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Purpose: During the last few years, the number of electric scooter (e-scooter) users has risen to an all-time high. This study aimed to analyze e-scooter related accidents and trauma prevention measures in a large European city (Vienna, Austria)., Methods: This retrospective study comprises a thorough data assessment and analysis of all e-scooter related accidents between 2018 and 2021 at a large level 1 trauma center in Vienna. Based on the data analysis, risk factors were identified, and possible prevention strategies were proposed., Results: During the observed period, 1337 patients sustained an injury from an e-scooter. Of these, 1230 were injured directly while driving (92%). The remaining 107 patients (8%) were classified as non-driving injuries. 927 injuries involved males (69.3%). The mean age was 32.1 years (range 4-86 years). Of all injured patients, 429 (32.1%) sustained at least one serious injury. The most common injuries included radial head fractures and concussions. Among the accidents treated, the use of protective equipment was sporadic. For example, helmets were worn in only 13.7% of cases. Wearing a helmet reduced the number of head injuries (24% versus 46.8%). In just three years, the number of patients increased 19-fold with a focus in the summer months., Conclusion: This study shows a substantial and sustained increase in e-scooter accidents with potentially serious injuries. Helmet use was found to be an effective form of head injury prevention. Further options for using protective equipment should be evaluated to improve the safety aspects of riding e-scooters., Competing Interests: Declarations. Ethics approval and consent to participate: The study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Review Board of the Austrian Workers’ Compensation Board (IRB Code EK 01/2022, approved on May 4th 2022) before data collection and analysis. Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Background: In the last years, there has been increasing use of shoulder arthroplasty. As a result, an increasing incidence of periprosthetic humerus fractures (PPHF) is expected. Therefore, this retrospective, multicenter analysis aimed to collect demographic data from patients with PPHF, their treatment strategies, and associated complications., Methods: Demographics of patients with PPHF were collected retrospectively from the database of six trauma hospitals between January 2000 and December 2020. All fractures were categorized according to the Wright and Cofield, and Worland classifications. In addition, the type of treatment for PPHF, as well as subsequent complications, were evaluated., Results: A total of 72 patients with a PPHF were identified. The mean age of the 55 female and 17 male patients was 77 years. PPHF occurred a mean of 50 months after primary arthroplasty implantation, almost exclusively as a result of a fall from standing height (n = 67). In-situ implant was a RTSA in 40 patients and a hemiarthroplasty in 32 patients. More than half of the fractures (n = 38) were type B fractures, according to Wright and Cofield. According to Worland, the majority of patients also had a type B fracture (type B1 (n = 22), type B2 (n = 28), type B3 (n = 10)). Associated comorbidities were found in 21 patients. A total of 31 patients were treated non-operatively, 27 with Open Reduction Internal Fixation (ORIF), and 14 with a revision arthroplasty. Nine primary radial nerve palsies were found (pre-operatively), and seven secondarily (post-operatively). Nine patients suffered from non-union (ORIF 4, non operative 4, stem replacement 1)., Conclusion: The treatment strategy for PPHF is primarily tailored to the individual patient. Decisive factors such as patient's age, fracture type, and primary palsies have to be considered for optimal treatment. In type B1 fractures, there is a recommendation for ORIF because of high non-union rates under non-operative treatment. In contrast, in type B2 fractures, a non-operative approach should be preferred, provided there are no radial nerve lesions., Level of Evidence: Level IV, epidemiologic study., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Background: We assessed intraarticular injuries in patients after primary anterior traumatic shoulder dislocation by comparing magnetic resonance arthrography (MRA) results with concomitant arthroscopic findings., Methods: All patients with primary traumatic shoulder dislocation who underwent arthroscopic surgery between 2001 and 2020 with preoperative MRA were included in this study. MRA was retrospectively compared with arthroscopic findings. Postoperative shoulder function was prospectively assessed using the Disabilities of Arm, Shoulder and Hand score (quick DASH), the Oxford Shoulder Score (OSS), the Subjective Shoulder Value (SSV), as well as the rate of return to sports., Results: A total of 74 patients were included in this study. A Hill-Sachs lesion was consistently found in the corresponding shoulders on MRA and arthroscopy in 35 cases ( p = 0.007), a Bankart lesion in 37 shoulders ( p = 0.004), and a superior labrum from anterior to posterior (SLAP) lesion in 55 cases ( p = 0.581). Of all cases, 32 patients were available for a clinical and functional follow-up evaluation. A positive correlation was found between the level of sport practiced and the Oxford Shoulder Score (redislocation subset) ( p = 0.032) and between the age at the time of surgery and the follow-up SSV ( p = 0.036). Conversely, a negative correlation was observed between the age at the time of surgery and the Oxford Instability Score (redislocation subset) ( p = 0.038)., Conclusions: The results of this study show a good correlation between MRA and arthroscopy. Therefore, MRA is a valid tool for the detection of soft tissue pathologies after primary anterior traumatic shoulder dislocation and can aid in presurgical planning.

Environmental biophysical interactions are recognized to play an essential part in the human biological processes associated with trauma recovery. Many studies over several decades have furthered our understanding of the effects that Pulsed Electromagnetic Fields (PEMF) have on the human body, as well as on cellular and biophysical systems. These investigations have been driven by the observed positive clinical effects of this non-invasive treatment on patients, mainly in orthopedics. Unfortunately, the diversity of the various study setups, with regard to physical parameters, molecular and cellular response, and clinical outcomes, has made it difficult to interpret and evaluate commonalities, which could, in turn, lead to finding an underlying mechanistic understanding of this treatment modality. In this review, we give a birds-eye view of the vast landscape of studies that have been published on PEMF, presenting the reader with a scaffolded summary of relevant literature starting from categorical literature reviews down to individual studies for future research studies and clinical use. We also highlight discrepancies within the many diverse study setups to find common reporting parameters that can lead to a better universal understanding of PEMF effects.

Chronic wounds remain a serious clinical problem with insufficient therapeutic approaches. In this study we investigated the dose dependency of rhVEGF 165 in fibrin sealant in both ischemic and non-ischemic excision wounds using our recently developed impaired-wound healing model. An abdominal flap was harvested from the rat with unilateral ligation of the epigastric bundle and consequent unilateral flap ischemia. Two excisional wounds were set in the ischemic and non-ischemic area. Wounds were treated with three different rhVEGF 165 doses (10, 50 and 100 ng) mixed with fibrin or fibrin alone. Control animals received no therapy. Laser Doppler imaging (LDI) and immunohistochemistry were performed to verify ischemia and angiogenesis. Wound size was monitored with computed planimetric analysis. LDI revealed insufficient tissue perfusion in all groups. Planimetric analysis showed slower wound healing in the ischemic area in all groups. Wound healing was fastest with fibrin treatment-irrespective of tissue vitality. Lower dose VEGF (10 and 50 ng) led to faster wound healing compared to high-dose VEGF. Immunohistochemistry showed the highest vessel numbers in low-dose VEGF groups. In our previously established model, different rhVEGF 165 treatments led to dose-dependent differences in angiogenesis and wound healing, but the fastest wound closure was achieved with fibrin matrix alone.

