Niall "Slippers" Madden will have an operation after suffering a suspected fractured arm at Kilbeggan on Saturday evening.The Grand National-winning rider had stepped in for the injured Paul Carberry on Carlesimo, but his mount crashed out at the first fence of the Hackett's Bookmakers Handicap Chase.Madden's agent Andrew Kelly said: "He's only OK and it's suspected he's broken two bones in his arm from his elbow down to his hand, so he'll be operated on. He's going to be off a little while anyway so we'll see how the operation goes."