**Acknowledgements**

This work has been supported through the German Research Foundation (FG 2195—DFG SCHM2977 and DFG DU298) and the Berlin-Brandenburg Center for Regenerative Therapies. We like to acknowledge Dr. Serafeim Tsitsilonis for providing X-ray images of fracture treatment examples from the orthopedic and trauma department of the Charité – Universitätsmedizin Berlin and Dr. Hanna Schell for providing histological images to visualize bone anatomy.
