Fractures of the left femoral neck are very serious. The femoral neck is divided into types I, II, III and IV. Type I femoral neck fractures are not too serious, but they are relatively serious compared to other fractures. The possibility of femoral head necrosis is very high after a femoral neck fracture, reaching more than 80%-90%, because the blood supply to the femoral head is completely interrupted by 80%-90% of a femoral neck fracture. For a fracture to heal, there must be an abundant blood supply, and a fracture of the femoral neck happens to cause an almost complete interruption of the blood supply, so it does not heal easily. Of course, even if the femoral neck fracture heals, there is still a possibility of femoral head necrosis 3-5 years later, and the chances of this occurring are very high. In general, femoral neck fractures are very serious and can cause complications later on.