Autologous bone graft harvesting: a review of grafts and surgical techniques

Synergistic enhancement of spinal fusion in preclinical models using low-dose rhBMP-2 and stromal vascular fraction in an injectable hydrogel composite

Spinal fusion surgery remains a significant challenge due to limitations in current bone graft materials, particularly in terms of bioactivity, integration, and safety. This study presents an innovative approach using an injectable hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) hydrogel combined with stromal vascular fraction (SVF) and low-dose recombinant human BMP-2 (rhBMP-2) to enhance osteodifferentiation and angiogenesis. Through a series of in vitro studies and preclinical models involving rats and minipigs, we demonstrated that the hydrogel system enables the sustained release of rhBMP-2, resulting in significantly improved bone density and integration, alongside reduced inflammatory responses. The combination of rhBMP-2 and SVF in this injectable formulation yielded superior spinal fusion outcomes, with enhanced mechanical properties and increased bone mass in both small and large animal models. These findings suggest that this strategy offers a promising and safer alternative for spinal fusion, with strong potential for clinical application.

[Resection of sternum body with anterior segments of ribs II-III and bone replacement with individual titanium implant]

Metastatic breast cancer is the most common malignancy and urgent problem due to high mortality. This fact emphasizes the need for development of innovative surgical approaches. Innovative approaches, including 3D modeling, provide unique opportunities for accurate reconstruction of the sternum. This method promises significant progress in individualized treatment with higher effectiveness and survival. We present resection of sternum body with anterior segments of ribs II-III and bone replacement with individual titanium implant in a patient with metastatic breast cancer.

FAM96B negatively regulates FOSL1 to modulate the osteogenic differentiation and regeneration of periodontal ligament stem cells via ferroptosis

BACKGROUND

Periodontal ligament stem cell (PDLSC)-based therapy is one of the methods to assist bone regeneration. Understanding the functional regulation of PDLSCs and the mechanisms involved is a crucial issue in bone regeneration. This study aimed to explore the roles of the family with sequence similarity 96 member B (FAM96B) in the functional regulation of PDLSCs.

METHODS

To assess the osteogenic differentiation of PDLSCs, the alkaline phosphatase (ALP) activity assay, Alizarin red staining, quantitative calcium analysis, and osteogenic marker detection were conducted. Transplantation PDLSCs under the dorsum of nude mice and into the rat calvarial defects were also performed. Then, FAM96B-overexpressed PDLSCs were used for RNA-sequencing and bioinformatic analysis. To evaluate the ferroptosis of PDLSCs, cytosolic reactive oxygen species (ROS), expression of glutathione peroxidase 4 (GPX4), mitochondrial morphology and functions including the mitochondrial ROS, mitochondria membrane potential, and mitochondrial respiration were detected.

RESULTS

The osteogenic indicators ALP activity, level of mineralization, and osteocalcin expression were decreased in PDLSCs by FAM96B, which demonstrated that FAM96B inhibited the osteogenic differentiation of PDLSCs. FAM96B knockdown promoted the new bone formation of PDLSCs subcutaneously transplanted to the dorsum of nude mice. Then, related biological functions were detected by the RNA-sequencing and the ferroptosis was focused. FAM96B enhanced the cytosolic ROS level and inhibited the expression of GPX4 and mitochondrial functions in PDLSCs. Hence, FAM96B promoted the ferroptosis of PDLSCs. Meanwhile, we found that FAM96B inhibition upregulated the target gene FOS like 1, AP-1 transcription factor subunit (FOSL1) expression and FOSL1 promoted the osteogenic differentiation of PDLSCs in vitro. FOSL1 also promoted the new bone formation of PDLSCs transplanted subcutaneously to the dorsum of nude mice and transplanted into rat calvarial defects. Then, the inhibitory effect of FOSL1 on the ferroptosis was confirmed.

CONCLUSIONS

FAM96B depletion promoted the osteogenic differentiation and suppressed the ferroptosis of PDLSCs. FAM96B negatively regulated the downstream gene FOSL1 and FOSL1 promoted the osteogenic differentiation of PDLSCs via the ferroptosis. Hence, our findings provided a foundation for understanding the FAM96B-FOSL1 axis acting as a target for MSC mediated bone regeneration.

The Impact of Intraoperative CT-Based Navigation in Congenital Craniovertebral Junction Anomalies: New Concepts of Treatment

BACKGROUND

Congenital craniovertebral junction anomalies (CCVJAs) encompass a diverse range of conditions characterized by distorted anatomy and significant variation in the pathways of neurovascular structures. This study aims to assess the safety and feasibility of tailoring posterior fixation for CCVJAs through intraoperative CT-based navigation.

METHODS

An in-depth retrospective analysis was conducted on eight patients diagnosed with CCVJAs (excluding Arnold-Chiari malformation). These patients underwent posterior fixation/arthrodesis facilitated by intraoperative CT-based navigation. The analysis included an examination of the fixation strategies, complication rates, length of stay, post-operative complications, and success of arthrodesis. Additionally, a comprehensive literature review was undertaken to contextualize and compare our findings.

RESULTS

Patients undergoing CVJ posterior fixation with intraoperative CT-based navigation exhibited a flawless record, devoid of complications related to the damage to neurovascular structures, as well as any instances of screw misposition, pullout, or breakage (0 out of 36 total screws). Furthermore, the entire cohort demonstrated a 100% arthrodesis rate. None of the patients required treatment with an occipital plate.

