Ascertaining the Effectiveness and Safety of Contact Low-Frequency Ultrasound (LFU) in an Acute, Post-Surgical Wound with Exposed Hardware

TITLE: ASCERTAINING THE EFFECTIVENESS AND SAFETY OF CONTACT LOW-FREQUENCY ULTRASOUND (LFU) IN AN ACUTE, POST-SURGICAL WOUND WITH EXPOSED HARDWARE

Background & Purpose: Hardware exposure within a wound heralds contamination and inhibits stable granulation tissue. This case report served to determine if LFU is a useful healing adjunct to negative pressure wound therapy (NPWT) in a wound with exposed hardware.

Case Description: The subject was a 64 year-old male status-post dehiscence of right tibiotalar-calcaneal arthrodesis. Pertinent past medical history included CAD, HTN, NIDDM and venous insufficiency. While practice algorithms favor hardware removal, implants were maintained to ensure bony fusion / joint stability. To visualize the wound, remove necrosis and provide aggressive cleansing, irrigation and surgical debridement occurred. Wound interventions included LFU and NPWT 3 times per week. Healing was assessed via wound measurements, tissue characteristics, drainage, and periwound integrity.

Outcomes: Within one week of post-operative debridement, hardware was fully concealed by granulation tissue and wound depth decreased 19%. Emerging granulation tissue appeared stable and within four weeks depth decreased 59%. Wound margin maceration during the first three weeks of care resulted in a 15% width increase and 0.6% length decrease. Within 2 weeks of converting to the traditional NPWT dressing, a 25% width decrease and 6.0% length decrease occurred.

Discussion: Results demonstrate concomitant use of LFU and NPWT promoted granulation over exposed hardware and favorably prepared the wound for closure. While long-term outcomes are unknown, no adverse effects to the orthopedic hardware, ultrasound probe, or wound itself were noted. One brief period of interrupted healing was overcome by discontinuation of the NPWT bridge component.