The choice of internal fixator for fractures around the femoral trochanter depends on area classification

PURPOSE In femoral trochanteric fractures, fractures whose fracture lines extend to the basal neck or to the subtrochanteric part have high instability. Area classification can identify such instable fractures. The best choices of internal fixators for femoral trochanteric fractures were investigated according to area classification. METHODS Femoral trochanteric fractures were investigated with respect to area classification. In area classification, the proximal femur is divided into 4 areas with 3 boundary lines: Line-1 is the center of the neck; Line-2 is the border between the neck and the trochanteric zone; and Line-3 links the inferior borders of the greater and lesser trochanters. A fracture in only the third area was classified as type 3; one in the second and third areas was classified as type 2-3. RESULTS Of 284 femoral trochanteric fractures, 50.0 % were type 3, 21 % were type 2-3, 22 % were type 3-4, and 7.4 % were type 2-3-4. Cases with cut-out or excessive telescoping of the internal fixator were defined as the Failure-group; 5.3 % of type 3 and 10.9 % of type 2-3 were in the Failure-group only when short femoral nails with a single rag screw were used. On the other hand, there were no Failure-group cases of type 2-3 with double rag screws. Only 1 case involved a long nail for type 3, while a long nail was used in about half of type 3-4 cases (Chi square test: P < 0.0001). CONCLUSIONS A double rag screw should be considered for type 2-3. A long nail should be considered for type 3-4.