Effects of Orthopedic Manual Therapy on Pain Sensitization in Patients With Chronic Musculoskeletal Pain

ObjectiveThe aim of this umbrella review with meta-meta-analysis was to assess the effectiveness of orthopedic manual therapy in isolation on pain sensitization in patients with chronic musculoskeletal pain.DesignA systematic search was performed in different databases including systematic reviews with or without meta-analysis. The outcome measures included were pressure pain threshold, temporal summation, and conditioned pain modulation. The results of the different reviews were statistically synthesized through a random-effect meta-analysis, of all standardized mean differences and the corresponding 95% confidence interval reported by each study.ResultsFor mechanical hyperalgesia, the meta-meta-analysis of three meta-analyses revealed a statistically significant small-moderate effect of orthopedic manual therapy, with no evidence of heterogeneity and moderate-quality evidence. In terms of temporal summation, one meta-analysis revealed a statistically significant small effect of orthopedic manual therapy intervention, with moderate heterogeneity and low quality of evidence. Finally, one review without meta-analysis found that orthopedic manual therapy improved endogenous analgesia with low-quality evidence.ConclusionOrthopedic manual therapy in isolation improved mechanical hyperalgesia with moderate-quality evidence, as well as temporal summation and conditioned pain modulation with low-quality evidence. However, its effects are limited only to immediate and short-term.