1. Tri-State Specialists, LLP, Sioux City, IA, USA
2. Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
3. Twin Cities Orthopedics, Burnsville, MN, USA
4. Department of Orthopedic Surgery, Washington University in St. Louis, Chesterfield, MO, USA