Ineffectiveness of lateral-wedge insoles on the improvement of pain and function for medial knee osteoarthritis: a meta-analysis of controlled randomized trials

OBJECTIVE: The study aimed to evaluate the role of lateral-wedge insoles in pain reduction and functional improvement among patients with medial knee osteoarthritis. MATERIALS AND METHODS: Three databases including Pubmed, Embase, and Web of science were searched from inception until October 2017 for studies investigating the role of lateral-wedge treatment in pain relief and functional recovery among patients with knee osteoarthritis. Eligible studies were pooled using fixed effect model or random-effects model based on Cochrane Q statistic and I(2) test. Moreover, subgroup analysis stratified by research area was performed, and sensitivity analysis was further designed to evaluate the strength of the meta-analysis. RESULTS: Ten studies with a total of 938 patients, of which 478 patients received lateral-wedge insoles and 460 patients were set as control, were included in the meta-analysis. The pooled statistics did not show significant improvement in knee pain (SMD = − 0.21, 95% CI − 0.50, 0.08; P = 0.16) and knee function (SMD = 0.22, 95% CI − 0.27, 0.70; P = 0.38) in lateral-wedge insoles treatment group compared with controls. However, subgroup analysis based on research area revealed a favorable outcome toward Asian patients who received lateral-wedge insoles in pain reduction when compared with control group. (SMD = − 0.88, 95% CI − 1.59, − 0.17; P = 0.02). No significant improvement was observed among patients in USA and other areas. Sensitivity analysis showed unchanged results when we omitted each study. No significant publication bias was observed among the included studies. CONCLUSION: Though for young Asian patients within normal BMI, to some extent, the lateral-wedge insoles seems to be helpful. However, there was no evidence to demonstrate the relationship between race and role of lateral-wedge insoles on pain reduction. All in all, based on current data, lateral-wedge insoles appear to be ineffective at attenuating knee pain and function improvement.