Smith–Petersen, Marius Nygaard (1886–1953), American orthopedic surgeon. Smith-Petersen practiced orthopedic surgery in Boston. He had long-term associations with Massachusetts General Hospital and Harvard Medical School. In 1925 he introduced a three-flanged steel nail for insertion across the fracture site in hip fractures. This innovation reduced considerably the death rate from hip fracture and brought about successful unions of fragments in a greater percentage of the cases. To further improve hip disabilities he developed an operative procedure which involved placing a Vitallium alloy cup or mold between surgically reshaped joint surfaces. The operation was widely adopted from 1938 on.