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Piezoelectric ceramics are piezoelectric materials with polycrystalline structure and have been widely used in many fields such as medical imaging and sound sensors. As knowledge about this kind of material develops, researchers find piezoelectric ceramics possess favorable piezoelectricity, biocompatibility, mechanical properties, porous structure and antibacterial effect and endeavor to apply piezoelectric ceramics to the field of bone tissue engineering. However, clinically no piezoelectric ceramics have been exercised so far. Therefore, in this paper we present a comprehensive review of the research and development of various piezoelectric ceramics including barium titanate, potassium sodium niobate and zinc oxide ceramics and aims to explore the application of piezoelectric ceramics in bone regeneration by providing a detailed overview of the current knowledge and research of piezoelectric ceramics in bone tissue regeneration. [ABSTRACT FROM AUTHOR]

PURPOSE OF THE STUDY The preclinical study aimed to compare the healing of segmental bone defects treated with biodegradable hyaluronic acid and tricalcium phosphate-based hydrogel with the established autologous spongioplasty. Another aim was to evaluate the hydrogel as a scaffold for osteoinductive growth factor of bone morphogenetic protein-2 (BMP-2) and stem cells. MATERIAL AND METHODS The study was conducted in an in vivo animal model. A standardized rabbit model of a 15 mm long segmental bone defect of left radius was used. A total of 40 animals were divided into 5 groups of 8 individuals. In the KO- (negative control) group, the created defect was left to heal spontaneously. In the KO+ (positive control) group, the defect was filled with morselized bone autograft prepared from the resected segment. In the study group A, the defect was filled with hydrogel based on hyaluronic acid derivative and tricalcium phosphate. In the study group B, the defect was filled with hydrogel based on hyaluronic acid derivative, tricalcium phosphate and bone marrow aspirate. In the study group C, the defect was filled with hydrogel based on hyaluronic acid derivative, tricalcium phosphate, bone marrow aspirate and BMP-2. Healing was assessed using radiographs at 1, 6, and 12 weeks postoperatively and histology specimens were collected at 16 weeks postoperatively. RESULTS Altogether 35 rabbits survived (KO- 7, KO+ 7, A 7, B 6, C 8) until the end of the study. As concerns the radiographic assessment, the best results were achieved by the groups KO+ and C, where new bone formation across the entire width of the bone defect was clearly seen at 6 and 12 weeks and the osteotomy line was completely healed too. At 12 weeks, complete bone remodelling was observed in all animals in the group KO+, whereas in the group C, bone remodelling was fully completed in 5 animals and partially completed in 3 animals. In terms of histological assessment, however, the best results were achieved by the group C, where the bone defect was completely remodelled into lamellar bone in 7 specimens, while in 1 specimen it healed with bony callus formation. In the group KO+, the defect was healed in 4 specimens by cartilaginous callus with loci of remodelling into bony callus, in 2 specimens the bony callus was predominant with cartilaginous callus areas, and only one defect was completely remodelled into lamellar bone. DISCUSSION Compared to autografts that manifest osteogenic, osteoinductive and osteoconductive properties, the biodegradable hyaluronic acid and tricalcium phosphate-based hydrogel has osteoconductive properties only. Thus, it was also tested in our study as a scaffold for bone marrow cells and BMP-2 osteoinductive growth factor. Thanks to its semi-liquid properties, the biodegradable hyaluronic acid and tricalcium phosphate-based hydrogel is a promising material for use in 3D printing. CONCLUSIONS The preclinical study in an in vivo animal model confirmed the beneficial effect of the biodegradable hyaluronic acid and tricalcium phosphate-based hydrogel on the healing of critical-size segmental bone defects. Better healing of these defects was also confirmed for filling composed of hydrogel and BMP-2 osteoinductive growth factor. The benefit of bone marrow aspirate mixed with hydrogel was not confirmed. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: The induced membrane technique (IMT) is a two-step procedure used for reconstructing segmental bone defects in the limbs. The osteogenic mechanism after bone grafting using IMT remains unclear, and efforts to modify the original techniques are limited to the investigative phase. Therefore, reviewing existing knowledge and identifying hotspots and new trends in IMT is critical. Methods: We retrieved reviews and articles associated with IMT published between 2004 and 2023 from the Web of Science Core Collection (WoSCC). The keywords included induced membrane technique, guided bone regeneration, bone defect reconstruction, bone graft, stem cells, Masquelet technique, management of bone defects, and scaffold. HistCite, VOSviewer, CiteSpace, and R-bibliometrics were used for scientometric analysis. Results: A total of 1019 publications from 374 academic journals with 33,995 co-cited references by 2,331 institutions from 65 countries or regions were included. China (n = 235) and the United States (n = 215) were the most productive countries, with Shanghai Jiao Tong University producing the most number of publications (n = 18). Journal Injury [co-citations = 1774; impact factor (IF) 2022 = 2.5] published the most manuscripts, while Masquelet AC and Giannoudis PV published literature with a significant influence on IMT, showing more co-citations (n = 727; n = 355). Two preface hotspots of IMT focused on investigating the microscopic mechanism (such as the membrane supporting graft-to-bone union and the role of inflammatory cells) and developing new techniques to improve IMT (such as bone tissue engineering and new drugs). Conclusion: This study comprehensively reviewed the literature about IMT published in the last 20 years using qualitative and quantitative methods, providing valuable information for researchers investigating IMT. [ABSTRACT FROM AUTHOR]

The repair of bone defects has been the focus of research at home and abroad in recent years. Gelatin methacryloyl (GelMA) hydrogels, with their good biocompatibility, low cost, photo-cross-linking structure, and easily adjustable physicochemical property, have been widely used in bone regeneration. GelMA hydrogels can overcome issues such as inadequate mechanical property, poor bioactivity, and uncontrolled degradation through various strategies. This paper presents a systematic review of recent advances in GelMA hydrogels in the field of bone defect repair, covering the preparation of GelMA hydrogels and the effect of reaction conditions on the property, the loading and controlled release of GelMA hydrogels (drugs, cells, growth factors, exosomes), material hybridization (organic nanomaterials, inorganic nanomaterials, organic and inorganic hybrid materials) of GelMA hydrogels, structural modulation (electrostatic spinning, microspheres, 3D printing), as well as the mechanism of osteogenic activity (vascular, neural, immunomodulation) in bone defects. Finally, we summarized this article and looked forward to the prospects and challenges of GelMA hydrogel in repairing bone defects. [ABSTRACT FROM AUTHOR]

Treatment of bone defects resulting after tumor surgeries, accidents, or non-unions is an actual problem linked to morbidity and the necessity of a second surgery and often requires a critical healthcare cost. Although the surgical technique has changed in a modern way, the treatment outcome is still influenced by patient age, localization of the bone defect, associated comorbidities, the surgeon approach, and systemic disorders. Three-dimensional magnesium-based scaffolds are considered an important step because they can have precise bone defect geometry, high porosity grade, anatomical pore shape, and mechanical properties close to the human bone. In addition, magnesium has been proven in in vitro and in vivo studies to influence bone regeneration and new blood vessel formation positively. In this review paper, we describe the magnesium alloy's effect on bone regenerative processes, starting with a short description of magnesium's role in the bone healing process, host immune response modulation, and finishing with the primary biological mechanism of magnesium ions in angiogenesis and osteogenesis by presenting a detailed analysis based on a literature review. A strategy that must be followed when a patient-adapted scaffold dedicated to bone tissue engineering is proposed and the main fabrication technologies are combined, in some cases with artificial intelligence for Mg alloy scaffolds, are presented with examples. We emphasized the microstructure, mechanical properties, corrosion behavior, and biocompatibility of each study and made a basis for the researchers who want to start to apply the regenerative potential of magnesium-based scaffolds in clinical practice. Challenges, future directions, and special potential clinical applications such as osteosarcoma and persistent infection treatment are present at the end of our review paper. [ABSTRACT FROM AUTHOR]

