Cheing 2008.

Methods	Design: Parallel group, three‐arm, single‐blind randomised controlled trial (Hong Kong) Interventions: Interferential current plus home exercises or electroacupuncture plus home exercises or no treatment Sample size calculation: Not reported Analysis: Per protocol analysis Source of funding: Not reported
Participants	Number of participants: 74 (25, 24, and 25 in each respective group) Baseline characteristics: Sex of participants was reported as 22 males and 48 females. Age range for all participants was reported as 33‐90 years Interferential current plus home exercises group: Mean (SD) duration of treatment = 6.7 (6.05) months Electroacupuncture plus home exercises group: Mean (SD) duration of treatment = 6.71 (6.5) months No treatment group: Mean (SD) duration of treatment = 8.26 (7.94) months Inclusion criteria: 1. Patients who reported localized pain over one shoulder, experienced night pain and had restricted active and passive shoulder motions Exclusion criteria: 1. History of trauma, fractures, previous shoulder surgery, cervical or thoracic pain syndrome, complex regional pain syndrome, malignancies, on anti‐coagulant therapy 2. Had received acupuncture treatment to the painful shoulder in the past six months
Interventions	Interferential current plus home exercises (N=25) Components of intervention: ‐ Interferential current: An interferential electrotherapy machine (a Phyaction Guidance E unit) delivered a current swept from 80 to 120 Hz, and 4 suction‐type electrodes were placed around the shoulder region in a coplanar arrangement. The intensity of the stimulation was adjusted to just below the pain threshold and the stimulation lasted for 20 minutes ‐ Home exercises: Participants were instructed to follow a chart and perform a standard set of shoulder mobilisation exercises five times a day, which included four directions: (i) forward flexion – with the help of an overhead pulley system; (ii) external rotation – keeping the arm close to trunk, using a small bamboo to externally rotate the shoulder through pushing against the palm; (iii) horizontal adduction – pressing a horizontally adducted arm against the chest with the other arm to achieve horizontal adduction; and (iv) internal rotation – placing the affected arm behind the back and grasping one end of a towel, the other hand then pulling the opposite end of the towel to achieve maximum internal rotation Dosage: ‐ Interferential current: 20 minutes ‐ Home exercises: Not reported Frequency of administration: ‐ Interferential current: 10 sessions over four weeks ‐ Home exercises: Five times a day for six months Provider: Physiotherapist Electroacupuncture plus home exercises (N=25) Components of intervention: ‐ Electrotheracupuncture: Sterile stainless steel acupuncture needles were inserted 15–25 mm intramuscularly into three acupoints including one trigger point, one local point (LI 15: Jianyu), and one distal point (ST38: Tiaokou) (14). Trigger points were identified by areas of greatest tenderness around the painful shoulder that were determined on an individual basis. The two needles in the shoulder region (trigger point and LI 15) were connected to an electroacupuncture device (Model: ES‐160, ITO Co. Ltd, 3‐3‐3 Tpupta, al‐M inami, Nerima‐ku, Tokyo 176‐86 05, Japan) and stimulated with an alternating frequency of 2–100 Hz at a pulse duration of 100– 400 μs for 20 minutes. The intensity of the stimulation was adjusted to a tolerance level of just below the pain threshold. The needle that was applied at the distal point S T38 (Tiaokou) was retained for 20 minutes and was manually lifted and thrusted every 10 minutes ‐ Home exercises: See above Dosage: ‐ Electroacupuncture: 40 minutes ‐ Home exercises: Not reported Frequency of administration: ‐ Electroacupuncture: Two to three times a week for four weeks (10 sessions in total) ‐ Home exercises: Five times a day for six months Provider: Physiotherapist No treatment (N=25)
Outcomes	Outcomes assessed at the end of 4 weeks treatment and at 1, 3 and 6 months follow‐up for Group 1 and 2, but only at the end of 4 weeks treatment for Group 3 No primary outcome was reported by the trialists 1. Constant score (0‐100 scale where a higher score indicates better functional ability) 2. Pain severity at the moment of assessment, measured using a 10cm visual analogue scale, with "No pain" anchored at the left and "Pain as bad as it could be" anchored at the right
Notes	No outcome data for the no treatment group was reported in the trial publication, so we could not analyse the comparison between interferential current and home exercises versus no treatment.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "The subjects were randomly allocated into: (i ) the EA group (n = 24); (ii) IFE group (n = 23); or (iii) control group (n = 23)" Comment: No information on how the allocation sequence was generated was reported
Allocation concealment (selection bias)	Unclear risk	Comment: No information on how the allocation sequence was concealed was reported
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote: "The study was a double‐blind, randomized, controlled clinical trial. An independent assessor was blind to the group allocation." Comment: Despite reporting this trial as "double‐blind", given the nature of the interventions (electrotherapy versus no treatment), participants were not blind to treatment, and may have had different expectations about the benefits of each intervention
Blinding of outcome assessment (detection bias) Self‐reported outcomes	High risk	Comment: Unblinded participants who may have had different expectations about the benefits of the intervention they received self‐reported pain and some components of the Constant score
Blinding of outcome assessment (detection bias) Objective outcomes	Low risk	Quote: "The study was a double‐blind, randomized, controlled clinical trial. An independent assessor was blind to the group allocation." Comment: Outcome assessors of some components of the Constant score were probably blind to treatment
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "One participant dropped out of each of the electroacupuncture group and interferential electrotherapy group, both because of time conflict, and two participants dropped out of the no treatment group because they experienced no improvement." Comment: While drop‐out is related to treatment in the no treatment group, the number of dropouts is small and unlikely to affect the function and pain outcomes
Selective reporting (reporting bias)	High risk	Comment: The trialists reported the mean (SD) scores for the Constant Murley Assessment scale and VAS pain at the end of four weeks treatment for the electroacupuncture and interferential current groups, but not for the no treatment group, because the no treatment group did not have a statistically significant improvement from baseline. Also, without a trial protocol it is unclear whether other outcomes were measured but not reported based on the results
Other bias	Low risk	Comment: No other sources of bias identified