1. Department of Physical Medicine and Rehabilitation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
2. Department of Orthopaedic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
3. Department of Biostatistics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
4. Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
5. Orthopedic Institute, Sioux Falls, South Dakota, USA
6. Department of Orthopaedic Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
7. King Edward VII Memorial Hospital, Hamilton, Bermuda