Is there an equivalent effect between an acupuncture needle retention time of 5 minutes compared to 20 minutes in patients with osteoarthritis of the knee? A pilot cross over randomised controlled trial

By Helen Walker



It is common in traditional Chinese medicine practice in the UK to retain acupuncture needles for 20 minutes or longer, with little reasoning on why. A paucity of research was found with regards to the optimum needle retention time and studies found reported a lack of consensus (Smith et al., 2001) as to the rationale behind needle retention time.


Aims and Objectives

The aim of this pilot study is to investigate differences between a 5 and 20 minute acupuncture needle retention time in participants suffering from knee osteoarthritis (OA).



14 participants with knee OA were randomly assigned to two study groups (Group A and Group B), both of which received six weekly acupuncture sessions (Phase 1) followed by a 4-6 week wash-out period of no acupuncture and then another six weekly sessions of acupuncture (Phase 2). In Phase 1, Group A had a 20 minute needle retention time and Group B had 5 minutes. In Phase 2, the groups crossed over and received the other needle retention time. A cross over trial was used as the participants act as their own control. Participants self scored on the pain intensity numerical rating scale (PI-NRS) before each acupuncture treatment. Quality of life, function and stiffness were measured by the knee injury and osteoarthritis outcome score (KOOS), which was self-completed by participants before and immediately after each treatment phase with the Western Ontario and McMaster Universities arthritis index (WOMAC) formulated from the KOOS.



Acupuncture for 5 and 20 minutes decreased pain levels (as measured by the PINRS) to clinically significant levels, however there was no statistically significant difference between the different needle retention times. During the washout phase there was a statistically significant increase in pain levels (P=0.01).

Quality of life, function, pain and stiffness were measured by the KOOS and the WOMAC and there was not enough improvement in scores in either needle retention time to show a clinically significant change. There was a statistically significant decline in the KOOS and WOMAC scores in Group A during the washout period, but no significant difference between the two needle retention times. In Group B the 5 minute needle retention time was significantly better than 20 minutes in both the KOOS and WOMAC scores, but only the KOOS showed a significant decline during the washout period.



Six acupuncture sessions were found to show clinical improvements in pain intensity in participants with knee OA, however no significant difference was found between 5 and 20 minute needle retention times. Effects were found to be short lived with a significant decline during a washout phase of 4-6 weeks. Function and quality of life scores did not improve to a clinically important level with either duration, possibly due to the short time participants received acupuncture. Further research might look at blinding the participants to the needle retention time they receive, delivering more frequent or more sessions in each phase, including a waiting list control and investigating effects in different conditions.