Background: Zoledronic acid improves bone microarchitecture and biomechanical properties after chronic rotator cuff repair (RCR) in rats. Besides the positive effects of zoledronic acid on bone mineral density and bone microarchitecture, bisphosphonates have positive effects on skeletal muscle function., Purposes/hypothesis: The purposes of this study were to (1) longitudinally evaluate circulating bone- and muscle-specific serum micro-ribonucleic acids (miRNAs) and (2) investigate supraspinatus muscle tissue after tenotomy and delayed RCR in a rat model. It was hypothesized that zoledronic acid would improve muscle regeneration after chronic RCR in rats., Study Design: Controlled laboratory study., Methods: A total of 34 male Sprague-Dawley rats underwent unilateral (left) supraspinatus tenotomy (time point 1) with delayed transosseous RCR after 3 weeks (time point 2). All rats were sacrificed 8 weeks after RCR (time point 3). Animals were randomly assigned to 2 groups. One day after RCR, the control group was given 1 mL of subcutaneous saline solution, and the intervention group was treated with a subcutaneous single-dose of 100 µg/kg body weight of zoledronic acid. All 34 study animals underwent miRNA analysis at all 3 time points. In 4 animals of each group, histological analyses as well as gene expression analyses were conducted., Results: Circulating miRNAs showed significantly different expressions between both study groups. In the control group, a significant downregulation was observed for muscle-specific miR-1-3p ( P = .004), miR-133a-3p ( P < .001), and miR-133b ( P < .001). Histological analyses showed significantly higher rates of regenerating myofibers on the operated side (left) of both study groups compared with the nonoperated side (right; P = .002). On the nonoperated side, significantly higher rates of regenerating myofibers were observed in the intervention group compared with the control group ( P = .031). The myofiber cross-sectional area revealed significantly smaller myofibers on both sides within the intervention group compared with both sides of the control group ( P < .001). Within the intervention group, significantly higher expression levels of muscle development/regeneration marker genes embryonal Myosin heavy chain ( P = .017) and neonatal Myosin heavy chain ( P = .016) were observed on the nonoperated side compared with the operated side., Conclusion: An adjuvant single-dose of zoledronic acid after RCR in a chronic defect model in rats led to significant differences in bone- and muscle-specific miRNA levels. Therefore, miR-1-3p, miR-133a-3p, and miR-133b might be used as biomarkers for muscle regeneration after RCR., Clinical Relevance: Adjuvant treatment with zoledronic acid may improve muscle regeneration after chronic RCR in humans, thus counteracting fatty muscle infiltration and atrophy.

Introduction: Within the last few decades, focused high-energy extracorporeal shockwave therapy (ESWT) has proven to be an effective alternative to standard of care revision surgery in delayed healing fractures or manifest non-unions in various anatomical regions., Materials and Methods: A retrospective multi-variant analysis of an open prospective, single-armed clinical study was conducted. Patients receiving focused high-energy ESWT for a delayed healing or an apparent non-union of a humeral fracture between January 1999 and December 2015 at a single trauma center were included in the study. Bony healing was defined as cortical continuity in three of four cortices and pain-free force loading and evaluated using CT scans and clinical examination at three- and six-month follow-ups after ESWT., Results: A total of 236 patients were included. N = 93 (43.8%) showed bony consolidation three months after ESWT and n = 105 (52.5%) after six months. Sub-group analysis showed significantly better healing for the proximal metaphyseal humerus (66.7% after six months, n = 42) compared to the diaphyseal region (48.1%, n = 133) and distal metaphyseal humerus (48.1%, n = 25). Regression analysis indicated significantly increased healing rates for patients of younger ages (p = 0.001) and a fracture diastasis of less than 5 mm (p = 0.002)., Conclusion: The findings of this study indicate that ESWT can be considered as a treatment option for a well-selected patient population despite the lower healing rates compared to other anatomical regions., (© 2021. Springer-Verlag GmbH Germany, part of Springer Nature.)

Extracorporeal shockwave therapy (ESWT) can stimulate processes to promote regeneration, including cell proliferation and modulation of inflammation. Specific miRNA expression panels have been established to define correlations with regulatory targets within these pathways. This study aims to investigate the influence of low-energy ESWT-applied within the subacute and chronic phase of SCI (spinal cord injury) on recovery in a rat spinal cord contusion model. Outcomes were evaluated by gait analysis, µCT and histological analysis of spinal cords. A panel of serum-derived miRNAs after SCI and after ESWT was investigated to identify injury-, regeneration- and treatment-associated expression patterns. Rats receiving ESWT showed significant improvement in motor function in both a subacute and a chronic experimental setting. This effect was not reflected in changes in morphology, µCT-parameters or histological markers after ESWT. Expression analysis of various miRNAs, however, revealed changes after SCI and ESWT, with increased miR-375, indicating a neuroprotective effect, and decreased miR-382-5p potentially improving neuroplasticity via its regulatory involvement with BDNF. We were able to demonstrate a functional improvement of ESWT-treated animals after SCI in a subacute and chronic setting. Furthermore, the identification of miR-375 and miR-382-5p could potentially provide new targets for therapeutic intervention in future studies.

Introduction: With the help of a J-shaped bicortical iliac crest bone graft, the morphology of the glenoid can be augmented without having to use screws to achieve glenohumeral stability. The aim of this retrospective clinical study was to evaluate the clinical stability and function of the shoulder joint as well as the radiological remodelling process and arthropathic outcomes following the J-bone graft technique., Materials and Methods: 34 patients with recurrent shoulder dislocations and bony glenoid defects were treated with the J-bone graft technique between 2010 and 2018 at our level-I trauma centre. 15 patients (18 shoulders) could be recruited for the study. Pain levels, ASES, UCLA, SST, DASH, Rowe and WOSI Scores were collected using questionnaires. In 13 patients (16 shoulders) the Constant Score, ROM, CT with 3D reconstruction of the glenoid to assess the graft remodelling and X-rays were performed additionally., Results: None of the patients suffered subluxations or recurrent dislocations during the follow-up period. The overall complication rate was 11%. The evaluation using objective and subjective shoulder function scores yielded good-to-excellent results. Radiological assessment at follow-up showed a low rate of moderate-to-severe arthritis (12%) and a high rate of shoulders without any signs of arthritic degeneration (53%). The CT scans all revealed an almost complete restoration of the glenoid with none of the grafts being resorbed. A rise in the average glenoid circumference and glenoid area could be demonstrated between preoperative measurements (81.6 and 82.4%, respectively) and follow-up measurements (104 and 102.5%, respectively)., Conclusion: The results of this study show a successful stabilisation of the shoulder joint and a low complication rate following the J-bone graft technique. Remodelling of the bone graft could be demonstrated, which in turn led to an almost perfect glenoid surface area of 100%., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

Background: Suture anchors (SAs) made of human allogenic mineralized cortical bone matrix are among the newest developments in orthopaedic and trauma surgery. Biomechanical properties of an allogenic mineralized suture anchor (AMSA) are not investigated until now. The primary objective was the biomechanical investigation of AMSA and comparing it to a metallic suture anchor (MSA) and a bioabsorbable suture anchor (BSA) placed at the greater tuberosity of the humeral head of cadaver humeri. Additionally, we assessed the biomechanical properties of the SAs with bone microarchitecture parameters., Methods: First, bone microarchitecture of 12 fresh frozen human cadaver humeri from six donors was analyzed by high-resolution peripheral quantitative computed tomography. In total, 18 AMSAs, 9 MSAs, and 9 BSAs were implanted at a 60° angle. All three SA systems were systematically implanted alternating in three positions within the greater tuberosity (position 1: anterior, position 2: central, position 3: posterior) with a distance of 15 mm to each other. Biomechanical load to failure was measured in a uniaxial direction at 135°., Results: Mean age of all specimens was 53.6 ± 9.1 years. For all bone microarchitecture measurements, linear regression slope estimates were negative which implies decreasing values with increasing age of specimens. Positioning of all three SA systems at the greater tuberosity was equally distributed (p = 0.827). Mean load to failure rates were higher for AMSA compared to MSA and BSA without reaching statistical significance between the groups (p = 0.427). Anchor displacement was comparable for all three SA systems, while there were significant differences regarding failure mode between all three SA systems (p < 0.001). Maximum load to failure was reached in all cases for AMSA, in 44.4% for MSA, and in 55.6% for BSA. Suture tear was observed in 55.6% for MSA and in 22.2% for BSA. Anchor breakage was solely seen for BSA (22.2%). No correlations were observed between bone microarchitecture parameters and load to failure rates of all three suture anchor systems., Conclusions: The AMSA showed promising biomechanical properties for initial fixation strength for RCR. Since reduced BMD is an important issue for patients with chronic rotator cuff lesions, the AMSA is an interesting alternative to MSA and BSA. Also, the AMSA could improve healing of the enthesis., (© 2022. The Author(s).)

