Frahm 1993.

Methods	RCT, DB, parallel groups Duration 11 days Assessment at on days 2, 4, 9, 11
Participants	Acute ankle or knee sprain within 24 h Patients had moderate or slight pain N = 156 (163 randomised, 7 protocol infringements) M = 98, F = 58 Mean age 32 years (range 18 ‐ 65)
Interventions	Salicylic acid (2%), mucopolysaccharide polysulphate (0.2%) cream (Movelat), n = 78 Placebo cream, n = 78 10 cm x 2 daily
Outcomes	PI on movement: 100 mm VAS PI at rest: 100 mm VAS Swelling Withdrawals Adverse events
Notes	Oxford Quality Score: R1, DB2, W0. Total = 3/5 No concomitant treatment allowed except max 1 g paracetamol x3 daily
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method used to generate random sequence not described. Block randomisation used
Allocation concealment (selection bias)	Unclear risk	Method not described
Blinding (performance bias and detection bias) All outcomes	Low risk	"There were no differences in the appearance, smell, or physical properties of the preparations"
Incomplete outcome data (attrition bias) All outcomes	Low risk	Exclusions (protocol infringements) < 10% (7/163)
Size	Unclear risk	50 ‐ 200 participants per treatment arm