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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.

Abstract Background Elastic Stable intramedullary Nailing (ESIN) of dislocated diaphyseal femur fractures has become an accepted method for the treatment in children and adolescents with open physis. Studies focused on complications of this technique showed problems regarding stability, usually in complex fracture types such as spiral fractures and in older children weighing > 40 kg. Biomechanical in vitro testing was performed to evaluate the stability of simulated spiral femoral fractures after retrograde flexible titanium intramedullary nail fixation with and without End caps. Methods Eight synthetic adolescent-size femoral bone models (Sawbones® with a medullar canal of 10 mm and a spiral fracture of 100 mm length identically sawn by the manufacturer) were used for each group. Both groups underwent retrograde fixation with two 3.5 mm Titanium C-shaped nails inserted from medial and lateral entry portals. In the End Cap group the ends of the nails of the eight specimens were covered with End Caps (Synthes Company, Oberdorf, Switzerland) at the distal entry. Results Beside posterior-anterior stress (4.11 Nm/mm vs. 1.78 Nm/mm, p < 0.001), the use of End Caps demonstrated no higher stability in 4-point bending compared to the group without End Caps (anterior-posterior bending 0.27 Nm/mm vs. 0.77 Nm/mm, p < 0.001; medial-lateral bending 0.8 Nm/mm vs. 1.10 Nm/mm, p < 0.01; lateral-medial bending 0.53 Nm/mm vs. 0.86 Nm/mm, p < 0.001) as well as during internal rotation (0.11 Nm/° vs. 0.14 Nm/°, p < 0.05). During compression in 9°- position and external rotation there was no statistical significant difference (0.37 Nm/° vs. 0.32 Nm/°, p = 0.13 and 1.29 mm vs. 2.18 mm, p = 0.20, respectively) compared to the "classic" 2-C-shaped osteosynthesis without End Caps. Conclusion In this biomechanical study the use of End Caps did not improve the stability of the intramedullary flexible nail osteosynthesis.

Purpose: The primary goal of this randomised controlled trial was to investigate whether there are differences in the outcome between the Gamma3 nail and a sliding hip screw (SHS) regarding quality of life 1 year after surgery., Methods: In a controlled randomised trial, we compared the Gamma3 nail (Stryker) and a SHS (Omega, Stryker) in the treatment of 193 patients with pertrochanteric fractures. The follow-up period was 12 months. The outcomes included the surgical duration, health-related quality of life measured with the EQ-5D Index and a Visual Analogue Scale (VAS), the living situation and use of walking aid before trauma and 52 weeks after surgery; the Parker Mobility Score; the Harris Hip Score; and the revision, complication and mortality rates., Results: The Gamma3 group had a significantly shorter surgical duration than the SHS group (p < 0.0001). Implant-related complications were significantly lower in the Gamma3 group (p > 0.05). The revision rate was significantly lower in the Gamma3 group based on intention-to-treat (p = 0.0336) as well as as-treated (p = 0.0302) analyses. Otherwise, we did not find significant difference between the two groups regarding the EQ-5D Index and VAS scores, the Parker Mobility Score, the Harris Hip Score, the mortality rate, the use of walking aids and the living situation., Conclusion: There were no detectable differences between the groups in terms of quality of life and clinical scores 12 months after surgery. The surgical duration and revision rate were superior for the Gamma3 group., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Besides the need for biomaterial surface modification to improve cellular attachment, laser-structuring is favorable for designing a new surface topography for external bone fixator pins or implants. The principle of this study was to observe how bioinspired (deer antler) laser-induced nano-microstructures influenced the adhesion and growth of skin cells. The goal was to create pins that allow the skin to attach to the biomaterial surface in a bacteria-proof manner. Therefore, typical fixator metals, steel, and titanium alloy were structured using ultrashort laser pulses, which resulted in periodical nano- and microstructures. Surface characteristics were investigated using a laser scanning microscope and static water contact angle measurements. In vitro studies with human HaCaT keratinocytes focused on cell adhesion, morphology, actin formation, and growth within 7 days. The study showed that surface functionalization influenced cell attachment, spreading, and proliferation. Micro-dimple clusters on polished bulk metals (DC20) will not hinder viability. Still, they will not promote the initial adhesion and spreading of HaCaTs. In contrast, additional nanostructuring with laser-induced periodic surface structures (LIPSS) promotes cell behavior. DC20 + LIPSS induced enhanced cell attachment with well-spread cell morphology. Thus, the bioinspired structures exhibited a benefit in initial cell adhesion. Laser surface functionalization opens up new possibilities for structuring, and is relevant to developing bioactive implants in regenerative medicine.