A delay or failure to heal is the most common possible complication in clavicle fractures, especially in cases primarily treated conservatively. As the current standard therapy, surgical revision achieves good healing results, but is associated with potential surgery-related complications. Shockwave therapy as a non-invasive therapy shows similar reasonable consolidation rates in the non-union of different localizations, but avoids complications. Compromised clavicle fractures in the middle and lateral third treated with focused high-energy shockwave therapy were compared with those treated with surgical revision (ORIF). In addition, a three-dimensional computer simulation for evaluating the pressure distribution during shockwave application accompanied the clinical study. A comparable healing rate in bony consolidation was achieved in both groups. Significantly fewer complications, however, occurred in the shockwave group. The simulations showed safe application in this instance, particularly in avoiding lung tissue affection. When applied correctly, shockwaves represent a safe and promising therapy option for compromised clavicle fractures in the middle and lateral third.

Background: The pathological mechanism in acute spinal cord injury (SCI) is dual sequential: the primary mechanical lesion and the secondary injury due to a cascade of biochemical and pathological changes initiated by the primary lesion. Therapeutic approaches have focused on modulating the mechanisms of secondary injury. Despite extensive efforts in the treatment of SCI, there is yet no causal, curative treatment approach available. Extracorporeal shock wave therapy (ESWT) has been successfully implemented in clinical use. Biological responses to therapeutic shock waves include altered metabolic activity of various cell types due to direct and indirect mechanotransduction leading to improved migration, proliferation, chemotaxis, modulation of the inflammatory response, angiogenesis, and neovascularization, thus inducing rather a regeneration than repair. The aim of this clinical study is to investigate the effect of ESWT in humans within the first 48 h after an acute traumatic SCI, with the objective to intervene in the secondary injury phase in order to reduce the extent of neuronal loss., Methods: This two-arm three-stage adaptive, prospective, multi-center, randomized, blinded, placebo-controlled study has been initiated in July 2020, and a total of 82 patients with acute traumatic SCI will be recruited for the first stage in 15 participating hospitals as part of a two-armed three-stage adaptive trial design. The focused ESWT (energy flux density: 0.1-0.19 mJ/mm 2 , frequency: 2-5 Hz) is applied once at the level of the lesion, five segments above/below, and on the plantar surface of both feet within the first 48 h after trauma. The degree of improvement in motor and sensory function after 6 months post-injury is the primary endpoint of the study. Secondary endpoints include routine blood chemistry parameters, the degree of spasticity, the ability to walk, urological function, quality of life, and the independence in everyday life., Discussion: The application of ESWT activates the nervous tissue regeneration involving a multitude of various biochemical and cellular events and leads to a decreased neuronal loss. ESWT might contribute to an improvement in the treatment of acute traumatic SCI in future clinical use., Trial Registration: ClinicalTrials.gov NCT04474106., (© 2022. The Author(s).)

Purpose: The aim of this study was to investigate the effect of extracorporeal shockwave therapy (ESWT) on bone microstructure as well as the bone-tendon-interface and the musculo-tendinous transition zone to explain the previously shown improved biomechanics in a degenerative rotator cuff tear animal model. This study hypothesized that biomechanical improvements related to ESWT are a result of improved bone microstructure and muscle tendon properties., Methods: In this controlled laboratory study unilateral supraspinatus (SSP) tendon detachment was performed in 48 male Sprague-Dawley rats. After a degeneration period of three weeks, SSP tendon was reconstructed transosseously. Rats were randomly assigned into three groups (n = 16 per group): control (noSW); intraoperative shockwave treatment (IntraSW); intra- and postoperative shockwave treatment (IntraPostSW). Eight weeks after SSP repair, all rats were sacrificed and underwent bone microstructure analysis as well as histological and immunohistochemical analyses., Results: With exception of cortical porosity at the tendon area, bone microstructure analyses revealed no significant differences between the three study groups regarding cortical and trabecular bone parameters. Cortical Porosity at the Tendon Area was lowest in the IntraPostSW (p≤0.05) group. Histological analyses showed well-regenerated muscle and tendon structures in all groups. Immunohistochemistry detected augmented angiogenesis at the musculo-tendinous transition zone in both shockwave groups indicated by CD31 positive stained blood vessels., Conclusion: In conclusion, bone microarchitecture changes are not responsible for previously described improved biomechanical results after shockwave treatment in rotator cuff repair in rodents. Immunohistochemical analysis showed neovascularization at the musculo-tendinous transition zone within ESWT-treated animals. Further studies focusing on neovascularization at the musculo-tendinous transition zone are necessary to explain the enhanced biomechanical and functional properties observed previously., Clinical Relevance: In patients treated with a double-row SSP tendon repair, an improvement in healing through ESWT, especially in this area, could prevent a failure of the medial row, which is considered a constantly observed tear pattern., Competing Interests: The authors have declared that no competing interests exist.

Background: The aims of this study are to determine (i) SARS-CoV-2 antibody positive employees in Austrian trauma hospitals and rehabilitation facilities, (ii) number of active virus carriers (symptomatic and asymptomatic) during the study, (iii) antibody decline in seropositive subjects over a period of around 6 months, (iv) the usefulness of rapid antibody tests for outpatient screening., Method: A total of 3301 employees in 11 Austrian trauma hospitals and rehabilitation facilities of the Austrian Social Insurance for Occupational Risks (AUVA) participated in this open uncontrolled prospective cohort study. Rapid lateral flow tests, detecting a combination of IgM and IgM against SARS-CoV-2), two different types of CLIA (Diasorin, Roche), RT-PCR tests and serum neutralization tests (SNTs) were performed. The tests were conducted twice, with an interval of 42.4 ± 7.7 (Min = 30, Max = 64) days. Positive participants were re-tested with CLIA/SNT at a third time point after 188.0 ± 12.8 days., Results: Only 27 out of 3301 participants (0.82%) had a positive antibody test at any time point during the study confirmed via neutralization test. Among positively tested participants in either test, 50.4% did not report any symptoms consistent with common manifestations of COVID-19 during the study period or within the preceding 6 weeks. In the group who tested positive during or prior to study inclusion the most common symptoms of an acute viral illness were rhinitis (21.9%), and loss of taste and olfactory sense (21.9%). Based on the neutralization test as the true condition, the rapid antibody test performed better on serum than whole blood as 84.6% instead of 65.4% could be detected correctly. Concerning both CLIA tests overall the Roche test detected 24 (sensitivity = 88.9%) and the Diasorin test 22 positive participants (sensitivity = 81.5%). In participants with a positive SNT result, a significant drop in neutralizing antibody titre from 31.8 ± 22.9 (Md = 32.0) at T1 to 26.1 ± 17.6 (Md = 21.3) at T2 to 21.4 ± 13.4 (Md = 16.0) at T3 (χ 2  = 23.848, df = 2, p < 0.001) was observed (χ 2  = 23.848, df = 2, p < 0.001)-with an average time of 42.4 ± 7.7 days between T1 and T2 and 146.9 ± 13.8 days between T2 and T3., Conclusions: During the study period (May 11th-August 3rd) only 0.82% were tested positive for antibodies in our study cohort. The antibody concentration decreases significantly over time with 14.8% (4 out of 27) losing detectable antibodies., (© 2021. The Author(s).)

