Classification of trochanteric fracture of the proximal femur: a study of the reliability of current systems

Five observers using the Jensen modification of the Evans classification and the AO classification (with and without subgroups) classified the radiographs of 88 trochanteric hip fractures. Each observer classified the radiographs independently on two occasions 3 months apart. Kappa statistical analysis was used for determination of intra- and inter-observer variation. For the Jensen classification, the mean kappa value was 0.52 (range: 0.44–0.60) for intra-observer variation and 0.34 (range: 0.17–0.38) for inter-observer variation. For the AO system with subgroups, the mean kappa value was 0.42 (range: 0.20–0.65) for intra-observer variation and 0.33 (range: 0.14–0.48) for inter-observer variation. For the AO classification system without subgroups, the mean kappa value was 0.71 (range: 0.60–0.81) for intra-observer variation and 0.62 (range: 0.50–0.71) for inter-observer variation. We recommend classifying trochanteric fractures into three groups as that of the AO system without the subgroups. For ease of use, these three groups may be termed stable trochanteric, unstable trochanteric and trans-trochanteric. Neither the Jensen classification nor the AO classification with subgroups is an acceptable classification system for trochanteric hip fractures.