Table 3 Quality assessment of cohort studies

Was the cohort recruited in an acceptable way (robust inclusion/exclusion criteria or consecutive recruitment)

Y

Y

Y

Was the study prospective?

Y

Y

Y

Was the intervention conducted in an explicit and standardised manner (e.g., guidelines/protocol applied)

Y

Y

Y

Was the outcome appropriately measured to minimise bias?

N

N

N

Did they identify important confounding factors (e.g., age at intervention, baseline angle of deviation)

Y

Y

Y

Did they adjust for confounding factors in the design and/or analysis where necessary

Y

Y

Y

Were they followed-up for at least 12 months?

Y

Y

Y

Are the authors’ conclusions substantiated by the reported data?

Y

Y

Y