According to Japanese clinical guidelines, avascular necrosis occurs in 4% to 21% of nondisplaced fractures and 46% to 57% of displaced fractures.[21] In a meta-analysis by Xu et al, the avascular necrosis rate for nondisplaced femoral neck fractures in the conservatively treated group was 10.3%, and in the surgically treated group, 7.7%.[22] Therefore, we selected patients with displaced femoral neck fractures as subjects in this study to observe the effect of CRIF with BMP-2 composite materials. Here, BMP2 is linked to avascular necrosis.