Simplify the following text for a Grade 12 native English-speaking person.
Original: The powerful performance of Landis up to stage 16 of the Tour de France and his comeback in stage 17 is particularly notable given his hip ailment , osteonecrosis , which was revealed in an article in The New York Times during the 2006 Tour de France .
Simplified: Landis performance up to Stage 16 of the Tour de France and his comeback in Stage 17 is surprising because of his hip ailment , called osteonecrosis , which was revealed in an article in The New York Times during the 2006 Tour de France . .