MUMBAI, OCT 10: A knee-replacement surgery was performed on Prime Minister Atal Bihari Vajpayee at the Breach Candy hospital in South Mumbai this morning.The operation, which began at 0930 hrs, lasted about one-and-a-half hour, hospital sources said. New york-based orthopeadic surgeon Chittaranjan Ranawat and his team of surgeons here performed the knee transplant.Union Home Minister L K Advani and Information Technology minister Pramod Mahajan were present in the hospital.