Introduction: Dynamization of proximal femoral nailing by removal of distal interlocking is one of the recommended treatment options for nonunions of femur fractures. However, in certain inter-/subtrochanteric fractures, gliding of the nail along the femoral shaft is blocked by lateral femoral cortical support of the lag screw. For these cases, Biber et al. proposed lateral cortical notching (LCN), in which the supporting lateral bone is removed. This study investigates the biomechanical effect of LCN on gliding of proximal femoral nailing and stress distribution at the bone/implant interface., Materials and Methods: In this finite element analysis a three-dimensional model of an unstable intertrochanteric fracture with proximal femoral nailing without distal interlocking was simulated using the FebioStudio software suite. To simulate LCN, the lag screw hole was lengthened to 15.34 mm at the lateral cortex. Displacement of the nail along the femoral shaft axis and von Mises stress distribution were compared between LCN model and standard implantation model., Results: Displacement of the nail along the femoral shaft axis was higher in the LCN model than in the standard implantation model (0.48 mm vs. 0.07 mm). Highest von Mises stresses of 176-178 MPa at the implant and of 52-81 MPa at the proximal femur were detected. Maximum von Mises stresses of the implant were comparable at all sides, except for a reduced von Mises stress at the lateral inferior side in the LCN model (80 vs. 102 MPa). At the inferior lateral screw hole and the anterior/posterior lateral screw hole maximum von Mises stress was reduced in the LCN model (2 vs. 49 MPa and 52 vs. 81 MPa), whereas the maximum von Mises stress at the inferior medial screw hole was higher in the LCN model than in the standard implantation model (53 vs. 27 MPa)., Conclusions: Lateral cortical notching facilitates gliding of a distally dynamized proximal femoral nail along the femoral shaft axis in intertrochanteric fractures. Additionally, the lack of lateral cortical bone support at the lag screw reduces von Mises stress at the bone/implant interface and thus could lower the risk for implant breakage and peri‑implant fractures., Competing Interests: Declaration of Competing Interest KS and CL are employees of Swemac Innovation (Germany) GmbH. The authors have no competing interests to declare that are relevant to the content of this article., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objectives. Exposure to hand-transmitted shocks is a widespread phenomenon in the workplace. Separate risk assessments for shocks do not exist in current international hand-arm vibration regulations, leading to potential underestimation of associated health risks. Methods . In a pilot study approach, eight healthy males were exposed to sets of 3 × 5 min of repetitive shocks and 1 × 5 min of random vibration, controlled at a weighted vibration total value of 10 m/s 2 . Baseline and post-exposure measurements of vibration perception thresholds, finger skin temperature, maximal grip/pinch force and the Purdue pegboard test were conducted. Muscle activity was monitored continuously by surface electromyography. Results . Shock exposures evoked a temporary increase of vibration perception thresholds with high examination frequencies. A decrease of skin temperature was hinted for shocks of 1 and 20 s -1 . Electromyographical findings indicated an additional load on two forearm muscles during shock transmission. Maximum grip force and manual dexterity were not affected, and pinch force only partially reduced after the exposures. Conclusion . Physiological effects from shock exposure conform to those described for hand-arm vibration exposure in principle, although some divergence can be hypothesized. Randomized designs are required to conclusively assess the need of occupational health concepts specifically for hand-transmitted shocks.

Introduction: Biomechanical studies have proved that locking plates have better primary stability besides versatility regarding fracture pattern while reducing bone contact and bridging the gap, whereas conventional nonlocking plates (plus lag screw) depend on bone-plate compression. The clinical benefit of locking plates over nonlocking plates remains unanswered, however. Therefore, this retrospective cohort study was set up to test the hypothesis that the use of locking plates for unstable ankle fractures will result in fewer re-displacements, superior bony healing, and functional and clinical outcomes better than observed in the nonlocking cohort., Methods: Bimalleolar ankle fractures (AO 44-B2) without syndesmotic injury treated with either a locking or a nonlocking plate were included. Groups were compared for complications, bone healing, secondary dislocation, progressions of osteoarthritis, and clinical outcome using patient-reported outcome measures., Results: Data revealed no clinical outcome differences (Olerud-Molander Ankle Score: nonlocking 88.2 ± 14.4, locking 88.8 ± 12.3, P = .69, robust two 1-sided test for equality (RTOST): P = .03; American Orthopaedic Foot and Ankle Score: nonlocking 91.2 ± 12.9, locking 91.8 ± 11.3, P = .96, RTOST: P = .04). Nevertheless, a significant postoperative progression of osteoarthritis was detected in both groups (P = .04). This was independent of implant (P = .16). Although difference was not significant, locking plates were preferred in older (P = .78) and sicker patients (P = .63) and in cases with severer osteoarthritis (P = .16), and were associated with a higher complication rate (P = .42) and secondary dislocation (nonlocking 9.4%, locking 18.2%; P = .42). Re-displacement, however, was not a compelling reason for revision., Conclusions: The present study shows statistically significant equality of both types of implants. Contrary to our expectation, locking plates seemed to be associated with a higher risk for re-displacement. Overall, the use of either locking or nonlocking plates for unstable AO 44-B2 fractures is safe and successful despite significant progression of osteoarthritis., Level of Evidence: III, Retrospective observational cohort study.

