1. Department of Orthopedic Surgery, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
2. College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
3. Department of Orthopedic Surgery, King Abdulaziz Medical City, Riyadh, Saudi Arabia
4. Department of Orthopedic Surgery, King Khalid University Hospital, Riyadh, Saudi Arabia
5. Biostatistics Unit, Epidemiology and Scientific computing Department, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia