Lady Gaga has cancelled the rest of her \"Born This Way Ball\" tour due to a long-standing hip problem that requires surgery. In a series of tweets, Lady Gaga said she had been hiding a show injury and chronic pain for some time and that it had become worse over the past month. \"I hid it from my staff, I didn\'t want to disappoint my amazing fans,\" she tweeted. The latest tweet described her condition as a case of synovitis, an inflammation of the joints. Tour operator Live Nation Global Touring said the superstar singer has a labral tear of the right hip. \"She will need surgery to repair the problem, followed by strict down time to recover,\" said a statement. \"This unfortunately will force her to cancel the tour so she can heal.\" Live Nation said refunds for the cancelled performances will be available starting Thursday. At the time of the announcement, Lady Gaga had 19 performances scheduled through March 20 at concert venues across the United States.