Orthopedic surgery or orthopedics (alternatively spelt orthopaedics), is the branch of surgery concerned with conditions involving the musculoskeletal system. Orthopedic surgeons use both surgical and nonsurgical means to treat musculoskeletal trauma, spine diseases, sports injuries, degenerative diseases, infections, tumors, and congenital disorders

Nicholas Andry coined the word in French as orthopédie, derived from the Ancient Greek words orthos ("correct", "straight") and παιδίον paidion ("child"), and published Orthopedie (translated as Orthopædia: Or the Art of Correcting and Preventing Deformities in Children in 1741. The word was assimilated into English as orthopædics; the ligature æ was common in that era for ae in Greek- and Latin-based words. As the name implies, the discipline was initially developed with attention to children, but the correction of spinal and bone deformities in all stages of life eventually became the cornerstone of orthopedic practice.

As with many words derived with the "æ" ligature, simplification to either "ae" or just "e" is common, especially in North America. In the US, the majority of college, university, and residency programmes, and even the American Academy of Orthopaedic Surgeons, still use the spelling with the digraph ae, though hospitals usually use the shortened form. Elsewhere, usage is not uniform; in Canada, both spellings are acceptable; "orthopaedics" is the normal spelling in the UK in line with other fields which retain "ae".