|Muscles, Bones and Joints|
Cats seem to be able to tolerate a lot of things without complaint. Recent research has highlighted the fact that many cats are living with changes in their bones and joints that would have a doggie whining! We know cats are tough, but why is it that changes on X-rays that if found in a dog would leave that dog in serious discomfort don’t deter Kitty from getting around?
Part of the explanation rests with the fact that cats are lightweight. A typical dog with joint dysfunction (with some exceptions) is heavier than a cat. Having a low body weight means that the support system of bones and muscles is not taxed as much during movement.
Another difference between the two species has to do with flexibility. Watch your cat groom, play and sleep and it will be apparent that she has superior flexibility to any dog on the block! This is a saving grace for cats with musculoskeletal problems because they can bend around a problem area very nicely! Compare a young child versus a senior citizen where the flexibility of the joints system is obviously different—the young child enjoys great elasticity.
For example, the hips of cats are by nature more lax (or less tightly seated) than in dogs. That means that the normal ranges for the measuring indexes we use for dogs with hip dysplasia are not accurate for cats. In other words, a cat with a laxity index value we see in breeds of dogs typically prone to hip problems may not produce lameness problems in cats. Cat hips naturally “hang loose” compared with most dogs. Hip dysplasia has been thought of a doggie problem historically, but recent studies have exposed the truth—cats are not exempt from this condition.
Studies have shown that disorders of bones and joints are significantly under-diagnosed in cats. This is partly because if the owner does not observe problems at home, there is no complaint to bring to the attention of the veterinarian! During the physical examination, Kitty as usual is stoic and generally gives nothing away even if there are degenerative changes present! Finally, the index of suspicion is low on the part of veterinarians since if cats do not react to the manipulations of the physical examination, and are not limping or stiff, who’s to know! There is also a shortage of good research regarding musculoskeletal problems in cats, so the level of awareness about the true frequency of these problems is low.
Some cat breeds seem to be predisposed to problems. Examples include large framed cats like the Maine Coon. Because they weigh on average about twice the typical cat, the body weight factor comes into play when looking at loads on bones and joints. Not enough population studies have been done to accurately establish true prevalence, but preliminary findings are that the joints of the large framed cats are more likely to experience degenerative changes.
Small cats such as the Devon Rex and Abyssinian have also been found to have a high prevalence of hip dysplasia, displaced knee cap (luxating patella) and degenerative joint disease (DJD) in limited population studies. These cats usually look just fine, and act just fine, but the X-rays tell a story of unrecognized changes. Maybe it is their low body weight that saves them from developing lameness or showing obvious pain?
Many other conditions can affect the musculoskeletal system. Malformations (congenital, inherited), fractures, muscle enzyme defects, joint swellings due to infection/immune mechanisms, and traumatic dislocations are just some of these.
Cats with clinically significant muscle, bone and joint problems may be managed with surgery, rest and physiotherapy, and specific treatment for infection and inflammation if these processes are the source of the problem. Cats with chronic painful conditions such as osteoarthritis and degenerative joint disease are not able to be medicated with some of the standard therapies we use in dogs and people because of a quirk of their metabolism which makes many drugs toxic to cats. NSAIDs (non-steroidal anti-inflammatory drugs) such as acetaminophen, carprofen, ibuprofen and ketoprofen are not processed normally in cats, and should not be given at home for bone or muscle pain in felines.