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The aim of this study was to investigate the accuracy of bone mineral density (BMD) determined by quantitative computed tomography (qCT) based on in situ and ex situ scans of cadavers of variable stature. The influence of surrounding tissue on the quantification of CT images of ex situ scanned femora was investigated in air and in water and compared with the in situ scanned femora. The study showed that the surrounding tissue has an impact on the grey value-based representation of the scanned object as well as on the calibration of BMD, influencing the determination of BMD. Local differences in BMD of up to 17.5% were observed, which might originate from beam hardening artifacts.

Abstract The cut-out of the sliding screw is one of the most common complications in the treatment of intertrochanteric fractures. The reasons for the cut-out are: a suboptimal position of the hip-screw in the femoral head, the type of fracture and poor bone quality. The aim of this study was to reproduce the cut-out event biomechanically and to evaluate the possible prevention of this event by the use of a biopolymer augmentation of the hip screw. Concerning the density and compression force of osteoporotic femoral bone polyurethane foam according to the terms of the Association for Standard Testing Material (ASTMF 1839-97) was used as test material. The polyurethane foam Lumoltan 200 with a compression force of 3.3 Mpa and a density of 0.192 g/cm3 was used to reproduce the osteoporotic bone of the femoral fragment (density 12 lbm/ft3). A cylinder of 50 mm of length and 50 mm of width was produced by a rotary splint raising procedure with planar contact. The axial load of the system was performed by a hydraulic force cylinder of a universal test machine type Zwick 1455, Ulm, Germany. The CCD-angle of the used TGN-System was preset at 130 degrees. The migration pattern of the hip screw in the polyurethane foam was measured and expressed as a curve of the distance in millimeter [mm] against the applied load in Newton [N] up to the cut-out point. During the tests the implants reached a critical changing point from stable to unstable with an increased load progression of steps of 50 Newton. This unstable point was characterized by an increased migration speed in millimeters and higher descending gradient in the migration curve. This peak of the migration curve served as an indicator for the change of the hip screw position in the simulated bone material. The applied load in the non-augmented implant showed that in this group for a density degree of 12 (0,192 g/cm3) the mean force at the failure point was 1431 Newton (± 52 Newton). In the augmented implant we found that the mean force at the failure point was 1987 Newton (± 84 Newton). This difference was statistically significant. In conclusion, the bone density is a significant factor for the stability of the hip screw implant. The osteosynthesis with screws in material with low density increases the chance for cut-out. A biopolymer augmented hip screw could significantly improve the stability of the fixation. The use of augmentation with a fast hardening bone replacement material containing polymer-ceramic changes the point of failure under axial load in the osteoporotic bone model and could significantly improve the failure point. Our study results indicate, that a decrease of failure in terms of cut-out can be achieved with polymer augmentation of hip screws in osteoporotic bones.

Introduction: Clinical trials currently evaluate the use of mesenchymal stem cells (MSCs) for the treatment of non-union bone fractures. The stem cells are injected directly into the non-union area of a bone via a cannula. During this injection process, pressure and shear forces affect the MSCs which could influence the viability of the cells. One parameter that influences the level of the shear forces is the volume flow. The aim of this study is to show whether the injection process with two different volume flows influences the cell viability. Methods: MSCs were isolated from bone tissue, harvested during arthroplasty. Afterwards, they were diluted to a concentration of 1 million cells/mL and 1 mL of this suspension was injected through a cannula with 200 mm length and 2 mm diameter (14 G) with volume flows of 38 and 100 mL/min. The evaluation was performed by detecting living, apoptotic, and dead cells using flow cytometry. The statistical analysis was performed with a Kruskal-Wallis-test to identify significant differences and with a TOST procedure for significant equivalence. The significance level was set to 5 % and the equivalence margin to 20 %. Results: The cell population of healthy cells was in the control group 85.88±2.98 %. After an injection with 38 mL/min the population of healthy cells was 86.04±2.53 % and with 100 ml/min 85.48±1.64 %. The statistical analysis revealed no significant difference between these groups (p = 0.99), but a significant equivalence between the control group and the two volume flows (38 mL/min: p = 0.002, 100 mL/min: p = 0.001). In addition the results show no increase of apoptotic and dead cells in the population after injection. Conclusion: The results indicate that the injection process through the cannula with these volume flows has no effect on the viability of the MSCs.

The Interoperability of medical devices and IT systems using various technologies in clinics and the preclinical area is still a research topic. The MOMENTUM project deals with the new 5G mobile technology and explores how they contribute to an improvement in emergency care. Different applications, as well as various technical and clinical aspects, including IT security, are considered. Integrated emergency care seems sensible, particularly for emergencies outside of metropolitan areas and for particularly critical cases.

Data from preclinical emergency care is often not available in an integrated, electronic way. Data flow between ambulances and trauma centers lacks a communication approach that allows for efficient aggregation, transmission and reuse. We present the results of the requirement analysis for 5G-supported emergency care scenarios. With the illustarted requirements and derived structural consequences, we conclude with a proposal that will allow us to provide mechanisms and technologies to enable integrated emergency communication for preclinical care using modern communication technologies.

The following work gives an overview of telemedical consultation in emergencies based on a research project. A telemedical centre located at a university hospital offers medical expertise for rural islands independent from place, time and urgency. Medical employees on the islands were relieved in matters of responsibilities and received medical support whenever it is necessary. Results from the projects mid-term evaluation compare the innovative concept with the conventional approach.