A luxating patella, or the dislocation of the kneecap, is one of the most common conditions diagnosed in canine orthopedics. It is present in around 7% of puppies. The condition is more common in small dogs compared to larger breeds; however, its occurrence in larger dogs has increased over the last 10 years.
Patellar luxation can cause discomfort and a loss of leg function in your dog. There is evidence that this condition is at least partially genetic. Find out how to treat this condition if a veterinarian diagnoses your dog with a luxating patella.
What is a luxating patella in dogs?
The patella is the bone of the kneecap — a small bone within the quadriceps muscles of the thigh. Normally, your dog’s patella should be well-aligned with the quadriceps and the patellar tendon to form the extensor mechanism. If your dog has a luxating patella, it means the patella is dislocated. The kneecap rides outside the groove within the femur when flexed rather than riding in the groove. Your dog may have a medial or lateral patellar luxation depending on whether the kneecap is riding on the inner or outer part of the knee.
Certain dog breeds are more prone to a luxating patella than others:
- Yorkshire terriers
- Boston terriers
- Miniature poodles
- French poodle
- Great Pyrenees
- Chinese Shar-Peis
- Flat-Coated Retrievers
Is a luxating patella painful for dogs?
While a luxating patella can be painful, it is more likely to only cause discomfort and trouble flexing the leg. There are rarely signs of pain in dogs with this condition. In about 50% of cases, the luxating patella affects both kneecaps rather than just one. Double patellar luxation can be more uncomfortable and debilitating than just one kneecap.
How do you treat patellar luxation in dogs?
Many dogs – especially small dogs – live their entire lives with a luxating patella without signs of pain or lost quality of life. If a veterinarian diagnoses your dog with a luxating patella, he or she may recommend minimal treatments, such as:
- Vitamins or oils to lubricate your dog’s joints
- Frequent exercise to strengthen the tendons
- Nutritional support to prevent arthritis
- Wearing a leg brace
- Getting massages, acupuncture treatments, or hydrotherapy
Over a few months or years, frequent patellar luxation can wear down the groove within the femur. This can lead to more frequent kneecap dislocations. A severe case of patellar luxation (such as if the kneecap gets stuck out of place) may require surgery, or else your pet may suffer permanently reduced function of the leg and complications such as a torn ligament. Recovery time will depend on your pet and the circumstances.
What causes a luxating patella in dogs?
The exact cause of a luxating patella remains unknown. However, it can be the outcome of a traumatic injury in your dog, such as a knee or leg injury. There is also evidence that it is partially genetic. Patellar luxation occurs when a dog’s thigh muscles contract, transmitting force through the ligament above the kneecap (the patellar ligament).
When this happens, the ligament pulls on the shin bone and straightens the knee. During this movement, the patella slides within its groove to keep the patellar ligament in place. If the contraction pulls the patella to the inside or outside of the knee rather than the groove of the femur, a luxating patella occurs.
What are the symptoms of a luxating patella in dogs?
The most common symptom of a luxating patella in a dog is the temporary inability to flex the knee. You may notice your dog limping on three legs for a moment, then returning to four as if nothing happened. Occasional limping or skipping, as well as an abnormal knee position while sitting, are all signs of patellar luxation.
The symptoms may vary based on whether your dog has moderate to severe luxation. Lameness is a sign of more severe luxation.
You may notice your dog self-treating the issue by kicking its leg to the side to put the patella back into its normal position. If you suspect a luxating patella in your dog, talk to your veterinarian for more information.
Alana Redmond is a content writer who specializes in law and consumer safety. She also works with Seidman, Margulis & Fairman, LLP, a personal injury law firm in Chicago that specializes in dog bite injuries and accidents.