Black Phosphorus (BP) is a new semiconductor material with excellent biocompatibility, degradability, and optical and electrophysical properties. A growing number of studies show that BP has high potential applications in the biomedical field. This article aims to systematically review the research progress of BP composite medical materials in the field of tissue engineering, mining BP in bone regeneration, skin repair, nerve repair, inflammation, treatment methods, and the application mechanism. Furthermore, the paper discusses the shortcomings and future recommendations related to the development of BP. These shortcomings include stability, photothermal conversion capacity, preparation process, and other related issues. However, despite these challenges, the utilization of BP-based medical materials holds immense promise in revolutionizing the field of tissue repair. [ABSTRACT FROM AUTHOR]

Background: Early detection of peri-implant bone defects can improve long-term durability of dental implants. By the advances in cone-beam computed tomography (CBCT) scanners and introduction of new algorithms, it is important to find the most efficient protocol for detection of bone defects. This study aimed to assess the efficacy of metal artifact reduction (MAR) and advanced noise reduction (ANR) algorithms for detection of peri-implant bone defects. Materials and methods: In this in vitro study, 40 titanium implants were placed in 7 sheep mandibles. Crestal, apical, and Full defects (n = 10 from each type) were created around the implants, and 10 implants were also placed as controls. CBCT scans were obtained in four modes: with MAR, with ANR, with both MAR and ANR, and without any filter. Totally, 28 scans were obtained and evaluated by a radiologist and a maxillofacial surgeon. The observers recorded their observations in a checklist, and data were analyzed by SPSS version 21 using the kappa coefficient of agreement, sensitivity and specificity values, area under the receiver operating characteristic (ROC) curve (AUC), intraclass correlation coefficient, t-test and paired t-test (P < 0.05). Results: The inter-observer agreement was high for detection of all defects in all modes except with ANR. No significant difference was found in AUC and diagnostic accuracy of different scan modes (P > 0.05). The most common diagnostic error was related to misdiagnosis of control group with full defect with ANR filter, such that the existing bone was not detected. Defect depth was averagely over-estimated while defect length was under-estimated. Correct diagnosis of defects had the highest frequency when both filters were on. Conclusion: The diagnostic accuracy and sensitivity for detection of different defect types were not significantly different in different scan modes but activation of ANR filter significantly decreased the specificity and positive predictive value compared with no use of filter. [ABSTRACT FROM AUTHOR]

Osteoporotic fractures are characterized by abnormal inflammation, deterioration of the bone microenvironment, weakened mechanical properties, and difficulties in osteogenic differentiation. The chronic inflammatory state characterized by aging macrophages leads to delayed or non‐healing of the fracture or even the formation of bone defects. The current bottleneck in clinical treatment is to achieve strong fixation of the comminuted bone fragments and effective regulation of the complex microenvironment of aging macrophages. Inspired by cement and gravel in concrete infrastructure, a biomimetic bone glue with poly(lactic‐co‐glycolic acid) microspheres is developed and levodopa/oxidized chitosan hydrogel stabilized on an organic‐inorganic framework of nanohydroxyapatite, named DOPM. DOPM is characterized via morphological and mechanical characterization techniques, in vitro experiments with bone marrow mesenchymal stromal cells, and in vivo experiments with an aged SD rat model exhibiting osteoporotic bone defects. DOPM exhibited excellent adhesion properties, good biocompatibility, and significant osteogenic differentiation. Transcriptomic analysis revealed that DOPM improved the inflammatory microenvironment by inhibiting the NF‐κB signaling pathway and promoting aging macrophage polarization toward M2 macrophages, thus significantly accelerating bone defect repair and regeneration. This biomimetic bone glue, which enhances osteointegration and reestablishes the homeostasis of aging macrophages, has potential applications in the treatment of osteoporotic bone defects. [ABSTRACT FROM AUTHOR]

Background: Bone defects and nonunion following initial treatment remain significant clinical challenges. The Ilizarov method constitutes a fundamental approach for addressing bone defects, and its integration with adjunctive techniques, such as the accordion maneuver, antibiotic spacers, or internal fixation, has become increasingly widespread. Despite this, limited research exists on the clinical outcomes specifically related to the use of the Ilizarov method combined with the accordion technique for treating long bone defects in the lower limbs. Objective: This study seeks to systematically review the application of the Ilizarov method in combination with the accordion technique for addressing long bone deficiencies in the lower limbs. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic review was performed in alignment with the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-Analyses), involving searches of Medline, Embase, Web of Science, and the Cochrane Library, with the search process concluding on August 20, 2024. The study population consisted of patients with bone defects who underwent treatment using the Ilizarov method in conjunction with the accordion technique. The methodological quality of the included studies was evaluated using the MINORS (Methodological Index for Non-Randomized Studies) scoring system. This study recorded and analyzed the participant count for each study that met the inclusion criteria, along with the number of patients who achieved bone healing, the bone and functional outcomes, and complications such as pin infections, pain, and refracture. Results: Drawing from eight studies involving 80 patients with bone defects treated through the Ilizarov method combined with the accordion technique, this systematic review evaluated the method's impact on bone regeneration. Of these patients, 24% presented with femoral defects, while 76% had tibial defects. The mean patient age was 32.8 years, with an average follow-up of 25.2 months. The accordion technique involved daily distraction and compression adjustments ranging from 0.25 to 1 mm, typically in more than two cycles, effectively promoting bone healing. The bone healing rate was high, with the majority of patients rated as having excellent or good functional recovery, according to standards such as ASAMI and Paley. Common complications included superficial pin tract infections (33.75%) and deep pin tract infections (6.25%), both of which were generally manageable with routine treatment. The accordion technique showed promising results in shortening healing time and enhancing the quality of bone healing. Conclusion: This systematic review demonstrates that despite variations in parameter settings across studies, the Ilizarov method combined with the accordion technique consistently shows strong efficacy and safety in promoting bone regeneration and functional recovery. While some complications may arise, they are generally well-managed with standard care. This approach represents a reliable option for complex bone reconstruction, with future research needed to optimize parameters and further enhance clinical outcomes. [ABSTRACT FROM AUTHOR]