Background: Plate osteosynthesis depicts the gold standard to surgically treat pubic symphysis disruptions. However, high rates of implant failure after plate osteosynthesis are reported, probably because of the iatrogenic arthrodesis of this fibrocartilaginous joint. Therefore, flexible implants for treatment of pubic symphysis disruptions appear to be a sensible solution., Methods: In this biomechanical screening study, we designed and investigated a flexible implant, which consists of two plates connected with an ultra-high molecular weight polyethylene fiber cord. We mechanically tested eye splices as a possible fixation method of the cords by performing tensile load to failure tests. Afterwards, we developed a biomechanically appropriate plate design and cord routing between the plates. Finally, we biomechanically tested the flexible implant under tensile and shear loading until failure., Findings: When fixing a 1 mm ultra-high molecular weight polyethylene fiber cord with eye splices, a load at failure of 1570.74 N was detected under tensile loading. None of the eye splices failed but the cords itself ruptured. The load at failure of the designed cord routing in criss-cross technique and fixation within the plates amounts 4742.09 N under tensile and 2699.77 N under shear load., Interpretation: We developed a novel flexible implant for repair of pubic symphysis disruptions using ultra-high molecular weight polyethylene fiber cords connected to osteosynthesis plates. We identified eye splices as a mechanically optimal fixation method and proved that the ultra-high molecular weight polyethylene fiber cord routing and fixation of the flexible implant clearly withstands physiological forces acting on the pubic symphysis., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: Until recently, no study had compared the quality of life of persons with transfemoral amputation treated with osseointegration to socket prosthesis users., Objectives: Comparison of quality of life in two types of prostheses users: a cohort of patients with osseointegration and patients equipped with a socket prosthesis who were group-matched for age, body mass index and mobility grade., Study Design: A cross-sectional study that compared METHODS:: The quality of life of 39 participants (22 in the osseointegration group and 17 in the socket prosthesis group) was measured using the Questionnaire for Persons with Transfemoral Amputation (Q-TFA) and European Questionnaire 5-dimension 3-level (EQ-5D-3L) surveys., Results: Compared with the socket prosthesis group, the osseointegration group had a significantly higher 'Global' score (p = 0.022) and a significantly lower 'Problem' score (p < 0.001) of the Q-TFA. The 'Mobility' (p = 0.051) and 'Use' scores (p = 0.146) of the Q-TFA, the EQ-5D-3L index (p = 0.723), and EQ-5D visual analog scale (p = 0.497) showed no significant differences between groups., Conclusions: Patients with osseointegration experienced less prosthesis-associated problems than socket prosthesis users and had a higher prosthesis-associated quality of life when assessed with the Q-TFA. General quality of life, as assessed with the EQ-5D-3L, was not different between groups.

Background: Loosening of prostheses and functional disorders represent a far-reaching problem in the clinic, and the long-term outcomes are essentially determined by wear. Despite all advances, up to 10% of prostheses still fail after 10 years. In particular, more active patients show increased revision rates., Methods: The objective of this thesis is to examine whether the applied microstructures of the articulating surfaces can lead to a reduction in abrasion. Three different structural geometries (dimples, offset lines, grid lines) were defined. In an experimental test setup according to DIN ISO 6474 (Deutsches Institut für Normung, International Organization for Standardization), a tribological test of metal and ceramic pairings was performed using two-dimensional ring-on-disc (RoD) tests., Results: In both material groups, the structuring had a positive effect on the wear behaviour. In the ceramic group, an abrasion reduction of 22.6% was achieved. However, it is important to take into account the limited informative value due to the hardness of the material. Two of the three Cobalt-Chrome-Molybdenum (CoCrMo) structure geometries (grids, offset lines) also showed a significant reduction in abrasion compared to the reference group, with a maximum wear reduction of 55.5%., Conclusion: By reducing abrasion, surface structuring could be used to extend the life of prostheses and minimise the number of revisions.

