Luxating Patella in Dogs

Does your dog sometimes skip a step while running or hold a hind leg up while going up the stairs? If so, your pup could have a dislocating kneecap, also known as a luxating patella. This is a very common condition in dogs, especially in smaller breeds. Here’s what you need to know about recognizing and treating luxating patella in dogs, so you can ensure the best care for your pet. 

What Is Luxating Patella?

A luxating patella occurs when your pet’s kneecap, also known as the patella, slides out of its normal position when the knee is flexed. This dislocation of the kneecap often occurs because the groove where the kneecap sits is abnormally shallow, allowing it to pop in and out of place.  The resulting intermittent dislocation can be painful and may cause a temporary loss of function in the affected limb.

Types and Grades of Luxating Patella

If your pet has been diagnosed with a luxating patella, you may hear your veterinarian refer to the condition as being unilateral or bilateral. Unilateral means that the condition occurs on only one side—only one hind leg is affected. Bilateral means that both of your dog’s knees have luxating patellas. Your vet may also describe the luxation as being medial or lateral. A medial luxation occurs when the kneecap moves toward the inside of the leg, while a lateral luxation is when the kneecap moves to the outside of the leg. These descriptors can help your veterinarian better characterize the type of dislocation that is occurring in your pet’s knee.

Your veterinarian may also describe your dog’s luxating patella using a grading system, which describes the severity of the dislocation. A luxating patella is ranked Grade I through IV, with Grade I being mild and Grade IV being the most severe.

• Grade I: The veterinarian can push the kneecap out of place but it snaps back to its normal position.
• Grade II: The kneecap moves out of place occasionally and the veterinarian can push it back into its normal position.
• Grade III: The kneecap stays out of place most of the time but the veterinarian can push it back into its normal position.
• Grade IV: The kneecap stays out of place all the time and the veterinarian cannot push it back into its normal position.

What Causes Luxating Patella in Dogs?

In most cases, patellar luxation is a genetic condition. It is especially common in small breed dogs, although it is becoming more prevalent in larger breeds, as well. Breeds predisposed to luxating patella include Boston Terriers, Yorkshire Terriers, Chihuahuas, Pomeranians, Miniature Poodles, Shar-Peis, Flat-Coated Retrievers, Akitas, and Great Pyrenees. Your dog is more likely to have a luxating patella if one or both of their parents had the condition.

Patellar luxation can also occur following trauma to the knee—injuries sustained after being hit by a car, for example—but this is much less common.  

Can Puppies Grow Out of Luxating Patella?

Patellar luxation is often diagnosed at a young age. Unfortunately, because this condition is genetic, puppies do not grow out of a luxating patella. They may require treatment if the condition is causing pain or a loss of function in the affected limb.

Symptoms of Luxating Patella in Dogs

In dogs with a low-grade patellar luxation, the symptoms are often quite subtle. Your dog may walk or run normally, then suddenly carry a hind limb up for a few steps as if they are skipping. Most dogs will then return to using the limb normally as if nothing happened. This is characteristic of a luxating patella. However, with more severe and frequent luxations, your dog may experience more significant symptoms, such as:

• Pain, especially when the kneecap has dislocated
• Bow-legged or knock-kneed appearance
• Chronic intermittent lameness on one or both hind legs
• Difficulty using the affected leg
• Difficulty running, jumping, or climbing stairs

Diagnosing Dogs with Luxating Patella

Early diagnosis of luxating patella can play an important part in the effective treatment of severe cases. There are two main methods veterinarians use to diagnose the condition and inform the treatment. 

Physical Examination. A luxating patella is often an incidental finding, meaning that your veterinarian may discover it during a routine physical examination. Your veterinarian will palpate (feel) your dog’s stifle (knee) joints and gently move them through their normal range of motion.  If your dog has a luxating patella, your veterinarian can often feel the kneecap sliding out of place during this simple exercise.

Radiographs. Your veterinarian may recommend taking X-ray images of your dog’s hind limbs to further evaluate the position of your dog’s patella bones. This can help determine the severity of the luxation, whether it is medial or lateral, and whether there is any arthritis associated with the affected joint.

How to Treat Luxating Patella in Dogs

The treatment for luxating patella depends on the severity of the condition and how it impacts your dog’s quality of life. Dogs with Grade I luxating patella often have few symptoms of the condition and can live a normal, pain-free life without treatment. Dogs with higher grade luxations may require pain control medications such as non-steroidal anti-inflammatory drugs (NSAIDs) to maintain comfort and quality of life. Joint supplements can also help manage any secondary arthritis that occurs due to chronic luxation.

Luxating Patella Surgery for Dogs

Surgery is typically recommended for dogs with luxating patella that causes chronic lameness or those that have Grades III or IV luxations. There are several different surgical approaches to correct a luxating patella, and your veterinary surgeon will decide the best procedure depending on your pet’s anatomy and the severity of the luxation present. Following the procedure, your pet will need to stay quiet and calm for several weeks while the surgical site heals. Your veterinarian will likely prescribe medication such as NSAIDs to manage pain and reduce inflammation at your dog’s surgery site. After the recovery period, most dogs experience a good to excellent return to function on the affected leg.

General Cost to Treat Luxating Patella

A conservative treatment plan (rest, NSAIDs, and joint supplements) is generally inexpensive. Pet parents can expect to spend around $200 or less on medications to manage a dog’s luxating patella. Luxating patella surgery, on the other hand, can be quite expensive and often requires referral to a specialist. Pet parents opting for surgical treatment should expect to spend several thousand dollars on the procedure and associated follow-up care.

How to Prevent Luxating Patella in Dogs

Luxating patella is a genetic condition in most cases, so animals with this condition should not be bred to prevent passing on the condition to the offspring.

Related Conditions

• Osteoarthritis
• Hip luxation
• Cranial cruciate ligament rupture