Extracorporeal shockwave therapy is a treatment modality, originally introduced into the clinic as lithotripsie, which has also been successfully used in the last two decades in the non-invasive treatment of delayed or non-healing fractures. Initially, the mechanism of action was attributed to microfracture-induced repair, but intensive basic research has now shown that the shockwave generates its effect in tissue via mechanotransduction. Numerous signal transduction pathways have already been demonstrated, which in their entirety trigger an endogenous regeneration process via cell proliferation, migration and differentiation. Clinically, these shockwave-conveyed biological signals support healing of acute, delayed and non-union fractures. The attainable outcome is comparable to surgery but avoiding an open approach with associated potential complications. These advantageous properties with a clearly positive cost-benefit ratio make shockwave therapy a first line treatment in delayed and non-union fractures., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: This study aimed to investigate whether rodent shoulder specimens fixed in formaldehyde for histological and histomorphometric investigations and specimens stained using Lugol's solution for soft tissue visualization by micro-computed tomography (microCT) are still eligible to be used for bone architecture analysis by microCT., Methods: In this controlled laboratory study, 11 male Sprague-Dawley rats were used. After sacrifice and exarticulation both shoulders of healthy rats were assigned into three groups: (A) control group (n = 2); (B) formaldehyde group (n = 4); (C) Lugol group (n = 5). Half of the specimens of groups B and C were placed in a 4% buffered formaldehyde or Lugol's solution for 24 h, whereas the contralateral sides and all specimens of group A were stored without any additives. MicroCT of both sides performed in all specimens focused on bone mineral density (BMD) and bone microstructure parameters., Results: BMD measurements revealed higher values in specimens after placement in Lugol's solution (p < 0.05). Bone microstructure analyses showed increased BV/TV and Tb.Th values in group C (p < 0.05). Specimens of group C resulted in clearly decreased Tb.Sp values (p < 0.05) in comparison to the control group. Formaldehyde fixation showed minimally altered BMD and bone microstructure measurements without reaching any significance., Conclusions: MicroCT scans of bone structures are recommended to be conducted natively and immediately after euthanizing rats. MicroCT scans of formaldehyde-fixed specimens must be performed with caution due to a possible slight shift of absolute values of BMD and bone microstructure. Bone analysis of specimens stained by Lugol's solution cannot be recommended.

Introduction: Multiple fractures are of high clinical relevance, as a significant increase in mortality rate has been described. The purpose of this study was to evaluate differences in age and gender distribution in multiple fractures dependent on severity of trauma. Furthermore, affected anatomic regions and frequently associated fracture regions were investigated., Methods: Patients who had sustained multiple fractures between 2000 and 2012 were included in this study. At hospital admission, patients were divided according to trauma severity (high- vs low-traumatic), gender, and age for demographic analysis. Fractures were grouped in anatomical regions, and multiple fracture event probabilities as well as frequently associated regions were calculated., Results: In total, 25,043 patients at an age range of 0-100 years (5.8% of all fracture patients; 14,769 male and 10,274 female patients) who sustained 57,862 multiple fractures were included. The lumbar/thoracic spine, cervical spine, femoral shaft, skull, and pelvis showed a probability of more than 40% of the presence of further fractures in each high-traumatic fracture event. In high-traumatic fracture events, male patients were more affected (p < 0.001). Considering low-traumatic fractures, female patients had a significantly higher proportion (p < 0.001) of multiple fractures among all fractures than male patients., Conclusions: As a novelty, gender as well as age distributions in multiple fracture patients and a probability statement with the most affected anatomic regions, the risk of presence of further fractures for every region, and the frequently associated fracture regions including the percentage of occurrence are provided. These aspects yield new opportunities for clinical work and may reduce the high rate of overlooked fractures stated in the literature.

Reconstructive surgery transfers viable tissue to cover defects and to restore aesthetic and functional properties. Failure rates after free flap surgery range from 3 to 7%. Co-morbidities such as diabetes mellitus or peripheral vascular disease increase the risk of flap failure up to 4.5-fold. Experimental therapeutic concepts commonly use a monocausal approach by applying single growth factors. The secretome of γ-irradiated, stressed peripheral blood mononuclear cells (PBMCsec) resembles the physiological environment necessary for tissue regeneration. Its application led to improved wound healing rates and a two-fold increase in blood vessel counts in previous animal models. We hypothesized that PBMCsec has beneficial effects on the survival of compromised flap tissue by reducing the necrosis rate and increasing angiogenesis. Surgery was performed on 39 male Sprague-Dawley rats (control, N = 13; fibrin sealant, N = 14; PBMCsec, N = 12). PBMCsec was produced according to good manufacturing practices (GMP) guidelines and 2 ml were administered intraoperatively at a concentration of 2.5 × 10 7 cells/ml using fibrin sealant as carrier substance. Flap perfusion and necrosis (as percentage of the total flap area) were analyzed using Laser Doppler Imaging and digital image planimetry on postoperative days 3 and 7. Immunohistochemical stainings for von Willebrand factor (vWF) and Vascular Endothelial Growth Factor-receptor-3 (Flt-4) were performed on postoperative day 7 to evaluate formation of blood vessels and lymphatic vessels. Seroma formation was quantified using a syringe and flap adhesion and tissue edema were evaluated clinically through a cranial incision by a blinded observer according to previously described criteria on postoperative day 7. We found a significantly reduced tissue necrosis rate (control: 27.8% ± 8.6; fibrin: 22.0% ± 6.2; 20.9% reduction, p = .053 vs. control; PBMCsec: 19.1% ± 7.2; 31.1% reduction, p = .012 vs. control; 12.9% reduction, 0.293 vs. fibrin) together with increased vWF+ vessel counts (control: 70.3 ± 16.3 vessels/4 fields at 200× magnification; fibrin: 67.8 ± 12.1; 3.6% reduction, p = .651, vs. control; PBMCsec: 85.9 ± 20.4; 22.2% increase, p = .045 vs. control; 26.7% increase, p = .010 vs. fibrin) on postoperative day 7 after treatment with PBMCsec. Seroma formation was decreased after treatment with fibrin sealant with or without the addition of PBMCsec. (control: 11.9 ± 9.7 ml; fibrin: 1.7 ± 5.3, 86.0% reduction, 0.004 vs. control; PBMCsec: 0.6 ± 2.0; 94.8% reduction, p = .001 vs. control; 62.8% reduction, p = .523 vs. fibrin). We describe the beneficial effects of a secretome derived from γ-irradiated PBMCs on tissue survival, angiogenesis, and clinical parameters after flap surgery in a rodent epigastric flap model., Competing Interests: 6The Medical University of Vienna has claimed financial interest and Hendrik J. Ankersmit holds patents related to this work and is a shareholder of Aposcience AG. All other authors declare no potential conflict of interest., (© 2020 The Authors. Bioengineering & Translational Medicine published by Wiley Periodicals LLC on behalf of American Institute of Chemical Engineers.)