Introduction: The annual incidence of proximal femoral fractures is 100-150/100,000 and continues to increase with an aging population. Cut-out of hip screws after fracture fixation has been quoted as 8% in the literature. The tip-apex distance (TAD) is the strongest predictor for cut-out after operative fracture stabilisation. The aim of this study was to evaluate the novel ADAPT system (Adaptive Positioning Technology, Stryker, USA), a navigation device for intramedullary nailing of trochanteric fractures and its effect on optimising the TAD. This is the first clinical study to evaluate this new technology., Methods: The study group of 36 consecutive patients with a pertrochanteric fracture underwent intramedullary nailing for fracture fixation using ADAPT technology, while the matched control group underwent conventional Gamma-3-nailing. Matching criteria included fracture classification, gender and age. We measured the operative time and the postoperative TAD in anteroposterior (AP) and lateral radiographs of the 72 patients., Results: The mean TAD using ADAPT was 16.9 mm (range 8.4-33.7 mm) compared with 24.9 mm (range 14.6-40.2 mm) in the reference group treated without ADAPT. Using the ADAPT system significantly improved (p < 0.0005) the accuracy of lag screw placement but had no effect on operating time in fixation of femoral pertrochanteric fractures., Conclusion: Working with the novel ADAPT system for positioning the lag screw using the Gamma-3-nail led to a statistically highly significant reduction of the TAD compared to the reference group (p < 0.001). The ADAPT system proved to be a very useful device in achieving higher surgical standards for the treatment of trochanteric fractures with intramedullary nailing. It enables higher accuracy in screw positioning and therefore better placement of the implant., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

This paper follows up on a recent systematic review of test methods and parameters for biomechanical testing of bone plates and it is the first study that contains recommendations for standardized mechanical testing of bone plate-screw constructs for osteosynthesis. Following the testing philosophy of ASTM F382 and ISO 9585, we have developed standardized quasi-static and dynamic testing methods for straight linear and anatomically shaped plates, including locked type and conventional systems. The test specification comprises torsion and bending tests along the implant axis and therefore modifies and extends the methods proposed by ASTM F382. We present specific test setups in order to determine product-specific characteristics of the mechanical construct, consisting of the bone plate with corresponding screws (such as construct stiffness, yield strength, ultimate strength and fatigue properties) under the condition that it is rigidly fixed to "healthy bone". We also address specific testing requirements that are important for the purpose of standardization, such as the positioning of the construct for testing or the number of screws in the diaphysis and metaphysis. Finally, we define the outcome parameters and associated failure criteria related to quasi-static and dynamic testing for comparative purposes. This paper does not intend to replace biomechanical testing of those devices under physiological loading conditions.

Background: The Study of Healthcare Personnel with Influenza and other Respiratory Viruses in Israel (SHIRI) prospectively follows a cohort of healthcare personnel (HCP) in two hospitals in Israel. SHIRI will describe the frequency of influenza virus infections among HCP, identify predictors of vaccine acceptance, examine how repeated influenza vaccination may modify immunogenicity, and evaluate influenza vaccine effectiveness in preventing influenza illness and missed work., Methods: Cohort enrollment began in October, 2016; a second year of the study and a second wave of cohort enrollment began in June 2017. The study will run for at least 3 years and will follow approximately 2000 HCP (who are both employees and members of Clalit Health Services [CHS]) with routine direct patient contact. Eligible HCP are recruited using a stratified sampling strategy. After informed consent, participants complete a brief enrollment survey with questions about occupational responsibilities and knowledge, attitudes, and practices about influenza vaccines. Blood samples are collected at enrollment and at the end of influenza season; HCP who choose to be vaccinated contribute additional blood one month after vaccination. During the influenza season, participants receive twice-weekly short message service (SMS) messages asking them if they have acute respiratory illness or febrile illness (ARFI) symptoms. Ill participants receive follow-up SMS messages to confirm illness symptoms and duration and are asked to self-collect a nasal swab. Information on socio-economic characteristics, current and past medical conditions, medical care utilization and vaccination history is extracted from the CHS database. Information about missed work due to illness is obtained by self-report and from employee records. Respiratory specimens from self-collected nasal swabs are tested for influenza A and B viruses, respiratory syncytial virus, human metapneumovirus, and coronaviruses using validated multiplex quantitative real-time reverse transcription polymerase chain reaction assays. The hemagglutination inhibition assay will be used to detect the presence of neutralizing influenza antibodies in serum., Discussion: SHIRI will expand our knowledge of the burden of respiratory viral infections among HCP and the effectiveness of current and repeated annual influenza vaccination in preventing influenza illness, medical utilization, and missed workdays among HCP who are in direct contact with patients., Trial Registration: NCT03331991 . Registered on November 6, 2017.

