Long-term results of olecranon fractures treated using the XS nail® system.

PURPOSE: Olecranon fractures are particularly vulnerable to distraction and subsequent fracture dislocation due to the high tensile forces. Surgical treatment aims at reducing the fracture and restoring the anatomical joint surface condition, as well as neutralizing the strain inhibiting fracture healing. The XS nail® (Intercus GmbH, Bad Blankenberg, Germany), an intramedullary implant exerting compression across the entire fracture surface, unlike plates, leaves a minimal extra-cortical profile, and can be secured with threaded locking wires, thereby retaining the anatomical reduction without displacement or steps within the articular surface, which was often found in tension band wiring. After encouraging initial results, the long-term outcome was assessed. METHODS: This retrospective study evaluated the long-term outcome of patients surgically treated at our trauma center between January 2002 and December 2005 using the XS nail®. Patients over the age of 18 years eligible for the study must have undergone surgery for isolated, recent (less than 14 days) traumatic olecranon fractures, without concomitant injuries to the ipsilateral elbow and forearm. Further exclusion criteria were pseudarthrosis, re-fractures and osteotomy for distal humerus surgery, as well as polytraumatized patients unable to aid in their own recovery. Data were retrospectively gathered by standardised questionnaire and patient records, as well as surgery and anesthesiology reports. Data analysis was performed using Microsoft Office Excel® 2016. RESULTS: There were 32 patients, 13 males (mean age 49.0 years) and 19 females (mean age 68.9 years) with 11 Schatzkers type D, 7 each type A and C, 5 type B and 2 type E at an average of 55.2 months, all showing complete consolidation. Of them, 6 patients had a loss of range of motion with more than 10° in the sagittal plane, and only 1 patient exceeded 10° reduction of supination. Twenty-five patients reported being pain-free under all circumstances, and all but 2 patients (93.75%) had returned to their previous activity level. The average disabilities of the arm, shoulder and hand score was 21.15 (range 0-88.3), and the overall Mayo elbow performance index was 91.87, without complications, such as wound infection, neurovascular impairment or premature hardware removal. CONCLUSION: Using the XS nail® system, all fracture types can be successfully treated and the rate of complications was lower than that treated by standard methods published in current literature. An excellent functional outcome, high range of motion as well as good retention of reduction without soft tissue irritation makes this a very suitable implant for fractures subject to tension.

Pursuing More Aggressive Timelines in the Surgical Treatment of Traumatic Spinal Cord Injury (TSCI): A Retrospective Cohort Study with Subgroup Analysis.

BACKGROUND: The optimal timing of surgical therapy for traumatic spinal cord injury (TSCI) remains unclear. The purpose of this study is to evaluate the impact of "ultra-early" (<4 h) versus "early" (4-24 h) time from injury to surgery in terms of the likelihood of neurologic recovery. METHODS: The effect of surgery on neurological recovery was investigated by comparing the assessed initial and final values of the American Spinal Injury Association (ASIA) Impairment Scale (AIS). A post hoc analysis was performed to gain insight into different subgroup regeneration behaviors concerning neurological injury levels. RESULTS: Datasets from 69 cases with traumatic spinal cord injury were analyzed. Overall, 19/46 (41.3%) patients of the "ultra-early" cohort saw neurological recovery compared to 5/23 (21.7%) patients from the "early" cohort (p = 0.112). The subgroup analysis revealed differences based on the neurological level of injury (NLI) of a patient. An optimal cutpoint for patients with a cervical lesion was estimated at 234 min. Regarding the prediction of neurological improvement, sensitivity was 90.9% with a specificity of 68.4%, resulting in an AUC (area under the curve) of 84.2%. In thoracically and lumbar injured cases, the estimate was lower, ranging from 284 (thoracic) to 245 min (lumbar) with an AUC of 51.6% and 54.3%. CONCLUSIONS: Treatment within 24 h after TSCI is associated with neurological recovery. Our hypothesis that intervention within 4 h is related to an improvement in the neurological outcome was not confirmed in our collective. In a clinical context, this suggests that after TSCI there is a time frame to get the right patient to the right hospital according to advanced trauma life support (ATLS) guidelines.

An In Vitro Evaluation of the Biological and Osteogenic Properties of Magnesium-Doped Bioactive Glasses for Application in Bone Tissue Engineering.

