Can playing piano the wrong way cause arthritis?

You should not worry about arthritis, depending on how you use your hands does not really cause arthritis, injury to a joint can cause arthritis. You should be more concerned with carpal tunnel. Playing the piano is like typing, more like a repetitive motion. Arthritis is usually caused by injury mostly in elderly people, Rheumatoid Arthritis is a disease that is progressive and is extremely painfull and is usually diagnosed by a Rheumatologist. So depending on your age, you should be just fine, just watch out for carpal tunnel