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

Table 2 Kappa consistency coefficients for radiological data assessment at the initial visit

Items	Intra-observer kappa		Inter-observer
	Observer 1	Observer 2	Kappa	P value
AROC stage	0.431	0.590	0.403	< 0.001
JIC classification	0.706	0.771	0.796	< 0.001
Lesion size	0.813	0.802	0.656	< 0.001
Collapse degree	0.627	0.804	0.525	< 0.001

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