Lady Gaga has been forced to cancel all 25 of the remaining US dates of the 'Born This Way Ball', after suffering a severe injury to her right hip that has been causing her chronic pain.A statement was posted on the 26-year-old star's official website on Wednesday (Feb 13), saying: "Live Nation Global Touring has confirmed that the remainder of the Lady Gaga 'Born This Way Ball' performances have been cancelled."After additional tests this morning to review the severity of the issue, it has been determined that Lady Gaga has a labral tear of the right hip. She will need surgery to repair the problem, followed by strict down time to recover. This unfortunately, will force her to cancel the tour, so she can heal. Refunds for the cancelled performances will be available at point of purchase starting Feb 14, 2013."The announcement came just one day after the singer issued a public apology after initially cancelling four shows due the injury and revealed she can barely walk due to the inflammation of her joints, known as synovitis.Gaga said: "I barely know what to say. I've been hiding a show injury and chronic pain for some time now, [and] over the past month it has worsened. I've been praying it would heal. "I hid it from my staff. I didn't want to disappoint my amazing fans. However, after last night's performance I could not walk and still can't."She admitted she is "devastated" about the cancellation and sought forgiveness from her fans, saying: "I hope you can forgive me, as it is nearly impossible for me to forgive myself. I'm devastated & sad. It will hopefully heal as soon as possible. I hate this. I hate this so much. I love you and I'm sorry."The world tour began in Seoul, South Korea on April 27, 2012 and was originally due to end in Tulsa, Oklahoma, on March 20, 2013.