Orthopedics, branch of surgery devoted to the diagnosis and treatment of illnesses, injuries, deformities, and malformations of the musculoskeletal system, including bones, joints, ligaments, muscles, and tendons. Orthopedists thus treat traumatic injuries to bones, such as fractures and dislocations; disturbances in joints, such as sprains, torn cartilages, or strained ligaments; and inflammation of muscle or connective tissues, such as bursitis, myositis, and tendinitis. They also treat back problems, such as strains, ruptured discs, or curvatures; foot problems, such as flat feet or high arches; and neck disorders, such as strains or arthritis. Surgeons employ mechanical appliances, such as braces, splints, and casts, and in surgical procedures extensively use hardware such as screws, pins, nails, and bolts and nuts, particularly in repairing broken bones. In the 20th century open operations are performed freely; many deformities are cured by operative means alone; and improved X-ray techniques have made the diagnosis of bone and joint lesions more exact and the results of treatment more satisfactory. The transplantation of bone, fascia, muscle, and tendon for the restoration of function to, or the replacement of, destroyed tissue and even the use of newly devised metal prostheses to replace arthritic joints are now commonplace.