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The recent trial by Hinman et al1 has overcome some of the methodological issues in acupuncture research by meticulously controlling for the treatment expectations of participants through the Zelen design and consideration of clinical relevance using minimal clinically important differences. However, some of the important practical issues highlighted by current evidence were not incorporated into the trial.
Randomised trials often fail to resolve conflicts or reduce gaps between current evidence and practice by failing to reflect properly the results of relevant systematic reviews during the initial planning and design of the study.2 The latest Cochrane review of acupuncture for knee osteoarthritis suggested further research into the use of electrical stimulation, based on the results of a sensitivity analysis that showed better analgesic effects compared to manual stimulation.3 However, this finding was not reflected at all in the trial by Hinman et al.1 In fact, the description of the type of needle stimulation, which is an important treatment component of acupuncture, was not specified in either the report or in the protocol.1 The Cochrane review also emphasised the potential importance of maintaining extended monthly treatment sessions during the long-term follow-up period to avoid attenuation of the effects of acupuncture over time,3 yet the trial by Hinman et al1 did not consider maintenance or tapered acupuncture treatments.
We understand that the study protocol by Hinman et al1 preceded the aforementioned Cochrane review,3 and that the authors may not have been able to incorporate the implications of the review into their design. However, suggestions that electroacupuncture is superior to manual acupuncture for osteoarthritic knee pain,4 and monthly maintenance acupuncture sessions should be considered before long-term assessment,5 had already been raised by a previous systematic review and a meta-analysis. At the very least, these two suggestions should have been considered in the interpretation of the findings.
Based on current practical evidence, we suggest that further trials incorporating electroacupuncture and follow-up maintenance treatments are conducted before any definitive conclusions about acupuncture for chronic knee pain are made.
Contributors All the authors conceived this letter and drafted and wrote the manuscript. All the authors approved the final manuscript and agreed to its submission for publication.
Competing interests None declared.
Provenance and peer review Not commissioned; internally peer reviewed.