Aim: Studying in rabbit model, the bone behavior during the process of osseointegration of dental implants mimicking vitamin deficiency D3. Materials and Methods: Six rabbits received implants in the area of the removed lower first incisor after creating a condition of vitamin D3 deficiency. Afterwards, the examinations were carried out on days 3, 5, 7, 30, and 90 when all animals were removed from the experiment. At that time, a bone block was collected within the installed dental implant, with the intact area and the area of the adjacent tooth. The samples were examined by histomorphometry analysis. Results: In rabbits with vitamin D3 deficiency, dental implants could be osseointegrated by the regeneration of the bone tissues after surgeries. However, a decrease in the number of cells involved in the construction of bone tissue—osteocytes—was recorded in the regenerated bone (40% ± 7%) as compared with the native bone immediately after implantation, before the bone remodeling processes. Conclusions: The study's results on the rabbit model in vivo confirmed the relationship between vitamin D3 and the process of osseointegration. This in vivo experiment can be the basis for future clinical study. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Osteoporosis is the property of Chinese Journal of Osteoporosis and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Hydroxyapatite (HA)-based materials are widely used in the bone defect restoration field due to their stable physical properties, good biocompatibility, and bone induction potential. To further improve their performance with extra functions such as antibacterial activity, various kinds of metal ion-doped HA-based materials have been proposed and synthesized. This paper offered a comprehensive review of metal ion-doped HA-based materials for bone defect restoration based on the introduction of the physicochemical characteristics of HA followed by the synthesis methods, properties, and applications of different kinds of metal ion (Ag+, Zn2+, Mg2+, Sr2+, Sm3+, and Ce3+)-doped HA-based materials. In addition, the underlying challenges for bone defect restoration using these materials and potential solutions were discussed. [ABSTRACT FROM AUTHOR]

Purpose: The present study aimed to evaluate and compare the effect of nanofibrillated cellulose (NFC)‐based composite with dicalcium phosphate dihydrate and an autologous blood clot (ABC) on the formation of new bone tissue in vivo by histological and histomorphometric assessment. Materials and Methods: A total of 72 rats with created femoral defects (2 mm) were used. The rats were divided into three groups: (1) with filling of the defect with an ABC, (2) NFC‐1—with filling of both the cortical plate and intramedullary space in the defect area, and (3) NFC‐2—with filling of only the intramedullary space in the defect area. Histological and histomorphometric analysis was performed to assess the healing of the bone defect after 14, 30 and 60 days. Results: Complete closure of the cortical plate defect was detected in the NFC‐2 group on Day 30 (p < 0.0001). Moreover, in both NFC groups on the 30th and 60th days, ongoing osteogenesis was observed, characterized by a large volume of newly formed circular pattern bone tissue in the intramedullary space. Сonclusion: This study demonstrated that the NFC‐based composite, which is located below the level of the cortical plate, tamponing only the intramedullary space (NFC‐2), improves bone tissue repair at the site of a bone defect of the cortical plate and has the potential of prolonged osteoinductivity. Level of Evidence: Not applicable. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Modern Medicine & Health is the property of Journal of Modern Medicine & Health and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Bone defects, resulting from substantial bone loss that exceeds the natural self-healing capacity, pose significant challenges to current therapeutic approaches due to various limitations. In the quest for alternative therapeutic strategies, bone tissue engineering has emerged as a promising avenue. Notably, excretory proteins from Toxoplasma gondii (TgEP), recognized for their immunogenicity and broad spectrum of biological activities secreted or excreted during the parasite's lifecycle, have been identified as potential facilitators of osteogenic differentiation in human bone marrow mesenchymal stem cells (hBMSCs). Building on our previous findings that TgEP can enhance osteogenic differentiation, this study investigated the molecular mechanisms underlying this effect and assessed its therapeutic potential in vivo. Methods: We determined the optimum concentration of TgEP through cell cytotoxicity and cell proliferation assays. Subsequently, hBMSCs were treated with the appropriate concentration of TgEP. We assessed osteogenic protein markers, including alkaline phosphatase (ALP), Runx2, and Osx, as well as components of the BMP/Smad signaling pathway using quantitative real-time PCR (qRT-PCR), siRNA interference of hBMSCs, Western blot analysis, and other methods. Furthermore, we created a bone defect model in Sprague-Dawley (SD) male rats and filled the defect areas with the GelMa hydrogel, with or without TgEP. Microcomputed tomography (micro-CT) was employed to analyze the bone parameters of defect sites. H&E, Masson and immunohistochemical staining were used to assess the repair conditions of the defect area. Results: Our results indicate that TgEP promotes the expression of key osteogenic markers, including ALP, Runx2, and Osx, as well as the activation of Smad1, BMP2, and phosphorylated Smad1/5—crucial elements of the BMP/Smad signaling pathway. Furthermore, in vivo experiments using a bone defect model in rats demonstrated that TgEP markedly promoted bone defect repair. Conclusion: Our results provide compelling evidence that TgEP facilitates hBMSC osteogenic differentiation through the BMP/Smad signaling pathway, highlighting its potential as a therapeutic approach for bone tissue engineering for bone defect healing. [ABSTRACT FROM AUTHOR]

Introduction: Infected tibial non-unions with associated bone loss can be challenging to manage. At present, the two main methods utilized in the management of these fractures include the Ilizarov technique of Distraction Osteogenesis (DO) using external fixator devices, or alternatively, the Induced Membrane Technique (IMT), devised by Masquelet. As there is a paucity of data directly comparing the outcomes of these techniques, there is no universal agreement on which strategy a surgeon should choose to use. Aims: This systematic review and meta-analysis aimed to summarize the outcomes of both DO and IMT, in terms of primary outcomes (bone union and infection elimination), and secondary outcomes (complication rates and functional outcomes). Methods: A PRISMA strategy was used. Medline, Web of Science, Cochrane Central Register of Controlled Trials (CENTRAL), and Google Scholar library databases were interrogated using pre-defined MeSH terms and Boolean operators. Quality of evidence was evaluated using OCEBM and GRADE systems. Results: Thirty-two studies with 1136 subjects met the inclusion criteria. With respect to the primary outcomes of interest, union was observed in 94.6% (DO method) and 88.0% (IMT method); this difference, however, was not significant between the two techniques (p = 0.45). In addition, infection elimination rates were also higher in the Ilizarov DO group when compared to Masquelet (Mq) IMT (93.0% vs 80.4% respectively). Again, no significant difference was observed (p = 0.06). For all secondary outcomes assessed (unplanned re-operations, re-fracture rates amputation rate), no statistically significant differences were documented between the treatment options. Conclusion: This study demonstrated that there is no clinical difference in outcomes for patients treated with Ilizarov DO versus Mq IMT techniques. The evidence base at present is relatively sparse and, therefore, we would recommend for further Level I studies to be conducted, to make more meaningful conclusions. [ABSTRACT FROM AUTHOR]

