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

Table 5 Overall distribution of clinical scores in patients pre-treatment and at the last follow-up

Items	Pre-treatment	Post-treatment	χ2	P value
ARCO stage (hips)
Stage I	2	2	31.966	< 0.0011
Stage II	41	31
Stage IIIa	59	34
Stage IIIb	17	39
Stage IV	0	13
JIC classification (hips)
Type A	12	15	7.071	0.070
Type B	26	21
Type C1	54	51
Type C2	27	32
Lesion size (hips)
< 15%	26	28	5.485	0.140
15%-30%	37	30
> 30%	56	61
Collapse degree (hips)
≤ 2 mm	102	67	25.002	< 0.001
> 2 mm	17	52

¹Indicates Fisher’s exact test.

ARCO: Association Research Circulation Osseous; JIC: Japanese Investigation Committee.