Purpose: The fibula flap has been established for orofacial reconstruction following ablative surgery. Donor-site morbidity of the lower leg may be explained by the harvest technique and particularly by detachment of the M. extensor halluces longus (EHL) and M. extensor digitorum longus (EDL)., Material and Methods: On cadaveric lower leg specimens, the tendons of the EHL and EDL were dissected at the proximal phalanges and loaded with corresponding weights. The average displacement of the muscle was evaluated during the harvesting procedure., Results: Cumulative detachment of the interosseous membrane caused considerable displacement of the EHL but less impairment of the EDL. Segmental and cumulative osteotomy of the fibula implicated significant displacement of both EHL and EDL., Conclusion: A recommendation can be given for cautious selection of osteotomy site of the fibula and for limited sacrifice of the fibula and adjacent attachments of the extensors to keep local-site morbidity at a minimum., (Copyright © 2018. Published by Elsevier Ltd.)

Cortical pores are determinants of the elastic properties and of the ultimate strength of bone tissue. An increase of the overall cortical porosity (Ct.Po) as well as the local coalescence of large pores cause an impairment of the mechanical competence of bone. Therefore, Ct.Po represents a relevant target for identifying patients with high fracture risk. However, given their small size, the in vivo imaging of cortical pores remains challenging. The advent of modern high-resolution peripheral quantitative computed tomography (HR-pQCT) triggered new methods for the clinical assessment of Ct.Po at the peripheral skeleton, either by pore segmentation or by exploiting local bone mineral density (BMD). In this work, we compared BMD-based Ct.Po estimates with high-resolution reference values measured by scanning acoustic microscopy. A calibration rule to estimate local Ct.Po from BMD as assessed by HR-pQCT was derived experimentally. Within areas of interest smaller than 0.5 mm 2 , our model was able to estimate the local Ct.Po with an error of 3.4%. The incorporation of the BMD inhomogeneity and of one parameter from the BMD distribution of the entire scan volume led to a relative reduction of the estimate error of 30%, if compared to an estimate based on the average BMD. When applied to the assessment of Ct.Po within entire cortical bone cross-sections, the proposed BMD-based method had better accuracy than measurements performed with a conventional threshold-based approach., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: This study aims to assess the association between socio-demographic and health characteristics of older adults in Eastern China and knowledge, attitudes, and practices (KAP) about the influenza virus and vaccine., Methods: A prospective cohort of 1506 older adults (aged ≥60 years) was enrolled from November to December 2015 in Jiangsu Province. We examined the association between demographics, health and functional status, and cognitive impairment at enrollment with awareness of influenza virus and vaccine and KAP items focused on five Health Belief Model domains. At a 12-month follow-up interview we assessed change in awareness and readiness to be vaccinated., Results: One in five older adults was aware of the influenza virus (21%) or vaccine (20%); even fewer reported having at least "a little" knowledge of the virus and vaccine (7% and 4%, respectively); less than 1% reported ever receiving an influenza vaccine. Retirement, higher education and income, and normal cognitive status were consistently associated with both awareness and knowledge of influenza virus. The odds of having at least "a little" knowledge of the vaccine was 2.9-fold (95% CI = 1.6-5.3) higher among older adults with at least some secondary schooling. Among the 108 with knowledge of the virus, 55% said they "worry about getting the flu this season." Among the 73 with knowledge of the vaccine, 92% believed the vaccine was at least somewhat effective and less than half (43%) thought that influenza vaccination was safe. At a 12-month follow-up interview, 33% (442/1333) increased from no knowledge to at least "a little"., Conclusions: If and when influenza vaccines become widely available to older adults in China, our results indicate that influenza vaccination campaigns with basic information on the virus and vaccine could be beneficial for all older adults, especially those with less education and/or more cognitive impairment., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Osteochondral injuries often lead to osteoarthritis of the affected joint. All established systems for refixation of osteochondral defects show certain disadvantages. To address the problem of reduced stability in resorbable implants, ultrasound-activated pins were developed. By ultrasound-activated melting of the tip of these implants, a more secure anchoring is assumed., Materials and Methods: The aim of the study was to investigate if ultrasound-activated pins can provide secure fixation of osteochondral fragments compared to screws and conventional resorbable pins. In a biomechanical laboratory setting, osteochondral fragments of the medial femoral condyle of sheep were refixated with ultrasound-activated pins [US fused poly(L-lactide-co-D,L-lactide) (PLDLLA) pins], polydioxanone (PDA) pins and conventional titanium screws. Anchoring forces of the different fixation methods were examined, registered and compared concerning shear force and tensile force., Results: Concerning the pull out test, the US fused PLDLLA pins and titanium screws (~122 N and ~203 N) showed comparable good results, while the PDA pins showed significantly lower anchoring forces (~18 N). Examination of shear forces showed a significantly higher anchoring of the screws (~248 N) than the US fused PLDLLA pins (~218 N). Nevertheless, the US fused PLDLLA pins could significantly outperform the PDA pins (~68 N) concerning shear forces., Conclusion: The US fused PLDLLA pins demonstrated a comparable anchorage to the fixation with screws, but were free from the disadvantages of metal implants, i.e. the need for implant removal. The PDA pin application showed inferior biomechanical properties.

