Meta-Analysis
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World J Meta-Anal. Aug 26, 2014; 2(3): 78-90
Published online Aug 26, 2014. doi: 10.13105/wjma.v2.i3.78
Efficacy of therapeutic ultrasound vs sham ultrasound on pain and physical function in people with knee osteoarthritis: A meta-analysis of randomized controlled trials
Norma J MacIntyre, Ahmed Negm, Adalberto Loyola-Sánchez, Mohit Bhandari
Norma J MacIntyre, Ahmed Negm, Adalberto Loyola-Sánchez, School of Rehabilitation Science, McMaster University, Hamilton, Ontario L8S 1C7, Canada
Mohit Bhandari, Department of Surgery, McMaster University, Hamilton, Ontario L8L 8E7, Canada
Author contributions: All authors contributed to the design of the research study and interpretation of the data; MacIntyre NJ, Negm A and Loyola-Sánchez A contributed to the acquisition of data as described in the methods; MacIntyre NJ performed the search and data analyses and wrote the paper; Negm A, Loyola-Sánchez A and Bhandari M reviewed the paper critically for important intellectual content and approved the version to be published.
Supported by The Canadian Institutes of Health Research Randomized Controlled Trials Mentorship Program (NJM, MB), No. MTP 108229
Correspondence to: Norma J MacIntyre, PT, PhD, Associate Professor, School of Rehabilitation Science, McMaster University, IAHS 403-1400 Main St W., Hamilton, Ontario L8S 1C7, Canada. macint@mcmaster.ca
Telephone: +1-905-5259140-21166 Fax: +1-905-5240069
Received: November 27, 2013
Revised: May 5, 2014
Accepted: May 28, 2014
Published online: August 26, 2014
Abstract

AIM: To determine the efficacy of therapeutic ultrasound vs sham for improving pain and physical function immediately post-intervention in people with knee osteoarthritis (OA).

METHODS: We hand searched meta-analyses on the topic published in 2010 and updated the search in three electronic databases (MEDLINE, EMBASE, CINAHL) January 1, 2009 to September 5, 2013 to identify relevant studies. The inclusion criteria were human randomized controlled trials published in the English language in which active therapeutic ultrasound was compared to sham ultrasound, data for people with knee OA were reported separately, participants were blinded to treatment allocation and outcomes assessed before and after treatment included pain, self-reported physical function and performance-based physical function. Two reviewers independently screened titles and abstracts retrieved in the search to identify trials suitable for full text review. Data extraction and risk of bias assessment of the identified trials were completed independently by two reviewers. Pooled analyses were conducted using inverse-variance random effects models.

RESULTS: We screened 1013 titles and abstracts. Meta-analysis of pain outcomes from 5 small trials (281 participants/OA knees) showed that, compared to sham ultrasound, therapeutic ultrasound improves pain [standardized mean difference (SMD) (95%CI) = -0.39 (-0.70, -0.08); P = 0.01] but not physical function [self-reported in 3 trials (130 participants/OA knees): SMD (95%CI) = -0.21 (-0.55, 0.14), P = 0.24; walking performance in 4 trials (130 participants/OA knees): SMD (95%CI) = -0.11 (-0.59, 0.37), P = 0.65). For the walking performance outcome, the dispersion of the estimated effects exceeded that expected due to sampling error (χ2 = 8.37, P = 0.04, I² = 64%). Subgroup analyses of three trials that administered high dose ultrasound improved the consistency (I2 = 28%) but the treatment effect remained insignificant.

CONCLUSION: Meta-analyzed double-blind placebo-controlled randomized trials provide low-strength evidence that therapeutic ultrasound decreases knee OA pain and very low-strength evidence that it does not improve physical function.

Keywords: Ultrasonic therapy, Physical therapy modalities, Osteoarthritis, Double-blind method, Evidence-based medicine

Core tip: Controversy exists regarding the efficacy of therapeutic ultrasound in the management of knee osteoarthritis (OA). Lack of participant blinding in effectiveness trials introduces bias known to exaggerate treatment effect estimates particularly for outcomes such as pain and self-reported physical function. We meta-analyzed data from double- and triple-blind trials only and high level evidence shows that therapeutic ultrasound decreases knee OA pain but does not increase physical function immediately following treatment. Due to the methodological quality of the included trials, we conclude that a large well-designed trial is required before this clinical question can be answered definitively.