Precursor of femoral neck fracture necrosis

Patients should not be afraid when they hear about femoral neck fracture. Although femoral neck fracture has the possibility of necrosis, most of the symptoms of femoral neck fracture will not cause necrosis as long as the patient pays good attention to care. If femoral neck fracture necrosis is not treated in time, it will affect the overall health of the bone. Therefore, patients need to understand the precursors of femoral neck fracture necrosis.

1. Precursor of femoral neck fracture necrosis

The precursors of femoral neck fracture necrosis are generally pain, redness, swelling, heat and pain at the fracture site. Whether femoral head necrosis (AVN) occurs after a fracture depends mainly on the degree of vascular damage, especially the posterior superior retinacular artery, which is crucial for the blood supply to the femoral head. If the fracture is more displaced, the probability of injury to the artery increases significantly. Furthermore, depending on the revascularization, adequate blood flow can be restored before the femoral head collapses.

2. Factors that induce ischemic necrosis in femoral neck fracture

1. Fracture site

The closer the fracture line is to the femoral head, the higher the necrosis rate. The necrosis rate is highest for oblique fracture lines passing through the posterior and superior part of the femoral neck.

2. Open surgery

This procedure is likely to disrupt the surviving blood supply, especially when extensive dissection or posterior capsule incision is performed, which is more likely to damage the posterosuperior or posterior blood supply.

3. Poor alignment

Improper reduction, such as excessive eversion, rotation, adduction, flexion, or separation and displacement, will increase the risk of necrosis.

4. Treatment time

The necrosis rate in early surgery is low, and even if necrosis occurs, it is partial and occurs relatively late; in elective surgery, necrosis is often complete and occurs relatively early.

5. Age Factor

The incidence of femoral head necrosis in children and young adults is higher than that in the elderly. This is because the bone in the femoral neck of children and young adults is relatively hard. When a fracture occurs, the force increases and the dislocation of the fracture ends becomes serious, so femoral head necrosis will occur.