Comparative effectiveness of moxibustion and acupuncture for the management of osteoarthritis knee: A systematic review and meta-analysis

Knee osteoarthritis represents one of the most challenging health problems facing the older population worldwide. This degenerative condition, characterized by progressive wear of joint cartilage, hardening of subchondral bone, and changes in joint shape, mainly affects the knees due to the weight they constantly bear. Symptoms include chronic pain, stiffness, restricted movement, and joint instability, significantly impacting patients' quality of life. In China, where this condition affects approximately 5-10% of middle-aged and older adults, population aging makes the search for effective treatments urgent.

While conventional approaches include exercise, weight loss, anti-inflammatory medications, and surgery in severe cases, traditional Chinese medicine offers alternatives such as acupuncture and moxibustion, both recognized for their efficacy with minimal adverse effects.

This study aimed to directly compare the efficacy of moxibustion versus acupuncture in the treatment of knee osteoarthritis, filling an important gap in the scientific literature. Moxibustion is an ancient technique that uses burning mugwort (a medicinal plant) at specific body points to stimulate blood circulation, often used together with acupuncture. The researchers conducted a comprehensive systematic review, rigorously following international guidelines for this type of research. They performed searches across multiple medical databases, including PubMed, EMBASE, MEDLINE, and specialized Chinese databases, covering the period from January 1964 through April 2022.

Only randomized controlled trials directly comparing these two techniques in adults with knee osteoarthritis were included. The analysis focused on two main outcomes: pain reduction and treatment success rate, using advanced statistical methods to combine results across studies.

The final analysis included 21 studies involving patients treated exclusively in China, with group sizes ranging from 28 to 120 participants. The results demonstrated clear superiority of moxibustion compared with conventional acupuncture. For pain reduction, moxibustion showed statistically significant benefits, with a standardized mean difference of -0.53, indicating lower pain intensity in patients treated with this technique. When the researchers specifically analyzed the type of moxibustion used, they found that the "fire needle" technique (a variation that combines acupuncture with intense heat) was particularly effective, providing superior pain relief compared with other moxibustion methods.

Interestingly, efficacy varied depending on the pain scale used: while scales such as VAS (Visual Analogue Scale) and ISOA showed clear benefits of moxibustion, the WOMAC scale did not show significant differences between treatments. Regarding the overall treatment success rate, moxibustion showed 1.39 times higher odds of success compared with acupuncture, with this result being statistically robust and clinically relevant.

From a clinical perspective, these findings have important implications for both patients and health professionals. For patients with knee osteoarthritis seeking nonpharmacologic alternatives, moxibustion — especially the fire-needle technique — emerges as a promising option that may offer superior pain relief and better therapeutic outcomes compared with traditional acupuncture. Proposed mechanisms for this superiority include moxibustion's ability to reduce cartilage damage, decrease inflammatory-cell infiltration, and improve local blood circulation through therapeutic heat. The technique has also shown the ability to inhibit specific inflammatory mediators and regulate growth factors important for joint repair.

For clinicians, these results suggest that moxibustion may be considered a first-line treatment within traditional Chinese medicine approaches, potentially integrating into broader treatment protocols that include physical therapy and pharmacologic management when necessary.

However, it is essential to recognize important limitations of this study that influence interpretation of the results. Approximately half of the included studies had high risk of methodological bias, compromising the reliability of the evidence. The GRADE analysis, an international system for assessing evidence quality, classified the findings as "very low quality," indicating considerable uncertainty about the results. In addition, publication bias was detected for the pain outcome, suggesting that studies with negative results may not have been published.

Significant heterogeneity across studies, reflecting differences in populations, specific techniques used, and outcome measures, also limits generalization of the findings. All studies were conducted in China, raising questions about the applicability of the results to other populations and health systems. Although promising, these results should be interpreted with caution, and patients interested in these approaches should discuss options with qualified professionals, considering individual needs and realistic expectations about the potential benefits. Future research with more rigorous methodology and more diverse samples is needed to definitively confirm the superiority of moxibustion in the treatment of knee osteoarthritis.