Ipsilateral femoral neck and shaft fractures. When do we need further image screening of the hip?

•Image protocols have been proposed to improve screening of femoral neck fractures combined with ipsilateral diaphyseal fractures.•However, adding further imaging protocols increases costs, adds time and demand health system resources whose availability may be limited.•The study aims to identify patterns of diaphyseal fractures on plain radiographs that are more associated with ipsilateral femoral neck fractures.•The main finding was the absence of AO/OTA 32 A1 and A2 femoral fractures when combined with the neck, during a ten-year observation period.•Additional image screening methods of the femoral neck may be unnecessary for AO/OTA A1 and A2 fractures. The objective of the present study was to identify patterns of femoral diaphyseal fractures which are associated with fractures of the ipsilateral femoral neck according to the AO classification. We propose an algorithm of investigation based on plain radiographs, recognizing cases that need additional screening with computed tomography. This observational retrospective study included patients with combined diaphyseal and femoral neck fractures. These patients were retrieved from a total of 1398 patients with the diagnoses of diaphyseal fractures of the femur, who were admitted to our hospital for surgical treatment between January 2009 and October 2019. All included cases had both fractures analyzed for their geometry and were classified according to the AO Classification, seeking to find a correlation between the types of fractures. Sixteen diaphyseal fractures associated with ipsilateral neck fractures were detected during the period. The distribution of the diaphyseal fractures according to the AO Classification was as follows: 5 of type A3 (31,2%) 6 type B2 (37.5%), 1 type B3 (6,2%), 2 type C2 (12,5%) and 2 type C3 (12,5%). One A2 femoral fracture occurred during the surgical procedure. No type A1 fractures were detected. The patterns of high-energy diaphyseal fractures (A3, B and C) have a higher prevalence of associated ipsilateral neck fractures. Our study suggests that routine additional methods of image investigation of femoral neck fractures may be unnecessary for diaphyseal fractures type A1 and A2.