Twenty-three studies (reported in 22 papers) were included.
Modified PEDro scores ranged from 2 to 11 out of 14. Methodological flaws included lack of the following: eligibility criteria, reporting of allocation concealment, blinding, intention-to-treat analysis, justification of sample size, and reporting of adverse events. There was no significant correlation between quality score and RR (p=0.60) or SMD (p=0.10).
Prevention (8 studies).
Foot orthoses were associated with a significant and reasonably sized reduction in the risk of injury compared with controls (RR 1.49, 95% CI: 1.07, 2.08; based on 4 studies). The results were similar for a fifth study that did not provide sufficient data for meta-analysis.
One study reported a clinically significant reduction in the risk of injury with foot orthoses compared with simple insoles.
There was no significant difference in the risk of injury between custom and prefabricated foot orthoses (based on 2 studies in one publication).
Treatment (15 studies).
There was no significant difference between foot orthoses and control for PPE or VAS (based on pooled data from 2 studies).
Studies compared foot orthoses with a great variety of different interventions; one or at most 2 studies reported each comparison, thus pooling data was not possible.
Up to 3 months, there was no significant difference between custom and prefabricated foot orthoses (based on pooled data from 2 studies). One study reported no treatment effect of either type of orthosis at 6 and 12 months.
Adverse effects (8 studies).
The main adverse effect was discomfort; this was the main reason for discontinuation in 2 studies. One study reported that 21% (30 out of 143) of patients discontinued use of foot orthoses in the first 14 days.