Background: This paper aimed to propose a modified technique of bone transport. An annular frame combined with a retrograde tibiotalocalcaneal arthrodesis nail was used in this novel technique for treating large distal tibial periarticular osteomyelitis and associated defects. Methods: Our team conducted a retrospective research. Forty-three patients with large distal tibial periarticular bone loss were involved in this study. Sixteen patients were treated using the modified hybrid transport technique (MHT group) while 27 were subjected to traditional bone transport (BT group). The mean bone loss was 7.8 ± 2.4 cm in the MHT group and 7.6 ± 2.6 cm in the BT group. The external fixation index, time in transport frame, self-rating anxiety scale, bone healing results and postoperative complications were recorded. Results: The mean time in frame for the MHT group was 3.6 ± 1.5 months, while that of the BT group was 10.3 ± 2.7 months (p < 0.05). The mean external fixation index of MHT group was 0.46 ± 0.08 months/cm versus 1.38 ± 0.24 months/cm of the BT group (p < 0.05). There was no statistical difference for the bone healing results between the MHT and BT groups (p = 0.856). The self-rating anxiety scale and total complication incidence of the MHT group were significantly lower than that of BT patients (p < 0.05). Conclusion: Compared to the traditional BT technique, our modified hybrid transport technique showed better clinical outcomes for treating large distal tibial periarticular bone loss, including less time in transport frame, lower external fixation index and complication incidence. Therefore, this modified technique should be further promoted and developed. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Modern Medicine & Health is the property of Journal of Modern Medicine & Health and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bones play an important role in maintaining exercise and protecting organs. Bone defect, as a common orthopedic disease in clinics, can cause tremendous damage with long treatment cycles. Therefore, the treatment of bone defect remains as one of the main challenges in clinical practice. Today, with increased incidence of bone disease in the aging population, demand for bone repair material is high. At present, the method of clinical treatment for bone defects including non-invasive therapy and invasive therapy. Surgical treatment is the most effective way to treat bone defects, such as using bone grafts, Masquelet technique, Ilizarov technique etc. In recent years, the rapid development of tissue engineering technology provides a new treatment strategy for bone repair. This review paper introduces the current situation and challenges of clinical treatment of bone defect repair in detail. The advantages and disadvantages of bone tissue engineering scaffolds are comprehensively discussed from the aspect of material, preparation technology, and function of bone tissue engineering scaffolds. This paper also summarizes the 3D printing technology based on computer technology, aiming at designing personalized artificial scaffolds that can accurately fit bone defects. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bone tissue engineering is a promising approach that uses seed-cell-scaffold drug delivery systems to reconstruct bone defects caused by trauma, tumors, or other diseases (e.g., periodontitis). Metformin, a widely used medication for type II diabetes, has the ability to enhance osteogenesis and angiogenesis by promoting cell migration and differentiation. Metformin promotes osteogenic differentiation, mineralization, and bone defect regeneration via activation of the AMP-activated kinase (AMPK) signaling pathway. Bone tissue engineering depends highly on vascular networks for adequate oxygen and nutrition supply. Metformin also enhances vascular differentiation via the AMPK/mechanistic target of the rapamycin kinase (mTOR)/NLR family pyrin domain containing the 3 (NLRP3) inflammasome signaling axis. This is the first review article on the effects of metformin on stem cells and bone tissue engineering. In this paper, we review the cutting-edge research on the effects of metformin on bone tissue engineering. This includes metformin delivery via tissue engineering scaffolds, metformin-induced enhancement of various types of stem cells, and metformin-induced promotion of osteogenesis, angiogenesis, and its regulatory pathways. In addition, the dental, craniofacial, and orthopedic applications of metformin in bone repair and regeneration are also discussed. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to identify a collagen-coating method that does not affect the physicochemical properties of bone graft material. Based on this, we developed a collagen-coated porcine xenograft and applied it to dogs to validate its effectiveness. Methods: Xenografts and collagen were derived from porcine, and the collagen coating was performed through N-ethyl-N'-(3-(dimethylamino) propyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) activation. The physicochemical characteristics of the developed bone graft material were verified through field emission scanning electron microscope (FE-SEM), brunauer emmett teller (BET), attenuated total reflectance-fourier transform infrared (ATR-FTIR), and water absorption test. Subsequently, the biocompatibility and bone healing effects were assessed using a rat calvarial defect model. Results: The physicochemical test results confirmed that collagen coating increased bone graft materials' surface roughness and fluid absorption but did not affect their porous structure. In vivo evaluations revealed that collagen coating had no adverse impact on the bone healing effect of bone graft materials. After confirming the biocompatibility and effectiveness, we applied the bone graft materials in two orthopedic cases and one dental case. Notably, successful fracture healing was observed in both orthopedic cases. In the dental case, successful bone regeneration was achieved without any loss of alveolar bone. Discussion: This study demonstrated that porcine bone graft material promotes bone healing in dogs with its hemostatic and cohesive effects resulting from the collagen coating. Bone graft materials with enhanced biocompatibility through collagen coating are expected to be widely used in veterinary clinical practice. [ABSTRACT FROM AUTHOR]

The repair of bone defects remains a major challenge in the clinic, and treatment requires bone grafts or bone replacement materials. Existing biomaterials have many limitations and cannot meet the various needs of clinical applications. To treat bone defects, we constructed a nanohydroxyapatite (nHA)/methylacrylylated silk fibroin (MASF) composite biological scaffold using photocurable 3D printing technology. In this study, scanning electron microscopy (SEM) was used to detect the changes in the morphological structure of the composite scaffold with different contents of nanohydroxyapatite, and FTIR was used to detect the functional groups and chemical bonds in the composite scaffold to determine the specific components of the scaffold. In in vitro experiments, bone marrow mesenchymal stem cells from SD rats were cocultured with scaffolds soaking solution, and the cytotoxicity, cell proliferation, Western blot analysis, Quantitative real-time PCR analysis, bone alkaline phosphatase activity and alizarin red staining of scaffolds were detected to determine the biocompatibility of scaffolds and the effect of promoting proliferation and osteogenesis of bone marrow mesenchymal stem cells in vitro. In the in vivo experiment, the skull defect was constructed by adult SD rats, and the scaffold was implanted into the skull defect site. After 4 weeks and 8 weeks of culture, the specific osteogenic effect of the scaffold in the skull defect site was detected by animal micro-CT, hematoxylin and eosin (HE) staining and Masson's staining. Through the analysis of the morphological structure of the scaffold, we found that the frame supported good retention of the lamellar structure of silk fibroin, when mixed with nHA, the surface of the stent was rougher, the cell contact area increased, and cell adhesion and lamellar microstructure for cell migration and proliferation of the microenvironment provided a better space. FTIR results showed that the scaffold completely retained the β -folded structure of silk fibroin, and the scaffold composite was present without obvious impurities. The staining results of live/dead cells showed that the constructed scaffolds had no significant cytotoxicity, and thw CCK-8 assay also showed that the constructed scaffolds had good biocompatibility. The results of osteogenic induction showed that the scaffold had good osteogenic induction ability. Moreover, the results also showed that the scaffold with a MASF: nHA ratio of 1: 0.5 (SFH) showed better osteogenic ability. The micro-CT and bone histometric results were consistent with the in vitro results after stent implantation, and there was more bone formation at the bone defect site in the SFH group.This research used photocurable 3D printing technology to successfully build an osteogenesis bracket. The results show that the constructed nHA/MASF biological composite material, has good biocompatibility and good osteogenesis function. At the same time, in the microenvironment, the material can also promote bone defect repair and can potentially be used as a bone defect filling material for bone regeneration applications. [ABSTRACT FROM AUTHOR]

