Osteoarthritis in cats: a retrospective radiological study

OBJECTIVES: To provide basic information about natural feline osteoarthritis (OA) as part of more extensive studies. METHODS: A retrospective study of cats (greater than one year of age) radiographed for any reason at a first opinion and referral veterinary practice was performed. Cats were classified as either having or not having radiographic OA. Computerised histories were searched for records of potential causes and clinical signs of OA. The genders and ages of the affected cats were compared with a control population using chi-squared tests. RESULTS: Of 491 cats, 292 (59 per cent) had undergone a diagnostic radiograph of at least one synovial joint. Sixty-three of 292 cats (22 per cent) showed evidence of radiographic OA; 21 (33 per cent) of which also had clinically evident OA. A potential cause of OA had been recorded in only seven of 63 cats (11 per cent). The population of cats with radiographic evidence of OA was older than the control population (P<0-001). CLINICAL SIGNIFICANCE: Radiographic OA was found in 22 per cent of the test population. In many cases there was no clinical evidence of OA recorded in the history, suggesting that either there is little correlation between clinical and radiographic OA or that clinical signs of OA in cats may not have been observed or recorded. Idiopathic/primary OA was common.