Figure 2: A) Preoperative radiograph of a patient with ankylosing spondylitis. The left hip has bony ankylosis, while the right hip has fibrous ankylosis. B) A Hip resurfacing Arthroplasty [Birminghan mid head resection implantTM (Smith and Nephew)] has been done on the right hip and Cementless THA [R3 cup-Synergy stemTM (Smith and Nephew) implanted in the left hip].