What is patellar luxation?

The patella (referred to in humans as the kneecap) is a small bone at the front of the knee, gliding up and down within a groove at the end of the thigh bone (femur) as the knee flexes and extends. In some animals, the patella can luxate (dislocate) out of its normal groove, resulting in lameness, pain and osteoarthritis.


What are the symptoms?

A luxating patella can affect both cats and dogs of any breed, but is most common in small or miniature dogs. Luxating patella in cats is most commonly found in domestic short-haired cats. Most animals start showing signs as puppies or young adults, although mature dogs can also suffer from patellar luxation.

Although the signs of patellar luxation can vary, you might notice your pet ‘skipping’ as they walk, with their hind leg carried for a few steps before quickly returning to normal. This happens when the patella slips out of the groove and stops when it goes back in again. Some animals will limp continuously, or – if both knees are affected – they may have difficulty walking, or move with a stiff gait.

 

 

The diagnosis

Your vet will normally refer you to a specialist orthopaedic surgeon if they suspect your pet has a luxating patella, or if you’ve noticed a ‘skipping’ motion as they walk. Once referred, Swift’s orthopaedic specialists will assess your pet, often using advanced imaging to get a clear overview of your their condition and assess the severity of the luxation.

 

How do we treat patellar luxation?

The treatment your pet requires depends on the severity of the luxation. Once they’ve examined your pet, the specialist will assign the luxation a diagnostic grade based on how mobile the kneecap is relative to the groove. There are four recognised diagnostic grades, with 1 being the lowest and 4 being the most severe.

For grade 3 and 4 patellar luxation, surgery is strongly advised, and may also be recommended for grade 2 cases if your pet is presenting persistent lameness. Surgery for patellar luxation is incredibly effective, freeing 90% of dogs from lameness and dysfunction.