Müller AO Classification of fractures

The Müller AO Classification of fractures is a system for classifying bone fractures initially published in 1987[1] by the AO Foundation as a method of categorizing injuries according to therognosis of the patient's anatomical and functional outcome.

It is one of the few complete fracture classification systems to remain in use today after validation.

For segment 2 (diaphyseal) fractures: For segment 1 and 3 (epiphyseal and metaphyseal) fractures: Subgroups are then used to describe the fractures in terms of displacement (versus apposition, which is the degree to which the parts are in contact with each other), rotation, angulation and shortening.

A pediatric version of the long-bone classification was published in 2006[4] to further classify fractures of immature bone and so the effects on future growth: The Orthopaedic Trauma Association Committee for Coding and Classification initially published their classification system covering the whole skeleton in 1996.

[5] In 2006[6] they published a revision, unifying the Muller/AO and OTA systems into a single alphanumeric classification, which has been further updated in 2018:[7]