Arthritis in Cats

Cartilage acts like a cushion between the bones in a joint, letting them glide past each other without pain. Arthritis develops when that cartilage becomes damaged and the joint grows inflamed and painful as a result. There are over 100 recognized forms of arthritis in humans; in cats, the most common by far is osteoarthritis, also known as degenerative joint disease. Less commonly, cats can also develop rheumatoid arthritis or septic arthritis, caused by a joint infection.

Arthritis tends to affect middle-aged and older cats most, though younger cats aren't immune to it. Because the condition often develops gradually alongside normal aging, it's easy for owners to write off early signs like a slight loss of playfulness as just "getting older," when their cat may actually be dealing with real, significant pain. This is especially true for cats, who are notably skilled at masking discomfort.

• Osteoarthritis

  Osteoarthritis is the most common form, largely caused by everyday wear and tear on the joint, though it can also follow an injury. It begins with cartilage damage, which, left unaddressed, eventually leads to the bones themselves wearing against each other. What starts as mild discomfort during activity can progress into constant pain, even at rest. Osteoarthritis most often affects weight-bearing joints but can involve joints of any size, and unlike rheumatoid arthritis, it's primarily a condition of older cats. There's no cure, but its progression can be slowed and managed. Physiotherapy that strengthens the surrounding muscles and joints can help, as can pain medication, and for some cats, weight loss meaningfully reduces the load on affected joints.

• Rheumatoid arthritis

  Rheumatoid arthritis happens when the immune system mistakenly attacks the body's own tissue, not just in the joint, but more broadly throughout the body. This leads to damage in the joint lining and cartilage, and eventually erosion of the bones that meet at the joint. Corticosteroids are among the medications used to manage this condition.

• Genetics

  Hip dysplasia is more commonly seen in Maine Coon, Persian, and Siamese cats; patellar luxation (a dislocating kneecap) is more common in Abyssinian and Devon Rex cats.

• Injury or Trauma

  Fractures, dislocations, and other joint injuries can alter joint development and function, often leading to secondary osteoarthritis.

• Obesity

  No evidence it directly causes arthritis, but it can significantly worsen an existing case.

Arthritis in cats is just as common as in dogs but far more likely to go unnoticed. One well-cited study found that over 90% of cats over 12 years old showed evidence of degenerative joint disease. The joints most commonly affected are the shoulders, hips, elbows, knees, and ankles (tarsi).

A veterinarian can diagnose arthritis through a physical exam, often supported by X-rays. In some cases, blood work or a sample of joint fluid may be needed to rule out infection as a cause.