Actually, osteopathic medicine (the D.O. degree) is precisely analogous to allopathic medicine (the M.D. degree), in that doctors of osteopathic medicine perform surgery, prescribe drugs, and are completely indistinguishable from their M.D. counterparts except in name only.
Osteopathy and allopathy are two forms of medicical education in the US that both result in a doctor of medicine degree.
Osteopathy is not compltementary medicine. It is medicine: surgeons, primary care, specialists.