Background: Bone mineral density at the humeral head is reduced in patients with chronic rotator cuff tears. Bone loss in the humeral head is associated with repair failure after rotator cuff reconstruction. Bisphosphonates (eg, zoledronic acid) increase bone mineral density., Hypothesis: Zoledronic acid improves bone mineral density of the humeral head and biomechanical properties of the enthesis after reconstruction of chronic rotator cuff tears in rats., Study Design: Controlled laboratory study., Methods: A total of 32 male Sprague-Dawley rats underwent unilateral (left) supraspinatus tenotomy with delayed transosseous rotator cuff reconstruction after 3 weeks. All rats were sacrificed 8 weeks after rotator cuff repair. Animals were randomly assigned to 1 of 2 groups. At 1 day after rotator cuff reconstruction, the intervention group was treated with a single subcutaneous dose of zoledronic acid at 100 µg/kg bodyweight, and the control group received 1 mL of subcutaneous saline solution. In 12 animals of each group, micro-computed tomography scans of both shoulders were performed as well as biomechanical testing of the supraspinatus enthesis of both sides. In 4 animals of each group, histological analyses were conducted., Results: In the intervention group, bone volume fraction (bone volume/total volume [BV/TV]) of the operated side was higher at the lateral humeral head ( P = .005) and the medial humeral head ( P = .010) compared with the control group. Trabecular number on the operated side was higher at the lateral humeral head ( P = .004) and the medial humeral head ( P = .001) in the intervention group. Maximum load to failure rates on the operated side were higher in the intervention group ( P < .001). Cortical thickness positively correlated with higher maximum load to failure rates in the intervention group ( r = 0.69; P = .026). Histological assessment revealed increased bone formation in the intervention group., Conclusion: Single-dose therapy of zoledronic acid provided an improvement of bone microarchitecture at the humeral head as well as an increase of maximum load to failure rates after transosseous reconstruction of chronic rotator cuff lesions in rats., Clinical Relevance: Zoledronic acid improves bone microarchitecture as well as biomechanical properties after reconstruction of chronic rotator cuff tears in rodents. These results need to be verified in clinical investigations.

Aims: As many current approaches for heart regeneration exert unfavourable side effects, the induction of endogenous repair mechanisms in ischaemic heart disease is of particular interest. Recently, exosomes carrying angiogenic miRNAs have been described to improve heart function. However, it remains challenging to stimulate specific release of reparative exosomes in ischaemic myocardium. In the present study, we sought to test the hypothesis that the physical stimulus of shock wave therapy (SWT) causes the release of exosomes. We aimed to substantiate the pro-angiogenic impact of the released factors, to identify the nature of their cargo, and to test their efficacy in vivo supporting regeneration and recovery after myocardial ischaemia., Methods and Results: Mechanical stimulation of ischaemic muscle via SWT caused extracellular vesicle (EV) release from endothelial cells both in vitro and in vivo. Characterization of EVs via electron microscopy, nanoparticle tracking analysis and flow cytometry revealed specific exosome morphology and size with the presence of exosome markers CD9, CD81, and CD63. Exosomes exhibited angiogenic properties activating protein kinase b (Akt) and extracellular-signal regulated kinase (ERK) resulting in enhanced endothelial tube formation and proliferation. A miRNA array and transcriptome analysis via next-generation sequencing were performed to specify exosome content. miR-19a-3p was identified as responsible cargo, antimir-19a-3p antagonized angiogenic exosome effects. Exosomes and target miRNA were injected intramyocardially in mice after left anterior descending artery ligation. Exosomes resulted in improved vascularization, decreased myocardial fibrosis, and increased left ventricular ejection fraction as shown by transthoracic echocardiography., Conclusion: The mechanical stimulus of SWT causes release of angiogenic exosomes. miR-19a-3p is the vesicular cargo responsible for the observed effects. Released exosomes induce angiogenesis, decrease myocardial fibrosis, and improve left ventricular function after myocardial ischaemia. Exosome release via SWT could develop an innovative approach for the regeneration of ischaemic myocardium., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

The innervation of the long head of the biceps tendon (LHBT) is not sufficiently documented. This is a drawback since pathologies of the LHBT are a major source of shoulder pain. Thus, the study aimed to characterize structurally and molecularly nervous elements of the LHBT. The proximal part of 11 LHBTs was harvested intraoperatively. There were 8 female and 3 male specimens. Age ranged from 66 to 86 years. For structural analyses, nervous elements were viewed in the transmission electron microscope. For molecular characterization, we used general neuronal markers including antibodies against neurofilament and protein gene product 9.5 (PGP9.5) as well as specific neuronal markers including antibodies against myelin basic protein (MBP), calcitonin gene-related product (CGRP), substance P (SP), tyrosine hydroxylase (TH), and growth-associated protein 43 (GAP43). Anti-neurofilament and anti-PGP9.5 visualized the overall innervation. Anti-MBP visualized myelination, anti-CGRP and anti-SP nociceptive fibers, anti-TH sympathetic nerve fibers, and anti-GAP43 nerve fibers during development and regeneration. Immunolabeled sections were analyzed in the confocal laser scanning microscope. We show that the LHBT contains unmyelinated as well as myelinated nerve fibers which group in nerve fascicles and follow blood vessels. Manny myelinated and unmyelinated axons exhibit molecular features of nociceptive nerve fibers. Another subpopulation of unmyelinated axons exhibits molecular characteristics of sympathetic nerve fibers. Unmyelinated sympathetic fibers and unmyelinated nociceptive fibers express proteins that are found during development and regeneration. Present findings support the hypothesis that ingrowth of nociceptive fibers are the source of chronic tendon pain.

Background: Massive rotator cuff (RC) tears still present a clinically challenging problem, with reported rerupture rates in up to 94%. The study objective was to determine the impact of synthetic patch augmentation for massive RC tears., Methods: Between June 2012 and 2014, we performed 50 arthroscopic RC reconstructions augmented with a synthetic polyester patch. Pre- and postoperative imaging methods included arthrographic magnetic resonance imaging, arthrographic computed tomography, and ultrasound examination to determine tendon integrity or rerupture. Clinical outcome was evaluated using the Constant-Murley score and the subjective shoulder value. Mean clinical midterm and final follow-up was 22 months (9-35 months) and 52 months (25-74 months), respectively., Results: The mean Constant-Murley score increased significantly from 36.5 (±16.4 standard deviation [SD]) preoperatively to a midterm value of 81.2 (±9.6 SD; P < .0001) and further improved to a mean of 83.4 (±10.8 SD) at final follow-up. The mean subjective shoulder value increased from 40.3 (±24.3 SD) to 89.2 (±12.9 SD; P < .0001) at midterm and to 89.6 (±15.2 SD) at final follow-up. We observed 7 complete reruptures (14%). However, reruptures did not correlate with revision surgery, which was performed in 8 patients. The main reason for revision was frozen shoulder or arthrofibrosis with an intact reconstruction and patch, which was performed in 6 cases., Conclusions: The retear rate of 14% compared favorably with nonaugmented RC repairs in the literature. Therefore, we conclude that patch augmentation in massive RC tears is feasible to reduce retears and to improve clinical outcome., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

The type II superior labrum anterior to posterior (SLAP) repair is a viable option in young and demanding patients, although a prolonged period of pain after surgery is described in the literature. The reason for this fact remains unknown. Thus, the purpose of this study was to investigate the molecular pattern of the biceps tendon anchor, where the sutures for repair are placed. The long head of the biceps tendon (LHBT), including the superior labrum, was dissected in the setting of reverse total shoulder arthroplasty. Immunohistochemical staining was performed using neurofilament (NF) and protein gene product (PGP) 9.5 as general markers for axons and calcitonin gene-related peptide (CGRP) and substance P for nociceptive transmission. A quantitative assessment was performed according to the two regions of interest (ROIs), i.e., the anterosuperior (ROI I) and the posterosuperior labrum (ROI II). Eleven LHBTs with a mean age of 73 years (range: 66-87 years) were harvested intraoperatively. Six LHBTs were gained in osteoarthrosis and five in fractures. We found an inhomogeneous distribution of axons in the anterosuperior and posterosuperior parts of the labrum in all the specimens irrespective of the age, gender, and baseline situation. There was a significantly higher number ( p < 0.01) as well as density ( p < 0.001) of NF-positive axons in ROI I compared to ROI II. Nociceptive fibers were always found along the NF-positive axons. Thus, our results indicate that the biceps tendon anchor itself is a highly innervated region comprising different nerve qualities. The anterosuperior labrum contains a higher absolute number and density of axons compared to the posterosuperior parts. Furthermore, we were able to prove the presence of nociceptive fibers in the superior labrum. The results obtained in this study could contribute to the variability of pain after SLAP repair.

