Wiiitis is real! It's a real term. I had it on Wednesday. It hurt more than "playstation thumb". :(
"When Dr. Julio Bonis awoke one Sunday morning with a sore shoulder, he could not figure out what he had done. It felt like a sports injury, but he had been a bit of a couch potato lately. Then he remembered his new Wii."
If you should get Wiiitis the treatment might be worse than the illness - it's ibuprofen for one week, as well as complete abstinence from playing Wii video games.