Acupuncture and knee osteoarthritis: a three-armed randomized trial.

Background: Despite the popularity of acupuncture, evidence of its efficacy for reducing pain remains equivocal.

Objective: To assess the efficacy and safety of traditional Chinese acupuncture (TCA) compared with sham acupuncture (needling at defined nonacupuncture points) and conservative therapy in patients with chronic pain due to osteoarthritis of the knee.

Design: Randomized, controlled trial.

Setting: 315 primary care practices staffed by 320 practitioners with at least 2 years' experience in acupuncture.

Patients: 1007 patients who had had chronic pain for at least 6 months due to osteoarthritis of the knee (American College of Rheumatology [ACR] criteria and Kellgren-Lawrence score of 2 or 3).

Interventions: Up to 6 physiotherapy sessions and as-needed anti-inflammatory drugs plus 10 sessions of TCA, 10 sessions of sham acupuncture, or 10 physician visits within 6 weeks. Patients could request up to 5 additional sessions or visits if the initial treatment was viewed as being partially successful.

Measurements: Success rate, as defined by at least 36% improvement in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score at 26 weeks. Additional end points were WOMAC score and global patient assessment.

Results: Success rates were 53.1% for TCA, 51.0% for sham acupuncture, and 29.1% for conservative therapy. Acupuncture groups had higher success rates than conservative therapy groups (relative risk for TCA compared with conservative therapy, 1.75 [95% CI, 1.43 to 2.13]; relative risk for sham acupuncture compared with conservative therapy, 1.73 [CI, 1.42 to 2.11]). There was no difference between TCA and sham acupuncture (relative risk, 1.01 [CI, 0.87 to 1.17]).

Limitations: There was no blinding between acupuncture and traditional therapy and no monitoring of acupuncture compliance with study protocol. In general, practitioner-patient contacts were less intense in the conservative therapy group than in the TCA and sham acupuncture groups.

Conclusions: Compared with physiotherapy and as-needed anti-inflammatory drugs, addition of either TCA or sham acupuncture led to greater improvement in WOMAC score at 26 weeks. No statistically significant difference was observed between TCA and sham acupuncture, suggesting that the observed differences could be due to placebo effects, differences in intensity of provider contact, or a physiologic effect of needling regardless of whether it is done according to TCA principles.