An orthopedist is a doctor who specializes in diagnosing and treating disorders of the musculoskeletal system. This includes bones, joints, ligaments, tendons, muscles and nerves. They can treat conditions such as fractures, dislocations, sprains and strains, arthritis, osteoporosis and scoliosis. Orthopedists may also perform surgical procedures to repair or replace damaged tissues. For example, they can repair a torn ACL or replace a joint altogether.   Orthopedists use various treatments such as medication, physical therapy and exercise to help their patients stay mobile and improve their quality of life. They may also recommend lifestyle changes such as improved diet and increased activity levels to aid in recovery.