Osteoarthritis of the knee joint. Composite image of a coloured magnetic resonance imaging (MRI) scan and an X-ray of the knee of a 58-year-old patient with tibiofemoral osteoarthritis. There is a localized lesion of the external tibiofemoral cartilage (connective tissue around the knee joint, where the tibia meets the femur). Osteoarthritis is a joint disease resulting from the breakdown of joint cartilage 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. Osteoarthritis causes joint pain and stiffness, and so as the disease progresses, walking becomes more painful, and movement patterns (gait) are typically affected. This is a 2D fast spin echo (FSE) MRI scan.