1. Division of Rheumatology; Philadelphia Veterans Affairs Medical Center; Perelman School of Medicine; University of Pennsylvania; Philadelphia Pennsylvania
2. Department of Orthopedic Surgery; Thomas Jefferson University; Philadelphia Pennsylvania
3. Department of Orthopedic Surgery; Rush University Medical Center; Chicago Illinois
4. Department of Orthopedic Surgery; Perelman School of Medicine; University of Pennsylvania; Philadelphia Pennsylvania
5. Department of Biochemistry; School of Dental Medicine; University of Pennsylvania; Philadelphia Pennsylvania
6. Philadelphia Veterans Affairs Medical Center, and Department of Physical Medicine and Rehabilitation; Perelman School of Medicine; University of Pennsylvania; Philadelphia Pennsylvania