Meta-analysis: Acupuncture for Osteoarthritis of the Knee

19 June 2007 | Volume 146 Issue 12 | Pages 868-877

Background: Knee osteoarthritis is a major cause of pain and functional limitation.

Purpose: To evaluate the effects of acupuncture for treating knee osteoarthritis.

Data Sources: Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE databases to January 2007. No language restrictions were applied.

Study Selection: Randomized trials longer than 6 weeks in duration that compared needle acupuncture with a sham, usual care, or waiting list control group for patients with knee osteoarthritis.

Data Extraction: Two authors independently agreed on eligibility, assessed methodological quality and acupuncture adequacy, and extracted outcome data on pain and function measures.

Data Synthesis: Eleven trials met the selection criteria, and 9 reported sufficient data for pooling. Standardized mean differences were calculated by using differences in improvements from baseline between patients assigned to acupuncture and those assigned to control groups. Compared with patients in waiting list control groups, patients who received acupuncture reported clinically relevant short-term improvements in pain (standardized mean difference, –0.96 [95% CI, –1.21 to –0.70]) and function (standardized mean difference, –0.93 [CI, –1.16 to –0.69]). Patients who received acupuncture also reported clinically relevant short- and long-term improvements in pain and function compared with patients in usual care control groups. Compared with a sham control, acupuncture provided clinically irrelevant short-term improvements in pain (standardized mean difference, –0.35 [CI, –0.55 to –0.15]) and function (standardized mean difference, –0.35 [CI, –0.56 to –0.14]) and clinically irrelevant long-term improvements in pain (standardized mean difference, –0.13 [CI, –0.24 to –0.01]) and function (standardized mean difference, –0.14 [CI, –0.26 to –0.03]).

Limitation: Sham-controlled trials had heterogeneous results that were probably due to the variability of acupuncture and sham protocols, patient samples, and settings.

Conclusions: Sham-controlled trials show clinically irrelevant short-term benefits of acupuncture for treating knee osteoarthritis. Waiting list–controlled trials suggest clinically relevant benefits, some of which may be due to placebo or expectation effects.

Editors' Notes Context Previous studies have come to inconsistent conclusions about the effectiveness of acupuncture for treating knee osteoarthritis. Contribution This meta-analysis of 9 trials showed that sham-controlled trials identified no clinically meaningful short-term benefits in pain or function with acupuncture for knee osteo-arthritis, although trials that did not use a sham control identified some benefits. Implications The use of different types of comparisons (sham acupuncture vs. interventions in which the participant knew whether they were receiving acupuncture) explains the variability in the conclusions of published trials about the effectiveness of acupuncture for treating knee osteo-arthritis. Placebo or expectation effects probably account for the observed benefits. —The Editors

 

Author and Article Information

From the University of Maryland School of Medicine, Baltimore, Maryland; Technische Universität München, Munich, Germany; and VU University Medical Center, Amsterdam, the Netherlands.

Note: All study data, including full details of the characteristics of each included RCT and all outcome data extracted from each included RCT, are included in a RevMan file, which will be made available to researchers on request for reproducing these results.

Acknowledgments: The authors thank Nancy Min, PhD, for her support in calculating estimated SDs of change from baseline for publications that did not directly report these but did report other data that could be used to estimate SDs of change; Byungmook Lim, MD, MPH, PhD, for performing data extraction for Witt and colleagues' 2005 RCT (47); Marcos Hsu, LAc, for assessing the adequacy of the acupuncture administered in the RCTs; and Elizabeth Kimbrough Pradhan, PhD, for providing helpful comments on the manuscript. They also thank Claudia Witt, PhD, for providing unpublished data specific to patients with only knee osteoarthritis from Witt and colleagues' 2006 RCT (48), and Birgitte Christensen, MD; Wenlin Lee, PhD; Jorge Vas, MD; and Steffen Witte, PhD, all coauthors of included RCTs, for confirming and providing data related to their respective RCTs.

Grant Support: Mr. Manheimer and Dr. Berman were funded by a grant from the National Institutes of Health, National Center for Complementary and Alternative Medicine (R24 AT001293). Drs. Lao and Berman were also funded by a grant from the National Center for Complementary and Alternative Medicine (P01 AT002605-01A1).

Potential Financial Conflicts of Interest: Honoraria: K. Linde (German Medical Acupuncture Society [Deutsche Ärztegesellschaft für Akupunktur], British Medical Acupuncture Society); Grants received: L. Lao (National Institutes of Health), K. Linde (Deutsche Angestellten Krankenkasse, Barmer Ersatzkasse, Kaufmännische Krankenkasse, Hamburg Münchener Krankenkasse, Hanseatische Krankenkasse, Gmünder Ersatzkasse, HZK Krankenkasse für Bau- und Holzberufe, Brühler Ersatzkasse, Krankenkasse Eintracht Heusenstamm, Buchdrucker Krankenkasse), B.M. Berman (National Institutes of Health); Grants pending: L. Lao (National Institutes of Health).

Requests for Single Reprints: Eric Manheimer, MS, Center for Integrative Medicine, University of Maryland School of Medicine, 2200 Kernan Drive, Kernan Hospital Mansion, Baltimore, MD 21207.

Current Author Addresses: Mr. Manheimer and Drs. Lao and Berman: Center for Integrative Medicine, University of Maryland School of Medicine, 2200 Kernan Drive, Kernan Hospital Mansion, Baltimore, MD 21207.

Dr. Linde: Centre for Complementary Medicine Research, Department of Internal Medicine II, Technische Universität München, Kaiserstrasse 9, 80801 Munich, Germany.

Dr. Bouter: VU University, Executive Board, VU-Windesheim, De Boelelaan 1105, Room 2d-18, 1081 HV Amsterdam, the Netherlands.

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