Osteoarthritis of the knee is a common cause of chronic pain and disability. Because medical treatment with anti-inflammatory drugs may be associated with serious side effects and may not provide adequate relief of symptoms, many patients have turned to acupuncture. Studies of acupuncture have not consistently demonstrated its effectiveness and have been criticized for methodologic flaws. In a recent study, Witt and colleagues compared acupuncture with minimal acupuncture (i.e., superficial needling at nonacupuncture points) or no intervention in patients with severe osteoarthritis of the knee.
Patients eligible for the study were 50 to 75 years of age and met American College of Rheumatology criteria for osteoarthritis. For the seven days before baseline assessment, participants had radiologic changes in the knee joint of grade 2 or more on standard Kellgren-Lawrence criteria and an average daily pain intensity of 40 or more on a 100-mm visual analog scale. Exclusion criteria included knee pain caused by inflammatory, malignant, autoimmune, or active disease processes other than osteoarthritis. Patients also were excluded if they had a history of knee surgery, acupuncture, or arthroscopy within the previous year; intra-articular injection within the previous four months; or any osteoarthritis therapy within the previous four weeks, including systemic corticosteroids or physical therapy. More general exclusion criteria were serious medical conditions, pregnancy, and coagulation disorders or the use of anticoagulant medication.
After baseline assessment, eligible patients were assigned randomly to one of two treatment groups or a “waiting-list” group. The 150 patients randomized to acupuncture were offered 12 sessions over an eight-week period, each session lasting 30 minutes. The 76 patients randomized to minimal acupuncture were offered identical sessions but received superficial needling at predefined, distant, nonacupuncture points. Patients were informed that the study was to compare different types of acupuncture. All patients completed questionnaires at baseline, after eight weeks of treatment, and at 26 and 52 weeks from baseline. The primary outcome was the score on the standardized Western Ontario and McMasters Universities Osteoarthritis (WOMAC) Index, but data also were gathered using scales for pain-related disability, emotional aspects of pain, depression, and quality of life. Patients were questioned about days with pain, lost productivity, and use of medication during the study.
The patients in all three groups were comparable at the beginning of the study. The average age was 64 years, and most patients reported at least nine years of osteoarthritis-related pain. On average, patients reported pain on at least 26 days per month. Outcomes data at eight weeks were available on 285 patients (97 percent). At eight weeks, the mean WOMAC Index score was significantly better in the acupuncture group (26.9) than in the minimal acupuncture group (35.8) or the waiting-list group (49.6). In the acupuncture group, 52 percent of patients achieved a decrease of at least 50 percent in the WOMAC Index score, compared with 28 percent in patients who received minimal acupuncture and only 3 percent in the waiting list patients. Significantly better scores were recorded for the acupuncture group on all WOMAC subscales, analgesic use, and other secondary measures. The differences between the two treatment groups narrowed over time and were no longer statistically significant by 26 weeks.
The authors conclude that an eight-week course of acupuncture treatment is associated with a reduction in symptoms and disability from osteoarthritis, but that the benefits are no longer statistically significant by 26 weeks.