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If you’ve never had a pet, “luxation” may sound like a spa treatment you’d like to investigate. But dog and cat owners know that patellar luxation in pets – commonly referred to as a “floating kneecap” – can be a painful condition that creates crippling discomfort and leads to more serious complications. It’s common, but it’s also treatable.
What Happens in Patellar Luxation?
The condition occurs when the kneecap, or patella, dislocates or moves out of its normal position within the groove of the thighbone, or femur. This can happen to humans, too; there it’s often called “trick knee” and may even repair itself over time.
The canine version is particularly prevalent in small dog breeds such as Pomeranians, Chihuahuas, Yorkshire terriers and Miniature Poodles. Large breed dogs can also be affected, often by some bowing in their femurs. Cats are less frequently affected but can also get patellar luxation. This often happens in breeds with genetic predispositions such as the Abyssinian or Devon Rex.
Causes of Patellar Luxation in Pets
Genetic factors may mean the conditions for this disorder are present from birth. Trauma or injury can also cause the kneecap to move out of place. Due to their anatomy, small dogs are always more susceptible. Cats with a history of leg injuries or genetic knee abnormalities may also develop the problem.
Common symptoms include intermittent limping, reluctance to run or jump, and a skipping or “hopping” gait, where the pet holds up the affected leg. Pets may cry out in pain when the kneecap slips. Over time, recurrent dislocation can lead to arthritis, muscle wasting and a permanent limp. It can also predispose animals to other knee ligament issues, such as ACL tears.
Diagnosing Kneecap Issues
A veterinarian will first perform a physical examination, often manipulating the knee joint to check for movement of the kneecap. Imaging tests such as X-rays or CT scans may be used to assess the severity and guide treatment decisions. Veterinarians use a four-grade system with these parameters:
- Grade I means the patella can be luxated out of the groove by putting pressure on it. However, it goes back in place on its own after pressure is released.
- In grade II, the patella intermittently pops out on its own and stays out until the leg is hyperextended and rotated; then the patella returns to the groove.
- In grade III, the patella generally stays out of the groove but can be pushed back manually into it.
- In grade IV, the most severe, the kneecap is permanently dislocated and can’t be repositioned manually.
Treatment Options
These depend on the severity of the condition. Owners may manage mild cases (grades I and II) with weight control, physical therapy and pain management strategies, notably anti-inflammatory medications. Surgery may address severe cases (grades III and IV) by repositioning the kneecap, deepening the groove in the thigh bone or realigning leg muscles to prevent further dislocation.
Surgery generally has a good prognosis, with most pets regaining full use of the leg after a recovery period of 6 to 12 weeks. Postoperative care includes restricted activity, physiotherapy and perhaps joint supplements to support healing and reduce arthritis risk.
Can You Prevent Patellar Luxation in Pets?
That’s not always possible, especially when it’s congenital. But maintaining a healthy weight, avoiding activities that might cause trauma, and regular veterinary check-ups can help avert it. If your pet shows signs of discomfort or altered gait, get to a veterinarian promptly to prevent long-term complications.
With timely diagnosis and appropriate management, animals can live comfortable lives. A vet can tailor an approach that best suits your pet’s needs and allow her to be as active as possible.
Charlotte Animal Referral and Emergency operates as the pet equivalent of a medical center for humans and stays open 24 hours a day, 365 days a year. CARE provides all types of treatment, from emergency attention to board-certified specialty work, once you get a referral from your primary care veterinarian. You can take a visual tour of the practice at carecharlotte.com/tour.
