Ahn 2017.

Study characteristics
Methods	Randomised controlled two‐arm parallel trial
Participants	40 children with flexible flat feet Age: average 10 (4.5) years Gender: 24 M, 16 F Location: Daejeon, Korea Setting: Department of Pediatric Rehabilitation at Chung Nam National University Hospital Inclusion criteria: flexible flatfoot defined as > 4° valgus RCSP, one abnormal x‐ray finding i.e. > 30° AP talo‐calcaneal angle, > 45° lateral talo‐calcaneal angles, > 4° lateral talo‐metatarsal angles, < 10° calcaneal pitch Exclusion criteria: rigid flatfoot, of any cause Baseline characteristics: matched except for age ‐ RFO 10.14 (4.99) years, TCFO 9.59 (4.24) years
Interventions	1. rigid foot orthoses (N = 20) 2. talus control foot orthoses (N = 20)
Outcomes	‐ RCSP ‐ x‐rays, 4 angles: AP talo‐calcaneal angle, lateral talo‐calcaneal angles, lateral talo‐metatarsal angles, calcaneal pitch Both measures were assessed at baseline and after 12 months
Source of funding	none reported
Notes	no mention of pain, or gait parameters
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Insufficient information about the sequence generation process to permit judgement of low risk or high risk. ‘Forty children were randomly prescribed a foot orthosis: 20 a RFO and 20 a TCFO’
Allocation concealment (selection bias)	Unclear risk	Insufficient information to permit judgement of low risk or high risk.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants were not blinded Personnel were not blinded
Blinding of outcome assessment (detection bias) ‐ self‐reported outcomes (e.g., pain, function)	High risk	N/A
Blinding of outcome assessment (detection bias) ‐ objective outcomes	Unclear risk	It was not clear if the person who measured resting calcaneal stance position or radiographs was blinded.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	The number of children who completed the study, or for whom outcome data were presented was not reported.
Selective reporting (reporting bias)	Unclear risk	No reference to study protocol. Insufficient information to permit judgement of low risk or high risk.
Other bias	Unclear risk	Funding source for orthoses was not stated.