Magnesium (Mg2+) is known to play a crucial role in mineral and matrix metabolism of bone tissue and is thus increasingly considered in the field of bone tissue engineering. Bioactive glasses (BGs) offer the promising possibility of the incorporation and local delivery of therapeutically active ions as Mg2+. In this study, two Mg2+-doped derivatives of the ICIE16-BG composition (49.46 SiO2, 36.27 CaO, 6.6 Na2O, 1.07 P2O5, 6.6 K2O (mol%)), namely 6Mg-BG (49.46 SiO2, 30.27 CaO, 6.6 Na2O, 1.07 P2O5, 6.6 K2O, 6.0 MgO (mol%) and 3Mg-BG (49.46 SiO2, 33.27 CaO, 6.6 Na2O, 1.07 P2O5, 6.6 K2O, 3.0 MgO (mol%)) were examined. Their influence on viability, proliferation and osteogenic differentiation of human mesenchymal stromal cells (MSCs) was explored in comparison to the original ICIE16-BG. All BGs showed good biocompatibility. The Mg2+-doped BGs had a positive influence on MSC viability alongside with inhibiting effects on MSC proliferation. A strong induction of osteogenic differentiation markers was observed, with the Mg2+-doped BGs significantly outperforming the ICIE16-BG regarding the expression of genes encoding for protein members of the osseous extracellular matrix (ECM) at certain observation time points. However, an overall Mg2+-induced enhancement of the expression of genes encoding for ECM proteins could not be observed, possibly due to a too moderate Mg2+ release. By adaption of the Mg2+ release from BGs, an even stronger impact on the expression of genes encoding for ECM proteins might be achieved. Furthermore, other BG-types such as mesoporous BGs might provide a higher local presence of the therapeutically active ions and should therefore be considered for upcoming studies.

Treatment of Traumatic Femoral Neck Fractures with an Intramedullary Nail in Osteoporotic Bones.

PURPOSE: Sufficient anchoring of intramedullary osteosynthesis in the femoral head in a femoral neck fracture is a challenge with increasing age of the patients and decreasing bone quality. For older patients with inferior bone quality, it has not been investigated whether the application of an intramedullary force carrier, as a minimally invasive and rapid intervention, can provide a considerable benefit and reduce the postoperative complication and lethality rate. This retrospective study aimed to investigate the stability and functionality after the acute treatment of a femoral neck fracture in osteoporotic bone using an intramedullary force carrier even with higher grade fracture types. MATERIAL AND METHODS: The retrospective analysis was based on a collective of 82 patients over 60 years of age with a femoral neck fracture treated with a gliding nail in our centre between 1999 and 2006. RESULTS: The average time to follow-up was 69.05 months (median 71.0; minimum 27.0-maximum 108.0). Female patients made up more than two-thirds of the patient collective at 63 of the 82 patients (76.83%). The average age of the patients was 77.76 years (median 78.00; range 60.00-93.00).In 66 patients (80.49%), the implantation showed good results and no complications or further treatments. 24/82 patients of our collective had died in our re-evaluation. In no case, a pseudarthrosis or severe impaction with neck shortening occurred (loss of offset).11/82 patients had femoral head necrosis which led to total hip replacement in 8 cases, a hemiarthroplasty in 2 cases and in 1 case a remaining Girdlestone situation because of a deep infection. Another five patients also had to undergo a total hip replacement because of a central perforation of the blade in one case, breakout of the blade after another fall in another two cases and a lateral dislocation of the blade in two cases. CONCLUSION: The use of an intramedullary force carrier in the osteoporotic bone can mean distinct advantages for the selected patient as a minimally invasive and rapid surgical method compared to extensive surgery, even in the case of severe injuries. However, the advantages and disadvantages for the patient should be considered critically.

Expression of VEGF in Peripheral Serum Is a Possible Prognostic Factor in Bone-Regeneration via Masquelet-Technique-A Pilot Study.

