Outcomes of the conservative hip preservation treatment in patients with osteonecrosis of the femoral head: With 4-year follow-up

Table 1 Patient demographic characteristics

Demographics	Value
Gender (male/female)	45/28
Age (years)	39.10 ± 11.22 (21-67)
BMI (kg/m2)	23.00 ± 3.48
Follow up time (month)	53.58 ± 26.80 (18-129)
THA (hips)	7
Hip preservation surgery (hips)	4
Etiology (hips)
Steroid	59
Alcohol	22
Trauma	13
Idiopathic	25
ARCO stage (hips)
Stage I	2
Stage II	41
Stage IIIa	59
Stage IIIb	17
JIC classification (hips)
Type A	12
Type B	26
Type C1	54
Type C2	27
Lesion size (hips)
< 15%	26
15%-30%	37
> 30%	56
Collapse degree (hips)
≤ 2 mm	102
> 2 mm	17

BMI: Body mass index; THA: Total hip arthroplasty; ARCO: Association Research Circulation Osseous; JIC: Japanese Investigation Committee.