Durable Effects of Acupuncture for Knee Osteoarthritis: A Systematic Review and Meta-analysis

Knee osteoarthritis is a degenerative disease that affects millions of people around the world, especially those over 40 years of age, causing chronic pain and difficulty walking and performing daily activities. This condition results from the progressive wear of the cartilage that protects the joints, leading to inflammation, stiffness, and restricted movement. Knee osteoarthritis is one of the leading causes of global physical disability, significantly impacting patients' quality of life and generating high costs for health care systems. The problem tends to worsen with the aging of the population and the increase in obesity cases, making it an increasingly relevant public health issue.

Conventional treatments available for knee osteoarthritis often have important limitations. Anti-inflammatory medications, although widely used, offer only temporary symptom relief and can cause serious side effects on the cardiovascular, digestive, renal, and hepatic systems. Intra-articular corticosteroid injections provide benefits for only 2 to 10 weeks, while other treatments such as physical exercise, although recommended, require prolonged adherence and are not always well tolerated by patients in pain. Given these limitations, there is a growing need for therapeutic alternatives that offer durable and safe benefits.

Acupuncture has shown promise in the treatment of chronic pain, but its ability to provide effects that persist after the end of treatment had not yet been well established.

To investigate this question, researchers conducted a comprehensive systematic review and meta-analysis, analyzing studies published through November 2023 in major medical databases. The study included 10 randomized clinical trials involving 3,221 participants with knee osteoarthritis, comparing acupuncture with different controls such as sham acupuncture, usual care, medications, and physical exercise. The methodology was rigorous, following international guidelines for systematic reviews and carefully assessing the quality of the included studies. The researchers focused specifically on results measured after the end of acupuncture treatment, using validated scales to assess pain and physical function, primarily the WOMAC index, which is considered the most reliable instrument for assessing patients with osteoarthritis.

The follow-up period ranged from 3 months to 1 year after the end of treatment, allowing for a comprehensive analysis of the durability of effects.

The results revealed that acupuncture can provide durable benefits for patients with knee osteoarthritis. When compared with sham acupuncture, true acupuncture showed improvements in physical function that persisted for up to 4.5 months after the end of treatment, in addition to overall pain reduction. Compared with usual care conventionally offered, acupuncture demonstrated clinically significant improvements in both pain and physical function that lasted up to 5 months after the end of sessions. When compared with diclofenac, a common anti-inflammatory medication, acupuncture showed benefits that extended up to 6 months after treatment.

A large study involving 661 participants found that improvements in pain and function persisted for 3 months after the end of acupuncture compared with receiving no treatment at all. All reported adverse effects were mild and temporary, such as pain at the needle site or small bruises, confirming the good safety profile of acupuncture.

The clinical implications of these findings are important for both patients and health care professionals. For patients, acupuncture offers a non-pharmacologic alternative that can provide durable pain relief and improvement in physical function, reducing dependence on anti-inflammatory medications and their potential side effects. The ability of acupuncture to maintain its benefits for months after the end of treatment suggests that it can be an economical and practical option, reducing the need for frequent interventions. For health care professionals, these results support the inclusion of acupuncture as part of a comprehensive treatment plan for knee osteoarthritis, especially for patients who do not respond adequately to conventional treatments or who wish to avoid medications.

The evidence of durable effects also suggests that acupuncture can help in the long-term management of this chronic condition, potentially slowing symptom progression and improving patients' quality of life.

It is important to acknowledge the limitations of this study when interpreting the results. The number of clinical trials included was relatively small, and some had methodological problems that may have influenced the results. Most outcomes were assessed through self-reported questionnaires, which may introduce some subjective bias. In addition, studies with longer follow-up periods are still lacking to assess whether the benefits of acupuncture can last beyond 6 months.

The definition of treatment response varied across studies, making some comparisons less precise. The researchers also observed that, when acupuncture was used as a complement to exercise-based physical therapy, it did not show significant additional advantages, suggesting that the context of treatment may influence its efficacy.

In conclusion, this systematic review provides encouraging evidence that acupuncture may offer durable benefits for patients with knee osteoarthritis, with improvements in pain and physical function persisting for 3 to 6 months after the end of treatment. These findings support the use of acupuncture as a valuable therapeutic option for the management of this debilitating condition, especially considering its excellent safety profile. However, more high-quality studies with longer follow-up periods are needed to definitively confirm these benefits and establish optimal treatment protocols. For patients suffering from knee osteoarthritis, acupuncture represents a promising alternative that can provide sustained symptom relief and improved quality of life, complementing or, in some cases, replacing conventional treatments that are more limited in their durability.