Objective

To ascertain if the prevalence of feline osteoarthritis (OA) increased between the 1970s and 1990/2000s. The recent interest in feline OA might be due to a true increase in prevalence or increased awareness of the presence of the condition.

Method

A sequence of 100 cats euthanatized at the Beaumont Animal Hospital, Royal Veterinary College, London, UK in 1970-73 had a series of radiographic images made of their skeletons. In 2007 this set of radiographs was read by two radiologists and each joint was allocated into a set with or without OA by the presence or absence of an osteophyte. Grading into more or less severe OA was judged by the size of the osteophyte and the presence of other features of degenerative joint disease. Additional skeletal abnormalities were noted. Basic clinical data from the cats were also available and age, sex and reason for euthanasia were recorded.

Results

The prevalence of OA in these 100 cats was 57%. This is higher than in comparative studies all of which included cats living more recently. The average age of the cats with OA was 10.1 years (1-22 years) and the median age was 10 years. The average age of the cats without OA was 4.7 years (1-21 years) and their median age was 2 years. This difference was significant (p<<0.001). Of the cats with known histories, 71% were male and only 44% of both sexes had been neutered. The prevalences of OA in each joint were: shoulder 21%, elbow 24%, carpus 3%, hip 34%, stifle 19%, tarsus 17%.

Eleven% of cats had a supinator sesamoid, 10% had hip dysplasia and 26% had meniscal mineralization with no other feature indicating degenerative joint disease of the stifle.

Clinical Significance

There is no evidence that feline OA is a "novel" disease. Rather, it is likely that recent interest in the condition has derived from more attention being paid to the diseases of cats. The prevalence of OA in cats may vary according to the population studied. The prevalence in this population of inner-city cats, with a low standard of care, as evidenced by relatively infrequent neutering, and living in a man-made environment, was higher than in previous studies of cats that presented to referral institutes or a suburban feline-only practice.