There are two basic factors that cause fractures in the elderly, osteoporosis bone strength decreases, coupled with the dense nourishing vascular pores in the upper femoral neck area, both of which can weaken the biomechanical structure of the femoral neck and make it vulnerable. In addition, because of the degeneration of the periprosthetic muscles and the slow response of the elderly, they cannot effectively counteract the harmful stresses on the hip, and because the hip is subjected to a higher stress (2-6 times the weight) and complex and variable local stresses, fractures can occur without much violence, such as slipping on a flat surface, falling from a bed or a sudden twisting of the lower limb, even without obvious trauma. In contrast, femoral neck fractures in young adults are often caused by serious injuries such as car accidents or falls from height. Fractures that occur gradually as a result of excessive heavy labor or walking are called fatigue fractures.