# SAR-Based Thermal Assessment of Dielectrophoretic Pulsed Electromagnetic Stimulation in Tibia Fractures with Metallic Implants

## TL;DR

This study examines how electromagnetic stimulation affects heating in tibia fracture models with metallic implants, showing implants heat up more than surrounding tissue.

## Contribution

The paper provides the first SAR-based experimental evaluation of dielectrophoretic stimulation in tibia fracture models with metallic implants.

## Key findings

- Metallic implants show a rapid temperature increase of ~0.4°C within minutes of DEPF exposure.
- Non-conductive resin phantoms show minimal temperature rise (~0.05°C) compared to implants.
- Eddy-current losses in implants dominate localized heating under DEPF stimulation.

## Abstract

Electromagnetic field-based stimulation has emerged as a promising noninvasive approach for enhancing bone fracture healing. Beyond conventional pulsed electromagnetic field (PEMF) therapies employing spatially uniform fields, dielectrophoretic-force-based (DEPF) stimulation exploits electromagnetic field non-uniformities to induce localized interactions to enhance fracture healing. However, the thermal behavior associated with DEPF-driven PEMF exposure in the presence of metallic orthopedic implants remains largely unexplored. In this study, the thermal response of tissue-like tibia phantoms with and without metallic implants is investigated using an integrated experimental and numerical framework. A custom-designed conical coil is employed to generate non-uniform DEPF excitation capable of affecting the fracture site. Surface temperature evolution is measured using infrared thermal imaging, while electromagnetic power absorption is quantified through specific absorption rate (SAR)-based thermal measurement coupled with a bio-heat formulation. Anatomically realistic tibia phantoms reconstructed from computed tomography data are fabricated via a 3D printer to represent clinically relevant fracture configurations. Experimental results show that the metallic implant exhibits a rapid temperature increase of approximately 0.4 °C within the first few minutes of exposure, followed by thermal stabilization, corresponding to an effective absorbed power of SAReff,implant≈2.2 W/kg inferred from the initial temperature slope. In contrast, the non-conductive resin phantom displays a temperature rise of only 0.05 °C over the same interval, yielding SAReff,resin≈0.8 W/kg. These findings demonstrate that implant-related eddy-current losses dominate localized heating under DEPF excitation, while tissue-like media remain weakly affected. This work provides SAR-based experimental evaluation of DEPF stimulation in implanted tibia fracture models, offering new insight into implant-induced electromagnetic heating and its implications for the safety and optimization of DEPF-based bone-healing therapies.