1. Total Knee Arthroplasty in Patients with Ankylosing Spondylitis by Javad Parvizi, Gavan P. Duffy, and Robert T. Trousdale J Bone Joint Surg Am Volume 83(9):1312-1316 September 1, 2001 ©2001 by The Journal of Bone and Joint Surgery, Inc.

2. Anteroposterior (Fig. 1-A) and lateral (Fig. 1-B) radiographs of a fifty-one-year-old man with ankylosing spondylitis show heterotopic ossification (arrow) four years postoperatively. Javad Parvizi et al. J Bone Joint Surg Am 2001;83:1312- 1316 ©2001 by The Journal of Bone and Joint Surgery, Inc.

3. Anteroposterior (Fig. 1-A) and lateral (Fig. 1-B) radiographs of a fifty-one-year-old man with ankylosing spondylitis show heterotopic ossification (arrow) four years postoperatively. Javad Parvizi et al. J Bone Joint Surg Am 2001;83:1312- 1316 ©2001 by The Journal of Bone and Joint Surgery, Inc.