River Plate midfielder Diego Buonanotte has undergone surgery on a broken right arm, an injury that occurred when a car he was driving on Dec. 26 crashed, killing the three other people in the vehicle. Doctors at Los Arcos hospital in Buenos Aires said the 21-year-old Buonanotte, considered River Plate's player, had responded well to Wednesday's surgery but it was expected to take 48 hours to give him the all clear. He is likely to be sidelined for seven months. Buonanotte has been hospitalized since the accident. He also had a broken collarbone and chest injuries. 