Non-contact low-frequency ultrasound therapy compared with UK standard of care for venous leg ulcers: a single-centre, assessor-blinded, randomised controlled trial

Abstract

'Hard-to-heal' wounds are those which fail to heal with standard therapy in an orderly and timely manner and may warrant the use of advanced treatments such as non-contact low-frequency ultrasound (NLFU) therapy. This evaluator-blinded, single-site, randomised controlled trial, compared NLFU in addition to UK standard of care [SOC: (NLFU + SOC)] three times a week, with SOC alone at least once a week. Patients with chronic venous leg ulcers were eligible to participate. All 36 randomised patients completed treatment (17 NLFU + SOC, 19 SOC), and baseline demographics were comparable between groups. NLFU + SOC patients showed a -47% (SD: 38%) change in wound area; SOC, -39% (38%) change; and difference, -7·4% [95% confidence intervals (CIs) -33·4-18·6; P = 0·565]. The median number of infections per patient was two in both arms of the study and change in quality of life (QoL) scores was not significant (P = 0·490). NLFU + SOC patients reported a substantial mean (SD) reduction in pain score of -14·4 (14·9) points, SOC patients' pain scores reduced by -5·3 (14·8); the difference was -9·1 (P = 0·078). Results demonstrated the importance of high-quality wound care. Outcome measures favoured NLFU + SOC over SOC, but the differences were not statistically significant. A larger sample size and longer follow-up may reveal NLFU-related improvements not identified in this study.

Keywords: Compression; Quality of life; Ultrasound therapy; Venous leg ulcers; Wound healing.

Figure 1

Study design flow diagram. NLFU, non‐contact low‐frequency ultrasound; SOC, standard of care. ^*Compression therapy and dressing change (with debridement if clinically necessary) at least once a week; wound assessments weekly. ^**Ultrasound therapy, with compression and dressing change (with debridement if clinically necessary) three times a week; wound assessments weekly.

Figure 2

Participant flow diagram. NLFU, non‐contact low‐frequency ultrasound; SAE, serious adverse event; SOC, standard of care.

Figure 3

Mean percentage change in wound area from randomisation (week 5) to each subsequent week in patients allocated to receive 8 weeks of either NLFU and standard care or standard care alone. NLFU, non‐contact low‐frequency ultrasound; SOC, standard of care. Error bars represent ±1 standard error. Data for the two arms at the same time points are offset for clarity.

Figure 4

Mean change in wound area (cm²) from randomisation (week 5) to each subsequent week in patients allocated to receive 8 weeks of either NLFU and standard care or standard care alone. NLFU, non‐contact low‐frequency ultrasound; SOC, standard of care. Error bars represent ±1 standard error. Data for the two arms at the same time points are offset for clarity.

Figure 5

Mean change in patient reported pain scores from randomisation (week 5) to each subsequent week in patients allocated to receive 8 weeks of either NLFU + SOC or SOC alone. NLFU, non‐contact low‐frequency ultrasound; SOC, standard of care. Pain was measured on a visual analogue scale (VAS) from 0 to 100. Error bars represent±1 standard error.