Foot orthoses in lower limb overuse conditions: a systematic review and meta-analysis--critical appraisal and...

Collins N, Bisset L, McPoil T, Vicenzino B. Foot orthoses in lower limb overuse conditions: a systematic review and meta-analysis. Foot Ankle Int. 2007;28(3):396-412.

Among patients with or at risk for musculoskeletal overuse conditions, (1) do foot orthoses provide clinically meaningful improvements, and (2) are foot orthoses cost-effective?

Studies published through September 28, 2005, were identified by using MEDLINE, EMBASE, CINAHL and Pre-CINAHL, Physiotherapy Evidence Database (PEDro), PubMed, SPORTDiscus, Biological Abstracts, Web of Science, Allied Health and Complementary Medicine Database, and the full Cochrane Library. The authors did not provide the search strategy used. Reference lists of included randomized controlled trials (RCTs) and identified systematic reviews were searched by hand.

Studies were included if (1) they were RCTs that included the use of foot orthoses (either custom or prefabricated) in 1 of the intervention groups, (2) the clinical problem was an overuse condition as defined by the American College of Foot and Ankle Orthopedics and Medicine guidelines for which foot orthoses were recommended, and (3) at least 1 clinically relevant outcome was measured for a minimum of 1 week. Limits were not placed on year of publication, status of publication, or language.

The journal, authors, and author affiliations of included RCTs were masked from 2 of the reviewers who independently assessed the included RCTs for methodologic quality using a modified PEDro scale plus 3 additional items (justification of sample size, use of outcome measures with known validity and reliability, and reporting of adverse or side effects). Disagreements on methodologic quality were resolved with consensus or by a third reviewer. The effect sizes for the included RCTs were represented by relative risk (RR) for dichotomous outcomes and standardized mean difference (SMD) for continuous data. Confidence intervals (CIs) were reported for RR and SMD. Study data were extracted directly from each of the included studies. If provided, data from intention-to-treat analysis were extracted. Study authors were contacted when insufficient data were reported. A meta-analysis (random-effects model) was conducted using Review Manager (version 4.2; The Nordic Cochrane Centre, Copenhagen, Denmark).

The search identified 3192 potentially relevant studies. Full articles were retrieved for 327 studies. Twenty-two of the 327 studies met the inclusion criteria. Because the authors of 1 study used the same methods to report on 2 populations, a total of 23 RCTs were included in the systematic review. Prevention of lower limb overuse conditions with the use of foot orthoses was reported in 8 RCTs (7 studies). The effect of foot orthoses in the treatment of lower limb overuse conditions was reported in 15 RCTs. Of the 23 RCTs, the cost-effectiveness of foot orthoses was reported in 2 and the adverse effects of foot orthoses were reported in 8. Across the prevention RCTs, data were available for analysis for a range of 47 to 417 participants with 8 to 16 weeks of follow-up. Based on 4 RCTs in which the researchers examined prevention of lower limb overuse conditions with foot orthoses versus control in military personnel, the RR was 1.49 (95% CI  =  1.07, 2.08). A clinically beneficial effect size was set a priori at 1.5 or greater for the foot-orthoses group or at 0.7 or less for the comparison group. Based on 2 RCTs reported in 1 study of the use of custom versus prefabricated foot orthoses for prevention of lower limb overuse conditions, no significant difference in risk was found (RR  =  1.14, 95% CI  =  0.90, 1.44). In their calculating and reporting of RR, the authors do not appear to have followed convention. Across the treatment RCTs, data were available for analysis for a range of 18 to 133 participants with 8 to 52 weeks of follow-up. The authors of the treatment RCTs reported a variety of outcome measures. Two of these, patient-perceived treatment effect (PPE) and pain on the visual analog scale (VAS), were used to calculate an overall treatment effect (PPE as RR and VAS as SMD). Based on 2 RCTs examining foot orthoses versus control, no significant difference in PPE was found (RR  =  1.01, 95% CI  =  0.61, 1.68). Based on 2 RCTs in which custom versus prefabricated foot orthoses were examined, no significant difference in PPE was found (RR  =  0.88, 95% CI  =  0.42, 1.81). The VAS data reported in the text appear to contradict the VAS data reported in Figure 2 for foot orthoses versus control for the treatment of lower limb overuse conditions. Specifically, the lower limit of the CI in the text was negative (-0.28) and in Figure 2 was positive. Because of this apparent contradiction, we did not interpret these data. Authors of 2 RCTs reported cost-effectiveness, but the data could not be pooled. Adverse events were reported in 8 of the 22 studies. The most common adverse effect reported was discomfort, which was the main reason for discontinuing foot-orthoses use in 2 studies.

The evidence supports the use of foot orthoses to prevent a first occurrence of lower limb overuse conditions and shows no difference between custom and prefabricated foot orthoses. The evidence was insufficient to recommend foot orthoses (custom or prefabricated) for the treatment of lower limb overuse conditions.