In the published literature there are controversial data to the biomechanical stability of monocortical comparing to the bicortical fixation of metacarpal fractures. The aim of this study was to compare the biomechanical stability of monocortical and bicortical locking osteosynthesis in quasi-static and dynamic 4-point bending tests of composite third metacarpal bone (4th Gen third metacarpal, Sawbones, Malmö, Sweden) fixed with 7-hole locking plate (XXS System, Biotech-Ortho, Wright, Memphis, TN). The tests to determine quasi-static yield and bending strength as well as fatigue strength were conducted in 4 groups of 10 samples after creating standardized mid-shaft transverse osteotomies using a diamont belt grinder (0.3 mm saw blade). The force applied was the dorsal apex loading, similar to the forces applied to metacarpals during normal finger flexion and extension.In the quasi-static testing, no plate breakage was observed in each group. All metacarpals broke at their thinnest part. The average bending strength of the bicortical samples (10.54 ± 0.998 Nm) was significantly higher comparing to the monocortical samples (8.57 ± 0.894 Nm) (P < .001).In the dynamic loading test, all constructs (8 monocortical samples and 7 bicortical) that failed broke at the osteotomy site and the average fatigue strength did not differ in both groups.Consequently, a unicortical plating method may provide adequate strength and stability to metacarpal fractures based on the results of the cyclical loading representative of in vivo loading.

Bone plates for osteosynthesis are subject to biomechanical testing for safety and regulatory purposes. International standards applicable for those devices are designed for bone plates used in the surgical fixation of the skeletal system but not necessarily for all device variants available. We intend to summarize the test methods and parameters presented in the literature to evaluate bone plates in a clinical environment, especially for modern anatomically shaped implants. We conducted a systematic review on published biomechanical studies for lower and upper extremities (clavicle, humerus, ulna, radius, metacarpal, femur, tibia, fibula, metatarsal). The search process led to the identification of 159 relevant articles containing 330 individual tests, which were analyzed concerning various test criteria including test methods and parameters per bone segment for static and dynamic loading tests, as well as number of cycles, chosen bone model and outcome variables. The biomechanical literature for bone plates is diverse, inconsistent and heterogeneous. Test methods are not commonly applied per bone plate location and test parameters are not uniformly specified and displayed. They vary in particular for bending and torsion tests as well as for the number of loading cycles for dynamic testing. Outcome variables are not commonly applied nor defined. Consequently this paper is the first in a planned chronological series of three to identify the need (this publication), to develop a systematic procedural approach (2. publication) and to apply the process exemplary on a bone plate sample (3. publication).

Background: Different hexapod-based external fixators are increasingly used to treat bone deformities and fractures. Accuracy has not been measured sufficiently for all models., Methods: An infrared tracking system was applied to measure positioning maneuvers with a motorized Precision Hexapod® fixator, detecting three-dimensional positions of reflective balls mounted in an L-arrangement on the fixator, simulating bone directions. By omitting one dimension of the coordinates, projections were simulated as if measured on standard radiographs. Accuracy was calculated as the absolute difference between targeted and measured positioning values., Results: In 149 positioning maneuvers, the median values for positioning accuracy of translations and rotations (torsions/angulations) were below 0.3 mm and 0.2° with quartiles ranging from -0.5 mm to 0.5 mm and -1.0° to 0.9°, respectively., Conclusions: The experimental setup was found to be precise and reliable. It can be applied to compare different hexapod-based fixators. Accuracy of the investigated hexapod system was high., (Copyright © 2014 John Wiley & Sons, Ltd.)

