1. Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA.
2. Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
3. Department of Orthopedic Surgery, Hospital for Special Surgery, New York, NY, USA.
4. Department of Orthopedic Surgery, University of North Carolina, Chapel Hill, NC, USA.
5. Department of Orthopedic Surgery, Lankenau Institute for Medical Research and Pennsylvania Orthopedic Center, Exton, PA, USA.
6. Department of Orthopedic Surgery, Penn Presbyterian Medical Center, University of Pennsylvania, Philadelphia, PA, USA.