Interpretation of and discussion on AO/OTA-2018 fracture classification of femoral per/inter-trochanteric fractures

The value of fracture classification lies in describing fracture features, representing injury severity, guiding treatment choice and predicting outcomes. The OA/OTA fracture classifications system (its first edition in 1996 and its second edition in 2007) is accepted worldwide. Its third revised edition published in 2018 has completely renewed the classification of femoral per/inter-trochanteric fractures, in which the cortical lateral wall is used as the secondary key element to replace the former lesser trochanter. The new classification gives clear directions for selecting extramedullary side-plate fixation (e.g.dynamic hip screw, DHS) for intact lateral wall (31A1) and intramedullary nailing (cephalomedullary nail) for vulnerable (31A2) or broken lateral wall (31A3). This paper will interpret and discuss the new classification. We believe that this classification system will be more accurate with high inter/intra-observer agreement if more 3D-CT images are supplemented. Key words: Hip; Fractures, bone; Internal fixators; Femoral trochanteric fractures; Fracture classification; AO/OTA society