Two-step Masquelet-technique established a new procedure in the treatment of osseous defects, addressing prerequisites postulated by the "diamond concept". Increase in blood perfusion and growth factors are enhanced by the "Masquelet-membrane". To describe this, we measured serum levels of Vascular Endothelial Growth Factor (VEGF) of patients with atrophic non-unions of long bones undergoing Masquelet-technique. From over 500 non-union patients undergoing Masquelet-technique with prospective follow-up we randomly selected 30 patients. 23 were included, 7 lost to follow-up or excluded because of incomplete data. Serum was drawn at specified intervals before and after surgery. Patients were followed for at least 6 months after step 2. Classification into both groups was performed according to radiological results and clinical outcome 6 months after step 2. Concentration of VEGF in patients' serum was performed via ELISA. 14 achieved osseous consolidation (responder group), 9 cases did not (non-responder). Responders showed a significant increase of serum-VEGF in the first and second week when compared to the preoperative values of step 1. Non-responders showed a significant increase of VEGF in the second week after Steps 1 and 2. Comparison of groups showed significantly higher increase of serum-VEGF week2 after step 1 and preoperative to step 2 for responders. Results show one possibility of illustrating therapeutic progress by monitoring growth factors and possibly allowing prognostic conclusions thereof. This might lead to a more targeted treatment protocol.

Prediction of survival odds in COVID-19 by zinc, age and selenoprotein P as composite biomarker.

SARS-CoV-2 infections cause the current coronavirus disease (COVID-19) pandemic and challenge the immune system with ongoing inflammation. Several redox-relevant micronutrients are known to contribute to an adequate immune response, including the essential trace elements zinc (Zn) and selenium (Se). In this study, we tested the hypothesis that COVID-19 patients are characterised by Zn deficiency and that Zn status provides prognostic information. Serum Zn was determined in serum samples (n = 171) collected consecutively from patients surviving COVID-19 (n = 29) or non-survivors (n = 6). Data from the European Prospective Investigation into Cancer and Nutrition (EPIC) study were used for comparison. Zn concentrations in patient samples were low as compared to healthy subjects (mean ± SD; 717.4 ± 246.2 vs 975.7 ± 294.0 µg/L, P < 0.0001). The majority of serum samples collected at different time points from the non-survivors (25/34, i.e., 73.5%) and almost half of the samples collected from the survivors (56/137, i.e., 40.9%) were below the threshold for Zn deficiency, i.e., below 638.7 µg/L (the 2.5th percentile in the EPIC cohort). In view that the Se status biomarker and Se transporter selenoprotein P (SELENOP) is also particularly low in COVID-19, we tested the prevalence of a combined deficit, i.e., serum Zn below 638.7 µg/L and serum SELENOP below 2.56 mg/L. This combined deficit was observed in 0.15% of samples in the EPIC cohort of healthy subjects, in 19.7% of the samples collected from the surviving COVID-19 patients and in 50.0% of samples from the non-survivors. Accordingly, the composite biomarker (SELENOP and Zn with age) proved as a reliable indicator of survival in COVID-19 by receiver operating characteristic (ROC) curve analysis, yielding an area under the curve (AUC) of 94.42%. We conclude that Zn and SELENOP status within the reference ranges indicate high survival odds in COVID-19, and assume that correcting a diagnostically proven deficit in Se and/or Zn by a personalised supplementation may support convalescence.

Effect of manganese, zinc, and copper on the biological and osteogenic properties of mesoporous bioactive glass nanoparticles.

Mesoporous bioactive glass nanoparticles (MBGNs) have demonstrated promising properties for the local delivery of therapeutically active ions with the aim to improve their osteogenic properties. Manganese (Mn), zinc (Zn), and copper (Cu) ions have already shown promising pro-osteogenic properties. Therefore, the concentration-dependent impact of MBGNs (composition in mol%: 70 SiO2 , 30 CaO) and MBGNs containing 5 mol% of either Mn, Zn, or Cu (composition in mol%: 70 SiO2 , 25 CaO, 5 MnO/ZnO/CuO) on the viability and osteogenic differentiation of human marrow-derived mesenchymal stromal cells (BMSCs) was assessed in this study. Mn-doped MBGNs (5Mn-MBGNs) showed a small "therapeutic window" with a dose-dependent negative impact on cell viability but increasing pro-osteogenic features alongside increasing Mn concentrations. Due to a constant release of Zn, 5Zn-MBGNs showed good cytocompatibility and upregulated the expression of genes encoding for relevant members of the osseous extracellular matrix during the later stages of cultivation. In contrast to all other groups, BMSC viability increased with increasing concentration of Cu-doped MBGNs (5Cu-MBGNs). Furthermore, 5Cu-MBGNs induced an increase in alkaline phosphatase activity. In conclusion, doping with Mn, Zn, or Cu can enhance the biological properties of MBGNs in different ways for their potential use in bone regeneration approaches.

