Table 3.

Study characteristics.

	n/N (%)
Studies published after 1 July 2005	46/78 (59%)
Study report indicating registration in a trial repository	8/46 (17%)
Sample size > 100	12/78 (15%)
Studies reporting a sample size calculation	26/78 (33%)
Randomized controlled trial study design
• Single-centre	49/78 (63%)
• Multi-centre	11/78 (14%)
• Inadequate information	18/78 (23%)
Randomization
• Randomized controlled trials	73/78 (94%)
• Quasi-randomized trials	5/78 (6%)
Study report indicating intention-to-treat analysis	14/78 (18%)
External funding source	13/78 (17%)
Comparison type
• Two different types of surgical treatment	16/78 (21%)
• One surgical treatment compared to one type of conservative treatment	16/78 (21%)
• Two different types of conservative treatment	46/78 (59%)