The aim of this scoping review is to analyse the biological effects of the orthodontic tooth movement (OTM) in areas with bone defects that are undergoing regeneration using different types of regenerative materials and techniques. The electronic research was performed on four databases as follows: PubMed, Scopus, EMBASE, and Web of Science. Data were extracted according to publication information, study design, sample characteristics, parameters of OTM, biological repercussions on the periodontium complex, methods of analysis, and conclusions. A total of thirty studies were included in the final review. In twenty-two studies, the most widely adopted grafting materials were alloplastics. In most studies, the orthodontic force used was 10 or 100 g, and the timing of application ranged from immediate to 6 months after grafting surgery. Twenty-four studies showed an increase in osteogenesis; in five studies, the clinical attachment level (CAL) increased; in five others, the probing pocket depth (PPD) decreased; in sixteen studies, there was root resorption of a different magnitude. Though the effects of OTM on the periodontium in the grafted areas were positive, the outcomes should be interpreted with caution as future preclinical and clinical studies are needed to extrapolate more valid conclusions. [ABSTRACT FROM AUTHOR]

Purpose: Although bone transport is a well-recognised technique to address segmental bone defects, optimal management of docking sites is not absolutely determined. Some surgeons routinely intervene in all cases, and others prefer to observe and intervene only if spontaneous union does not occur. Primary aim of the study was to compare rates of docking site union between patients who underwent routine docking site intervention and those who did not. Methods: A systematic literature review using the keywords "bone transport", "docking", "tibia", and "femur" was performed in PubMed using PRISMA guidelines. Studies published in English from January 2000 to August 2022 were included and assessed independently by two reviewers. Pooled analysis was undertaken dividing patients into two groups: those managed by routine intervention and those initially observed. Results: Twenty-three clinical studies met the eligibility criteria for pooled analysis, including 1153 patients, 407 in the routine intervention and 746 in the observed group. The rate of union after initial treatment was 90% in the routine intervention group and 66% in the observed group (p < 0.0001). Overall union rates at the end of treatment were similar at 99% in both groups. Patients in the observed group required an average of 2.2 procedures to achieve union overall compared with 3.8 in the routine intervention group. Time in frame was similar between groups. Conclusion: Based on the current literature, routine docking site interventions cannot be recommended, since this may lead to unnecessary interventions in two thirds of patients. Timely selective intervention in those at high risk or after a defined period of observation would appear to be a logical approach. [ABSTRACT FROM AUTHOR]

Methods of treating bone defects include autogenous bone and allogeneic bone transplantation, tissue engineering technology, gene therapy, growth factor and adjuvant therapy of physical therapy, etc. However, most treatment schemes have obvious disadvantages. The purpose of this paper is to study the application of graphene-based nanomaterials combined with early exercise rehabilitation training in the treatment of patients with infectious bone defects. The biomedical properties and biomedical applications of graphene are briefly introduced through literature research and investigation, and bone defect diseases and commonly used treatment methods are analyzed. Graphene is used in many biomedical fields, such as disease diagnosis, biosensing, antibacterial and antiviral materials, cancer targeting, photothermal therapy, drug delivery, cell electrical stimulation, tissue engineering, stem cell technology, DNA sequencing and fluorescent (FL) tracking molecular probes. The effects of graphene-based nanomaterials and rehabilitation exercise on the treatment of infectious bone defects were compared through controlled experiments. The results show that although the repair effect of graphene-based nano-materials is not as good as that of autogenous bone, the difference is not significant, and it is better than calcium phosphate cement. After rehabilitation exercise, the curative effect of graphene experimental group was improved. In the 12th week, the tensile strength reached 5.78 N, and the torsional strength reached 0.93 N m, which exceeded the group of autogenous bone without rehabilitation exercise. This paper discusses the strength-related repair effect, but the in vivo toxicity of graphene needs further study. [ABSTRACT FROM AUTHOR]

Objective: To prepare a bone repair material with certain mechanical strength and biological activity, this paper used calcium sulfate hemihydrate (CSH) powder compounded with calcium hydroxide (Ca(OH)2) powder to prepare a bone repair scaffold material for physicochemical property characterization and testing. Methods: The physical and chemical properties and characterization of the dried and cured bone repair materials were determined by Fourier infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy; Universal material testing machine to determine the mechanical and mechanical strength of composite materials. Results: XRD showed that the structure of the composite material phase at 5% concentration was calcium sulfate hemihydrate and calcium hydroxide after hydration. The FT-IR and XRD analyses were consistent. Scanning electron microscopy (SEM) results showed that calcium hydroxide was uniformly dispersed in the hemihydrate calcium sulfate material. 0%, 1%, 5%, and 10% specimen groups had compressive strengths of 3.86±3.1, 5.27±1.28, 8.22±0.96, and 14.4±3.28 MPa. 10% addition of calcium hydroxide significantly improved the mechanical strength of the composites, but also reduced the the porosity of the material. Conclusion: With the addition of calcium hydroxide, the CSH-Ca(OH)2 composite was improved in terms of mechanical material and is expected to be a new type of bone repair material. [ABSTRACT FROM AUTHOR]

Background:There are numerous animal models available to study bone healing as well as test strategies to accelerate bone formation. Sheep are commonly used for evaluation of long bone fractures due to similar dimensions and weight bearing environments compared to patients. Large critical-size defects can be created in sheep to facilitate the study of implantable materials, osteogenic proteins, and stem cell treatments. Studies have been published using plates to stabilize large critical size defects in femoral, tibial, and metatarsal defects. External fixators have also been used to stabilize tibial defects in sheep.Methods: The purpose of the current paper is to detail the surgical technique for creation of a 42 mm mid-diaphyseal femoral defect stabilization with an intramedullary device in sheep. Additional surgical details are provided for dynamization, reverse dynamization, and device removal.Conclusion: The article provides multiple technical tips applicable to this and other ovine osteotomy models and concludes with a discussion comparing the use of each stabilization technique in clinically significant large critical-size bone defects. [ABSTRACT FROM AUTHOR]

