Clinical Prognostic Analysis Of The Correlation Between The Mechanism Of Injury Of Femoral Neck Fracture And Body Imaging Study

Femoral neck fracture, whose incidence rate is3.6%,is a common fracture and more common in elderly patients, mainly due to the many elderly people having osteoporosis, even slight violence can also lead to fracture. Femoral neck fracture increases every year, mostly due to severe trauma. Recent years, with the fixation techniques improving and materials changing, femoral head necrosis and collapse rate has not decreased significantly. As lack of blood supply can not fully explain the mechanism of femoral head necrosis, more and more scholars emphasize that the biomechanical factor plays a crucial role in the necrotic process. Regrettably, the structure of the hip is complex, and the vast patients injured is not very clear about the external force and the position, so on the issue of mechanism of injury and trabecular bone morphology didn’ t reach consensus.A separate X-ray doesn’t tell the correlation between fracture and internal trabecular bone. This study attempts to investigate the intrinsical correlation between femoral neck fracture mechanism of injury and the trabecular bone structure from CT, providing some evidences to explain the nonunion and femoral head necrosis after femoral neck fracture. The positive significance is to guide clinical judgment of prognosis and select the treatment. Objective To explore the correlation between injury mechanisms of femoral neck under-head-type fracture and the structure of trabecular bone and provide evidences explaining the nonunion and the osteonecrosis of femoral head resulting from femoral neck fracture.Methods The clinic and imageology datas of120cases with femoral neck under-head-type fractures were admitted from Feb.2010to Otc.2011in Chinese traditional medicine hospital of Hubei Province and Zhongnan hospital of Wuhan University and were studied retrospectively from the images of coronal, sagittal, horizontal plane and3D CT combining with the structure of trabecular bone as well as the Mechanics analysis of the fracture. Evaluate the force of the fracture fragments.Results83.3%cases’fracture lines follow the lateral of main pressed trabecular bone (medial of ward’s triangle) on the coronal CT.88.3%cases’fracture lines go along the junction of femoral head and neck on the horizontal CT. About90.8%cases’fracture have an angulation forward with femoral head displaced backward on sagittal CT.Conclusion "anterior tensile stress posterior compressive stress" Femoral neck Under-head-type fracture with bill cortical bone goes along the trabecular bone and the two rarefied area. This kind of fracture is extremely instability and very common, what is important for the clinical judgment of prognosis and treatment choice.