Li 2013.

Methods	R, DB, PC, multicentre, parallel groups Plaster applied x 2 daily for 7 days PI assessed daily, overall treatment efficacy and tolerability assessed at 7 days
Participants	Mild or moderate ankle or knee sprain, muscle strain or contusion (< 72 hours), PI ≥ 50/100 N = 384 M 144, F 240 Mean age 42 years
Interventions	DHEP plaster, x 2 daily, n = 192 Placebo plaster, x 2 daily, n = 192 Rescue medication: paracetamol to maximum 2 g daily
Outcomes	≥ 50% reduction in PI at 7 days Overall treatment efficacy: 5‐point scale (responder = "good" or "excellent") Overall tolerability: 5‐point scale (responder = "good" or "excellent") Rescue medication Adverse events Withdrawals
Notes	Oxford Quality Score: R2, DB2, W1. Total = 5/5
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated
Allocation concealment (selection bias)	Unclear risk	Method not fully described: "sealed envelopes", "concealed from investigators and participants"
Blinding (performance bias and detection bias) All outcomes	Low risk	"identical in texture, size, color and odor"
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Withdrawals 2%. Methods states LOCF, but appears to describe BOCF for withdrawals
Size	Unclear risk	50 to 200 participants per treatment arm