Table 2.

Quality assessment of included studies [7–10]

Study	Randomization	Allocated concealment	Blinding	Length of follow-up	Withdrawal or lost to follow-up (%)
Barthel et al. [7]	Adequate	Unclear	Unclear	12 months	7
Van der Heide et al. [8]	Adequate	Adequate	Adequate	12 months	6
Grohs et al. [9]	Adequate	Adequate	Adequate	15 months	4
Saudan et al. [10]	Adequate	Adequate	Unclear	3 months	4