Bone stress injuries are commonly due to repetitive loading, as often described in competitive athletes or military recruits. The underlying pathophysiology of bone stress injuries is multifactorial. The present cross-sectional study investigated (i) cortical and trabecular bone microstructure as well as volumetric bone mineral density in subjects with bone stress injuries at the tibial diaphysis, measured at the distal tibia and the distal radius by means of high-resolution peripheral quantitative computed tomography (CT), (ii) areal bone mineral density using dual-energy X-ray absorptiometry as well as calcaneal dual X-ray absorptiometry and laser, and (iii) the influence on bone turnover markers of formation and resorption at the early phase after injury. A total of 26 Caucasian male professional soldiers with post-training bone stress injury at the tibial diaphysis were included (case group). A total of 50 male, Caucasian professional soldiers from the same military institution served as controls (control group). High-resolution peripheral quantitative CT revealed a higher total area at the radius within the case group. Cortical bone mineral density was reduced at the radius and tibia within the case group. The trabecular number and trabecular thickness were reduced at the tibia in the case group. The trabecular network was more inhomogeneous at the radius and tibia within the case group. Calcaneal dual X-ray absorptiometry and laser was significantly reduced in the case group. This study quantified differences in bone microstructure among otherwise healthy individuals. Differences in bone microarchitecture may impair the biomechanical properties by increasing the susceptibility to sustain bone stress injuries. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2516-2523, 2019., (© 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Background: Tendon pathologies are common and several data suggests that the peripheral nervous system is involved in this disorder. Immunohistochemistry (IHC) is one of the pillars to characterize nervous structures and their implication in the pathogenesis of chronic tendon pain. Most commonly, formalin-fixed, paraffin-embedded (FFPE) tendons are used for immunohistochemical characterization of the innervation. However, FFPE specimens exhibit major disadvantages: First, antigens (proteins) are masked and antigen retrieval is necessary to restore antigenicity. Second, FFPE specimens involve immunolabeling with enzyme-conjugated antibodies but this approach has limitations when multiple antigens are of interest simultaneously. Consequently, there is a demand in the orthopedic community for an alternative immunohistochemical approach to visualize tendon innervations., Results: Here, we present a guide how to visualize tendon innervation. This guide couples paraformaldehyde fixation, cryo-embedding, immunofluorescence, and confocal laser scanning microscopy. We demonstrate the utility of our approach in the long head of the biceps tendon. For nerve fiber characterization, we used different neuronal markers including antibodies against neurofilament, protein gene product 9.5, calcitonin gene related peptide, and substance P. We show that it is possible to collect high quality, multicolor images of the innervation pattern of tendons. To map immunolabeled structures and the anatomical structures of the tendon fluorescence images and bright field images were merged., Conclusion: For the orthopedic community our approach might be a convenient research tool to simultaneously utilize multiple neuronal markers on the same tissue section and to define with greater accuracy the heterogeneity of tendon innervation., (Copyright © 2019 Elsevier GmbH. All rights reserved.)

Background: Characteristics of chronic rotator cuff tears include continuous loss of tendon structure as well as tendon elasticity, followed by a high failure rate after surgical reconstruction. Several studies have already shown the beneficial effect of extracorporeal shockwave therapy (ESWT) on tissue regeneration in tendon pathologies., Hypothesis: ESWT improves biomechanical tendon properties as well as functional shoulder outcomes in chronic rotator cuff reconstruction in rodents., Study Design: Controlled laboratory study., Methods: After tendon detachment and 3 weeks of degeneration, a subsequent transosseous reattachment of the supraspinatus tendon was performed in 48 adult male Sprague-Dawley rats (n = 16 per group). Rodents were randomly assigned to 3 study groups: no ESWT/control group, intraoperative ESWT (IntraESWT), and intra- and postoperative ESWT (IntraPostESWT). Shoulder joint function, as determined by gait analysis, was assessed repeatedly during the observation period. Eight weeks after tendon reconstruction, the rats were euthanized, and biomechanical and gene expression analyses were performed., Results: Macroscopically, all repairs were intact at the time of euthanasia, with no ruptures detectable. Biomechanical analyses showed significantly improved load-to-failure testing results in both ESWT groups in comparison with the control group (control, 0.629; IntraESWT, 1.102; IntraPostESWT, 0.924; IntraESWT vs control, P ≤ .001; IntraPostESWT vs control, P ≤ .05). Furthermore, functional gait analyses showed a significant enhancement in intensity measurements for the IntraPostESWT group in comparison with the control group ( P ≤ .05). Gene expression analysis revealed no significant differences among the 3 groups., Conclusion: Clearly improved biomechanical results were shown in the single-application and repetitive ESWT groups. Furthermore, functional evaluation showed significantly improved intensity measurements for the repetitive ESWT group., Clinical Relevance: This study underpins a new additional treatment possibility to prevent healing failure. Improved biomechanical stability and functionality may enable faster remobilization as well as an accelerated return to work and sports activities. Furthermore, as shockwave therapy is a noninvasive, easy-to-perform, cost-effective treatment tool with no undesired side effects, this study is of high clinical relevance in orthopaedic surgery. Based on these study results, a clinical study has already been initiated to clinically confirm the improved functionality by ESWT.

Fibrin, a natural hydrogel, is the end product of the physiological blood coagulation cascade and naturally involved in wound healing. Beyond its role in hemostasis, it acts as a local reservoir for growth factors and as a provisional matrix for invading cells that drive the regenerative process. Its unique intrinsic features do not only promote wound healing directly via modulation of cell behavior but it can also be fine-tuned to evolve into a delivery system for sustained release of therapeutic biomolecules, cells and gene vectors. To further augment tissue regeneration potential, current strategies exploit and modify the chemical and physical characteristics of fibrin to employ combined incorporation of several factors and their timed release. In this work we show advanced therapeutic approaches employing fibrin matrices in wound healing and cover the many possibilities fibrin offers to the field of regenerative medicine., (Copyright © 2017. Published by Elsevier B.V.)