Osteogenic properties of manganese-doped mesoporous bioactive glass nanoparticles.

Mesoporous bioactive glass nanoparticles (MBGNs) based on the SiO2 -P2 O5 -CaO system have demonstrated promising properties for the local delivery of therapeutically active ions with the aim to improve their osteogenic properties. Manganese (Mn) has been identified as a candidate ion for local application in bone tissue engineering applications. It remains unknown how SiO2 -P2 O5 -CaO-based MBGNs influence human bone marrow-derived mesenchymal stromal cells (BMSCs) in terms of viability, proliferation, and differentiation and how these features can be modified by the addition of Mn to the MBGNs' composition. Therefore, in this study, MBGNs (composition in mol%: 50 SiO2 , 40 CaO, 10 P2 O5 ) and its Mn-doped derivate 5Mn-MBGNs (composition in mol%: 50 SiO2 , 35 CaO, 10 P2 O5 , 5 MnO) were applied to a culture of BMSCs in two different concentrations. With increasing concentration, 5Mn-MBGNs supported osteogenic differentiation and enhanced the upregulation of genes encoding for extracellular matrix proteins but also negatively influenced cell viability and proliferation. When applied in lower concentrations, MBGNs showed not only viability- and growth-enhancing effects but also significant pro-osteogenic features-however, these positive properties deteriorated with increasing concentration. Two major conclusions can be drawn from this study: (a) supplementation with Mn enhances the osteogenic properties of MBGNs in a dose-dependent manner and (b) MBGNs constitute an attractive vector for therapeutically active ions since it exhibits an intrinsic pro-osteogenic potential that can be improved and/or modified by incorporation of therapeutically active ions. Future studies should focus on the evaluation of further candidate ions that are known to influence osteogenic differentiation positively.

Bioactive Glass (BG) ICIE16 Shows Promising Osteogenic Properties Compared to Crystallized 45S5-BG.

The ICIE16-bioactive glass (BG) (48.0 SiO2, 6.6 Na2O, 32.9 CaO, 2.5 P2O5, 10.0 K2O (wt %)) has been developed as an alternative to 45S5-BG, the original BG composition (45.0 SiO2, 24.5 Na2O, 24.5 CaO, 6.0 P2O5 (wt %)), with the intention of broadening the BG sintering window while maintaining bioactivity. Because there is a lack of reports on ICIE16-BG biological properties, the influence of ICIE16-BG on viability, proliferation, and osteogenic differentiation of human mesenchymal stromal cells (MSCs) was evaluated in direct comparison to 45S5-BG in this study. The BGs underwent heat treatment similar to that which is required in order to fabricate scaffolds by sintering, which resulted in crystallization of 45S5-BG (45S5-CBG) while ICIE16 remained amorphous. Granules based on both BGs were biocompatible, but ICIE16-BG was less harmful to cell viability, most likely due to a more pronounced pH alkalization in the 45S5-CBG group. ICIE16-BG outperformed 45S5-CBG in terms of osteogenic differentiation at the cellular level, as determined by the increased activity of alkaline phosphatase. However, granules from both BGs were comparable regarding the stimulation of expression levels of genes encoding for osseous extracellular matrix (ECM) proteins. The addition of therapeutically active ions to ICIE16-BG might further improve its ability to stimulate ECM production and should be investigated in upcoming studies.

Complications and imaging artifacts related to MRI in patients with intramedullary osteosynthesis after proximal femur fracture.

BACKGROUND: Fractures of the proximal femur is one of the most frequent human injuries, and most of the patients are treated with osteosynthesis, such as intramedullary nails. These patients often require magnetic resonance imaging (MRI) scans in their further lives due to various reasons. This raises the question of whether complications with implanted osteosynthesis material such as implant loosening, burning, dislocation, or other complications are to be expected or whether an MRI examination is even suitable with regard to imaging artifacts. METHODS: The aim of this retrospective study was to investigate the rate and type of complications after MRI examinations in patients with inserted intramedullary osteosynthesis device. Furthermore, artifacts in MRI caused by this device were assessed. RESULTS: MRI scans of the head (20 of 62), spine (20 of 62), pelvis (10 of 62), and lower extremity (6/62) were performed. Three of the 62 patients received an MRI of the abdomen, and 2 of the 62 patients received an MRI of the thorax and the upper extremity. Of the 62 patients, noneexperienced complications during the immediate examination. Similarly, none of the patients showed early complications within the first 2 weeks after MRI. In our long-term follow-up examination, no long-term complication after MRI was observed in the recorded 15 patients. Artifacts were found in 14 patients: in MRI scans of the pelvis (10/10), of the abdomen (2/3), and of the lower extremity (2/6). CONCLUSION: There were no complications during the MRI scan, in the first 2 weeks after MRI, or in the recorded long-term results. MRI with an enclosed intramedullary nail provided good image quality unless the immediate implant site was imaged. MRI diagnosis is thus possible in patients with an inserted intramedullary nail. The inserted intramedullary nail should therefore not be an exclusion criterion when sectional imaging with MRI is required.

