Table 3.

Relationship between the duration from the onset of pain to the first clinic visit and severity

Severity	Duration from the onset of pain to first visit to medical office or hospital
	<1 week	1 week ~3 months	3 months ~1 year	~1 year
I	18 knees	8 knees	13 knees	2 knees
II	2 knees	10 knees	5 knees	0 knee
III	2 knees	8 knees*	5 knees	8 knees*,**,***

Notes: There was a significant difference between the duration from the onset of pain to the first visit to medical office or hospital and radiographic severity of Osgood–Schlatter disease determined by the chi-squared test (P < 0.01);

^*There was a significant difference by the Mann–Whitney U test (vs “<1 week” group: P < 0.01);

^**There was a significant difference by the Mann–Whitney U test (vs “1 week ~3 months” group: P < 0.01);

^***There was a significant difference by the Mann–Whitney U test (vs “3 months ~1 year” group: P < 0.05).