Dear editor

We are writing to express our appreciation for the recent study “The impact of Fu’s subcutaneous needling on lower limb muscle stiffness in knee osteoarthritis patients: study protocol for a pilot randomized controlled trial”.¹

This research introduces a novel approach by utilizing shear wave elastography (SWE) to examine the effects of Fu’s subcutaneous needling (FSN) on lower limb muscle stiffness in patients with knee osteoarthritis (KOA).

In recent years, the emerging technology of SWE offers real-time, non-invasive imaging with rapid acquisition and strong reproducibility, enabling quantitative assessment of tissue elasticity. This technique has gradually been applied in studying acupuncture treatments for musculoskeletal disorders. A recent observational study² indicated that FSN could reduce lower limb muscle stiffness in KOA patients; however, the authors concluded that further verification is required through randomized controlled trials. The standardized SWE operational protocol proposed in this study could effectively reduce measurement errors and provide a valuable reference for future research. This method will offer new insights into how FSN alleviates joint pain and functional impairments. Furthermore, the authors reference previous studies multiple times, such as the impact of FSN on quadriceps stiffness and the confounding effects of subcutaneous fat layers. Therefore, we suggest that the authors clearly articulate how this current research improves upon or expands the findings of earlier studies.

Additionally, we noticed that the authors employed more frequent evaluations using the Numeric Rating Scale (NRS) and WOMAC compared to previous acupuncture studies³ on KOA. This raises a critical question: is it necessary to conduct evaluations at such a high frequency? While frequent assessments may provide detailed monitoring of therapeutic effects, it would benefit the authors to justify this approach, especially if previous studies utilized less frequent evaluations. Clarifying the rationale behind this decision would enhance understanding the study design and its implications.

Finally, the authors’ preliminary research utilized transcutaneous electrical nerve stimulation as a control,⁴ whereas this study protocol has opted for electroacupuncture. It would be beneficial for the authors to further elucidate the rationale for this change in control intervention and discuss any potential implications for the study’s outcomes. The current study must be differentiated from the authors’ previous preliminary research.

I look forward to the results of this important research and its potential implications for treating knee osteoarthritis. Thank you for considering these points to enhance the clarity and impact of this significant work.