Effects of mechanical and electrical stimulation on accelerating greenstick fracture Healing: Insights from finite element analysis and experimental validation.

Abstract

<h4>Background</h4>Greenstick fractures are common forearm injuries in children, with 75-84 % occurring in the distal third of the radius. Conservative treatments such as detachable braces or plaster backslabs permit early physiotherapy intervention, including muscle activation exercises and electrotherapy. This study investigated the biomechanical and electrophysiological effects on fracture healing to improve bone strength and reduce refracture risk, using finite element analysis (FEA) and experimental validation.<h4>Objective</h4>To evaluate the effect of controlled isometric muscle contractions and localized electrical stimulation on fracture healing in pediatric distal radius greenstick fractures, integrating computational modeling with experimental case validation.<h4>Participants and setting</h4>The experimental component involved two pediatric patients (aged 8-10 years) diagnosed with distal third greenstick fractures of the radius. Clinical management and data collection were conducted in a physiotherapy outpatient department at a tertiary care hospital.<h4>Methods</h4>A 3D model of a radius bone with a distal third greenstick fracture was developed. FEA using ANSYS analyzed strain distribution under isometric contraction of the brachioradialis muscle, with repetitions ranging from 5 to 30. COMSOL Multiphysics also simulated electrical stimulation by applying a 6.25 V potential across the fracture site, assessing displacement and strain alterations. Experimental validation included two pediatric cases: Child A received standard conservative treatment with immobilization, while Child B received local electrical stimulation. Healing progression was quantified by measuring fracture gap reduction by MATLAB-based image analysis.<h4>Results</h4>ANSYS simulations indicated that low-repetition (3-5) isometric muscle contractions may enhance callus formation. COMSOL simulations demonstrated a low strain gradient with electrical stimulation, but experimental validation showed a significant 58.8 % reduction in fracture gap area using electric stimulation, compared to 31.8 % with conservative treatment.<h4>Conclusions</h4>Applying controlled isometric mechanical loading and electrical stimulation may reduce the fracture gap in greenstick distal radius fractures, accelerate healing and recovery. Future studies should explore direct current electrical stimulation (DCES) for potentially more robust effects on bone remodeling.