Evidence from RCTs on optimal acupuncture treatment for knee osteoarthritis--an exploratory review.

There are many differing opinions on what constitutes an optimal acupuncture dose for treating any particular patient with any particular condition, and only direct comparisons of different methods in a clinical trial will provide information on which reliable decisions can be made. This article reviews the recent research into acupuncture treatment for osteoarthritis of the knee, to explore whether any aspects of treatment seem more likely to be associated with good outcome of treatment. Among four recent, high quality RCTs, one showed a much greater treatment response than the other three, and the possible factors are discussed. A recent systematic review included 13 RCTs, and this article discusses the possible explanations for differences in their outcomes. It is speculated that optimal results from acupuncture treatment for osteoarthritis of the knee may involve: climatic factors, particularly high temperature; high expectations of patients; minimum of four needles; electroacupuncture rather than manual acupuncture, and particularly, strong electrical stimulation to needles placed in muscle; and a course of at least 10 treatments. These factors offer some support to criteria for adequate acupuncture used in the recent review. In addition, ethnic and cultural factors may influence patients' reporting of their symptoms, and different versions of an outcome measure are likely to differ in their sensitivity - both factors which may lead to apparent rather than real differences between studies. The many variables in a study are likely to be more tightly controlled in a single centre study than in multicentre studies.