Biomechanics important to interpret radiographs of the hip.

Biomechanic principles have important implications to film interpretation. Angulation of the femoral neck results in four different types of forces: compression on the medial side, tension on the lateral side, shear stress in the center, and torque forces at the neck-shaft angle. The body's response to these forces results in recognizable trabecular patterns which respond in a predictable manner to disease states. Surgical intervention in the form of hip replacement or fracture fixation must reflect these engineering considerations.