Background:Available research about the anatomic patts of intertrochanteric fractures is lacking,and fracture mapping has not previously been performed on intertrochanteric fractures.This study aimed to determine the major trajectories of intertrochanteric fracture lines using computed tomography data from a series of surgically treated patients.Methods:In this study,504 patents with intertrochanteric fractures were retrospectively analyzed.Fracture patts were graded according to Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification.Fracture lines were transcribed onto proximal femoral templates and graphically superimposed to create a compilation of fracture maps that were subsequently divided into anterior,posterior,lateral,and medial fracture maps to create a three-dimensional (3D) patt by reducing fragments in the 3D models.The fracture maps were then converted into frequency spectra.The major fracture patts were assessed by focusing on the lateral femoral wall,lesser trochanter,intertrochanteric crest,and inner cortical buttress.Results:Anterior,posterior,lateral,and medial fracture maps were created.The majority of fracture lines (85.9％,433/504) on the anterior maps were along the intertrochanteric line where the iliofemoral ligament was attached.In the medial plane,the majority of fracture lines (49.0％,247/504) shown on the frequency spectrum included the ting point involving the third quadrant.In the posterior plane,the majority of fracture lines (52.0％,262/504) involved the intertrochanteric crest from the greater to the lesser trochanter.In the lateral plane,the majority of fracture lines (62.7％,316/504) involved the greater trochanter at the gluteus medius attachment.Conclusions:The fracture patts observed in the present study might be used to describe morphologic characteristics and aid with management strategies.Further classifications or modifications that incorporate the fracture patts identified in this study may be used in future research.