To share our experience of establishing a bone bank in Pakistan, and the clinical use of these indigenously produced bone grafts. We retrospectively reviewed our experience of the procurement, processing, and storage of bone grafts at a bone bank in Karachi, Pakistan, the first bone bank to be established in a public sector hospital in Pakistan. The bone bank was established at Sindh Institute of Urology and Transplantation (SIUT), Karachi, in collaboration with Department of Orthopaedic Surgery, Dow University of Health Sciences/Civil Hospital, Karachi (CHK) in May, 2015. Since then, a large number of bone grafts from the tissue bank have been used for various orthopedic procedures. This paper describes the problems and challenges faced in establishing and running a tissue bank in a Muslim and a developing country and the progress of the bone bank over the first 4 years. A total of 93 bone grafts were retrieved and preserved in the bone bank over the 4-year period. Among these, 56 (60.2%) bones were retrieved from male donors and 37 (39.8%) from females. The mean age of all donors was 55.9 ± 15.34 years (range: 16–90 years). All bone donors were living patients. No c bones were obtained from deceased donors. Types of bone grafts included: femoral heads, 68; head with neck of femur, 19; radius and ulna, 1; lower femur, knee joint, lower leg and foot bones, 4; and skull bone, 1. All grafts were subjected to aerobic and anaerobic bacterial cultures, as well as fungal cultures. Microbiological contamination was observed in 18/93 (19.35%). All culture positive bones were discarded. Bone grafts issued from the bank and transplanted were 51/93 (54.8%) in all. Bone grafts were used in a variety of tumor and non-tumor orthopaedic procedures in CHK. Nine bone grafts were donated to the other hospitals to be used for revision total hip replacement and tumor surgeries. There were no service charges. Two patients (3.92%) developed infections postoperatively, one superficial and one deep. No other complications were noted. This is the preliminary report on the establishment and functioning of a bone bank in a public sector hospital in Pakistan. The favorable outcome has inculcated confidence in orthopedic surgeons for greater use of bone allografts for a variety of indications in this country. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Large bone defects require complex treatment, multidisciplinary resources, and expert input, with surgical procedures ranging from reconstruction and salvage to amputation. The aim of this study was to provide the results of a case series of open comminuted intra-articular distal femoral fractures with significant bone loss that were managed by early fixation using anatomical plates and a modified Masquelet technique with the addition of surgical propylene mesh. Methods: This retrospective study included all patients referred to our institution with OTA/AO C3 distal femur open fractures and meta-diaphyseal large bone loss between April 2019 and February 2021. We treated the fractures with irrigation and debridement, acute primary screw and plate fixation in the second look operation, and Masquelet method using shell-shaped antibiotic beads supplemented by propylene surgical mesh to keep the cements in place. The second step of the procedure was conducted six to eight weeks later with bone grafting and mesh augmentation to contain bone grafts. Surprisingly, hard callus formation was observed in all patients at the time of the second stage of Masquelet procedure. Results: All five patients' articular and meta-diaphyseal fractures with bone loss healed without major complications. The average union time was 159 days. The mean knee range of motion was 5–95 degrees. The average Lower Extremity Functional Score (LEFS) was 49 out of 80. Conclusions: Combination of early plate fixation and the modified Masquelet technique with polypropylene mesh is an effective method for managing large bone defects in open intra-articular distal femoral fractures with bone loss, resulting in shorter union time possibly associated with the callus formation process. This technique may also be applicable to the management of other similar fractures specially in low-income and developing areas. [ABSTRACT FROM AUTHOR]

Limitations of bone defect reconstruction include poor bone healing and osteointegration with acrylic cements, lack of strength with bone putty/paste, and poor osteointegration. Tissue engineering aims to bridge these gaps through the use of bioactive implants. However, there is often a risk of infection and biofilm formation associated with orthopedic implants, which may develop anti-microbial resistance. To promote bone repair while also locally delivering therapeutics, 3D-printed implants serve as a suitable alternative. Soft, nanoporous 3D-printed filaments made from a thermoplastic polyurethane and polyvinyl alcohol blend, LAY-FOMM and LAY-FELT, have shown promise for drug delivery and orthopedic applications. Here, we compare 3D printability and sustained antibiotic release kinetics from two types of commercial 3D-printed porous filaments suitable for bone tissue engineering applications. We found that both LAY-FOMM and LAY-FELT could be consistently printed into scaffolds for drug delivery. Further, the materials could sustainably release Tetracycline over 3 days, independent of material type and infill geometry. The drug-loaded materials did not show any cytotoxicity when cultured with primary human fibroblasts. We conclude that both LAY-FOMM and LAY-FELT 3D-printed scaffolds are suitable devices for local antibiotic delivery applications, and they may have potential applications to prophylactically reduce infections in orthopedic reconstruction surgery. [ABSTRACT FROM AUTHOR]

Background: Tissue-engineered bone materials are an effective tool to repair bone defects. In this study, a novel biodegradable polycaprolactone (PCL)/β-tricalcium phosphate (β-TCP)/calcium sulfate (CS) composite scaffold was prepared by using three-dimensional (3D) printing technology. Methods: Scanning electron microscopy, gas expansion displacement, and contact goniometry were used to examine the 3D-printed PCL/β-TCP/CS composite scaffolds. The results showed that the PCL/β-TCP/CS scaffolds possessed controllable porosity, hydrophobicity, biodegradability, and suitable apatite mineralization ability. To confirm the bone regenerative properties of the fabricated composite scaffolds, scaffold extracts were prepared and evaluated for their cytotoxicity to bone marrow mesenchymal stem cells (BMSCs) and their ability to induce and osteogenic differentiation in BMSCs. Results: The PCL/β-TCP/CS composite scaffolds induced a higher level of differentiation of BMSCs than the PCL scaffolds, which occurred through the expression of bone metastasis-related genes. The New Zealand white rabbit radial defect experiment further demonstrated that PCL/β-TCP/CS scaffolds could promote bone regeneration. Conclusions: In summary, the 3D-printed PCL/β-TCP/CS composite porous artificial bone has good cytocompatibility, osteoinductivity, and histocompatibility, which make it an ideal bone material for tissue engineering. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Limb salvage surgery (LSS) is now considered the gold standard surgical treatment for lower limb bone sarcomas. However, there is a paucity of literature comparing the various LSS reconstructive options. The aim of this systematic review and meta‐analysis was to compare functional outcomes and complications of LSS reconstructive techniques. Methods: The primary aim of the meta‐analysis was to determine functional outcomes from the pooled data utilizing the Musculoskeletal Tumour Society score (MSTS). Comparisons could then made for this outcome between biological and prosthetic, vascularised and non‐vascularised, and prosthetic and composite reconstructions. The secondary aim was to compare complication outcomes of each reconstruction. Standardized mean difference (Cohen's d) and odds ratios were estimated using a random effects model. Results: Fourteen studies with a total of 785 patients were included. We found structural failure was 75% less likely to occur in prosthetic reconstruction compared to biological (OR = 0.24; 95% CI: 0.07–0.79; P = 0.02). We did not find any evidence of difference in function (MSTS score) between vascularised verses non‐vascularised reconstructions (Cohen's d = −1.14; 95% CI = −3.06 to 0.78; I2 = 87%). Other analyses comparing complications found no difference between the reconstructive groups. Conclusion: The study found no correlation between functional outcomes and the type of LSS reconstruction. Structural failure was more likely to occur in biological when compared with prosthetic reconstruction. There was no correlation between the incidence of other complications and the type of LSS technique. This suggests a role for improved approaches to reconstruction methods including bioprinting and bioresorbable devices. [ABSTRACT FROM AUTHOR]

