Bilateral knee osteoarthritis. X-ray of the legs of a female 60-year-old patient with knee pain resulting from osteoarthritis (OA). The scan shows bilateral narrowing of the knee joint (at the tibial plateau, upper part of the shinbone), which suggests the patient has bilateral osteoarthritis (affecting both knee joints). Osteoarthritis is a joint disease resulting from the breakdown of joint cartilage (connective tissue) and the underlying bone. It often affects the large weight-bearing joints, such as the hips and knees, as well as the hands, feet and spine of patients. This patient experienced knee pain when walking and when static.