Modelling and Simulation of Soft Tissue Loading Reduction at the Posterior Heel by a Moisture-Responsive Prophylactic Dressing

Abstract

Pressure ulcers/injuries at the posterior heel commonly develop in patients with limited mobility or sensation, where movements such as sliding in bed generate shear forces that elevate the deep soft tissue stresses. Prophylactic multilayer dressings are recommended to reduce this injury risk, yet many current products incorporate high-friction silicone adhesives for attaching the dressing to the skin, which may increase shear transfer to the skin and subdermally while a patient is moving or being moved. This study evaluated a multilayer dressing featuring an Aquacel Hydrofiber Technology skin-contact layer that exhibits moisture-responsive friction reduction. Finite element models of a posterior heel resting on a support surface were developed to simulate compressive and shear loading during patient sliding-in-bed, comparing no dressing, dry (new) and moist (used) dressing conditions. Moisture exposure reduced the skin-dressing coefficient of friction from 1.55 to 0.22, leading to substantial reduction in soft tissue strain and stress exposures, such that high-magnitude strain and stress concentrations (> 75th-percentile) were effectively absent within the modelled loading domain under the simulated conditions. Moisture-induced friction reduction facilitated controlled micro-sliding at the skin interface, attenuating shear transfer into skin and subcutaneous tissues. These findings demonstrate that moisture-responsive interfacial friction adaptation is an important mechanism of action contributing to the biomechanical protective efficacy of prophylactic dressings.