Structural Peculiarities of the Proximal Femur Meta- Epiphysis in the Idiopathic Coxarthrosis According to Localization

Background: The hip essentially represents the major weight-bearing joint of the human organism. It is conspicuously characterized by its mobility and complex origination, specific organization and development. The anatomic structures referred to as acetabulum and femoral head arise from the same primitive mesenchymal cells and, by the end of the 11 week of gestation, the hip joint becomes fully formed and continues to develop throughout intrauterine life. During embryonic life, the femoral head grows at a faster rate than the acetabulum, and at the end of gestation the femoral head is approximately less than 50% covered, and after birth, the growth rate of the acetabular cartilage surpasses that of femoral head thus resulting in progressively increased coverage. Methods: Cartilaginous at birth, the ossification of acetabulum is set at around a three-month age period, while ossification centers of the proximal femur start to appear at 4 to 7-months. Several developmental abnormalities regarding the relationship between femoral head and acetabulum are therein described; all of those anatomic aberrations may technically result in hip instability, manifested by dislocation, subluxation, dysplasia and arthrosis. Results: From a biomechanical standpoint, three pathological conditions are shown to have arisen mainly at the region of the femoral neck: i) congenital coxa vara, ii) pseudoarthrosis of the neck of the femur and iii) coxarthrosis. All of the aforementioned conditions are caused and maintained by different types of mechanical stress and, in advanced stages, they may necessitate surgical interventions to alter the angle of the femoral neck in order to relieve the pressure at the level of the affected joint mainly during movement. Furthermore, we indicate that there is no standard to adopt regarding the surgical change of the femoral neck angle, though biomechanical assessment has to be worked out and established in each of the affected individual. Conclusion: Plain film radiography plays an important role in the assessment of a dysplastic hip, especially in adults, where operative management is essentially based on various radiographic measurements. Several average values of stresses and strains of the proximal femur were identified on the basis of Wolff’s trajectorial hypothesis, where they revealed a trabecular architectural changes and structural remodeling in response to mechanical stress. It is concluded that these pathological conditions (congenital coxa vara, pseudoarthrosis of the neck of the femur and coxarthrosis) that were shown to have arisen mainly at the region of the femoral neck may contribute to understanding pathophysiologic and patho-anatomic peculiarities of the femoral bone.