Bok 2016.

Study characteristics
Methods	Randomised controlled four‐arm parallel trial
Participants	21 children with symptomatic flexible flat feet Age: aged 8 to 13 years Gender: 8 M, 13 F Location: Jung‐gu, Daejeon, South Korea Setting: Department of Rehabilitation Medicine, Chungnam National University Hospital Inclusion criteria: severe flat feet with pain, RCSP > 6° everted Exclusion criteria: (i) a fixed foot deformity (ii) reported previous intervention (e.g. orthoses or surgery) (iii) congenital and developmental foot disease (iv) neuromuscular or central nervous system disease Children with a history of overuse or traumatic injury to the lower limb in the past 6 months, bony surgery to the lower limb, or systemic endocrine, neurogenic, or musculoskeletal disorders were also excluded. Baseline characteristics: 8 M:13 F
Interventions	All children trialled 4 shoes with different degrees of orthotic (N = 21): 1. shoes 2. shoes and 0° orthotic 3. shoes and 15° orthotic 4. shoes and 30° orthotic
Outcomes	Plantar pressures ‐ peak pressure, maximum force, contact area Reported shoe and orthotic condition, as immediate effects on plantar pressures
Source of funding	orthoses supplied by Korean company
Notes	‐ did not include any pain evaluation (yet all participants were symptomatic at baseline) ‐ immediate effects only, hence, we did not include this trial in further analyses
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	‘The 4 orthotic conditions were tested in a random order to minimize potential sequencing effects.’ Insufficient information about the sequence generation process to permit judgement of low risk or high risk.
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	Unclear risk	Each child participated in each orthotic condition. No blinding was performed. Research staff dispensed the orthoses to the children. It was unclear how involved the research staff were in preparing each child for each trial, for example, fitting the orthoses in the shoes.
Blinding of outcome assessment (detection bias) ‐ self‐reported outcomes (e.g., pain, function)	Unclear risk	Immediate effects only
Blinding of outcome assessment (detection bias) ‐ objective outcomes	Unclear risk	Outcomes included assessment of gait parameters. Both the participant and the researcher were considered to be outcome assessors, as both could influence the result. The participants were not blinded. No mention was made of blinding of researchers involved in outcome assessment.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Insufficient reporting of attrition/exclusions to permit judgement of low risk or high risk.
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	It was not clear if participants were allowed an adjustment period for each orthotic design. The more aggressively posted orthoses may require a longer period to adjust to normalise gait.