Evaluation of the clinical use of the ETN PROtect® in non-union therapy.

INTRODUCTION: Non-union of a long bone fracture remains a challenge in orthopaedic and trauma surgery. In the current study, we sought to determine the clinical effectiveness of tibial non-union treatment utilizing an antibiotic-coated intramedullary nail (Expert Tibia Nail (ETN) PROtect®) regarding prevention and treatment of infection and the clinical outcome. PATIENTS AND METHODS: 36 patients suffering from tibial non-unions that were treated with the ETN PROtect® in the course of non-union treatment between February 2010 and March 2015 were included in this clinical observational study. Clinical and radiological examinations were performed preoperatively as well as 4, 6 and 12 weeks and 6 and 12 months postoperatively as part of a standardized follow-up program. Data regarding perioperative complications, weight-bearing capacity, radiological signs of consolidation and subjective health status were assessed at each time point. Laboratory parameters such as C-reactive protein (CRP) and leukocyte count were collected preoperatively in order to assess the patients' risk profile for infection. RESULTS: Patients had an average of 6.2 previous surgeries and 22 patients (61.1%) had a positive bacterial culture from intraoperatively removed tissue during the first operative treatment. 29 patients (80.6%) achieved full weight-bearing after an average of 7.7 months, furthermore 80.6% of patients achieved osseous consolidation. 3 deep infections occurred, including one amputation. Subjective health status increase based on the SF-12 questionnaire during our follow-up program. CONCLUSION: The results from the current study indicate that the use of the ETN PROtect® in the applied non-union therapy has a high clinical effectiveness regarding osseous consolidation and time to weight bearing. In addition, the use of gentamicin-coated nails in the treatment of tibial non-unions might contribute to both successful treatment of the underlying infection and prevention of perioperative infection. The gentamicin-coated nail may serve as a beneficial adjunct treatment in the applied non-union therapy in addition to all established techniques in the treatment of infected non-unions.

Pooling of Patient-Derived Mesenchymal Stromal Cells Reduces Inter-Individual Confounder-Associated Variation without Negative Impact on Cell Viability, Proliferation and Osteogenic Differentiation.

Patient-derived mesenchymal stromal cells (MSCs) play a key role in bone tissue engineering. Various donor-specific factors were identified causing significant variability in the biological properties of MSCs impairing quality of data and inter-study comparability. These limitations might be overcome by pooling cells of different donors. However, the effects of pooling on osteogenic differentiation, proliferation and vitality remain unknown and have, therefore, been evaluated in this study. MSCs of 10 donors were cultivated and differentiated into osteogenic lineage individually and in a pooled setting, containing MSCs of each donor in equal parts. Proliferation was evaluated in expansion (assessment of generation time) and differentiation (quantification of dsDNA content) conditions. Vitality was visualized by a fluorescence-microscopy-based live/dead assay. Osteogenic differentiation was assessed by quantification of alkaline phosphatase (ALP) activity and extracellular calcium deposition. Compared to the individual setting, generation time of pooled MSCs was shorter and proliferation was increased during differentiation with significantly lower variances. Calcium deposition was comparable, while variances were significantly higher in the individual setting. ALP activity showed high variance in both groups, but increased comparably during the incubation period. In conclusion, MSC pooling helps to compensate donor-dependent variability and does not negatively influence MSC vitality, proliferation and osteogenic differentiation.

Osteogenic differentiation of mesenchymal stem cells is enhanced in a 45S5-supplemented ß-TCP composite scaffold: an in-vitro comparison of Vitoss and Vitoss BA.

