Eriksson 1991.

Methods	Randomised trial comparing US plus standard care with sham US plus standard care in Sweden.
Participants	People with venous leg ulcers referred from departments of internal medicine and surgery, and primary care providers Exclusion criteria: allergy to the standard treatment, or evidence of peripheral arterial disease, rheumatoid arthritis, diabetic ulcers, or traumatic venous ulcers US group: n = 19; Sham US group: n = 19
Interventions	US group: US 1 W/cm2 at 1 MHz, for 10 minutes twice a week for 8 weeks, plus standard treatment Sham US group: standard treatment plus sham US as above, but with no output. Standard care comprised cleansing with saline; paste bandage, support bandage plus exercise advice.
Outcomes	Number of ulcers known to be completely healed at 8 weeks (of those randomised) Percentage ulcer area healed at 8 weeks (SD) Withdrawals with reasons, and by group
Notes	Duration of follow‐up: 8 weeks
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "patients were randomly assigned to either a control group ... or a treatment group"
Allocation concealment (selection bias)	Unclear risk	See above.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Participants: this was a placebo (sham) US controlled trial, therefore, it was implied that the participants did not know their allocation. Personnel: unclear (they may have been responsible for setting the ultrasound machine to zero).
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Outcome assessors: unclear whether those responsible for taking ulcer tracings were blinded. Those responsible for analysing the tracings were blinded, quote: "At the end of the 8 week study all tracings were analysed using a computer graphics program to calculate the areas of each ulcer...The tracings were identified by code numbers to exclude observer bias."
Incomplete outcome data (attrition bias) Ulcer healing	Unclear risk	38 people randomised; 13 withdrew. Not clear how these were handled. Quote: "The cumulative percentage of healed ulcers in the two groups was compared by the use of life table methods" (censoring not mentioned), and. In the Results section: "If analysed by intention to treat there were similar non‐significant findings between the groups".
Selective reporting (reporting bias)	Unclear risk	No details provided.
Other bias	Unclear risk	No details provided.