Objective: The main objective of this systematic review and meta-analysis was to determine the short-, medium-, and long-term effectiveness of dry needling (DN) applied by physical therapists to myofascial trigger points for the treatment of pain.
Methods: PubMed, Scopus, SportDiscus, and Web of Science databases were searched from their inception to February 2020. Randomized controlled trials that compared DN with other treatments or placebo and measured pain with a visual analog Scale or another numerical pain rating scale were included. Two authors used a personalized form to collect the following data relevant to the objectives of the review from each article independently: study design, purpose, sample size, diagnosis, characteristics of DN intervention, characteristics of placebo intervention, outcome measures, period of assessment, body region, DN technique, and number of sessions. The initial search identified 1771 articles. After the selection, 102 articles were assessed for eligibility; 42 of these articles measuring pain were used for the meta-analysis. Four meta-analyses were performed according to the follow-up period from the last reported treatment.
Results: This meta-analysis found a large effect to decrease pain within 72 hours (standardized mean difference [SMD] = -0.81; 95% CI = -1.21 to -0.40), a moderate effect in 1 to 3 weeks (SMD = -0.69; 95% CI = -1.02 to -0.35), a large effect in 4 to 12 weeks (SMD = -0.85; 95% CI = -1.30 to -0.40), and a large effect in 13 to 24 weeks (SMD = -0.81; 95% CI = -1.64 to -0.03). The risk of bias was generally low; however, the heterogeneity of the results downgraded the level of evidence.
Conclusions: Low-quality evidence that the immediate to 72-hour (large) effect, 4- to 12-week (large) effect, 13- to 24-week (large) effect, and moderate-quality 1- to 3-week (moderate) effect suggested that DN performed by physical therapists was more effective than no treatment, sham DN, and other therapies for reducing pain.
Impact: DN is commonly used by physical therapists to treat musculoskeletal pain, and it is very important for physical therapists to know the clinical conditions and time periods for which DN is effective in reducing pain in their patients.
Keywords: Pain; Physical Therapy; Randomized Controlled Trial; Trigger Points.
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