Since the amount of autologous bone for the treatment of bone defects is limited and harvesting might cause complications, synthetic bone substitutes such as the popular ß-tricalcium phosphate (ß-TCP) based Vitoss have been developed as an alternative grafting material. ß-TCPs exhibit osteoconductive properties, however material-initiated stimulation of osteogenic differentiation is limited. These limitations might be overcome by addition of 45S5 bioactive glass (BG) particles. This study aims to analyze the influence of BG particles in Vitoss BA (20 wt% BG particles with a size of 90-150 µm) on osteogenic properties, cell vitality and cell proliferation in direct comparison to Vitoss by evaluation of the underlying cellular mechanisms. For that purpose, Vitoss and Vitoss BA scaffolds were seeded with human mesenchymal stem cells (MSC) and underwent osteogenic differentiation in-vitro for up to 42 days. Cell vitality, proliferation, and osteogenic differentiation were monitored by quantitative gene expression analysis, determination of alkaline phosphatase activity, PrestoBlue cell viability assay, dsDNA quantification, and a fluorescence-microscopy-based live/dead-assay. It was demonstrated that BG particles decrease cell proliferation but do not have a negative impact on cell vitality. Especially the early stages of osteogenic differentiation were significantly improved in the presence of BG particles, resulting in earlier maturation of the MSC towards osteoblasts. Since most of the stimulatory effects induced by BG particles took place initially, particles exhibiting another surface-area-to-volume ratio should be considered in order to provide long-lasting stimulation.

Relation of selenium status to neuro-regeneration after traumatic spinal cord injury.

INTRODUCTION: The trace element selenium (Se) is crucial for the biosynthesis of selenoproteins. Both neurodevelopment and the survival of neurons that are subject to stress depend on a regular selenoprotein biosynthesis and sufficient Se supply by selenoprotein P (SELENOP). HYPOTHESIS: Neuro-regeneration after traumatic spinal cord injury (TSCI) is related to the Se status. STUDY DESIGN: Single-centre prospective observational study. PATIENTS AND METHODS: Three groups of patients with comparable injuries were studied; vertebral fractures without neurological impairment (n = 10, group C), patients with TSCI showing no remission (n = 9, group G0), and patients with remission developing positive abbreviated injury score (AIS) conversion within 3 months (n = 10, group G1). Serum samples were available from different time points (upon admission, and after 4, 9 and 12 h, 1 and 3 days, 1 and 2 weeks, and 1, 2 and 3 months). Serum trace element concentrations were determined by total reflection X-ray fluorescence, SELENOP by ELISA, and further parameters by laboratory routine. RESULTS: Serum Se and SELENOP concentrations were higher on admission in the remission group (G1) as compared to G0. During the first week, both parameters remained constant in C and G0, whereas they declined significantly in the remission group. Similarly, the concentration changes between admission and 24 h were most pronounced in this group of recovering patients (G1). Binary logistic regression analysis including the delta of Se and SELENOP within the first 24 h indicated an AUC of 90.0% (CI: 67.4%-100.0%) with regards to predicting the outcome after TSCI. CONCLUSION: A Se deficit might constitute a risk factor for poor outcome after TSCI. A dynamic decline of serum Se and SELENOP concentrations after admission may reflect ongoing repair processes that are associated with higher odds for a positive clinical outcome.

Gelatin coating increases in vivo bone formation capacity of three-dimensional 45S5 bioactive glass-based crystalline scaffolds.

Recent studies have demonstrated that surface characteristics, porosity, and mechanical strength of three-dimensional 45S5-type bioactive glass (BG)-based scaffolds are directly correlated with osteogenic properties. Three-dimensional BG-based scaffolds obtained from maritime natural sponges (MNSs) as sacrificial templates exhibit the required morphological properties; however, no in vivo data about the osteogenic features are available. In this study, uncoated (Group A) and gelatin-coated (Group B) crystalline MNS-obtained BG-based scaffolds were evaluated mechanically and seeded with human mesenchymal stem cells prior to subcutaneous implantation in immunodeficient mice. Before implantation and after explantation, micro-computed tomography scans were conducted, and scaffolds were finally subjected to histomorphometry. Scaffolds of both groups showed bone formation. However, Group B scaffolds performed distinctly better as indicated by a significant increase in scaffold volume (8.95%, p = 0.039) over the implantation period compared with a nonsignificant increase of 5.26% in Group A scaffolds in micro-computed tomography analysis. Furthermore, percentage bone area was 10.33% (±1.18%) in the Group B scaffolds, which was significantly (p = 0.007) higher compared with the 8.53% (±0.77%) in the Group A scaffolds in histomorphometry. Compressive strength was enhanced significantly by gelatin coating (9 ± 2 vs. 4 ± 1 MPa; p = 0.029). The presence of gelatin on the remnant parts was verified by scanning electron microscopy and X-ray spectroscopy, demonstrating the coatings' resilience. MNS-obtained BG-based scaffolds were thus confirmed to exhibit osteogenic properties in vivo that can significantly be enhanced by gelatin coating.

