The fundamental principle of this classification is the division of all fractures of a bone segment into three types and their further subdivision into three groups and their subgroups, and the arrangement of these in an ascending order of severity according to the morphologic complexities of the fractures, the difficulties inherent in their treatment, and their prognosis. Which type? ... Which group? ... Which subgroup? ... These three questions, and the three possible answers to each, are the key to the classification.
The 3 types are labelled A, B, and C. Each type is divided into 3 groups: A1,A2, A3 - B1, 82, B3 - C1, C2, and C3. Thus, there are 9 groups. As each group is further subdivided into 3 subgroups, denoted by a number:.1,.2, and .3, there are 27 subgroups for each segment. The subgroups represent the 3 characteristic variations within the group.The colours green, orange and red, as well as the darkening arrows, indicate the increasing severity: Al indicates the simplest fracture with the best prognosis and C3 the most difficult with the worst prognosis. Thus when one has classified a fracture one has established its severity and obtained a guide to its best possible treatment.