Purpose: For pediatric femoral shaft fractures, elastic stable intramedullary nailing (ESIN) is an accepted method of treatment. But problems regarding stability with shortening or axial deviation are well known in complex fracture types and heavier children. Biomechanical in vitro testing was performed to determine whether two modified osteosyntheses with an additional tension screw fixation or screw fixation alone without nails could significantly improve the stability in comparison to classical ESIN., Methods: A total of 24 synthetic adolescent-sized femoral bone models (Sawbones, 4th generation; Vashon, Washington, United States) with an identical spiral fracture (length 100 mm) were used. All grafts underwent retrograde fixation with two C-shaped steel nails (2C). Of the 24, 8 osteosyntheses were supported by one additional tension screw (2C1S) and another 8 by two screws (2S) in which the intramedullary nails were removed before testing. Each configuration underwent biomechanical testing in 4-point bending, external rotation (ER) and internal rotation (IR). Furthermore, the modifications were tested in axial physiological 9 degrees position for shifting and dynamic compression as well as dynamic load., Results: Both screw configurations (2C1S and 2S) demonstrated a significantly higher stability in comparison to the 2C configuration in 4-point bending (anterior-posterior, 0.95 Nm/mm [2C] < 8.41 Nm/mm [2C1S] and 15.12 Nm/mm [2S]; posterior-anterior, 8.55 Nm/mm [2C] < 12.65 Nm/mm [2C1S] and 17.54 Nm/mm [2S]; latero-medial, 1.17 Nm/mm [2C] < 5.53 Nm/mm [2C1S] and 9.15 Nm/mm [2S]; medio-lateral, 1.74 Nm/mm [2C] < 9.69 Nm/mm [2C1S] and 12.20 Nm [2S]; all p < 0.001) and during torsion (ER, 0.61 Nm/degree [2C] < 4.10 Nm/degree [2C1S] and 9.29 Nm/degree [2S]; IR, 0.18 Nm/degree [2C] < 6.17 Nm/degree [2C1S] and 10.61 Nm/degree [2S]; all p < 0.001]. The shifting in compression in 9 degrees position was only slightly influenced. The comparison of 2S versus 2C1S showed more stability for 2S than 2C1S in all testing, except the axial 9 degrees compression tests for shifting. In contrast to the 2C configuration, both modifications (2C1S and 2S) turned out to be stable in dynamic 9 degrees axial compression with a force of 100 up to 1,000 N at 2.5 Hz in 250,000 load cycles., Conclusions: In this in vitro adolescence femur spiral fracture model, the stability of ESIN could be significantly improved by two modifications with additional tension screws. If transferred in clinical practice, these modifications might offer earlier weight bearing and less problems of shortening or axial deviation., (Georg Thieme Verlag KG Stuttgart · New York.)

Background: Elastic stable intramedullary nailing (ESIN) is accepted widely for treatment of diaphyseal femur fractures in children. However, complication rates of 10 to 50 % are described due to shortening or axial deviation, especially in older or heavier children. Biomechanical in vitro testing was performed to determine whether two modified osteosyntheses with end caps or a third nail could significantly improve the stability in comparison to classical elastic stable intramedullary nailing in a transverse femur fracture model., Methods: We performed biomechanical testing in 24 synthetic adolescent femoral bone models (Sawbones®) with a transverse midshaft (diaphyseal) fracture. First, in all models, two nails were inserted in a C-shaped manner (2 × 3.5 mm steel nails, prebent), then eight osteosyntheses were modified by using end caps and another eight by adding a third nail from the antero-lateral (2.5-mm steel, not prebent). Testing was performed in four-point bending, torsion, and shifting under physiological 9° compression., Results: The third nail from the lateral showed a significant positive influence on the stiffness in all four-point bendings as well as in internal rotation comparing to the classical 2C configuration: mean values were significantly higher anterior-posterior (1.04 vs. 0.52 Nm/mm, p < 0.001), posterior-anterior (0.85 vs. 0.43 Nm/mm, p < 0.001), lateral-medial (1.26 vs. 0.70 Nm/mm, p < 0.001), and medial-lateral (1.16 vs. 0.76 Nm/mm, p < 0.001) and during internal rotation (0.16 vs. 0.11 Nm/°, p < 0.001). The modification with end caps did not improve the stiffness in any direction., Conclusions: The configuration with a third nail provided a significantly higher stiffness than the classical 2C configuration as well as the modification with end caps in this biomechanical model. This supports the ongoing transfer of the additional third nail into clinical practice to reduce the axial deviation occurring in clinical practice.

