Analysis of the natural collapse course of non-traumatic osteonecrosis of the femoral head based on the matrix model

Table 2 Univariate analysis of 202 hips between collapse and non-collapse groups

	Total	Collapse	Non-collapse	P value
	n	n/%	n/%	P value
Number of hips	202	98/48.5	104/51.5
Age (x ± s)	52.48 ± 12.18	47.60 ± 12.57	0.006^a**
BMI (x ± s)	23.03 ± 2.76	22.90 ± 2.47	0.725^a
Sex				0.426^b
Male	141	71/35.1	70/34.7
Female	61	27/13.4	34/16.8
Invasive hip				0.473^b
Unilateral	52	23/11.4	29/14.4
Bilateral	150	75/37.1	75/37.1
Etiology				0.608^b
Idiopathic	100	52/25.7	48/23.8
Glucocorticoid	79	36/17.8	43/21.3
Alcohol	23	10/5.0	13/6.4
ARCO staging				0.000^b***
Stage I	40	4/2.0	36/17.8
Stage II	162	94/46.5	68/33.7
JIC classification				0.000^b***
Type A	19	2/1.0	17/8.4
Type B	54	16/7.9	38/18.8
Type C1	86	48/23.8	38/18.8
Type C2	43	32/15.8	11/5.4
Area				0.000^b***
< 30%	91	30/14.9	61/30.2
30–50%	77	40/19.8	39/19.3
> 50%	34	28/13.9	4/2.0

ARCO the Association Research Circulation Osseous, JIC Japanese Investigation Committee
*Significant difference (P < 0.05)
**Extremely marked difference (P < 0.01)
***Extremely marked difference (P < 0.001)
^aIndependent sample t-test
^bChi-square test

ISSN: 1749-799X