Osteoarthritis in Cats

Laurie Anne Walden, DVM

Public domain image from pixy.org

Osteoarthritis is very common in cats but often goes undetected. In most cats, joint pain doesn’t cause obvious signs like limping. Instead, it causes changes in mobility and behavior that can be misinterpreted as normal aging. Cat owners’ recognition of these changes is the first step in diagnosing and relieving joint pain.
 
Cause
Osteoarthritis is a chronic disease in which the protective cartilage in a joint wears down. Eventually the bones and other structures in the joint deteriorate, causing pain that worsens over time. Degenerative joint diseases like osteoarthritis can be caused by trauma or by problems with the structure of a joint, but often the cause is not known.
 
Senior cats are by far the most likely to develop osteoarthritis. Younger cats can be affected too. Osteoarthritis in cats most often involves the hips, elbows, knees, and hocks. Cats can also develop degenerative joint disease in the spine. Various studies have shown that between about 60% and 90% of cats have evidence of degenerative joint disease on radiographs (x-ray images).[1-3] Not all of these cats have pain, though, at least not at first.
 
Signs
In cats, signs of joint pain are subtle. Cats tend to hide signs of pain. Osteoarthritis often affects joints on both sides of cats’ bodies, so they don’t develop lameness—it’s hard to limp with both front legs or both rear legs at the same time. Signs of osteoarthritis in cats reflect their limited mobility, reduced activities of daily living, and general grumpiness caused by chronic pain:

• Reluctance to jump up or down
• Missing jumps or jumping less high than usual
• Slowness or difficulty going up or down stairs
• Stiff movements unlike the usual fluid movements of a healthy cat
• Urinating or defecating outside the litter box
• Sleeping or resting more than usual
• Lying in the same spot longer than usual
• Playing less than usual
• Matted or unkempt coat caused by grooming less than usual (some cats overgroom painful areas)
• Overgrown or flaky claws caused by scratching less than usual
• Avoiding interaction with people or other animals
• Spending more time alone
• Intolerance to being petted
• Intolerance to contact with other animals[4]

 
Diagnosis
The most important diagnostic tool is cat owners’ observations of signs of joint pain at home. Treatment is often started just on the basis of behavior changes consistent with pain. Cat owners can use questionnaires like the Feline Musculoskeletal Pain Index (https://painfreecats.org/) to record and score their cats’ signs of pain. These assessment tools help veterinarians diagnose joint pain and are also very useful to track changes over time and monitor response to treatment.
 
Cats with signs of pain should receive a physical examination to be sure the signs are caused by joint or back pain and not by something else. A full orthopedic examination of a cat is challenging (sort of like examining an uncooperative bowl of jello that doesn’t tell you when it hurts and won’t trot on leash), but sometimes an examination reveals joint thickening or other physical changes of osteoarthritis. Radiographs can show evidence of degenerative joint disease but aren’t always needed. The decision to use imaging depends on the individual cat.
 
Treatment
Never give a cat pain medication, including nonprescription over-the-counter remedies, without consulting a veterinarian. Some medications that are safe for people and dogs are very dangerous for cats.
 
In cats, joint pain is managed with a combination of nondrug and drug treatments. A multimodal approach (using several strategies) tailored to each cat’s pain level and living conditions is the best way to help relieve chronic pain in cats.
 
Nondrug treatments include weight management, adjunctive therapies like acupuncture, dietary supplements such as glucosamine, and environmental modifications like ramps, steps, soft bedding, and litter boxes with low sides. Drug options are more limited for cats than they are for dogs, but a number of drugs are available. A new injectable treatment for osteoarthritis pain avoids the need to give a cat a pill by mouth.[3]
 
References
1. Lascelles BD, Henry JB 3rd, Brown J, et al. Cross-sectional study of the prevalence of radiographic degenerative joint disease in domesticated cats. Vet Surg. 2010;39(5):535-544. doi:10.1111/j.1532-950X.2010.00708.x
2. Slingerland LI, Hazewinkel HA, Meij BP, Picavet P, Voorhout G. Cross-sectional study of the prevalence and clinical features of osteoarthritis in 100 cats. Vet J. 2011;187(3):304-309. doi:10.1016/j.tvjl.2009.12.014
3. Gruen ME, Myers JAE, Lascelles BDX. Efficacy and safety of an anti-nerve growth factor antibody (frunevetmab) for the treatment of degenerative joint disease-associated chronic pain in cats: a multisite pilot field study. Front Vet Sci. 2021;8:610028. doi:10.3389/fvets.2021.610028
4. Bennett D, Zainal Ariffin SM, Johnston P. Osteoarthritis in the cat: 1. How common is it and how easy to recognise? J Feline Med Surg. 2012;14(1):65-75. doi:10.1177/1098612X11432828
 
Image source: https://pixy.org/6310117

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