Patellar Luxation in Dogs

What is patellar luxation in dogs? 

Luxating means out of place or dislocated, meaning a luxating patella is a knee cap that pops out or dislocates. Dogs with an occasional skip in their step are likely to have patellar luxation. 

Causes of patellar luxation in dogs

To understand the causes of patellar luxation in dogs, it’s important to first understand how the patellar works. The patellar (knee cap) sits underneath the patellar ligament which is attached to the large thigh muscles to a point on the centre front of the shin bone. This causes extension or straightening of the knee. The patellar then slides up and down in its groove in turn helping to keep the patellar ligament in place when moving. 

Patellar luxation can be caused by bowlegs as the point of attachment of the ligament isn’t in the centre of the shinbone. In most cases it’s too far away from the body or the inside of the leg. When the thigh muscles contract the force applied to the patella pulls it toward the inside of the knee. Years or months of this can cause the inner side of the groove to wear down, leading the knee to become dislocated. 

Dogs with genetic predispositions to patellar luxation include:

• Maltese.
• Chihuahuas.
• Poodles.
• Bichon Frise.

Grades of patellar luxation in dogs

There are four grades of patellar luxation with the higher grades being more severe. 

• Grade 1 - This is where the patellar can be luxated when pressure is applied, but when the pressure is released it goes back into place. 
• Grade 2 - This is where the knee will pop out on its own intermittently and won’t go back into place until it's hyperextended and rotated.
• Grade 3 - This is where the patellar is out of the groove most of the time and can be put back in place when manually pushed.
• Grade 4 - The patellar is permanently out of place and cannot be manually put back. 

Dogs can experience patellar luxation in one or both of their knees, with 50% of dogs affected by it experiencing it in both. 

Signs of luxating patella in dogs

• Quick incidents of lameness.
• Holding up their leg for a few steps.
• Appearing as though they’re skipping a step.
• Extending their hind leg out behind them.
• Weakness or hobbling on their hind legs.
• An inability to jump.
• A reluctance to run or exercise.
• Looking bow legged or knock kneed.
• Yelping when running or playing.

How to treat patellar luxation in dogs

Luxating kneecaps won’t heal on their own and do require veterinary treatment. For dogs suffering from grade 1 patellar luxation they may be able to cope with the pain and restricted exercise, but anti-inflammatory medicine will help it become more manageable. However, as they age they’re likely to develop arthritis. 

Surgery may also be an option but surgeons may suggest waiting to see if the condition worsens before performing it.

Dogs with patellar luxation are also predisposed to other knee conditions like torn cruciate ligaments or degenerative disease in the hip.

Pros and cons of luxating patella surgery

Pros

• It has a 90% success rate with most dogs having a good to excellent outcome.
• When proper rehabilitation takes place dogs should be able to return to how they were before the injury.

Cons

• There is a small risk that complications will occur such as an infection, blood clotting or neurovascular damage.
• Discomfort may be felt if the surgery is completed after arthritis is developed and can lead to it progressing further. 

How to prevent patellar luxation in dogs

Patellar luxation in dogs can’t be prevented but it is suggested the breeds predisposed to the condition shouldn’t be bred. However, if a dog is kept in good shape and their weight is monitored it can help to prevent arthritis developing after patellar luxation occurs. 

FAQs

What is lateral patellar luxation in dogs?

This occurs more in giant and large breeds and happens when the patellar rides on the outside of the knee or due to hip dysplasia causing abnormal rotation of the femur. 

If lateral patellar occurs in smaller dogs it’s usually due to a breakdown in soft tissue rather than skeletal defects and tends to happen to dogs between 5 and 8 years old. Lateral patellar can also be caused by trauma or over exertion.

Should you walk a dog with a luxating patellar?

A dog with low grade patellar luxation can still be taken for a walk but it’s recommended that they’re prevented from jumping as it puts a lot of stress on their joints. 

How much does luxating patellar surgery cost?

Luxating patella surgery begins at around £2,500 but can easily exceed £4,000 depending on the dog's breed, weight and condition. 

If you’re looking to insure a dog with a luxated patellar complete our medical screening process today to see if we can cover them.