A Randomized Controlled Trial of Acupuncture for Osteoarthritis of the Knee: Effects of Patient-Provider Communication

This study represents an important milestone in research on acupuncture for knee osteoarthritis, being the first randomized clinical trial to systematically investigate the effects of patient-therapist communication on treatment outcomes. The research was conducted with 527 patients with confirmed knee osteoarthritis, aged 50 years or older, who had never previously received acupuncture. The experimental design included a waitlist control group and treatment groups receiving traditional Chinese acupuncture (TCA) or sham acupuncture, nested within two different communication styles: "high expectations" and "neutral." Acupuncturists were trained to interact consistently with each style, with those in the "high expectations" group using phrases such as "I believe this will work for you" and "I've had a lot of success treating knee pain," while the "neutral" group used expressions like "It may or may not work" and "It really depends on the patient." The acupuncture protocol used electroacupuncture with standardized points for all patients. For TCA, traditional points such as Xiyan, Heding, GB-34, SP-6, SP-9, and auricular points were used, with needles inserted to depths of 0.2 to 1.2 cun and continuous electrical stimulation.

The sham group received thinner, more superficial needles at points located off the relevant meridians, with minimal electrical stimulation. Blinding was successful, with only 52% of TCA group patients and 43% of sham group patients believing they had received traditional acupuncture. The main results showed no statistically significant differences between traditional and sham acupuncture for any outcome measure. Both treatment groups showed significant improvements compared with the control group, with reductions in pain measured by the J-MAP (-1.1 and -1.0 versus -0.1, p<0.001) and by the WOMAC (-13.7 and -14.0 versus -1.7, p<0.001).

Surprisingly, acupuncturist communication style had significant effects on outcomes. Patients in the "high expectations" group showed greater pain reduction and greater treatment satisfaction compared with the "neutral" group, with effect sizes of 0.25 and 0.22, respectively, at 3 months. This finding suggests that part of the analgesic benefits of acupuncture may be mediated by placebo effects related to therapist behavior. The clinical implications are substantial.

The study questions the importance of the specific meridians and points emphasized by traditional Chinese medicine, suggesting that the analgesic effect of acupuncture may be smaller than traditionally believed and may result from incomplete blinding or nonspecific effects of the needling procedure. The finding that communication style influences outcomes opens new perspectives for optimizing pain treatments through improvement of the therapeutic relationship. The study has some important limitations. First, it was not possible to make inferences about less invasive placebo procedures, such as retractable nonpenetrating needles.

Second, although verbal interactions were recorded, nonverbal communication may also be important in the acupuncture context and was not measured. Third, despite efforts to blind the study, some patients may have perceived which treatment they were receiving, although no differential responses were observed when specifically questioned. Treatment safety was adequate, with minor adverse events including exacerbation of knee pain (7.2% TCA vs 4.9% sham), needle-site bruising (5.8% vs 4.6%), and rare cases of muscle cramps, headache, and needle-site infection. This study contributes significantly to our understanding of the mechanisms of action of acupuncture and highlights the importance of contextual factors in pain treatment, providing robust evidence to guide both clinical practice and future research in the field.