Acupuncture may be an effective therapy for hip osteoarthritis. A recent study reviewed the small number of clinical trials that have been conducted to investigate the effectiveness of this potential therapy.
Osteoarthritis is a painful, chronic condition that occurs when the protective cartilage in the joints wears away due to age or prolonged wear and tear. Hip osteoarthritis affects somewhere between 3 and 11% of adults in Western countries. There is no cure, with most treatments involving exercise, physical therapy, or pain-killing and anti-inflammatory drugs. Severe hip osteoarthritis may require surgery, and 200,000 hip replacements are performed in the United States every year.
Traditional Chinese acupuncture involves inserting needles into specific parts of the body. This is based on a belief that energy circulates throughout the body along certain pathways, and that the disruption of this energy flow can cause pain or ill health. According to this belief, inserting needles into key nodes in the energy pathways can re-normalize energy flow. There is no scientific evidence for this concept.
There has been some evidence that inserting acupuncture needles could stimulate the body to release natural pain-killing molecules, or could temporarily decrease the ability of the nervous system to sense pain. Furthermore, acupuncture is a relatively safe procedure. There have been a number of clinical trials attempting to test the effectiveness of acupuncture as a treatment for hip osteoarthritis.
A group of American and Chinese researchers sought to collect the results of all these previous studies, and re-analyze the results as a group. They recently published the results of their study in the Cochrane Database of Systematic Reviews.
Acupuncture had a low risk of serious side effects
The researchers searched the scientific literature for clinical trials comparing acupuncture to other treatments in patients with hip osteoarthritis. They found six clinical trials meeting their criteria. Participants in the trials had average ages ranging from 61 to 67 years, and two-thirds of them were women. They had experienced hip osteoarthritis pain for an average of two to eight years prior to the studies.
Patients received acupuncture for between 4 and 13 weeks. Four of these trials included information on the safety of the treatment; none of them reported any serious adverse effects due to acupuncture. There were minor side effects in some patients, such as minor bruising, pain or bleeding where needles were inserted.
Acupuncture is not better than sham acupuncture for treating hip osteoarthritis
In the ideal clinical trial, both the study participants and the personnel conducting the study are “blinded”. That is, they are not aware of who is receiving the treatment or the control treatment that it is being compared to.
Blinding in clinical trials is important for two reasons. First, the knowledge of who is receiving certain treatments could result in study personnel treating the two groups differently. For example, doctors may pay more attention to study participants who are receiving the treatment of interest, potentially resulting in them getting better medical care than those in the control group. Second, patients knowingly receiving the treatment may experience a placebo effect, where their preconceived ideas of the treatment’s effectiveness could actually increase its effect through biological mechanisms that are still unclear. This is obviously a challenging problem for an acupuncture study, where it is very difficult to hide the fact that someone received the treatment.
Some studies approach the issue of trial blinding by comparing acupuncture to a sham acupuncture procedure. Sham acupuncture uses needles that do not actually penetrate the skin, or that are inserted in improper locations.
The researchers found two studies that compared the effectiveness of acupuncture to a sham acupuncture procedure. Both studies found that acupuncture was no better than the sham procedure at decreasing pain or improving hip function. One study found that acupuncture resulted in a small improvement to the study participant’s perception of their quality of life; the other study did not attempt to measure the quality of life.
The researchers assessed the quality of the clinical studies that they reviewed. They rated the sham acupuncture studies as of medium quality, with the main deficiency being their small size (62 and 88 participants).
Weak evidence that acupuncture is more effective than conventional hip osteoarthritis therapy
The researchers found four studies that compared the effectiveness of conventional medical care alone to conventional medical care in addition to acupuncture. However, they rated these studies to be of low, or very low, quality. These studies were also very small (between 28 and 137 participants), did not blind the study participants or the study staff, and some studies may have allowed study participants to choose whether they were in the acupuncture or control groups.
The least-poor of these studies found that acupuncture plus routine physician care was more effective than routine care alone at decreasing pain, improving bodily function and increasing physical, but not mental, quality of life. The researchers considered the remaining studies to be of very low quality. Two of these studies reported that the combination of acupuncture and conventional care was superior to conventional care alone (patient education or diclofenac, an anti-inflammatory drug). The final study found that the combination of acupuncture, advice and exercise was not more effective than advice and exercise alone.
A need for high-quality clinical studies of acupuncture and hip osteoarthritis
Overall, the researchers concluded that acupuncture likely offers no benefit over sham acupuncture. There is evidence that acupuncture was superior to conventional therapy, but weaknesses in the design of the clinical trials limited the reliability of these results. Notably, many of these studies did not account for placebo effects.
Better quality studies, with more participants and proper blinding, are needed to conclusively determine if acupuncture is truly effective for hip osteoarthritis. However, acupuncture did not cause any serious adverse effects. If individual patients wish to pursue this option in addition to standard therapy, it should be safe to do so.
Written by Bryan Hughes, PhD
Reference: Manheimer, E., Cheng, K., Wieland, L. S., Shen, X., Lao, L., Guo, M. & Berman, B. M. Acupuncture for hip osteoarthritis. Cochrane Database of Systematic Reviews (2018)