Comparative efficacy of biomechanical treatments on knee osteoarthritis pain: a network meta-analysis of randomized controlled trials

Purpose: To compare the efficacy of biomechanical treatments intended to reduce biomechanical parameters of knee load, on knee pain severity in people with medial tibiofemoral osteoarthritis (TFOA). Methods: We performed a network meta-analysis of randomized controlled trials. Four electronic databases (PubMed, Embase, CINAHL, Cochrane Central Register of Controlled Trials) were searched from inception through to May 2020, as well as grey literature sources (reference lists of eligible articles and relevant systematic reviews, clinical trial registries (ClinicalTrials.gov, ANZCTR.org.au)). We selected randomised controlled trials evaluating the effects of customized shoes, knee braces, insoles, cane or gait retraining, compared to each other or non-biomechanical treatment, on self-reported knee pain in symptomatic and/or radiological medial TFOA. Two reviewers independently extracted data and assessed risk of bias using the Cochrane Risk of Bias Tool (version 2). A network meta-analysis using random-effect models was conducted and the Grading of Recommendations, Assessment, Development and Evaluation framework used to appraise confidence in the evidence. Results: Twenty-seven eligible trials involved 2,413 participants and 10 treatment nodes: valgus braces, combined brace treatment (with added non-biomechanical treatment), wedged insoles, combined insole treatment, contra-lateral cane use, gait retraining, customized shoes, neutral biomechanical treatment (neutral or placebo insoles/shoes/sleeve), combined neutral biomechanical treatment, and control (no treatment, non-operative non-biomechanical treatments). Except for treatment nodes of cane use and gait retraining, the network appeared well-connected overall. Approximately half the studies (n=14 (52%)) were at high risk of bias. Most comparisons had low to very low certainty of evidence. With the exception of canes (standardized mean difference (SMD) [95% CI]: 6.24 [3.58, 8.91]), compared to control, no biomechanical treatment associated with pain. Considering all biomechanical treatments, combined bracing showed the most pain relief, with significant differences versus brace (-5.87 [-9.48,2.26]), canes (-6.29 [-9.84, -2.73]), gait retraining (-5.87 [-9.03, -2.71]), insoles (-6.05 [-9.92, -2.19]), isolated (-6.80 [-10.42, -3.18]) and combined (-5.97 [-9.52, -2.41]) neutral biomechanical treatments, shoes (-6.08 [-9.85, -2.31]). Compared to brace, canes, insoles, gait retraining and neutral biomechanical treatments, combination insole treatment also significantly associated with pain (SMDs ranging 4.71 to 5.64, favouring combination insole treatment). Findings of relative efficacy of combined brace or insole treatments remained similar after exclusion of studies with high risk of bias. Conclusions: Except for canes, no biomechanical treatment (in isolation or combination) appeared superior to non-biomechanical treatment for pain relief. Of the biomechanical treatments evaluated, combination knee brace or insoles treatments most likely reduced pain.