NEW YORK (ES)Lady Gaga has undergone hip surgery. The ‘Bad Romance’ hitmaker recently cancelled her ‘Born This Way Ball’ tour and revealed she is using a wheelchair after contracting a painful injury and inflammation of her joints, known as synovitis, and has now gone under the knife to help her back to health. She tweeted on Wednesday: ‘’Going in for surgery now. Thank you so much for sending me love and support. I will be dreaming of you.’’