Frequency of Rx in OAK

Stimulated by Lin et al 2020.[1]

Image from HVAC photoshoot 2012.[2]

This paper caught my eye for two reasons. First because the title implied the results might be useful for clinical practice, and second because it was an acupuncture trial published in the journal Pain, a journal that does not publish acupuncture trials very often.

It is not a huge trial (n=60), and technically it is not a positive trial, but it did show some differences between groups. Some will be surprised that they managed to show any difference between groups when both received electroacupuncture (EA) to local points for their OAK (OsteoArthritis of the Knee). That is what is quite unique about this paper, because there was a big difference between groups in terms of the frequency and total number of treatments applied.

EA was applied for 30 minutes to LR9–GB33 and two other points based on the location of pain, and the related meridian points. The extra points Xiyan were used, but I was pleased to see that the angulation and depth parameters made it possible that entry to the joint space may have been avoided – 30o to 45o or 90o angulation and 10–30mm depth is quoted, but it is not clear which parameters applied to Xiyan. The rather pricey HANS-200A stimulator was used at the expected 2/100Hz, but the intensity was quoted as 0.1–1.0mA. This seems rather low, but it does depend on the pulse width settings, which are not stated in the paper, and I cannot find online…

Oh, wait, I have just received a message from a colleague in Brazil (Fabio Athayde). He tells me the pulse width for this device is 600µs at 2Hz and 200µs at 100Hz. 600µs is about three times wider than I tend to use, so at 1mA that might just reach a reasonable stimulus strength for OAK.

One group received weekly treatment (OSWA), and the other group were treated 3 times per week (TSWA), so by the end of the 8 weeks of treatment, whilst OSWA had received a quite reasonable 8 sessions, the TSWA group had notched up 24.

The main outcome was responder rate at 8 weeks, and a responder was determined by a reduction in numerical rating score (NRS) of pain by >=2. NRS and WOMAC were measured as secondary outcomes at 4, 8 and 16 weeks.

If you have read this far and haven’t looked at the results yet, what do you think? I have already given you a clue above when I said “technically… not positive”.

Well the responder rates were 64.7% (TSWA) versus 50.0% (OSWA) at 8 weeks (p=0.435). But there were rather larger differences at 4 and 16 weeks, which were both highly significant (p<0.001): 58.0% versus 13.3% (4 weeks) and 60.6% versus 14.7% (16 weeks).

These results are entirely believable…

These results are entirely believable and consistent with my experience of using EA in OAK. You do not generally see the maximum effect until 6 to 8 sessions, and the effect drops off after 4 to 6 weeks of no treatment. So, at 4 weeks of treatment, whilst OSWA is yet to reach peak effects, TSWA have already had 12 sessions. The aspect that I could not predict from my clinical experience was the extended length of action in the TSWA group. There seems to be minimal decline in the effect after 8 weeks of no treatment in the follow-up period, but this is after 24 sessions. In my clinical practice, I would spread out 24 sessions over nearly a year and a half and aim to have my patients pain free for the majority of the time.

I’m not sure why, but I thought I would check up on the main author. It is usually the last author, and or the corresponding author on a paper. The last author on this paper is Liu Cun-Zhi. Liu is also the family name of the current president of WFAS (World Federation of Acupuncture Societies), the same Liu responsible for some of the enormous clinical trials in recent years. The two authors do not appear to have published together as of the date of writing this, but they are both from Beijing, and have both published with colleagues from BUCM (Beijing University of Chinese Medicine).

I put Liu CZ [au] AND acup* into PubMed…

I put Liu CZ [au] AND acup* into PubMed and got 118 citations, 2 SRs and 24 RCTs. I looked down the SRs and RCTs; some were familiar, some even published in Acupuncture in Medicine,[3–5] but others did not spark any memory. It was interesting to browse the different designs and check the results against my expectations. There were a number of protocols,[6–10] and not all of them had subsequent publication of the results. I hunted around and found some results listed but unpublished in a couple of trials,[7,9] and no results in a couple more.[6,8] I am intrigued by those that remain unpublished, with no results listed despite them both being completed over 5 years ago. I am left to guess why, especially in an era when publishing negative trials of acupuncture tends to be easier and get you into higher profile journals.

Both trials with results that remain hidden have similar designs. They both used 4 parallel arms in a 2×2 factorial design as follows:

  1. Local acupuncture points plus distal acupuncture points
  2. Local acupuncture points plus distal non-acupuncture points
  3. Local non-acupuncture points plus distal acupuncture points
  4. Local non-acupuncture points plus distal non-acupuncture points.

Given that this author seems to consistently publish results that are in line with what we might expect from a Western perspective, I will leave the reader to guess the implications of publishing the results of these two trials for someone who lives in Beijing.


1         Lin L-L, Tu J-F, Wang L-Q, et al. Acupuncture of different treatment frequency in knee osteoarthritis: a pilot randomised controlled trial. Pain Published Online First: 29 May 2020. doi:10.1097/j.pain.0000000000001940

2         Cummings M. The Development of Group Acupuncture for Chronic Knee Pain Was All about Providing Frequent Electroacupuncture. Acupunct Med 2012;30:363–4. doi:10.1136/acupmed-2012-010260

3         Sun N, Tu JF, Lin LL, et al. Correlation between acupuncture dose and effectiveness in the treatment of knee osteoarthritis: a systematic review. Acupunct Med 2019;37:261–7. doi:10.1136/acupmed-2017-011608

4         Sun N, Wang L-Q, Shao J-K, et al. An expert consensus to standardize acupuncture treatment for knee osteoarthritis. Acupunct Med Published Online First: 20 April 2020. doi:10.1177/0964528419900789

5         Wang T-Q, Li Y-T, Wang L-Q, et al. Electroacupuncture versus manual acupuncture for knee osteoarthritis: a randomized controlled pilot trial. Acupunct Med 2020;:096452841990078. doi:10.1177/0964528419900781

6         Shi G-X, Han L-L, Liu L-Y, et al. Acupuncture at local and distant points for tinnitus: study protocol for a randomized controlled trial. Trials 2012;13:224. doi:10.1186/1745-6215-13-224

7         Xue Z, Liu C-Z, Shi G-X, et al. Efficacy and safety of acupuncture for chronic dizziness: study protocol for a randomized controlled trial. Trials 2013;14:429. doi:10.1186/1745-6215-14-429

8         Fu Q-N, Shi G-X, Li Q-Q, et al. Acupuncture at local and distal points for chronic shoulder pain: study protocol for a randomized controlled trial. Trials 2014;15:130. doi:10.1186/1745-6215-15-130

9         Sun N, Shi G-X, Tu J-F, et al. Traditional Chinese acupuncture versus minimal acupuncture for mild-to-moderate knee osteoarthritis: a protocol for a randomised, controlled pilot trial. BMJ Open 2016;6:e013830. doi:10.1136/bmjopen-2016-013830

10       Lin L-L, Tu J-F, Shao J-K, et al. Acupuncture of different treatment frequency in knee osteoarthritis: a protocol for a pilot randomized clinical trial. Trials 2019;20:423. doi:10.1186/s13063-019-3528-8

Declaration of interests MC

One thought on “Frequency of Rx in OAK

Comments are closed.