Chemokine analysis as a novel diagnostic modality in the early prediction of the outcome of non-union therapy: a matched pair analysis.

BACKGROUND: Despite the regenerative capability of skeletal tissue fracture, non-union is common. Treatment of non-unions remains challenging, and early determination of the outcome is impossible. Chemokines play an important role in promoting the formation of new bone and remodeling existing bone. Despite their importance regarding the regulation of bone biology, the potential of chemokines as biological markers reflecting osseous regeneration is unknown. The purpose of this study was to determine (1) if serum chemokine expression levels correlate with the outcome of non-union surgery and (2) if chemokine expression analysis can be used to identify patients at risk for treatment failure. METHODS: Non-union patients receiving surgical therapy in our institution between March 2012 and March 2014 were prospectively enrolled in a clinical observer study. Regular clinical and radiological follow-up was conducted for 12 months including collection of blood during the first 12 weeks. Based on the outcome, patients were declared as responders or non-responders to the therapy. To minimize biases, patients were matched (age, sex, body mass index (BMI)) and two groups of patients could be formed: responders (R, n = 10) and non-responders (NR, n = 10). Serum chemokine expression (CCL-2, CCL-3, CCL-4, CXCL-10, CCL-11, and interferon gamma (IFN-γ)) was analyzed using Luminex assays. Data was compared and correlated to the outcome. RESULTS: CCL-3 expression in NR was significantly higher during the course of the study compared to R (p = 0.002), and the expression pattern of CCL-4 correlated with CCL-3 in both groups (NR: p < 0.001 and r = 0.63). IFN-γ expression in NR was continuously higher than in R (p < 0.001), and utilization of CCL-3 and IFN-γ serum expression levels 2 weeks after the treatment resulted in a predictive model that had an AUC of 0.92 (CI 0.74-1.00). CONCLUSION: Serum chemokine expression analysis over time is a valid and promising diagnostic tool. The chemokine expression pattern correlates with the outcome of the Masquelet therapy of lower limb non-unions. Utilization of the serum analysis of CCL-3 and IFN-γ 2 weeks after the treatment resulted in an early predictive value regarding the differentiation between patients that are likely to heal and those that are prone to high risk of treatment failure.

A Preliminary Study of Contrast-Enhanced Ultrasound (CEUS) and Cytokine Expression Analysis (CEA) as Early Predictors for the Outcome of Tibial Non-Union Therapy.

The current study investigates if contrast-enhanced ultrasound (CEUS) or cytokine expression analysis (CEA) evaluating vascularization are capable of predicting the outcome of non-union therapy. Patients with tibial non-unions were surgically treated and participated in our follow-up program including perioperative collection of blood as well as CEUS analysis. Two groups were formed: Responders in group 1 (G1, N = 8) and Non-Responders in group 2 (G2, N = 5). Serum cytokine expression and local microperfusion were compared and correlated to the radiologic outcome. Evaluation of TNF-α expression revealed significantly lower values prior to first surgery in G1 (G1: 9.66 ± 0.96 pg/mL versus G2: 12.63 ± 1.2 pg/mL; p = 0.045); whereas after treatment both CEA and CEUS indicated a higher potential for angiogenesis in Responders. Logistic regression modelling revealed the highest predictive power regarding eventual osseous consolidation for the combination of both CEUS and serum CEA. The results provide first evidence regarding a link between changes in the serum expression of distinct pro-angiogenic cytokines and alterations in the local microperfusion assessed via both non-invasive and radiation-free diagnostic modalities. In addition, a combination of CEUS and CEA is a promising novel tool in early prediction of the outcome of non-union therapy.

Insulin-Like Growth Factor-1 as a Possible Alternative to Bone Morphogenetic Protein-7 to Induce Osteogenic Differentiation of Human Mesenchymal Stem Cells in Vitro.

