Arthritis - the xray on the left shows normal knee joints ( stifles) of a cat and the xray on the right shows arthritic stifles of an older cat. The arthritic xray shows extra bone formation around the joint which is the bodies attempt to stabilize the joint. Signs of arthritic joints can be altered gait, stiffness, reluctance to jump up and sometimes not using the litterbox if it is causing the cat some pain - i.e. down flights of stairs, elevated, or with a high lip around it. Cats may never show signs of arthritic joints and it can be found with an annual wellness exam or in a routine xray.