Erhart‐Hledik 2012.

Methods	RCT; randomisation procedure not described; outcome assessment partially blinded
Participants	Medial compartment knee OA: n = 79 Male/female: 42/37 Mean age (years): 60 Mean BMI (kg/m2): 27.7
Interventions	I = Variable‐stifness shoe (n = 40) vs C = constant stiffness shoe (n = 39) Follow‐up = 6 and 12 months
Outcomes	WOMAC
Notes	6‐Month results were presented earlier. Patients were included on the basis of MRI. Anteroposterior radiograph was used during follow‐up
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "using a random number generator"
Allocation concealment (selection bias)	Low risk	Quote: "The randomization code was revealed to the study coordinator in charge of subject recruitment and in contact with the subjects regarding WOMAC scores, once recruitment, data collection, and analyses were completed"
Blinding (performance bias and detection bias) All outcomes	Low risk	Quote: "Subjects were blinded to their shoe type"
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "Subjects were blinded to their shoe type (The researcher performing the gait analysis was not blinded to the shoe type)"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "Subjects were blinded to their shoe type"
Incomplete outcome data (attrition bias) All outcomes	Low risk	Intention‐to‐treat
Selective reporting (reporting bias)	Low risk	Complete data were reported; study author provided additional data for this review