Revolutionising Bone Healing with Computer Models

Around 170 million bone fractures occur worldwide every year, often leaving those affected facing months of limited mobility. Yet conventional fixation methods, such as implanted plates and screws, are not always successful. In some cases, bones fail to heal as expected despite being stabilised. So far, medicine lacks a reliable method for predicting such healing complications in individual patients at an early stage. To improve this process, Prof. Dr. Sara Checa Esteban from the Institute of Biomechanics at Hamburg University of Technology (TUHH) is developing computer-based simulation models. These are designed to help predict healing outcomes more accurately and tailor treatments to individual patients.

At a formal ceremony marking her inaugural lecture, Prof. Arne Speerforck, Dean of Mechanical Engineering, highlighted Prof. Checa’s impressive international career. Her academic journey took her from studying industrial engineering in Málaga to completing her doctorate at the University of Southampton, followed by a position at Trinity College Dublin and many years as a professor at the Julius Wolff Institute at Charité in Berlin. Following a brief welcome address by TUHH President Prof. Andreas Timm-Giel, Checa presented her research to a large audience in Audimax II.

Understanding the Language of Cells

In her inaugural lecture, Checa demonstrated how computer-based simulations can support bone healing under the guiding concept of “Digital Healing”. Her research lies at the intersection of medicine and engineering. Its biological foundation is mechanobiology, which investigates how living cells respond to external physical stimuli, such as pressure or movement, and convert them into biological signals.

Rather than simply waiting to see how a complex fracture heals, software can simulate the regeneration process in advance. The system acts as a “digital twin” of the injured bone. To perform its analysis, the computer translates the fracture into chemical and physical data. Much like zooming in through a powerful microscope, the software must account for multiple levels of detail, from the visible bone and different types of tissue down to microscopic cells. The aim of the research is to capture these complex interactions accurately and gain a fundamental understanding of skeletal health.

Customised Implants Designed by Computer

Because every person and every injury has its own unique characteristics, the Institute of Biomechanics focuses on personalised simulations. “Patient-specific simulation means creating an individual model for each patient,” Checa explained. “Depending on the research question, we also incorporate computed tomography (CT) scans. In practice, we then optimise the design of an implant or fixation device and investigate the effects of mechanical loading.”

This approach is particularly valuable in cases involving severe bone defects, where large sections of bone are completely missing. In such situations, artificial implants known as “scaffolds” are used to support new bone growth. Simulations can help optimise the design of these structures in advance, enabling the body's own cells to populate them effectively and bridge the gap in the bone.

According to Checa, however, the technology is not yet ready for routine clinical use. The models are currently undergoing extensive testing and are being prepared for application in hospitals. In the future, predictive simulations could help doctors make difficult treatment decisions and spare patients lengthy rehabilitation periods.