Objective: Passive, opt-out recruitment strategies have the potential to improve efficiency and enlarge the participant pool for clinical studies. We report on the feasibility of using a passive consent strategy for a multicenter pediatric study., Methods: We assessed the response to passive and active control recruitment strategies used in a multicenter pediatric cohort study and describe the variability in acceptance among institutional review boards (IRBs) and parents of pediatric patients., Results: Twenty-six pediatric centers submitted IRB applications; 24 centers participated. Sixteen IRBs approved the proposed passive recruitment strategy, and 6 IRBs required active consent strategies; 2 centers used a modified participation mode using control subjects from neighboring centers. In all, 4529 potential participants were identified across 22 centers. In the pre-enrollment phase, opt-out rates were significantly lower in the passive consent group compared with the active recruitment centers (1.6% vs. 11.8%; P < .001). During the enrollment phase, however, refusal rates in the passive consent group were significantly higher (38.1% vs. 12.2%; P = .004). The overall refusal rate across both groups was 33.3%., Conclusions: IRB variability in interpretation and application of regulations affects consistency of study procedure across sites and may reduce validity of study findings. Opt-out consent allowed us to create a large representative pool of control subjects. Parents were more likely to refuse to be approached for a study in the pre-enrollment phase when active consent was used, but were more likely to decline actual study enrollment when passive consent was used in the pre-enrollment period., (Copyright © 2014 by the American Academy of Pediatrics.)

Background: The present study aimed to biomechanically evaluate a novel locking plate intended for osteosynthesis of coronoid fracture compared to mini L-plates and cannulated screws., Methods: Biomechanical tests were performed on a fracture model in synthetic bones. Three groups, each with eight implant-bone-constructs, were analyzed in quasi-static and dynamic tests. Finally, samples were tested destructively for maximum strength., Results: The mean (SD) highest stiffness was measured for the novel plate [693 (18) N/mm], followed by the mini L-plate [646 (37) N/mm] and the cannulated screws [249 (113) N/mm]. During the cycling testing of the novel plate and the mini L-plate, no failures occurred, although three of the eight samples of cannulated screws failed during the test. The mean (SD) maximum strength during the destructive testing was 1333 (234) N for the novel plate, 1338 (227) N for the mini-L-plate and 459 (56) N for the cannulated screws. No statistical differences were found during the destructive testing between the two plates (p = 0.999), although statistical differences were found between both plates and the cannulated screws (p = 0.000 each)., Conclusions: Osteosynthesis of the coronoid process using the novel plate is mechanically similar to the mini L-plate. Both plates were superior to osteosynthesis with cannulated screws.

Open reduction and fixation of low condylar fractures of the mandible can be achieved by many osteosynthesis systems that differ in size, shape, and site of placement according to the surgical approach. We investigated the maximum load and rigidity of 4 osteosynthesis systems: the standard double 4-hole straight miniplates, the inverted y-miniplate (with and without self-drilling screws), and the TriLock Delta condyle trauma plate. The standard double 4-hole straight miniplate osteosynthesis achieved the best fixation and resistance in view of a mean (SD) maximum load of 539.8 (100.2)N, followed by the inverted y-miniplate with the self-drilling screws (246.5 (23.8)N), the inverted y-miniplate with standard screws (242.4 (27.2)N), and finally the TriLock Delta plate (167.4 (39.2)N). Analysis of the slope of the force-displacement diagram from 80N to 100N in each group showed that the TriLock Delta miniplate had the highest values for rigidity (17.3 (5.1)N/μm), followed by the inverted y-miniplate groups with self-drilling screws (14.1 (6.4)N/μm), and with standard screws (12.6 (2.5)N/μm). The double 4-hole straight miniplate osteosynthesis had the lowest rigidity (8.7 1.4)N/μm). Despite the significant difference in the maximum load between the double 4-hole miniplates and other investigated osteosynthesis patterns, all groups had sufficient load for the fixation of low condylar fractures of the mandible when postoperative bite forces and the slowly increasing voluntary clenching during healing were considered., (Copyright © 2014 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Background: The aim of our study was to develop a test setup combining realistic force transmission with physiological movement patterns at a frequency that mimicked daily use of the elbow, to assess implants in orthopedic joint reconstruction and trauma surgery., Methods: In a multidisciplinary approach, an in vitro biomechanical testing machine was developed and manufactured that could simulate the repetitive forceful movement of the human elbow joint. The construction involved pneumatic actuators. An aluminum forearm module enabled movements in 3 degrees of freedom, while motions and forces were replicated via force and angular sensors that were similar to in vivo measurements., Results: In the initial testing, 16 human elbow joint specimens were tested at 35 Nm in up to 5000 cycles at a range of 10° extension to 110° flexion. The transmitted forces led to failure in 9 out of the 16 tested specimens, significantly more often in females and small specimens., Conclusions: It is possible to construct a testing machine to simulate nearly physiological repetitive elbow motions. The prototype has a number of technical deficiencies that could be modified. When testing implants for the human elbow with cadaver specimens, the specimen has to be chosen according to the intended use of the implant under investigation.