| Study | Sequence generation | Allocation concealment | Blinding of participants and personnel and outcome assessors | Incomplete outcome data | Selective outcome reporting | Other sources of bias |
| Carroll et al. 2013 | Low | Low | Highb | Highc | Low | Uncertaind |
| Meier et al. 2013 | Low | Low | Highb | Highc | Low | Uncertaind |
| Furlan et al. 2012 | Low | Low | Highb | Highc | Low | Uncertaind |
| Saver et al. 2017 | Low | Low | Highb | Highc | Low | Uncertaind |
| Søndergaard et al. 2017 | Low | Low | Highb | Low | Low | Uncertaind |
| Mas et al. 2017 | Low | Low | Highb | Highc | Low | Uncertaind |