In general practice OA in cats still remains overall underdiagnosed disease although there is an increasing awareness for the disease in recent years leading to more cats being treated.
Osteoarthritis (OA) is a chronic disease characterized by loss of the smooth cartilage that covers and protects the end of the bones in a movable joint. When the cartilage wears away the bone is exposed and when the two bone ends in the joint touch each other it leads to pain and inflammation. In association, there are other abnormalities present that include new bone formation around the joint (osteophytosis) as a response to increased instability and inflammation in the joint also leading to pain.
In cats the primary cause of OA often times cannot be identified and is less well understood compared to dogs where it usually occurs secondary to some other abnormality (hip dysplasia, elbow dysplasia, cranial cruciate ligament disease). The joints most commonly affected in cats are the hip, stifle, tarsus, and elbow.
Due to their reluctance to be manipulated and held, cats are challenging to examine. Different types of performance tests are used to assess their mobility and impairment. In these tests cats are encouraged to walk from one side of the room to the other and they are placed on a chair and encouraged to jump down and jump up to get to the carrier. If they are resistant to jumping that may be an indication of pain and discomfort.
As in dogs, diagnosis of OA in cats is made by combination of physical exam and different imaging modalities such as X-rays. In cats, X-ray changes of OA are apparent in up to 90 percent of cats, with only an estimated 50 percent of these having clinical signs of impairment due to joint pain.
It can be challenging for clinicians to diagnose OA in cats, especially if the physical exam is difficult to perform or in some instances unremarkable. Nonetheless management should include attempting to improve cat’s living environment and minimizing stressful situations.