American Airlines flight 2760 encountered turbulence while descending through 7,000 ft to land at Chicago O’Hare International Airport (ORD), Chicago, Illinois, and a flight attendant fractured her kneecap. The captain was the pilot flying and the first officer was monitoring. The flight was in day visual meteorological conditions (VMC), and the weather radar was on, with no signs of convective activity ahead. The captain made the announcement to the cabin crew to prepare for landing and the seatbelt sign was illuminated. The flight crew stated that ATC informed them that between HIHRY and RINNO intersections there were reports of moderate turbulence. The captain called the No. 1 flight attendant to inform her that in five minutes there was the possibility of turbulence, “likely moderate chop”, and for her to inform the rest of the cabin crew. At 7000 ft the flight encountered about 2 to 3 brief moments of moderate turbulence, but the remainder of the flight was smooth. While taxiing to the gate the flight crew was informed that the No. 1 flight attendant, who had been walking through the aisle to prepare for landing, had fallen to her knees because of the turbulence. The flight attendant was taken to the hospital where she was diagnosed with a fractured kneecap.