Table 1.

Subscale structure of the KOOS in young active patients with ACL tears based on a five-factor exploratory factor analysis

Factor 1 Impairment	Factor 2 Sport	Factor 3 Symptoms	Factor 4 Quality of life	Factor 5 Recommend removing
Symptoms (7 items)
		1
2
3
		4
		5
6		6
7		7
Pain (9 items)
1
		2
		3
		4
5
6
7
8
9
ADL (17 items)
1
2
3
4
5
6
7
8
				9
10
				11
12
13
14
15				15
16
17
Sport and recreation (5 items)
	1
	2
	3
	4
	5
QOL (4 items)
			1
			2
			3
			4

Fit indices: χ² = 1237.03; p < 0.001, TLI = 0.828, RMSEA = 0.076 (90% CI 0.073 to 0.079), and SRMR = 0.03. Items were assigned to a factor (column) if their loading onto that factor > 0.3; if the five-factor exploratory analysis was to support the intended structure of the KOOS, all items in one subscale would be grouped into one column, with no items from other subscales in that column, no items fitting into more than one column; TLI = Tucker-Lewis index, RMSEA = root mean square error of approximation, SRMR = standardized root mean square residual, ADL = activities of daily living, QOL = quality of life.