Fracture risk assessment in children with benign bone lesions of long bones

Table 1 Variables for calculation of score

	Score
Risk factor	0	1	2	3
Lesion-to-bone width	None	1/3	1/3-2/3	> 2/3
Axial cortical involvement	None	< 20 mm	20-30 mm	> 30 mm
Pain	None	Mild	severe
Lesion type	Blastic	Mixed	Lytic

Table 2 Comparison of demographic characteristics between the fracture and non-fracture groups

Characteristic	Fracture group (n = 40)	Non-fracture group (n = 56)	P value
	Mean (SD)	Mean (SD)	Univariate
Age (yr)	8.1 ± 3.6	8.3 ± 3.5	0.77
Sex
Females	24	31	0.65
Males	16	25
Histological diagnosis			0.58
Simple bone cyst	10	15
Aneurysmal bone cyst	7	11
Fibrous dysplasia	8	11
Non-ossifying fibroma	3	8
Langerhans histiocytosis	6	9
Endochondroma	3	1
Osteoblastoma	3	1
Lesion location			0.33
Upper limp	16	17
Lower limp	24	39
Lesion type			0.021
Osteolytic	28	29
Mixed	12	19
Osteoblastic	0	8
Pain			0.004
Severe	12	4
Mild	17	22
None	11	30
Lesion-to-bone width			0.006
Size > 2/3	24	15
1/3 < Size ≤ 2/3	14	30
Size ≤ 1/3	2	10
Axial cortical involvement
> 30 mm	31	24	0.002
30 mm ≥ Size > 20 mm	5	12
≤ 20 mm	4	20

SD: Standard deviation.

Table 3 The mean and median values for interobserver variability of score

Observer	Total population			Fracture group			Non- fracture group
	No. patient	Mean	Median	No. patient	Mean	Median	No. patient	Mean	Median
A	96	6.88	7	40	7.98	8	56	6.01	6
B	96	6.91	7	40	8.00	8	56	6.12	6

Table 4 Comparison of score between the fracture and non-fracture groups

	No. patient	Score	Mean (SD)	P value
Fracture group	40	5-10	7.98 (1.37)	0.00
Non-fracture group	56	3-9	6.01 (1.55)

SD: Standard deviation.

Table 5 Diagnostic efficiency at different cutoff value

Score	Fracture	Non-fracture	Sensitivity	Specificity	Positive predictive value	Negative predictive value	Accuracy	Fracture probability	Youden index
3	0	4	100%	7%	43%	100%	46%	0	0.07
4	0	4	100%	14%	45%	100%	50%	0	0.14
5	3	11	92%	34%	50%	86%	58%	0.08	0.31
6	3	15	85%	64%	60%	85%	71%	0.15	0.41
7	6	11	70%	80%	72%	79%	76%	0.3	0.5
8	12	8	40%	95%	84%	69%	72%	0.6	0.35
9	12	3	10%	100%	100%	61%	63%	0.9	0.1
10	4	0	0%	100%	0%	58%	58%	1	0