[Analysis of the "user friendliness" of the AO classification of fractures].

The AO-classification of long bone fractures has been introduced as a universal system and depends mainly on morphological characteristics and fracture-location. It includes the fracture severity and outcome and should be a basis for treatment. To evaluate the AO-classification in the "daily use", we were interested if this system is really userfriendly, where the problems of coding occur and which is the agreement in different codings of several surgeons in relation to segment, type, group and subgroup. 58 fractures were classified, totally we got 456 classifications. The agreement in relation to segment was 95%, to type 79%, to group 63% and to the subgroup only 45%. Endsegment-fractures had a better agreement than shaft fractures. Common mistakes are discussed and some "user-guidelines" are given.