Acupuncture can result in clinically significant results for the treatment of shoulder impingement syndrome. In a randomised trial carried out in Spain, 68 participants received either true acupuncture (TA) or sham acupuncture (SA) at non-acupoints. The treatment was carried out over four weeks, with participants receiving one session per week. The results showed significant differences between the two groups. Immediately after the treatment, pain intensity was found to have decreased by 44.13 millimetres on a Visual Analogue Scale (VAS) in the TA group, compared with 19.84 millimetres for SA. Three months later, this between-group difference was still apparent (87.58 millimetres for TA versus 20 millimetres). Shoulder function scores also showed clinically meaningful changes in support of TA.
Acupuncture treatment of shoulder impingement syndrome: A randomized controlled trial. Complement Ther Med. 2016 Apr;25:92-7.

Research from Brazil has found that acupuncture can reduce pain intensity and improve range of motion in women with neck and shoulder pain. Sixty women with at least one trigger point in the upper trapezius muscle, and local or referred pain lasting more than six months, were randomised into electroacupuncture (EAC), acupuncture (AC) and sham groups. Needles were inserted bilaterally into Jianjing GB-21 and Fengchi GB-20 and unilaterally into Hegu L.I.-4 and Taichong LIV-3, and a maximum of two needles on each side were inserted into ashi points. EAC was carried out with alternating frequency (2 Hz – 100 Hz), while the AC group received the same needling without electrostimulation. The sham group had needles inserted one centimetre distally from the verum acupoints. Eight acupuncture sessions were scheduled and a follow-up was conducted after 28 days. The results showed a reduction in general pain in the EAC and AC groups after eight sessions. A significant decrease in pain intensity occurred for the right trapezius in all groups and for the left trapezius in the EAC and AC groups. Intergroup comparisons showed improvement in general pain in the EAC and AC groups and in local pain intensity in the EAC group. The EAC group also showed an increase in left rotation while the AC group showed increases in inclination (sustained until follow-up) and rotation to the right. (Pain intensity and cervical range of motion in women with myofascial pain treated with acupuncture and electroacupuncture: a double-blinded, randomized clinical trial. Braz J Phys Ther. 2015 Jan-Feb;19(1):34-43).

Trigger point acupuncture (TrPAcu) is significantly better than sham treatment at reducing pain and improving function in patients with chronic shoulder pain, say Japanese investigators. Eighteen patients with non-radiating shoulder pain for at least six months were randomised into two groups who received five treatment sessions. The TrPAcu group received treatment at muscular trigger points, while the sham group received acupuncture treatment on the same muscle. After five weeks of treatment, pain intensity in the TrPAcu group was found to have decreased significantly from baseline, while shoulder function had increased significantly. Comparison between the two groups demonstrated a significant difference in favour of TrPAcu. (Randomized trial of trigger point acupuncture treatment for chronic shoulder pain: a preliminary study. J Acupunct Meridian Stud. 2014 Apr;7(2):59-64). http: / /www.ncbi.nlm.nih.gov / pubmed / 24745863