股骨粗隆间骨折内固定课件.ppt

* * (A) Among adults (age range c.20 to 64 years): (1) the superolateral femoral neck cortex is half as thick as the inferomedial cortex in both sexes(31,68); (2) there is a similar average femoral neck cortical thickness in both sexes(52); and (3) the male femoral neck remains one‐third larger in cross‐sectional area than in women throughout life.(52,53) (B–C) Among older adults (age range65 years) of both sexes: (1) the superolateral cortex shows three times faster thinning with aging than the inferomedial cortex(54); (2) women have two times faster cortical thinning with aging than men(54); (3) the weight‐loaded inferomedial cortex is preserved in both sexes(31,35,54); (4) only one‐half of young adult trabecular bone density remains in the very old(31,52); and (5) very old men have 10% larger femoral neck medullary area and 5% less cortical bone than old men.(66) The femurs were courtesy of the Melbourne Femur Collection, Chairman Professor John Clement (Melbourne Dental School). Traffic sign images are UK crown copyright. * * For the internal fixation system, there are two categories: extramedullary or intramedullary. * For the internal fixation system, there are two categories: extramedullary or intramedullary. * * * Normally, a vertical force passing from the center of the femoral head tends to move the affected hip into varus as soon as the patient is mobilized. This leads to normal sliding of both proximal screws achieving the expected compression at the fracture site. In some cases this sliding occurs only to one of the proximal screws, while the other remains in its initial position leading to penetration of the femoral head. The reverse Z-effect is characterized by movement of the sliding screw towards the lateral side. The mechanism is similar, but the sliding screw is sliding back, whereas the neck screw remains impacted to the hole of the nail.72,73 * Normally, a vertical force passing from the center of the femoral head tends to move the affected hip