Calling all the Little Monsters: Mama needs you. Lady Gaga has cancelled the rest of her "Born This Way Ball" tour due to a hip injury that will need surgery, followed by a period of recovery. The singer is suffering from synovitis, a severe inflammation of the joints. Early on Wednesday, she tweeted that she could no longer walk after Monday’s performance in Montreal: "I hid it from my staff, I didn't want to disappoint my amazing fans."
