1. Feinberg School of Medicine, Northwestern University, Chicago, IL 60208, USA
2. College of Medicine, Northeast Ohio Medical University, Rootstown, OH 44272, USA
3. Campbell University School of Osteopathic Medicine, Lillington, NC 27546, USA
4. Department of Orthopedics and Rehabilitation, University of Iowa, Iowa City, IA 52242, USA
5. Department of Orthopaedic Surgery, Duke University, Durham, NC 27708, USA
6. Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI 48109, USA