Patellar Luxation in Cats: A Hidden Source of Pain 

Patellar luxation is one of the most common causes of hind limb lameness treated at our animal hospital. While the condition is frequently seen in dogs, it also occurs in cats. Although it may be less prevalent in felines, it is a serious issue that should not be ignored. Not only does it cause an abnormal gait, but it can also lead to significant pain and discomfort for your cat, affecting their overall quality of life.

Patellar luxation is a condition where the kneecap (patella)—which normally sits securely in the femoral groove at the front of the knee joint—slips out of its proper position. This displacement can occur in one or both hind legs and may shift toward either the inner (medial) or outer (lateral) side of the knee. In cats, the most common presentation is Medial Patellar Luxation, where the kneecap slides toward the inside of the leg."

The 4 Grades of Patellar Luxation in Cats 

• Grade 1 The kneecap sits normally in the groove but can be manually pushed out when pressure is applied and the ankle is rotated. It slips back into place immediately.
• Grade 2 The kneecap remains in the groove but frequently slips out during limb rotation or movement. 
• Grade 3 The kneecap sits outside the groove most of the time, but it can still be manually pushed back into the groove by a veterinarian.
• Grade 4 The kneecap is permanently displaced outside the groove and cannot be pushed back into its original position manually.

Symptoms vary by grade. In Grades 1 and 2, cats may show intermittent limping or occasional discomfort in their hind legs. However, in Grades 3 and 4, the cat may be unable to fully extend their hind legs, often resulting in a visible deformity or a permanent change in how they walk.  

Causes of Patellar Luxation in Cats 

The causes of patellar luxation in cats can be categorized into three main factors: congenital abnormalities (present from birth), physical trauma or injury, or a combination of both. While this condition can affect cats of any breed, certain breeds are predisposed to it due to genetics, most notably the Devon Rex and the Abyssinian. 

Diagnostic Procedures for Patellar Luxation

The diagnosis begins with a thorough physical examination by a veterinarian, who will manually palpate the knee joint, rotate the ankle, and attempt to gently displace the kneecap to determine its stability. In addition, Digital Radiography (X-rays) is used to assess any bone deformities in the hind limbs and to evaluate for signs of joint inflammation (arthritis) or other secondary changes in the joint capsule 

Treatment Options for Patellar Luxation  

The treatment for patellar luxation can be either surgical or non-surgical, depending on the grade and severity of the condition. To ensure your cat receives the best care before the condition progresses to a more severe stage, it is crucial to seek professional advice early. If you notice your cat walking abnormally or showing any signs of pain, please bring them in for a veterinary consultation as soon as possible