Tendon Rupture by Acupuncture? Reporting of Not Probable Causality Might Exaggerate Harm of Acupuncture
Article information
This letter to the editor summarizes the correspondence regarding an article written by Liew and Teh, “Flexor pollicis longus rupture following acupuncture for trigger thumb: A case report,” written published in Acupuncture in Medicine [1].
Liew and Teh [1] presented a case report of a 48-year-old female patient with a flexor pollicis longus (FPL) rupture who had developed pain and right-sided trigger thumb 3 months previously (she did not have a previous trauma history). The patient presented with mild swelling of her right thumb which had lost some flexibility. Two months previously, she had received 3 sessions of traditional acupuncture which she recalled were painful (especially the last session). The needling was located at 2 points along the palmar surface midline of her thumb.
The authors proposed that complete rupture of FPL was attributable to 3 sessions of acupuncture treatment. However, we found that other possible causal factors of rupture aside from the needling had been overlooked in this case. The authors only stated whether there was a history of trauma prior to the onset of symptoms and there was no evidence of medical history except for acupuncture treatment. It has previously reported that 3.75% of FPL ruptures are spontaneous [2]. Before the authors concluded that acupuncture had caused a FPL rupture, it would have been pertinent to determine whether there was a history of local injections of corticosteroid, whether the patient had inflammatory arthritis, diabetes mellitus, or labor-associated tendon loading [3,4]. Given that the patient had developed pain and symptoms of trigger thumb 3 months prior to presentation, whether the patient had felt or heard a pop during the acupuncture needling would be a more relevant detail needed to help diagnose traumatic tendon rupture. Instead mild swelling, pain, and restriction of flexion in the thumb was reported to be attributable to acupuncture treatment.
In addition, how plausible would it be that just 3 treatments of acupuncture could cause complete rupture? A normal FPL tendon of an adult woman is composed of strong bundle Type I collagen fibers with a thickness of 4 mm [5,6]. As it is a viscoelastic material capable of resisting high tensile force, there would need to be tension loading over 8% of strain to lead to complete tendon rupture according to the stress-strain curve [7]. Considering that general types of acupuncture needle are 0.20–0.25 mm in diameter, its tip would pass through the tendon sheaths, it cannot dissect them because unlike an acupotomy needle which is a sharp-bladed scalpel, the traditional acupuncture needle is a thin filiform needle. So, despite the acupuncture needle piercing the tendon, it would be very unlikely that this traditional acupuncture (needled twice over 3 sessions) would cause macroscopic failure to FPL.
Moreover, we have concerns regarding the details of the acupuncture treatment in this case. From acupuncture experts’ points of view, we recommend the authors to describe, specifically, the needling site, insertion depth, and include the needle direction upon insertion, and needle type (e.g., length, diameter, material) to better understand the clinical condition under which acupuncture was applied. However, the authors, only depending on the patient’s memory of the needling site, presumed that the acupuncturist may have incorrectly located the Wuhu acupuncture points. As Wuhu points are anatomically strictly distant from the actual 2 needling points used, it might be more probable that selection of the needling site was based on treating Ashi or tender points rather than Wuhu points. Furthermore, we cannot be certain that the acupuncture needle actually pricked the tendon, as the FPL tendon path could vary in accordance with abduction or adduction of the thumb [8].
Lastly, the authors confused the location of acupuncture points when mentioning, “Taiyang, PC6 (Neiguan) and LI4 (Hegu) in the hand,” in the Commentary section, though Taiyang and Neiguan are located on the temple and the upper limb, respectively. This kind of fundamental error of needling point location appears to be trivial, however, meticulous consideration of the details of acupuncture treatment is required to sustain the credibility of case reports regarding acupuncture-related adverse events.
In conclusion, although a case report is a useful method to reveal unexpected adverse events of acupuncture treatment, its academic value would be degraded if the causality were not properly investigated or overexaggerated. Therefore, the authors should have recognized that acupuncture is a complex intervention, not merely an invasive tool, and they should have considered the related technique in detail with more precise diagnostic process.
Acknowledgements
This letter was not suitable for publication in Acupuncture in Medicine due to the journal’s policy of not accepting letters to the editor, commentaries or post-publication peer reviews. This commentary was therefore submitted to Perspectives on Integrative Medicine.
Notes
Author Contributions
Conceptualization: T-HK, JWK. Formal investigation: S-AK. Data analysis: JWK. Writing original draft: S-AK. Writing - review and editing: T-HK, JWK.
Conflicts of Interest
The authors have no conflicts of Interest to declare.
Funding
None.
Ethical Statement
This letter did not include any personal information. We followed general research ethics guidelines for this letter.
Data Availability
There is no usable data in this article.