Having been born and raised in England, I can attest to the fact that we British folk love our vowels, i.e. colour, honour, catalogue, and dialogue. When my family moved to the United States, I was an exceptionally confused seventh grader – with zero cultural American knowledge, a very different vocabulary, a skirt that was far longer than anyone else’s, and an accent that made it impossible to be a wallflower.
Luckily for me, I escaped grade school unscathed, and I learned very quickly that there are some general rules concerning the differences between British English and American English. One such rule governs the oft-puzzling interchangeability of Orthopedic vs. Orthopaedic.
Many words are written with ae/æ or oe/œ in British English, but a single e in American English, such as paediatric, anaemia, anaesthesia, and orthopaedic. Curiously, however, The American Orthopaedic Association uses the British form rather than the American. Orthopaedic is thus considered appropriate for more formal usage than the American spelling.
As to the origin of the word itself, Nicholas Andry is credited with coining the word in 1741. Derived from Greek words for “correct” or “straight” (“orthos”) and “child” (“paidion”), it was included in the title of Andry’s book, Orthopaedia: or the Art of Correcting and Preventing Deformities in Children.