise you on an exercise regime and any medication that your dog goes home with.

It goes without saying that their weight will also need to be maintained, as to not put a strain on the repaired knee. Gradually exercise can be built up as this will help with muscle tone around the knee area – this doesn’t mean chasing a ball at high-speed, but a gentle lead exercise walk.

Sometimes in unfortunate cases, where both knees are dislocating, the veterinary surgeon may decide to do the worst knee before the better one, this helps you by having a dog that can still walk!

Will happen again?

Following treatment or surgery, re-occurring problems of this nature are uncommon. You may find that your dog suffers a little more with osteoarthritis, but in the knee area this does not usually cause pain or for them to become lame. You may find them being stiffer when moving, especially when getting up off the floor after sleep. These conditions can be managed (osteoarthritis cannot yet be cured) and as your pet gets older, they can be given supplements and anti-inflammatory drugs to help ease any aches and pains.