Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Osteoarthritis ?
    ### Response:
    Osteoarthritis is the most common form of arthritis. It causes pain, swelling, and reduced motion in your joints. It can occur in any joint, but usually it affects your hands, knees, hips or spine.    Osteoarthritis breaks down the cartilage in your joints.
    