Table 2 Quality scores of the articles selected.

Articles	Questions								Outcome
	Definition	Demographics	Prospective design	80% follow up	Withdrawals	Blinding	Data presentation	Multivariate analysis
Taunton et al, 200319	+	+	+	+	–	–	+	+	6
Lun et al, 200412	+	+	+	–	+	+	+	–	6
Satterthwaite et al, 199917	+	+	+	+	–	–	+	+	6
Wen et al, 199821	+	+	+	–	+	+	+	+	7
Bennell et al, 19969	+	+	+	+	–	+	+	–	6
Macera et al, 199123	+	+	–	+	–	–	+	+	5
Macera et al, 198914	+	+	+	–	+	–	+	+	6
Walter et al, 198920	+	+	+	–	+	+	+	–	6
Jakobsen et al, 198922	+	+	–	–	–	–	+	–	3
Kretsch et al, 198411	+	–	+	–	–	–	+	–	3
Nicholl & Williams, 198215	+	+	+	+	–	+	+	–	6
Nicholl & Williams, 198225	+	+	–	+	–	+	+	–	5
Steinacker et al, 200118	–	+	+	–	–	na	na	na	2
Satterthwaite et al, 199616	+	+	+	+	–	na	na	na	4
Bovens et al, 198910	+	+	+	–	+	na	na	na	4
Lysholm & Wiklander, 198713	+	+	+	+	–	na	na	na	4
Maughan & Miller, 198324	+	+	–	–	–	na	na	na	2

Questions that could be answered with yes are “+”; those answered with no or unknown are “−”; “+” scores 1 and “–” scores 0.

na, not applicable.