1. Departments of Physical Medicine and Rehabilitation and
2. Orthopedics, Hospital Provincial de Rosario, Rosario, Argentina;
3. Department of Physical Medicine and Rehabilitation, University of Kansas Medical Center, Kansas City, Kansas;
4. Department of Physical Therapy, Instituto Universitario del Gran Rosario, Rosario, Argentina;
5. Department of Physical Medicine and Rehabilitation, Dell Children's Medical Center, Austin, Texas; and
6. Department of Biostatistics, University of Kansas Medical Center, Kansas City, Kansas