You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Primary osteoahritis affect all except: and explain in detail?
Osteoahritis involves DIP and PIP with sparing of MCP. Rheumatoid ahritis involves PIP and MCP with sparing of DIP. Osteoahritis commonly involves knee joint in India. Hip joint is rarely involved in osteoahritis.