Mirpur - Paul Collingwood will undergo knee surgery after the World Cup, but remains available for the remainder of the tournament. He has been struggling since the one-day series in Australia and will now miss at least the beginning of the IPL next month following a keyhole operation once England's World Cup campaign is complete.Collingwood, 34, retired from Test cricket after the Ashes in January, and repeatedly said he wanted to prolong his one-day and Twenty20 career despite a prolonged slump in form. He was dropped for two of England's six group matches, and didn't play in the crunch game against West Indies last week, but remains the Twenty20 captain."Paul felt some discomfort in his left knee during the group stages of the World Cup, and a precautionary scan ahead of England's match against South Africa showed no significant damage," said the ECB's chief medical officer, Dr Nick Peirce. "However, further assessment suggests a loose piece of cartilage floating in his knee that will require surgical removal."We'll be able to establish a definitive rehabilitation timescale following surgery, but we expect Paul to make a full recovery in due course."Collingwood had been due to take up his deal with Rajasthan Royals shortly after the World Cup finishes, but that will now be on the back burner although an appearance later in the tournament remains a possibility.England play their quarter-final against Sri Lanka, in Colombo, on March 26 and despite his 197-match career Collingwood could again find himself on the sidelines after Luke Wright hit an important 44 against West Indies in his first appearance of the competition.The squad has been struck by a number of injury problems during the World Cup with Kevin Pietersen (hernia), Stuart Broad (side strain) and Ajmal Shahzad (hamstring) all returning home early.