BackgroundLateral wedge insoles are traditionally used to reduce the adduction moment that crosses the knee during walking in people with medial knee osteoarthritis. However, the best degree to reduce knee joint load is not yet well established.MethodsElectronic databases were searched from their inception until May 2017. Included studies reported on the immediate biomechanical effects of different degrees of lateral wedge insoles during walking in people with knee osteoarthritis. The main measures of interest relating to the biomechanics were the first and second peak of external knee adduction moment and knee adduction angular impulse. For the comparison of the biomechanical effects of different degrees of insoles, the studies were divided in three subgroups: insoles with a degree higher than 0° and equal to or lower than 5°; insoles higher than 5° and equal to or lower than 9°; and insoles higher than 9°. Eligible studies were pooled using random-effects meta-analysis.ResultsFifteen studies with a total of 415 participants met all eligibility criteria and were included in the final review and meta-analysis. The overall effect suggests that lateral wedge insoles resulted in a statistically significant reduction in the first peak (standardized mean difference [SMD] –0.25; 95% confidence interval [CI] –0.36, − 0.13; P < 0.001), second peak (SMD –0.26 [95% CI –0.48, − 0.04]; P = 0.02) and knee adduction angular impulse (SMD –0.17 [95% CI –0.31, − 0.03]; P = 0.02). The test of subgroups found no statistically significant differences.ConclusionSystematic review and meta-analysis suggests that lateral wedge insoles cause an overall slight reduction in the biomechanical parameters. Higher degrees do not show higher reductions than lower degrees. Prior analysis of biomechanical parameters may be a valid option for selecting the optimal angle of wedge that best fits in knee osteoarthritis patients with the lowest possible degree.

Background: Lateral wedged insoles are one of the biomechanical interventions recommended for individuals with medial knee osteoarthritis to reduce external knee adduction moment. Several approaches have already been tested to reduce the forces that crosses the knee. However, an approach based on individual biomechanical assessment of the acute effects of different angles of lateral wedge insoles is necessary. Purpose: To assess the intra-session reliability of different angles of lateral wedge insoles on knee biomechanics during gait in healthy adults. Methods: Twenty-five healthy volunteers (15 males, with mean age of 21.6±5.5 years, body mass of 65.2±8.7 kg, and height 169±7.5 cm) were recruited. A Qualisys Oqus motion analysis system was used for kinematic and kinetic data collection during gait with the six experimental conditions: 0°, 2°, 4°, 6°, 8° and 10-degree wedge insoles. The intraclass correlation (ICC) and their 95% confidence intervals, the standard error of measurement (SEM) and the minimal detectable change (MDC) were calculated for each insole. Results: For all kinematic parameters, ICC was superior to 0.924, showed an excellent consistency. For the kinetic parameters, the external knee abduction moment was the least consistent (ICC>0.540). It was found that the estimated value for SEM was 0.014 Nm/kg for the first and second peak of external knee adduction moment with a corresponding MDC of 0.039 Nm/kg for both. Conclusions: This study provides preliminary data which may be useful for clinical interpretation and decision to recommend the insole that best fits to the condition of the patient with medial knee osteoarthritis.

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