There is continual demand for animal models that allow a quantitative assessment of angiogenic properties of biomaterials, therapies, and pharmaceuticals. In its simplest form, this is done by subcutaneous material implantation and subsequent vessel counting which usually omits spatial data. We have refined an implantation model and paired it with a computational analytic routine which outputs not only vessel count but also vessel density, distribution, and vessel penetration depth, that relies on a centric vessel as a reference point. We have successfully validated our model by characterizing the angiogenic potential of a fibrin matrix in conjunction with recombinant human vascular endothelial growth factor (rhVEGF165). The inferior epigastric vascular pedicles of rats were sheathed with silicone tubes, which were subsequently filled with 0.2 ml of fibrin and different doses of rhVEGF165, centrically embedding the vessels. Over 4 weeks, tissue samples were harvested and subsequently immunohistologically stained and computationally analyzed. The model was able to detect variations over the angiogenic potentials of growth factor spiked fibrin matrices. Adding 20 ng of rhVEGF165 resulted in a significant increase in vasculature while 200 ng of rhVEGF165 did not improve vascular growth. Vascularized tissue volume increased during the first week and vascular density increased during the second week. Total vessel count increased significantly and exhibited a peak after 2 weeks which was followed by a resorption of vasculature by week 4. In summary, a simple implantation model to study in vivo vascularization with only a minimal workload attached was enhanced to include morphologic data of the emerging vascular tree.

Delayed wound healing and the potentially resulting chronic wounds are a challenging clinical problem. Available therapeutic strategies are limited in both number and efficacy. For developing and establishing novel treatment approaches appropriate clinically relevant animal models are essential. The aim of the study was to establish a reliable and reproducible delayed wound healing model, which simulates the clinical scenario of compromised vascular tissue perfusion (hypoxia/ischemia). Therefore a standard rodent ischemic flap model was modified by challenging the tissue with ascending degrees of ischemia using different surgical approaches (minimal, mild, moderate, and severe ischemic invasive approach). Then a full-thickness circular wound was excised in both the non-/hypoperfused flap area and in the normally perfused contralateral region serving as an internal control. Wound healing progress was compared. Superficial tissue perfusion was measured by Laser Doppler imaging technique, which showed persistent ischemia in the moderate and severe invasive surgical approaches 7 days after wounding. Wound closure assessed by planimetric analysis occurred significantly slower in the ischemic wounds compared to the contralateral nonischemic wounds in the moderate invasive approach. Histologic evaluations in this approach showed signs of tissue necrosis and impaired angiogenesis in the ischemic wounds. Therefore, it can be concluded that this clinically relevant animal model is suitable to study mechanism in ischemia-impaired wound healing. Furthermore, it allows evaluating the efficacy of therapeutic strategies for impaired wound healing and comparing the results with an internal control wound.

Background: The postoperative course after arthroscopic superior labrum anterior to posterior (SLAP) repair using suture anchors is accompanied by a prolonged period of pain, which might be caused by constriction of nerve fibres. The purpose was to histologically investigate the distribution of neurofilament in the superior labrum and the long head of the biceps tendon (LHBT), i.e. the location of type II SLAP lesions., Methods: Ten LHBTs including the superior labrum were dissected from fresh human specimen and immunohistochemically stained against neurofilament (NF). All slides were scanned at high resolution and converted into tagged image file format, and regions of interest (ROIs) were defined as follows: ROI I-superior labrum anterior to the LHBT origin, ROI II-mid-portion of the superior labrum at the origin of the LHBT, ROI III-superior labrum posterior to the LHBT origin and ROI IV-the most proximal part of the LHBT before its attachment to the superior labrum. The entire images were automatically segmented according to the defined ROIs and measured using a programmed algorithm specifically created for this purpose. The NF-positive cells were counted, and their total size and the area of other tissue were measured separately for the different ROIs., Results: Distribution of NF-positive cells in absolute numbers revealed a clear but insignificantly higher amount in favour of ROI I, representing the superior labrum anterior to the LHBT origin. Setting ROI I at 100%, a significant difference could be seen compared to ROI III, representing the superior labrum posterior to the LHBT origin (ROI I vs. ROI III with a p value < 0.05)., Conclusions: Summarizing, the density of neurofilament is inhomogeneously distributed throughout the superior labrum with the highest number of neurofilament in the anterior superior labrum. Thus, suture placement in type II SLAP repair could play an important role for the postoperative pain-related outcome.

Skeletal ischaemia-reperfusion (I-R) injury may influence patient outcome after severe vascular trauma or clamping of major vessels. The aim of this study was to observe whether locally applied vascular endothelial growth factor (VEGF) in fibrin could induce the expression of VEGF-receptor-2 (VEGFR-2) and improve the outcome after I-R injury. Transgenic mice expressing VEGFR-2 promoter-controlled luciferase were used for the assessment of VEGFR-2 expression. Ischaemia was induced for 2 h by a tension-controlled tourniquet to the hind limb, followed by 24 h of reperfusion. The animals were locally injected subcutaneously with fibrin sealant containing 20 or 200 ng VEGF; control animals received no treatment or fibrin sealant application. In vivo VEGFR-2 expression was quantified upon administration of luciferin at several observation times. For oedema and inflammation quantification, wet:dry ratio measurements and a myeloperoxidase assay of the muscle tissue were performed. Laser Doppler imaging showed that ischaemia was present and that the blood flow had returned to baseline levels after 24 h of reperfusion. VEGFR-2 expression levels in the fibrin + 200 ng VEGF were significantly higher than in all other groups. Granulocyte infiltration was reduced in both treatment groups, as well as reduced oedema formation. These results showed that VEGF released from fibrin had a positive effect on early I-R outcome in a mouse model, possibly via VEGFR-2. Copyright © 2016 John Wiley & Sons, Ltd., (Copyright © 2016 John Wiley & Sons, Ltd.)

Tibial non-unions are common cause of demanding revision surgeries and are associated with a significant impact on patients' quality of life and health care costs. Extracorporeal shockwave therapy (ESWT) has been shown to improve osseous healing in vitro and in vivo. The main objective of present study was to evaluate the efficacy of ESWT in healing of tibial non-unions unresponsive to previous surgical and non-surgical measures. A retrospective multivariant analysis of a prospective open, single-centre, clinical trial of tibia non-union was conducted. 56 patients with 58 eligible fractures who met the FDA criteria were included. All patients received 3000-4000 impulses of electrohydraulic shockwaves at an energy flux density of 0.4mJ/mm(2) (-6dB). On average patients underwent 1.9 times (±1.3SD) surgical interventions prior to ESWT displaying the rather negatively selected cohort and its limited therapy responsiveness. In 88.5% of patients receiving ESWT complete bone healing was observed after six months irrespective of underlying pathology. The multivariant analysis showed that time of application is important for therapy success. Patients achieving healing received ESWT earlier: mean number of days between last surgical intervention and ESWT (healed - 355.1 days±167.4SD vs. not healed - 836.7 days±383.0SD; p<0.0001). ESWT proved to be a safe, effective and non-invasive treatment modality in tibial non-unions recalcitrant to standard therapies. The procedure is well tolerated, time-saving, lacking side effects, with potential to significantly decrease health care costs. Thus, in our view, ESWT should be considered the treatment of first choice in established tibial non-unions., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Controlled delivery of growth factors from biodegradable biomatrices could accelerate and improve impaired wound healing. The study aim was to determine whether platelet-derived growth factor AB (PDGF.AB) with a transglutaminase (TG) crosslinking substrate site released from a fibrin biomatrix improves wound healing in severe thermal injury. The binding and release kinetics of TG-PDGF.AB were determined in vitro. Third-degree contact burns (dorsum of Yorkshire pigs) underwent epifascial necrosectomy 24 h post-burn. Wound sites were covered with autologous meshed (3:1) split-thickness skin autografts and either secured with staples or attached with sprayed fibrin sealant (FS; n = 8/group). TG-PDGF.AB binds to the fibrin biomatrix using the TG activity of factor XIIIa, and is subsequently released through enzymatic cleavage. Three doses of TG-PDGF.AB in FS (100 ng, 1 µg and 11 µg/ml FS) were tested. TG-PDGF.AB was bound to the fibrin biomatrix as evidenced by western blot analysis and subsequently released by enzymatic cleavage. A significantly accelerated and improved wound healing was achieved using sprayed FS containing TG-PDGF.AB compared to staples alone. Low concentrations (100 ng-1 µg TG-PDGF.AB/ml final FS clot) demonstrated to be sufficient to attain a nearly complete closure of mesh interstices 14 days after grafting. TG-PDGF.AB incorporated in FS via a specific binding technology was shown to be effective in grafted third-degree burn wounds. The adhesive properties of the fibrin matrix in conjunction with the prolonged growth factor stimulus enabled by this binding technology could be favourable in many pathological situations associated with wound-healing disturbances. Copyright © 2013 John Wiley & Sons, Ltd., (Copyright © 2013 John Wiley & Sons, Ltd.)

