“…Five trials were at low risk of bias due to random sequence generation (Friesen et al., 2017; Hedman-Lagerlöf et al., 2018; Salaffi et al., 2015; Simister et al., 2018; Vallejo et al., 2015) and incomplete outcome data (Friesen et al., 2017; Hedman-Lagerlöf et al., 2018; Salaffi et al., 2015; Tavallaei et al., 2018; Vallejo et al., 2015). However, six studies were at high risk of bias in relation to the blinding of participants and personnel (Friesen et al., 2017; Hedman-Lagerlöf et al., 2018; Nes et al., 2017; Salaffi et al., 2015; Simister et al., 2018; Tavallaei et al., 2018) and five were at high risk of bias regarding the blinding of the outcome assessment (Friesen et al., 2017; Hedman-Lagerlöf et al., 2018; Nes et al., 2017; Salaffi et al., 2015; Vallejo et al., 2015). In addition, four trials had an unclear risk of bias related to allocation concealment (Friesen et al., 2017; Nes et al., 2017; Tavallaei et al., 2018; Vallejo et al., 2015) and selective reporting (Nes et al., 2017; Salaffi et al., 2015; Tavallaei et al., 2018; Vallejo et al., 2015).…”