1. Department of Osteoarticular Rehabilitation, Instituto Nacional de Rehabilitación, México, D.F., Mexico;
2. Postgraduate Division, Instituto Nacional de Rehabilitación, México, D.F., Mexico;
3. Department of Investigation, Instituto Nacional de Rehabilitación, México, D.F., Mexico;
4. Department of Orthopedic Rehabilitation, Instituto Nacional de Rehabilitación, México, D.F., Mexico