An algorithm for assessment of fracture displacement and pin positions in femoral neck fractures.
A method for determination of both the displacement of the femoral head and the position of the fixation device in fixed femoral neck fractures is described. In routine AP and lateral radiographs of the hip, measurements are made of femoral neck-shaft angle, the diameter of the femoral head and neck, the distances from the center of the femoral head to the femoral neck axis and the distances from the femoral neck axis to the fixating screws. From these values the position of the femoral head and the fixating screws are determined by geometric calculations. A computer program in Q-BASIC was devised to perform the calculations and to produce graphic displays of cross-sections of the femoral head and neck, with the displacement of the head and the screw positions indicated. The accuracy of the method was evaluated by a new method using axial radiographs of hip specimens, which were compared with the computer-plotted graphs of the femoral head and neck. The mean error of the method was found to be +/- 5% of the femoral head diameter, approximately 2.5 mm.
Lindequist
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Karolinska Institute, Department of Orthopedics, Huddinge Hospital, Sweden.
D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001858:Bone Nails; D005260:Female; D005265:Femoral Neck Fractures / Q000000981:diagnostic imaging* / Q000601:surgery; D005593:Fracture Fixation, Internal; D006621:Hip Joint / Q000503:physiopathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D004204:Joint Dislocations / Q000000981:diagnostic imaging; D008297:Male; D012399:Rotation; D012984:Software; D012985:Software Design; D014057:Tomography, X-Ray Computed