Osteoarthritis in the cat: 1. how common is it and how easy to recognise?

PRACTICAL RELEVANCE: Osteoarthritis (OA) is very common, particularly in older cats, but its clinical significance has largely gone unrecognised until recently. As in other species, OA is often painful and appropriate treatment is required to improve the animal's quality of life. Most cases appear to be primary or idiopathic. It is important for the clinician to actively seek these cases in the practice population. CLINICAL CHALLENGES: The recognition of chronic arthritic pain is a major challenge since most cats will not exhibit lameness. The main features of feline OA are changes in behaviour and lifestyle, which develop gradually and which owners tend to interpret as simply being the effects of old age. A meaningful physical orthopaedic examination can be difficult to achieve. A lack of familiarity with feline joint radiographs, and the fact that major cartilage pathology can be present in the absence of any bony change, mean that radiographic identification of OA in the cat can also be problematic. CLIENT QUESTIONNAIRE: The recognition of chronic arthritic pain in the cat is based on owner questionnaires designed to elicit information about changes in mobility, activity levels, grooming habits and general demeanour. EVIDENCE BASE: Several publications now report on the significance of behavioural and lifestyle changes as indicators of chronic arthritic pain in the cat. However, there is not as yet a fully validated owner-based questionnaire for recognising chronic pain in the cat. Furthermore, the aetiopathogenesis of feline OA still requires detailed investigation. Such studies are likely to make a major contribution to comparative rheumatology, since feline OA, more so than the canine disease, shows many similarities with human OA.