The Arbeitsgemeinschaft für Osteosynthesefragen (AO), also known as the Orthopaedic Trauma Association, is a Swiss–German organization dedicated to the advancement of fracture management. In English, AO translates to the “Association for the Study of Internal Fixation.”
The AO Classification System provides a standardized and systematic approach to describing fractures, improving communication, research, education, and clinical decision-making worldwide.
The AO Adult Fracture Classification is designed for skeletally mature patients and covers all major long bones and anatomical regions using a structured alphanumeric system.
The AO Paediatric Fracture Classification accounts for growth plates, age-dependent bone structure, and unique fracture patterns seen in children and adolescents.