Orthopaedic surgery is a branch of surgery concerned with conditions involving the musculoskeletal system. Orthopaedic surgeons use both surgical and nonsurgical means to treat musculoskeletal trauma, sports injuries, degenerative diseases, infections, tumors, and congenital disorders. Many developments in orthopedic surgery resulted from experiences during wartime. While orthopaedic surgeons are familiar with all aspects of the musculoskeletal system, many orthopaedists specialize in certain areas, such as the foot and ankle, spine, hip or knee. They may also choose to focus on specific fields like pediatrics, trauma or sports medicine.