Objectives: The reconstruction of bone defects in tibial revision knee arthroplasty is challenging. In this study, we evaluated the primary stability of a novel three‐dimensional (3D)‐printed custom‐made metaphyseal cone for Anderson Orthopedic Research Institute (AORI) IIb or III bone defect reconstruction in tibial revision knee arthroplasty using the combination of finite‐element analysis and biomechanical experiments. Methods: In the finite‐element analysis, AORI II b and III medial tibial bone defects were designed at varying depths. A novel 3D‐printed custom‐made metaphyseal cone was designed and used to reconstruct the bone defect with or without a stem in simulated revision total knee arthroplasty (RTKA). A no‐stem group and a stem group were established (based on whether a stem was used or not). Von Mises stress and micromotion were calculated with varying depths of bone defects, ranging from 5 mm to 35 mm, and then micromotions at the bone–implant interface were calculated and compared with the critical value of 150 μm. In the biomechanical experiment, the no‐stem group was used, and the same bone defects were made in four synthetic tibias using patient‐specific instruments. Micromotions at the bone–implant interface were investigated using a non‐contact optical digital image correlation system and compared with the critical value of 150 μm. Results: When the bone defect was <30 mm, micromotions at the bone–implant interface in the finite‐element analysis were all below 150 μm both in the stem groups and no‐stem groups, whereas those in the biomechanical experiment were also below 150 μm in the no‐stem group. Conclusions: The 3D‐printed custom‐made metaphyseal cone in RTKA has excellent primary stability and does not require stems in reconstructing tibial AORI type IIb or III bone defects with a depth of <30 mm. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The reconstruction of long-bone segmental defects remains challenging, with the three common methods of treatment being bone transport, vascularized bone transfer, and the induced membrane technique (IMT). Because of its simplicity, replicability, and reliability, usage of IMT has spread all over the world in the last decade, with more than 300 papers published in the PubMed literature database on this subject so far. Most of the clinical studies have reported high rates of bone union, yet some also include more controversial results with frequent complications and revision surgeries. At the same time, various experimental research efforts have been designed to understand and improve the biological properties of the induced membrane. This literature review aims to provide an overview of IMT clinical results in terms of bone union and complications and to compare them with those of other reconstructive procedures. In light of our findings, we then propose an original classification scheme of IMT failures distinguishing between preventable and nonpreventable failures. [ABSTRACT FROM AUTHOR]

Featured Application: Autogenous particulate bone collector (chips) for bone repair and implantation. Autogenous bone grafts can be harvested from either intraoral or extraoral sources. Intra-oral sources include healing tooth extraction wounds, a bone from edentulous ridges, bone trephined from within the jaw using trephine drills, bone formed in wounds, and bone from the maxillary tuberosity, ramus, and mandibular symphysis. Extra-oral sources are the iliac crest, which provides cancellous bone marrow, and the tibia and calvaria. Autogenous bone grafting aids in probing depth reduction, gaining clinical attachment, the bone filling of osseous defects, and the regeneration of new bone, cementum, and periodontal ligaments in teeth. An innovative biomedical device is presented in the form of an autogenous bone collector that can fill defects of 96.91 mm3 with bone particulates, and may be used in bioengineered scaffolds. Experimental studies on synthetic bone have demonstrated the feasibility and applicability of the amount of bone obtained. [ABSTRACT FROM AUTHOR]

Large-volume bone defect regeneration is complex and demands time to complete. Several regeneration phases with unique characteristics, including immune responses, follow, overlap, and interdepend on each other and, if successful, lead to the regeneration of the organ bone's form and function. However, during traumatic, infectious, or neoplastic clinical cases, the intrinsic bone regeneration capacity may exceed, and surgical intervention is indicated. Scaffold-guided bone regeneration (SGBR) has recently shown efficacy in preclinical and clinical studies. To investigate different SGBR strategies over periods of up to three years, we have established a well-characterized ovine large segmental tibial bone defect model, for which we have developed and optimized immunohistochemistry (IHC) protocols. We present an overview of the immunohistochemical characterization of different experimental groups, in which all ovine segmental defects were treated with a bone grafting technique combined with an additively manufactured medical-grade polycaprolactone/tricalcium phosphate (mPCL-TCP) scaffold. The qualitative dataset was based on osteoimmunological findings gained from IHC analyses of over 350 sheep surgeries over the past two decades. Our systematic and standardized IHC protocols enabled us to gain further insight into the complex and long-drawn-out bone regeneration processes, which ultimately proved to be a critical element for successful translational research. [ABSTRACT FROM AUTHOR]

Skeletons play an important role in the human body, and can form gaps of varying sizes once damaged. Bone defect healing involves a series of complex physiological processes and requires ideal bone defect implants to accelerate bone defect healing. Traditional grafts are often accompanied by issues such as insufficient donors and disease transmission, while some bone defect implants are made of natural and synthetic polymers, which have characteristics such as good porosity, mechanical properties, high drug loading efficiency, biocompatibility and biodegradability. However, their antibacterial, antioxidant, anti-inflammatory and bone repair promoting abilities are limited. Flavonoids are natural compounds with various biological activities, such as antitumor, anti-inflammatory and analgesic. Their good anti-inflammatory, antibacterial and antioxidant activities make them beneficial for the treatment of bone defects. Several researchers have designed different types of flavonoid-loaded polymer implants for bone defects. These implants have good biocompatibility, and they can effectively promote the expression of angiogenesis factors such as VEGF and CD31, promote angiogenesis, regulate signaling pathways such as Wnt, p38, AKT, Erk and increase the levels of osteogenesis-related factors such as Runx-2, OCN, OPN significantly to accelerate the process of bone defect healing. This article reviews the effectiveness and mechanism of biomaterials loaded with flavonoids in the treatment of bone defects. Flavonoid-loaded biomaterials can effectively promote bone defect repair, but we still need to improve the overall performance of flavonoid-loaded bone repair biomaterials to improve the bioavailability of flavonoids and provide more possibilities for bone defect repair. [ABSTRACT FROM AUTHOR]

Bone nonunion and bone defect are common postoperative complications in clinic. Membrane induction or Ilizarov technique is often used to repair bone defect. Autologous bone is often used for bone defect repair and reconstruction, and the anterior superior iliac spine, posterior superior iliac spine or fibula bone is used as the donor area for bone extraction, but there are problems of donor area complications. In recent years, the development of bone marrow aspiration (RIA) has provided a new alternative way for the source of autogenous bone. We report a 48-year-old female patient with a comminuted supracondylar intercondylar fracture of the left humerus due to a car accident. After 8 months of emergency debridement and suture with Kirschner wire internal fixation, the fracture was found to be unhealed with extensive bone defects. We used membrane induction combined with RIA technology to repair and reconstruct the patients, and found good osteogenesis through late follow-up. In theory, membrane induction technique can realize the reconstruction of large segmental bone defects, but the scope of repair is often limited by the lack of autologous bone source. The emergence and development of RIA technology provides us with a new autologous bone donor area for bone repair and reconstruction surgery. It can provide a large amount of high-quality cancellar bone mud through minimally invasive means. Meanwhile, it can reduce patients' pain, infection, fracture, aesthetics and other problems caused by iliac bone extraction, and shorten patients' bed time. Maximize the preservation of the patient's autologous bone source. For the first time in the world, we reported the combination of membrane induction technology and RIA technology in the treatment of segmental bone defects, providing a new idea for the treatment of bone defects. [ABSTRACT FROM AUTHOR]

