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With the aging of society, the increasing number of osteoporosis intertrochanteric fractures in the elderly probability of an upward trend. Traditional treatment bed traction, high incidence of mortality in patients with varus. From the clinical use of fractures with open reduction and internal fixation, the mortality rate was significantly lower cure rate was significantly improved. Through clinical observation, but we often use three methods (gamma-nail, Richard nails, AO plate), due to fixture unstable, nail plate from the broken fixtures have occurred, leading to fracture displacement, causing nonunion or malunion, the treatment effect is not satisfactory. Therefore, the study of proximal femoral trabecular bone anatomical structures designed truss structure with which to adapt fixtures are important for guiding clinical surgery, reduce complications. The experimental samples using of fresh cadavers femur in 25 cases, the specimen sorting, measuring the specimen geometry. First, the use of the PQ2000 computer tomography (CT) scan of the femur on segment level, a thickness of 2 mm. Second, random 20 the femur specimens imitation Evan's femur intertrochanteric femur classification, artificial fracture. Were randomly divided into a fixed group of the truss structure, gamma-nail fixation group, Richard screw fixation group, AO plate fixation group, a total of four groups of five specimens each, compared with the normal specimen group, by universal testing machine compression test . CT: The results show that cross-integration with the tension of trabecular bone in the femoral head center position; by the the trabecular beam radiation from the the lesser trochanter leading edge of the medullary cavity to the greater trochanter outside, with the rise of the plane, the trabecular bone gradually concentrated, convex to the medullary cavity formed calcar and tension of trabecular bone in multi-point, multi-faceted harmony and harmony are more concentrated in the greater trochanter of the posterolateral region. Load experimental results show that: (1) truss structure torsional strength, stiffness, than Richard's nail, of AO steel strength 29% and 54% (p lt; 0.05); gamma-nail and the original bone, and torsional stiffness high 36% and 46% (p lt; 0.05), proof of the truss structure torsional deformation are strong, a great help to fracture fixation stability. (2) truss structure limit superior mechanical properties than Richard's nails, of AO steel plate by 16% and 29% higher. Load capacity up to 3046N quite gamma nail, the original bone. ⑶ under the action of the load of 1200N, fracture cross-section opening angle alpha size change: Richard's nails, AO steel open angle larger than the truss structure 26% and 40% (p lt; 0.05), compared with the gamma-nail, both no significant difference (p gt; 0.05), high tensile strength truss structure. (4) truss structure stress shielding rate of only 17.39%, than Richard's nails, AO steel is 22% smaller and 18%, the gamma nail stress shielding rate as high as 26%, it will help prevent varus and delayed fracture healing. Truss structure fixed equipment than Richard's nail, gamma-nail, AO steel fixing performance advantages, superior mechanical properties. Therefore, we draw the following conclusions: the trabecular bone of the proximal femur plays a very important role in the maintenance of the proximal femur structure; treatment of intertrochanteric fracture internal fixation in the proximal femur biomechanical structure designed truss structure, effective internal fixation device.
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