Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Osteoarthritis ?
    ### Response:
    Osteoarthritis is the most common form of arthritis among older people. It affects hands, low back, neck, and weight-bearing joints such as knees, hips, and feet. Osteoarthritis occurs when cartilage, the tissue that cushions the ends of the bones within the joints, breaks down and wears away.
    