The acupuncturist will carry out a consultation at each session as per normal practice. After the needles have been inserted and the moxa cones have been placed on needles the acupuncturist leaves and an assistant acupuncturist enters the room. The assistant acupuncturist will place a screen in front of the patient to prevent them from seeing their knees. The assistant acupuncturist will then remove one cone at a time and light it. In the treatment group the lit cone is placed on the needle. In the control group the lit cone is place in a small dish close to the knee, a replacement unlit cone is placed on the needle. This process is repeated until all the cones are lit. The unlit cone is replaced on the needle of the control group to try and ensure they experience the same sensations as the treatment group. The use of a second acupuncturist to light the moxa ensures that the acupuncturist who carries out the consultation and inserts the needles is blinded to group allocation.