Acupuncturing of myofascial pain trigger points for the treatment of knee osteoarthritis: A systematic review and meta-analysis
Lin et al. · Medicine · 2022
Evidence Level
MODERATEOBJECTIVE
Evaluate the efficacy and safety of acupuncture at myofascial trigger points for treatment of knee osteoarthritis
WHO
724 patients with knee osteoarthritis from 9 randomized controlled trials
DURATION
Ranged from 3-6 weeks across the included studies
POINTS
Periarticular myofascial trigger points of the knee, primarily in the quadriceps muscle
🔬 Study Design
Trigger-point acupuncture
n=372
Needling of myofascial trigger points
Control
n=352
Traditional acupuncture, electrotherapy, or medication
📊 Results in numbers
Total effectiveness rate
Pain reduction (VAS)
Functional improvement (Lysholm)
Joint function (WOMAC)
📊 Outcome Comparison
Clinical efficacy
This study analyzed 9 trials on the treatment of knee osteoarthritis with acupuncture at painful points in the muscles around the joint. The results showed that this technique was more effective than conventional treatments for reducing pain and improving knee movement, and was considered safe.
Article summary
Plain-language narrative summary
Knee osteoarthritis is a chronic degenerative joint disease affecting millions of people, causing significant pain and functional limitation. This systematic review and meta-analysis investigated a specific therapeutic approach: needling of periarticular myofascial trigger points of the knee for treatment of this condition.
The review included nine randomized controlled trials with 724 patients diagnosed with knee osteoarthritis, analyzing data from five major databases through December 2021. The experimental group received acupuncture targeting myofascial trigger points — specific areas of muscle tension and pain around the knee — while the control group received various treatments such as traditional acupuncture, electrotherapy, or oral medication.
The theory behind this approach is based on the understanding that muscle dysfunction plays a key role in the development and progression of knee osteoarthritis. Myofascial trigger points are areas of intramuscular hypertension that may cause biomechanical imbalance of the joint. Inactivation of these points through acupuncture aims to restore muscle balance and reduce joint overload.
The meta-analysis results showed statistically significant superiority of trigger-point treatment across multiple outcomes. The total clinical effectiveness rate showed a standardized mean difference of 2.53, indicating substantial benefit. On the Visual Analogue Scale for pain, there was significant reduction (SMD=-0.83), representing clinically relevant relief of painful symptoms.
Knee function was assessed using specific scales. The Lysholm score, which measures knee function and symptoms, showed considerable improvement (SMD=6.94). Similarly, the WOMAC index, which assesses pain, stiffness, and physical function specific to osteoarthritis, showed significant reduction in limitation scores (SMD=-5.94), indicating important functional improvement.
Regarding safety, only two cases of dropout for personal reasons were reported, with no significant adverse events documented in seven of the nine studies. This suggests that the technique has a favorable safety profile.
The clinical implications are promising, suggesting that needling of myofascial trigger points may be an effective and safe alternative for conservative management of knee osteoarthritis. The technique offers a targeted approach to the underlying biomechanical causes, not just symptoms.
However, important limitations restrict the immediate applicability of the findings. The methodological quality of the included studies was considered moderate to low, with risks of bias in several categories. Heterogeneity across studies was significant for some outcomes, indicating variability in populations, interventions, or measures used. In addition, the individual sample size of the studies was relatively small.
Strengths
- 1Meta-analysis including multiple relevant clinical outcomes
- 2Documented safety assessment
- 3Comprehensive search across multiple databases
- 4Appropriate statistical analysis with random-effects models
Limitations
- 1Low to moderate methodological quality of included studies
- 2Significant heterogeneity across studies for some outcomes
- 3Small sample size in individual studies
- 4Possible publication bias detected in funnel-plot analysis
Expert Commentary
Dr. Marcus Yu Bin Pai
MD, PhD · Pain Medicine · Physical Medicine and Rehabilitation · Medical Acupuncture
▸ Clinical Relevance
Knee osteoarthritis accounts for an enormous share of the demand in any musculoskeletal pain service, and conservative management frequently bumps up against the analgesic limits of NSAIDs, restrictions on prolonged opioid use, and a pre-surgical window that can extend for years. This meta-analysis of 724 patients positions needling of periarticular myofascial trigger points of the knee as a therapeutic option with clinically meaningful effect magnitude on pain and function — outcomes measured by VAS, Lysholm, and WOMAC, which are precisely the instruments we use to track clinical progress in the office. The favorable safety profile, with no significant adverse events documented, makes the technique applicable to polymedicated older patients in whom minimizing pharmacologic load is a priority. Patients in Kellgren-Lawrence grades II and III, with documented periarticular myofascial pain and moderate functional limitation, represent the group that may most clearly benefit from this intervention within the conservative treatment algorithm.
▸ Notable Findings
The finding that draws most attention is not the simple reduction in pain — the SMD of -0.83 on the VAS would already be enough to justify the technique — but the magnitude of functional improvement captured by Lysholm (SMD=6.94) and WOMAC (SMD=-5.94), scales that reflect the patient's actual ability to climb stairs, perform transfers, and maintain functional gait. These effects exceed those of active controls, which included traditional acupuncture, electrotherapy, and oral medication — relevant comparators, not passive placebo groups. From a mechanistic perspective, the central hypothesis of the work deserves attention: active myofascial trigger points in the periarticular musculature of the knee — vastus medialis, rectus femoris, gastrocnemius — generate force imbalance at the joint and central nociceptive amplification. Inactivating these foci restores biomechanical balance and reduces chondral overload, addressing a pathophysiologic component frequently overlooked in conventional treatment of osteoarthritis.
▸ From My Experience
In my practice in the musculoskeletal pain clinic, I have observed that patients with knee osteoarthritis rarely present with purely articular pain — there is almost invariably an overlapping myofascial component in the vastus medialis, hamstrings, or medial gastrocnemius, identifiable on palpation and frequently responsible for a significant portion of functional limitation. I typically see a clinical response within the first three needling sessions, with improvement in morning stiffness and range of motion. For maintenance, I work with cycles of six to eight sessions, combined with quadriceps strengthening and pain education — without supervised exercise, the analgesic gain tends to be partial and short-lived. I do not use the technique in isolation in patients with advanced Kellgren-Lawrence grade IV and severe structural deformity in varus or valgus, where surgical indication should prevail. The profile that responds best, in my experience, is the patient at moderate stage, with predominantly mechanical pain and clearly identifiable trigger points on physical examination — exactly the profile this work appears to have captured in its nine studies.
Full original article
Read the full scientific study
Medicine · 2022
DOI: 10.1097/MD.0000000000028838
Access original articleScientific Review
Marcus Yu Bin Pai, MD, PhD
CRM-SP: 158074 | RQE: 65523 · 65524 · 655241
PhD in Health Sciences, University of São Paulo. Board-certified in Pain Medicine, Physical Medicine and Rehabilitation, and Medical Acupuncture. Scientific review and curation of every entry in this library.
Learn more about the author →Medical disclaimer: This content is for educational purposes only and does not replace consultation, diagnosis, or treatment by a qualified professional. Some information may be assisted by artificial intelligence and is subject to inaccuracies. Always consult a physician.
Content reviewed by the medical team at CEIMEC — Integrated Centre for Chinese Medicine Studies, a reference in Medical Acupuncture for over 30 years.
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