Table 4. The results of Cox proportional-hazards model for conversion to THA.

Variable selected	B	SE	Wald	P	HR	95% CI
Gender	−0.630	0.365	2.980	0.084	0.532	0.260~1.089
Age	−0.923	0.424	4.744	0.029	0.397	0.173~0.912
BMI	0.197	0.333	0.351	0.554	1.218	0.634~2.338
Bilateral hip involvement	0.112	0.429	0.068	0.794	1.119	0.483~2.591
Preoperative HHS	−0.293	0.338	0.752	0.386	0.746	0.385~1.447
Bone marrow edema	0.467	0.323	2.086	0.149	1.595	0.846~3.006
ONFH etiologies			0.527	0.768
etiology (Corticosteroids)	0.311	0.496	0.393	0.531	1.365	0.516~3.606
etiology (Alcohol)	0.091	0.517	0.031	0.861	1.095	0.398~3.014
ARCO stage	−1.020	0.385	7.020	0.008	0.361	0.170~0.767
CJFH type			3.920	0.141
type (L1)	−13.931	272.997	0.003	0.959	0.000	0.000~2.11E226
type (L2)	−0.615	0.310	3.918	0.048	0.541	0.294~0.994

B: regression coefficient; SE: standard error; HR: hazard ratio; Bold value indicate the significant P value.