Title : Anatomical structure and radiographic parameters as predictor of hip fracture: An update look
Abstract:
There is increasing evidence that the geometric structure of hip anatomy plays an important role in the etiology of fractures. Most publications agree that there is an association between an increase in the degrees of the neck shaft angle (NSA) and a 4.87 percent higher risk of hip fracture in patients who have already experienced a fracture. According to theoretical biomechanics, it is concluded that the greater the angulation of a lever (which translates in anatomy as a decrease in degrees between its components), the resistance of the lever decreases, resulting in an area of weakness in the angulation. However, despite this logical conclusion, the evidence provided by research directly associating the dimensions of this angle with the presence of hip fractures has shown the opposite. These weaknesses in the angulation are resolved by the nature of the bone. The internal structure of the proximal portion of the femur distributes loads through the trabeculae, which form the framework of the spongy bone substance specific to this region. The lines of forces and tension and their arrangement from the coxal to the femur evaluating the hip as a joint, as well as the thickness of the cortex and calcar of the femur, in its association with hip fracture, consequently, being the density bone and the geometric anatomical components of the bone, both at the macroscopic and microscopic levels, which determine the strength of the bone are, therefore, the most analyzed to predict the sensitivity to the occurrence of fractures.
Is important too the notable difference between the NSA values according to gender, the female sex being lower than those of the male sex in the majority of published works. This characteristic confirms the structure with a tendency to varism in the hips of women, the increase of one standard deviation of the NSA is associated with the increase in the risk of fracture, related to an odds ratio of hip fracture of 2.45 in men and 3.48 in women, and more frequent in this female gender in a proportion of 2.5. On the other hand, the tendency to increase in degrees of this angle is related to the increased risk of hip fracture. Therefore, the authors consider that, in justifying the higher frequency of hip fracture reported in women, the anatomical characteristic of the varus arrangement of the hip in women should not be included as a risk factor for suffering from hip fracture.
Other measurements analysed were the femoral axis, hip axis, the length and width of the femoral neck, as well as acetabular measurements. A consent doesn't exist, in the measure of the long one of the femoral neck or of the femoral axis, in spite of being an important component of the structure. The characteristics of the structural components of the bone, both in their internal configuration as in the external one, prove there is association between the dimensions of anatomic structures of the articulation of the hip and the susceptibility to fractures.
