The new configuration of cannulated hip screws for the fixation of femoral neck fractures: A biomechanical study
Abstract
Na takuatoong N
Femoral neck fracture is one of fracture that is frequently faced in our practice.In Pauwels 3, compression force is less but varus and shearing force is more. This cause more instability as angle of fracture line increasing.Although there is a number of studies about number, position, or direction of screws to make the strongest formation of im- plant to reduce the rate of fixation failure, but in the fact, there is no study that show the formation we accepted has enough strength to withstand the fixation failure espe- cially in Pauwels 3 and osteoporosis bone.The objective of this study is to study about biomechanics of two con- figuration of screws that is normal inverted triangle (con- ventional screw fixation; CFIX), and new configuration that make biplane screw support and penetrated more calcar (Double calcar cannulated screw fixation; DCCS). The axial stiffness was significantly higher in the DCCS group than the CFIX group(1755 Newton/mm vs 1130 Newton/mm, p = 0.03). The axial failure load was signifi- cantly higher in DCCS group than the CFIX group(1040 Newton vs 815 Newton, p = 0.04). The AP stiffness was comparable in the DCCS group and the CFIX group (4.95 Nm/degree vs 4.32 Nm/degree, p = 0.08)
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