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11.06.2025 10:41

Monitoring bone healing without X-ray radiation: A new approach lights the way

Claudia Ehrlich Pressestelle der Universität des Saarlandes
Universität des Saarlandes

A medical research team at Saarland University, led by Professor Bergita Ganse, has discovered a new approach to monitoring bone fracture healing by measuring blood supply to the tissue at the fracture site and the level of oxygen in the blood. Bone regeneration can be monitored quickly and easily using near-infrared light rather than harmful shorter wavelength radiation. Up until now, doctors have had to rely on X-ray images and CT scans to provide occasional snapshots of the fracture site. Ganse and her team have now published their findings in the journals ‘Biosensors and Bioelectronics’ and ‘Journal of Functional Biomaterials’.

Imagine pulling a small device out of your pocket, placing it onto the skin above the fracture site and after just a few seconds, you know how well the fracture is healing. If a plaster cast has been fitted, there would be a small opening in the cast to enable skin contact. This intriguing idea could soon be part of standard post-operative follow-up around the world. The new method enables blood flow and blood oxygen levels in the fracture tissue to be monitored precisely without needing to deploy harmful short-wavelength radiation. ‘The commercially available devices for examining blood flow and oxygen saturation in skin and muscles use non-harmful LED and laser light that is bright enough to penetrate down to the underlying bone tissue,’ explains Bergita Ganse. Working with her team at Saarland University, Ganse has discovered that these devices can also be used to monitor the bone fracture healing process. The team recently demonstrated the success of this approach by applying the methodology to study patients with fractured shin bones (tibia).

‘Our method is not intended to replace X-ray imaging. We regard it as a useful adjunct – a rapid control method that provides supplementary information in areas where existing techniques leave gaps,’ explains Bergita Ganse, who holds the Werner Siemens Foundation Endowed Professorship in Innovative Implant Development at Saarland University’s Medical Campus in Homburg. Until now, bone fractures have been monitored using X-ray imaging or computed tomography scans, which meant exposing the patient to high-energy radiation – something that cannot be repeated too often. ‘Another drawback of using X-rays and CT scans is their delayed sensitivity to early healing activity in bone. As the fracture heals, soft bone tissue forms across the fracture gap, but the bone density is still not high enough for X-ray detection. Increased bone density occurs when calcium salts are deposited at the fracture site (mineralization) – but this only happens later in the healing process,’ explains trauma surgeon and physiologist Bergita Ganse. Before mineralization has occurred, the healing process is essentially invisible, and it is difficult to determine whether the fracture is healing properly or not. ‘CT scans and X-ray images only ever provide us with snapshots, but what unfolds between two scans or two images is largely invisible,’ says Bergita Ganse.

The new technique developed in Saarland enables continuous, non-invasive monitoring of bone healing – directly through the skin. As a result, patients acquire a better understanding of how the healing process is progressing. This additional monitoring of the fracture site means that potential complications can be detected earlier. ‘We know from studying lower leg fractures, that in 14 out of 100 cases, complications arise – but these are often only detected at a late stage,’ explains Professor Ganse. ‘The earlier we notice that something isn’t progressing as it should, the sooner we can intervene, and early intervention can significantly improve patient outcomes. We have a whole range of tools available for targeted remedial treatment, such as pulsed ultrasound, shockwave and magnetic field therapies,’ say Ganse. Sometimes the issue is mechanical: ‘There may simply be too much movement at the fracture site, which can disrupt the repair process and require improved fixation.’
Professor Ganse sees real promise in making this monitoring technology widely accessible: ‘Small, affordable monitoring devices could improve fracture care in settings without access to large, expensive equipment like X-ray machines – particularly in low-resource countries or remote areas.’

Fracture repair is a complex, multi-phase process. Bergita Ganse explains the bone regeneration process: ‘At first, a thin connective structure made of fibrous tissue begins to bridge the fracture. Over time, new bone tissue forms and is gradually supplied with blood as new blood vessels form.’ The team at Saarland University has studied the details of the fracture healing process and have measured how blood flow and oxygen saturation change as bone repair progresses. In two separate studies, Ganse and her doctoral students Oana Scholz and Cedric Nowicki monitored the healing process in 55 patients with tibial fractures over several months and compared their data with a control group of 51 healthy individuals. The findings were striking: ‘Blood flow and oxygen saturation follow a very characteristic pattern during bone regeneration,’ says Ganse. This is the first time such detailed observations of the fracture healing process have been made in human patients.