A major obstacle to bone tissue repair is the difficulty in establishing a rapid blood supply areas of bone defects. Vascular endothelial growth factor (VEGF)-infused tissue-engineered scaffolds offer a possible therapeutic option for these types of injuries. Their role is to accelerate angiogenesis and improve bone healing. In this study, we used electrostatic spinning and biofactor binding to construct polylactic acid (PLA)/hydroxyapatite (HA)-VEGF scaffold materials and clarify their pro-vascular role in bone defect areas for efficient bone defect repair. PLA/HA nanocomposite fibrous membranes were manufactured by selecting suitable electrostatic spinning parameters. Heparin and VEGF were bound sequentially, and then the VEGF binding and release curves of the fiber membranes were calculated. A rat cranial defect model was constructed, and PLA/HA fiber membranes bound with VEGF and unbound with VEGF were placed for treatment. Finally, we compared bone volume recovery and vascular recovery in different fibrous membrane sites. A VEGF concentration of 2.5 µg/mL achieved the maximum binding and uniform distribution of PLA/HA fibrous membranes. Extended-release experiments showed that VEGF release essentially peaked at 14 days. In vivo studies showed that PLA/HA fibrous membranes bound with VEGF significantly increased the number of vessels at the site of cranial defects, bone mineral density, bone mineral content, bone bulk density, trabecular separation, trabecular thickness, and the number of trabeculae at the site of defects in rats compared with PLA/HA fibrous membranes not bound with VEGF. VEGF-bound PLA/HA fibrous membranes demonstrate the slow release of VEGF. The VEGF binding process does not disrupt the morphology and structure of the fibrous membranes. The fibrous membranes could stimulate both osteogenesis and angiogenesis. Taken together, this research provides a new strategy for critical-sized bone defects repairing. [ABSTRACT FROM AUTHOR]

Some reports in the literature show the advantages of fluoride-containing apatite ceramics over hydroxyapatite (HAP), at least in some aspects. While HAP has been used extensively in the treatment of bone defects, fluoridated apatite has hardly been tested in vivo. In order to verify the biological properties of fluoride-doped apatite and to assess its therapeutic potential, we synthesized fluorapatite (FAP) and applied it as a filling in bone defects of experimental animals (rabbits). The treatment effects were evaluated on extracted bones after 3 and 6 months from implantation using peripheral quantitative computed tomography (pQCT), dual-energy X-ray absorptiometry (DXA), radiography (X-ray) and histological staining. The study proved the integration between FAP and the bone tissue, thus indicating its stimulating effect on new bone formation and mineralization. The results achieved after 3 months of treatment were difficult to interpret unequivocally and suggested the transient delay in FAP integration of bone in comparison with HAP. The reasons for this phenomenon are unclear. Most likely, these differences between FAP and HAP resulted mainly from the different porosities, densities and ionic reactivity of the ceramics, which in our opinion affected their solubility, integration and degree of bone tissue resorption. However, it was shown that 6 months after implantation, similar level of bone defect regeneration was achieved for both FAP and HAP. In this article, we present our hypothesis concerning the basis of this phenomenon. [ABSTRACT FROM AUTHOR]

Bone defect is still a challenging problem in orthopedic practice. Injectable bone substitutes that can fill different geometry of bone defect and improve biological environment for bone regeneration are attracting attention. Herein, silk fibroin (SF) is noticeable polymer regarding its biocompatible and biodegradable properties. Thus, the calcium phosphate particles incorporated in silk fibroin/methylcellulose (CAPs‐SF/MC) and only methylcellulose (CAPs‐MC) hydrogels are developed and compared their physicochemical properties. Both CAPs‐hydrogels solutions can be administered with a low injectability force of ~6 N, and they require ~40‐min to change to hydrogel at physiological temperature (37°C). The CAPs are evenly distributed throughout the hydrogel matrix and are capable transformed to bioactive hydroxyapatite at pH 7.4. The CAPs in CAPs‐SF/MC have a smaller size than those in CAPs‐MC. Moreover, CAPs‐SF/MC exhibit gradual degradation, as prediction of the degradation mechanism by the Peppas‐Sahlin model and show a greater ability to sustain CAPs release. CAPs‐SF/MC has good biocompatibility with less cytotoxicity in a dose‐dependent manner on mouse preosteoblast cell line (MC3T3‐E1) when compared to CAPs‐MC. CAPs‐SF/MC hydrogels also have better possibility for promoting cell proliferation and differentiation. In conclusion SF incorporated into composite injectable hydrogel potentially improve biological characteristics and may provide clinical advantages. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Masquelet's induced membrane (IM) has osteogenesis activity, but IM spontaneous osteogenesis (SO) has not been described previously. Objectives: To report on varying degrees of IMSO and analyze its possible causes. Methods: Twelve eight-week-old male Sprague-Dawley rats with 10 mm right femoral bone defects who received the first stage of IM technique (IMT) were used to observe the SO. In addition, clinical data from patients with bone defects who received the first stage of IMT with an interval of > 2 months post-operatively and exhibited SO between January 2012 and June 2020 were retrospectively analyzed. The SO was divided into four grades according to the amount and characteristics of the new bone formation. Results: At twelve weeks, grade II SO was observed in all rats, and more new bone was formed in the IM near the bone end forming an uneven margin. Histology revealed bone and cartilage foci in the new bone. Four of the 98 patients treated with the first stage of IMT exhibited IMSO, including one female and three males with a median age of 40.5 years (range 29–52 years). The bone defects were caused by severe fractures and infection in two cases and by infection or tumor in one case each. Partial or segmental defects occurred in two cases. The time interval between inserting a cement spacer and diagnosis of SO ranged from six months to nine years. Two cases were grade I, and one case each of grades III and IV. Conclusion: Varying degrees of SO confirm the existence of the IMSO phenomenon. Bioactive bone tissue or local inflammation and a long time interval are the primary reasons underlying enhancement of the osteogenic activity of IM and leading to SO, which tends to take place as endochondral osteogenesis. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Dental Science is the property of Brazilian Dental Science Journal-ICT-UNESP and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: Additive techniques in dog orthopedics has recently emerged as a valuable approach in fabricating individualized implants for receiver-specific needs. The scaffolds made by 3D printing are used to replaces bones damaged by injuries sustained in accidents, tumour resections and defects resulting from disease, e.g., osteoporosis. In this way, the growth and reconstruction of bone defects structure can be promoted. These implants should have the right properties to ensure the right conditions for bone fusion. It is also important to determine the time of degradation, which is associated with a significant loss of mechanical properties. Methods: Polylactic acid (PLA) scaffolds with different dimensions were fabricated via fused deposition modeling (FDM) by CABIOMEDE for bone tissue reconstruction in veterinary application. During the research, the mechanical properties and impact of the soaking process in Ringer's solution for 1, 3, 6 months and steam sterilization for 1, 2, 3 cycles of the scaffolds were assessed. The static compression and three-point bending tests, material wettability, and macro and microscopic observations were carried out. Results: Compressive test results indicated that PLA scaffolds showed elastic-plastics deformation in longitudinal and transverse directions. The compressive strength of the scaffold in initial state were Rcw = 5-6 MPa in the longitudinal direction and Rcp = 0.33-1 MPa in the transverse direction, depending on size. The flexular strength of the scaffolds were Rg = 348-865 MPa, depending of size. The soaking and steam sterilization process increased the elastic modulus of the material and decreased the flexural strength. Hydrolytic degradation initiated by exposure to Ringer's solution resulted in a change in structure from amorphous to semicrystalline. This indicates partial dissolution of the amorphous phase and thus, an increase in the percentage of the crystalline phase, which caused the material to become brittle. Progressive degradation resulted in brittle fracture of the material, as can be observed in implants after 6 months of soaking. Conclusions: The mechanical properties of the PLA scaffolds were close to the properties of cancellous bone. The PLA scaffolds can be anticipated as promising scaffold biomaterials for bone tissue engineering applications by virtue of their bone mimicking porous structure and good mechanical properties. [ABSTRACT FROM AUTHOR]