Burn wounds pose a serious threat to patients and often require surgical treatment. Skin grafting aims to achieve wound closure but requires a well-vascularized wound bed. The secretome of peripheral blood mononuclear cells (PBMCs) has been shown to improve wound healing and angiogenesis. We hypothesized that topical application of the PBMC secretome would improve the quality of regenerating skin, increase angiogenesis, and reduce scar formation after burn injury and skin grafting in a porcine model. Full-thickness burn injuries were created on the back of female pigs. Necrotic areas were excised and the wounds were covered with split-thickness mesh skin grafts. Wounds were treated repeatedly with either the secretome of cultured PBMCs (Sec(PBMC)), apoptotic PBMCs (Apo-Sec(PBMC)), or controls. The wounds treated with Apo-Sec(PBMC) had an increased epidermal thickness, higher number of rete ridges, and more advanced epidermal differentiation than controls. The samples treated with Apo-Sec(PBMC) had a two-fold increase in CD31+ cells, indicating more angiogenesis. These data suggest that the repeated application of Apo-Sec(PBMC) significantly improves epidermal thickness, angiogenesis, and skin quality in a porcine model of burn injury and skin grafting.

Background: Extracorporeal shock wave therapy (ESWT) can modulate cell behavior through mechanical information transduction. Human periodontal ligament fibroblasts (hPDLF) are sensible to mechanical stimulus and can express pro-inflammatory molecules in response. The aim of this study was to evaluate the impacts of shock waves on interleukin-6 (IL-6), interleukin-8 (IL-8), monocyte chemotactic protein 1 (MCP-1), and tumor necrosis factor-alpha (TNF-α) expression by hPDLF., Material/methods: After being treated by shock waves with different parameters (100-500 times, 0.05-0.19 mJ/mm(2)), cell viability was tested using CCK-8. IL-6, IL-8, MCP-1, and TNF-α gene expression was analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) and IL-6 and IL-8 protein was measured by enzyme-linked immunosorbent assay (ELISA) at different time points., Results: Shock waves with the parameters used in this study had no significant effects on the viability of hPDLF. A statistical inhibition of IL-6, IL-8, MCP-1, and TNF-α expression during the first few hours was observed (P<0.05). Expression of IL-8 was significantly elevated in the group receiving the most pulses of shock wave (500 times) after 4 h (P<0.05). At 8 h and 24 h, all treated groups demonstrated significantly enhanced IL-6 expression (P<0.05). TNF-α expression in the groups receiving more shock pulses (300, 500 times) or the highest energy shock treatment (0.19 mJ/mm(2)) was statistically decreased (P<0.05) at 24 h., Conclusions: Under the condition of this study, a shock wave with energy density no higher than 0.19 mJ/mm(2) and pulses no more than 500 times elicited no negative effects on cell viability of hPDLF. After a uniform initial inhibition impact on expression of inflammatory mediators, a shock wave could cause dose-related up-regulation of IL-6 and IL-8 and down-regulation of TNF-α.

Sustained, local, low dose growth factor stimulus of target tissues/cells is believed to be of imminent importance in tissue regeneration and engineering. Recently, a technology was developed to bind growth factors to a fibrin matrix using the transglutaminase (TG) activity of factor XIIIa, thus allowing prolonged release through enzymatic cleavage. In this study we aimed to determine whether TG-PDGF.AB in fibrin could improve tissue regeneration in a standard ischemic flap model. In vitro determination of binding and release kinetics of TG-PDGF.AB allowed proof of concept of the developed binding technology. A single spray application of TG-PDGF.AB in fibrin matrix at a concentration of 10 and 100ng/ml significantly reduced ischemia-induced flap tissue necrosis in vivo on day 7 after ischemic impact compared to controls. TG-PDGF.AB at a concentration of 100ng/ml fibrin induced distinct angiogenesis as reflected by significantly improved tissue perfusion assessed by laser Doppler imaging as well as enhanced von Willebrand factor (vWF) protein expression determined by immunohistochemical means. In addition, significantly more mature microvessels were observed with 100ng/ml TG-PDGF.AB in fibrin compared to control and vehicle groups as evidenced by an improved smooth muscle actin (sma)/vWF protein ratio. In conclusion, PDGF.AB in a conjugated fibrin matrix effectively reduced ischemia-induced tissue necrosis, increased tissue perfusion and induced the growth of a mature and functional neovasculature. The sealing properties of the fibrin matrix in conjunction with the prolonged growth factor stimulus enabled by the TG-hook binding technology may present an innovative and suitable tool in tissue regeneration., Statement of Significance: In our experimental study we elucidated recombinant platelet derived growth factor (PDGF) as a potential candidate in inducing angiogenesis. To avoid preterm growth factor degradation in vivo PDGF.AB was covalently linked to a fibrin scaffold using a bi-domain functionalized peptide (FXIII substrate site and plasmin cleavage site). This allowed PDGF binding to fibrin during spray application to the donor site and subsequent prolonged release via endogenous plasmin. This resulted in a mature vascular network thus enhancing tissue perfusion and consequently improved clinical outcome. With our present work we could certainly provide researchers and clinicians with an innovative versatile and reproducible technology not only to induce functional vascularity but also to improve attempts in tissue engineering in general by e.g. using different growth factors. Hence, we believe that this approach studied in the present work may provide a valuable input in an effort to drive the aim forward bringing experimental work in tissue engineering to clinic by using a clinically well characterized and used fibrin scaffold in combination with a human recombinant growth factor (fibrin scaffold linked with the specific binding technology)., (Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Fracture non-unions are still a challenging problem in orthopedics. The treatment of non-unions remains highly individualized, complex, and demanding. In most countries the surgical approach with debridement of the non-union gap, anatomical reduction and appropriate osteosynthesis along with autologous bone grafting is considered as the standard of care. One of the very first non-urologic applications of extracorporeal shockwave treatment (ESWT) concerned non-healing fractures. Since the early 1990ties the knowledge of the working mechanism has increased enormously. The purpose of this review article is to demonstrate by peer-reviewed literature in conjunction with our own experiences that ESWT can be an efficient, non-invasive, almost complication-free and cost effective alternative to surgical treatment of non-healing fractures., (Copyright © 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.)

Diabetic foot ulcers (DFUs) are among the most common foot disorders with ulceration, infection, and gangrene that may ultimately lead to lower extremity amputation. The goals of treatment include the control of diabetes and proper shoe wear. An effective therapy and appropriate foot care are important in wound healing in DFUs. Recently, extracorporeal shockwave therapy (ESWT) was reported to significantly promote and accelerate the healing of complex soft tissue wounds as compared to the standard methods of treatment in DFUs. ESWT showed positive results in short-term and long-term outcomes in diabetic patients suffering from foot ulcers. In this article, we review the clinical results of ESWT in DFUs., (Copyright © 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.)