Growth factors and mesenchymal stem cells (MSC) support consolidation of bone defects. Bone Morphogenetic Protein-7 (BMP-7) has been used clinically and experimentally, but the outcomes remain controversial. Increased systemic expression of Insulin-like Growth Factor-1 (IGF-1) significantly correlates with successful regeneration of bone healing disorders, making IGF-1 a promising alternative to BMP-7. There is no experimental data comparing the osteoinductive potential of IGF-1 and BMP-7. Therefore, in this study, the influence of IGF-1 and BMP-7 in different concentrations on the osteogenic differentiation of two human MSC-subtypes, isolated from reaming debris (RMSC) and iliac crest bone marrow (BMSC) has been assessed. A more sensitive reaction of BMSC towards stimulation with IGF-1 in concentrations of 400⁻800 ng/mL was found, leading to a significantly higher degree of osteogenic differentiation compared to stimulation with BMP-7. RMSC react more sensitively to stimulation with BMP-7 compared to BMSC. Lower concentrations of IGF-1 were necessary to significantly increase osteogenic differentiation of RMSC and BMSC compared to BMP-7. Therefore, IGF-1 should be considered as a valuable option to improve osteogenic differentiation of MSC and merits further experimental consideration. The MSC subtype and method of differentiation factor application also have to be considered, as they affect the outcome of osteogenic differentiation.

Safety study: is there a pathologic IGF-1, PDGF and TGF-ß cytokine expression caused by adjunct BMP-7 in tibial and femoral non-union therapy?

BACKGROUND: In this prospective safety study, we investigated if the characteristic cytokine expression during bone regeneration is manipulated by the local application of bone morphogenetic protein-7 (BMP-7) in non-union surgery. Therefore, the levels of insulin like growth factor 1 (IGF-1), platelet-derived growth factor AB (PDGF-AB) and transforming growth factor beta (TGF-ß) were compared between patients with the gold standard use of autologous bone graft (ABG) and those with additional application of BMP-7 as part of the diamond concept. PATIENTS AND METHODS: Between 2009 and 2014, of the 153 patients with tibial and femoral non-unions, a matched pair analysis was performed to compare the serological cytokine expressions. Blood samples were collected preoperatively, 1, 2 and 6 weeks as well as 3 and 6 months after non-union surgery. Matching criteria were smoking status, fracture location, gender, age and body mass index (BMI). Patients in G1 (n=10) were treated with ABG and local BMP-7 while their matching partners in G2 (n=10) received ABG only. The routine clinical and radiologic follow-up was 1 year. RESULTS: Although the IGF-1 quantification in G2 showed higher pre- and postoperative values compared to G1 (p<0.05), the courses of both groups were similar. Likewise, PDGF-AB and TGF-ß expressions appeared similar in G1 and G2 with peaks in both groups at 2 weeks follow-up. Osseous consolidation was assessed in all operated non-unions. The adjunct application of BMP-7 did not cause any pathologic cytokine expression. CONCLUSION: Similar expressions of the serum cytokines IGF-1, PDGF-AB and TGF-ß were demonstrated in non-union patients treated with ABG and additional application of BMP-7 according to the diamond concept. Our findings indicate that the local application of BMP-7, which imitates the physiologic secretion of growth factors during bone regeneration, is safe and without the risk of abnormal systemic cytokine expression. Studies with higher patient numbers will have to validate these assumptions.

Continuous stimulation with differentiation factors is necessary to enhance osteogenic differentiation of human mesenchymal stem cells in-vitro.

Bone defect treatment belongs to the most challenging fields in orthopedic surgery and requires the well-coordinated application of mesenchymal stem cells (MSC) and differentiation factors. MSC isolated from reaming material (RMSC) and iliac crest (BMSC) in combination with bone morphogenetic protein-7 (BMP-7) and insulin-like growth factor-1 (IGF-1) have been used. The short half-life of both factors limit their applications: a burst release of the factor can probably not induce sustainable differentiation. We stimulated MSC in osteogenic differentiation medium with three different concentrations of BMP-7 or IGF-1: Group A was stimulated continuously, group B for 24 h and group C remained without any stimulation. Osteogenic differentiation was measured after seven and 14 days by alizarin red staining and alkaline phosphatase (ALP) activity. Continuous stimulation led to higher levels of osteogenic differentiation than short-term stimulation. This could lead to a reconsideration of established application forms for differentiation factors, aiming to provide a more sustained release.