‘Initially, blood flow rises sharply and reaches a peak. After about two to three weeks, the levels begin to decline again.’ Oxygen saturation in the tissue surrounding the fracture site also follows a characteristic pattern: it initially drops to a minimum before rising again after two to three weeks as new blood vessels begin to form. ‘We can track both of these processes with relatively simple, non-invasive measurements,’ explains Professor Ganse. ‘We used a commercially available device that combines laser Doppler technology to monitor blood flow with white light spectroscopy to detect oxygen saturation in the tissue. If the values fail to return to normal after a few weeks, it's often an early sign that something isn’t progressing as it should.’

The team’s initial findings suggest that the patterns of blood flow and oxygen saturation vary depending on the underlying cause of delayed healing. ‘As we’ve only seen a few cases so far in which the fracture has failed to heal, more research is needed before we can draw firm conclusions about these differences,’ says Bergita Ganse. There are many reasons why a fracture might fail to heal properly. ‘A patient may have moved too much, and not immobilized the fractured limb sufficiently, or there may be associated risk factors underlying conditions – such as smoking or cancer – that impair healing,’ explains Ganse. ‘If you’re using X-rays, these problems only become visible at a relatively late stage. But our method seems capable of detecting them earlier.’ However, one current limitation with the light-based monitoring method is measurement depth. ‘At the moment, we are unable to probe fractures that lie more than five centimetres beneath the skin,’ explains Bergita Ganse.

Ganse’s team is also working on other innovative ways to monitor bone fracture healing, such as the use of self-sensing shape memory materials that can provide data on changes in the stiffness and elasticity of the fracture site as the bone heals.

The research work is part of the ‘Smart Implants’ project that is coordinated by Professor Ganse and has received €8 million in funding from the Werner Siemens Foundation. The project, which has been running for five years, involves interdisciplinary collaboration between research groups at Saarland University working in the fields of medicine, engineering and computer science. The teams have already developed several prototypes and patents for smart fracture plates. These custom implants are designed to not only monitor healing from the moment of surgery but also to actively support it – for example, by providing micromechanical stimulation of the fracture site or by dynamically adjusting the stiffness of the implant. And data from the new laser Doppler and white light spectroscopy monitoring research is now being integrated into the next generation of these smart implants. Currently, the teams are working on miniaturizing the technology so that it can be incorporated inside intramedullary nails, which are only a few millimetres wide. Additional funding has come from the EU under the Horizon Europe programme as part of the research project SmILE (Smart Implants for Life Enrichment).

Ganse and her team are now looking to go beyond tibial fractures and are working to apply their new method to other types of fractures and bone defects. ‘I’m excited to see how quickly this technology will find use in both research work and routine clinical care,’ says Professor Ganse, who brings a unique perspective from her background in space medicine. Ganse collaborates with the European Space Agency (ESA), the German Aerospace Center (DLR) and NASA in the US, studying, among other things, how bone and muscle degrade in space. Her research has contributed to the development of training programmes that help astronauts counteract this type of musculoskeletal degeneration during long-duration missions.

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Wissenschaftliche Ansprechpartner:

Prof. Dr. med. Bergita Ganse, Werner Siemens Foundation Endowed Professorship in Innovative Implant Development
Tel.: +49 6841 16-31570
Email: Bergita.Ganse@uks.eu

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Originalpublikation:

Biosensors and Bioelectronics
‘New sensor options for smart fracture implants and wearable devices: Laser-Doppler and white-light spectroscopy allow monitoring of bone regeneration via perfusion measurement’, Oana Scholz, Cedric Nowicki, Elke Warmerdam, Sandra Rother, Bergita Ganse. DOI: 10.1016/j.bios.2025.117442;
https://doi.org/10.1016/j.bios.2025.117442

Journal of Functional Biomaterials
‘Near-Infrared Spectroscopy Allows for Monitoring of Bone Fracture Healing via Changes in Oxygenation’, Cedric Nowicki und Bergita Ganse.
DOI: 10.3390/jfb15120384
https://doi.org/10.3390/jfb15120384

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Weitere Informationen:

https://doi.org/10.1016/j.bios.2025.117442 - Biosensors and Bioelectronics
https://doi.org/10.3390/jfb15120384 - Journal of Functional Biomaterials

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Trauma surgeon Bergita Ganse holds the Werner Siemens Foundation Endowed Professorship in Innovative ...
Credit: Oliver Dietze
Saarland University

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Professor Bergita Ganse
Credit: Oliver Lang/WSS
WSS

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Merkmale dieser Pressemitteilung:
Journalisten, Wirtschaftsvertreter, Wissenschaftler, jedermann
Ernährung / Gesundheit / Pflege, Medizin
überregional
Forschungsergebnisse, Wissenschaftliche Publikationen
Englisch

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