High-frequency and noncontact low-frequency ultrasound therapy for venous leg ulcer treatment: a randomized, controlled study

Abstract

Ultrasound therapy can be utilized to manage chronic wounds, including venous leg ulcers (VLUs). A randomized, controlled clinical study was conducted to compare the effectiveness of standard treatment and standard treatment plus either high-frequency ultrasound (HFU) or noncontact low-frequency ultrasound (NCLFU) on VLU outcomes. Ninety (90) outpatients (47 men, 43 women, average age 38.3 [SD 11.5] years) were randomized into the standard care (n = 30), HFU (n = 30), or NCLFU group (n = 30). Standard care included multilayered compression bandaging (40 mm Hg of pressure at the ankle graduated to 17 mm Hg to 20 mm Hg below the knee), nonadherent dressing, and regular debridement. Standard care dressing changes and ultrasound therapy were provided three times per week for 3 months or until healed. HFU delivers high-intensity (0.5-1 W/cm2), high-frequency (1-3 MHz) ultrasound for 5 to 10 minutes; and NCLFU delivers low-intensity (0.1-0.8 W/cm2), low-frequency (40 kHz) ultrasound for 4-10 minutes. After 3 months, patients continued to be followed until healed. Wound size, wound pain, and lower leg edema were assessed at baseline and after 2 and 4 months. Data were analyzed using Student's t-test, ANOVA, chi-square, or Fisher's exact test. P <0.05 was considered significant. Initial wound measurements were 9.60 cm2 (SD 5.54), 9.86 cm2 (SD 3.95), and 10.01 cm2 (SD 4.58) for the standard treatment, HFU, and NCLFU groups, respectively; after 4 months, measurements were 4.28 cm2 (SD 2.80), 3.23 cm2 (SD 2.39), and 2.72 cm2 (SD 2.16), a statically significant difference (P = 0.04). All wounds were healed after an average of 8.50 (SD 2.17), 6.86 (SD 2.04), and 6.65 (SD 1.59) months in the standard treatment, HFU, and NCLFU groups, respectively (P = 0.001). Differences in the amount of edema and pain rating scores were also significant at the 4-month, follow-up visit (P <0.05). Outcomes of both methods of ultrasound therapy were better than standard care alone, and some differences between the two ultrasound therapy groups were observed, but they were not statistically significant.