As shown in Table 2, for the -75 G > A SNP of apoAI gene, AA genotype frequency (0.501) was significantly higher in patients with osteonecrosis than that in control (0.462) subjects (P <0.001), GA genotype frequency (0.170) was significantly lower than that in the control (0.310) group (P <0.0001). This evidence concerns the gene APOA1 and osteonecrosis.