Inspired by Yu et al 2021.
PoPS – principles of point selectionkey to acronyms
OA – osteoarthritis
VAS – visual analogue scale
ROM – range of movement
HNCS – heterotopic noxious conditioning stimulation
DNIC – diffuse noxious inhibitory control
I will immediately admit that I am always biased in this debate in favour of local needling. My bias is probably categorised as confirmational bias, although in this case I am motivated to highlight and argue against the results of this research paper because it does not seem to support my pre-existing world view.
I am biased in favour of local needling in most circumstances based on a mechanistic perspective of the effects of needling. The local approach can theoretically provide both local antinociception as well as segmental (regional) inhibition of nociception, not to mention the general effects of needling in reducing the perception of suffering. I don’t really see this as bias, but more as mechanistic logic; however, we always have to consider that whilst our theories based on good basic science and laboratory data may be highly plausible, sometimes they simply may not be relevant in the real world of clinical medicine on humans.
So, studies like this comparing local with distant needling in knee osteoarthritis may be legitimate, even though I would never ask this research question myself.
In this case the title seems to imply that distant needling is superior, and thus it attracted my critical eye.
Let’s just clear up the terminology for a minute. The terms I was first introduced to were local and distal – if a treatment involved local points on a certain meridian, then distal points on the same meridian were often chosen to compliment them. Often distal points in limbs are segmentally relevant to more proximal conditions, but as I studied segmental approaches more, I soon changed the distal term to distant in our PoPS, so as to be inclusive of other segmental approaches that were not distal relative to the site of the problem. Paraspinal segmental needling is probably the best example here.
This paper uses the term proximal rather than local, and distal rather than distant, although the so-called distal points they use for knee OA are around the elbow. The study is relatively neat in that 3 points are used in each of 3 groups. The 3 points around the knee were GB34, SP9 & Heding (just above the patella). The 3 points in the arm were LI11, HT3 and TE10. The third group was a sham needling group using Streitberger-style non-penetrating needling at CV12 & ST21 bilaterally.
There is no competition here, is there? You would always go for the points around the knee to treat knee OA. So, how is it that this group managed to make the distant points appear to be the best approach?
It all comes down to the outcome chosen. In this case the primary outcome was pain VAS and knee ROM immediately after treatment. Whilst I am sure acupuncturist readers have prominent memories of patients with knee OA springing off the couch after treatment, jumping around and declaring that they are cured, these cases are relatively infrequent but quite memorable. The more frequent and less memorable patients will feel some post-needling soreness for a while, and if that soreness is in the region of the original pain it will be difficult to make any immediate evaluation. If, however, that soreness is somewhere else, it will distract the patient from the background pain in their knee. But the distraction will only last as long as the soreness, whereas those that have been treated locally or segmentally (regionally) can expect an improvement the following day, when descending inhibitory systems are maximally engaged, or at least have had time to mediate their effects.
This decision to measure immediate effects seems like a logical ‘own goal’ in terms of a research question, but it is not the first time this has been done!
So, will I start needling the elbows of my patients with knee OA? Of course not. Not unless I am in some competition to gain a very short-term effect. A bit like the techniques that are used to distract a patient from their pain temporarily so they can get on a couch and receive the definitive treatment, or the distant needling technique tested by Jorge Vas and his team in chronic shoulder pain.
I had the opportunity to experience this technique first-hand from Jorge because the paper was published a week before he was due to speak at a BMAS meeting in York. He inserted a 100mm needle most of the way through my lower leg from ST38 through tibialis anterior, the interosseous membrane, tibialis posterior, soleus and gastrocnemius to BL57. When he rotated the needle, I could feel the sensation in all 3 muscular compartments at the same time and could imagine that the sensation might distract me from any pain I felt on mobilising my bad shoulder, should I have been a patient in his trial.
This form of strong distant needling probably acts in a similar way to what is now referred to as HNCS and was first called DNIC. I say probably because the acupuncture, whilst it can create a strong sensation, it is seldom actually noxious. By comparison most laboratory studies on HNCS apply the conditioning stimulus to skin, and any high threshold stimulus to skin is usually noxious… so, there is another advantage of acupuncture for you.
1 Yu W-Z, Huang C-M, Ng H-P, et al. Distal Acupoints Outperform Proximal Acupoints in Treating Knee Osteoarthritis: A Randomized Controlled Trial. Evid-Based Complement Altern Med ECAM 2021;2021:4827123. doi:10.1155/2021/4827123
2 Irnich D, Behrens N, Gleditsch JM, et al. Immediate effects of dry needling and acupuncture at distant points in chronic neck pain: results of a randomized, double-blind, sham-controlled crossover trial. Pain 2002;99:83–9. doi:10.1016/S0304-3959(02)00062-3
3 Vas J, Ortega C, Olmo V, et al. Single-point acupuncture and physiotherapy for the treatment of painful shoulder: a multicentre randomized controlled trial. Rheumatol Oxf Engl 2008;47:887–93. doi:10.1093/rheumatology/ken040