CONCLUSIONS

The incorporation of intraoperative CT-based navigation proves to be an invaluable asset in executing CVJ posterior fixation within the context of CCVJAs. This technology facilitates the customization of posterior constructs, a crucial adaptation required to navigate the anatomical challenges posed by these anomalies. The secure placement of screws into the occipital condyles, made possible by navigation, has proven highly effective in achieving CVJ fixation, obviating the need for an occipital plate. This technological leap represents a significant advancement, enhancing the safety, precision, and overall outcomes for patients undergoing this surgical procedure, while concurrently reducing the necessity for more invasive and morbid interventions.

Development and verification of a novel bone collector with automatic size separating function for orthopedics surgery

BACKGROUND

Autologous bone dust can be filled in bone defects to promote effective bone healing but typically it is lost when using suction during surgery. The aim of this study was to develop a novel bone collector that can be used to collect bone chips/dust of varying sizes without changing current surgical procedures.

RESEARCH DESIGN AND METHODS

This collector was designed to connect to a surgical continuous suction system and comprised a plate filter with a 3 mm hole and featured a taper filter with a mesh size of 0.27 mm for the separation and collection of both coarse and fine bone chips/dust. The bone collector was manufactured using nylon 3D printing and plastic injection with biocompatible materials.

RESULTS

The bone collector functional test revealed high bone chip collection efficiency (93%) with automatic size separation function. Low (3.42%) filtration errors showed that most of the water can be drained smoothly from the bone collector. In clinical usability testing, bone collectors can provide functions demonstrated in in vivo spinal fusion and femoral fracture surgeries with different bone grafting size requirements.

CONCLUSIONS

The novel bone collector has been validated as a viable and effective surgical device, offering surgeons an additional option to enhance patient outcomes.

Autologous rib grafts for craniocervical junction surgery in children: a clinical application

OBJECTIVE

Autologous iliac bone is commonly used as a bone graft material to achieve solid fusion in craniocervical junction (CVJ) surgery. However, the developing iliac bone of children is less than ideal as a bone graft material. The matured rib bone of children presents a potential substitute material for iliac bone. The aim of this study was to evaluate the efficacy of autologous rib grafts for craniocervical junction surgery in children.

METHODS

The outcomes of 10 children with abnormalities of the craniocervical junction who underwent craniocervical junction surgery between January 2020 and December 2022 were retrospectively reviewed. All patients underwent posterior fusion and internal fixation surgery with autologous rib grafts. Pre- and post-operative images were obtained and clinical follow-ups were conducted to evaluate neurological function, pain level, donor site complications, and bone fusion rates.

RESULTS

All surgeries were successful. During the 8- to 24-month follow-up period, all patients achieved satisfactory clinical results. Computed tomography at 3-6 months confirmed successful bone fusion and regeneration of the rib defect in all patients with no neurological or donor site complications.

CONCLUSION

Autologous rib bone is a safe and effective material for bone grafting in craniocervical junction fusion surgery for children that can reduce the risks of donor site complications and increase the amount of bone graft, thereby achieving a higher bone fusion rate.

Bone-Regeneration Therapy Using Biodegradable Scaffolds: Calcium Phosphate Bioceramics and Biodegradable Polymers

Calcium phosphate-based synthetic bone is broadly used for the clinical treatment of bone defects caused by trauma and bone tumors. Synthetic bone is easy to use; however, its effects depend on the size and location of the bone defect. Many alternative treatment options are available, such as joint arthroplasty, autologous bone grafting, and allogeneic bone grafting. Although various biodegradable polymers are also being developed as synthetic bone material in scaffolds for regenerative medicine, the clinical application of commercial synthetic bone products with comparable performance to that of calcium phosphate bioceramics have yet to be realized. This review discusses the status quo of bone-regeneration therapy using artificial bone composed of calcium phosphate bioceramics such as β-tricalcium phosphate (βTCP), carbonate apatite, and hydroxyapatite (HA), in addition to the recent use of calcium phosphate bioceramics, biodegradable polymers, and their composites. New research has introduced potential materials such as octacalcium phosphate (OCP), biologically derived polymers, and synthetic biodegradable polymers. The performance of artificial bone is intricately related to conditions such as the intrinsic material, degradability, composite materials, manufacturing method, structure, and signaling molecules such as growth factors and cells. The development of new scaffold materials may offer more efficient bone regeneration.

Effects of glass-ceramic produced by the sol-gel route in macrophages recruitment and polarization into bone tissue regeneration

Effective bone substitute biomaterials remain an important challenge in patients with large bone defects. Glass ceramics produced by different synthesis routes may result in changes in the material physicochemical properties and consequently affect the success or failure of the bone healing response. To investigate the differences in the orchestration of the inflammatory and healing process in bone grafting and repair using different glass-ceramic routes production. Thirty male Wistar rats underwent surgical unilateral parietal defects filled with silicate glass-ceramic produced by distinct routes: BS - particulate glass-ceramic produced via the fusion/solidification route, and BG - particulate glass-ceramic produced via the sol-gel route. After 7, 14, and 21 days from biomaterial grafting, parietal bones were removed to be analyzed under H&E and Massons' Trichome staining, and immunohistochemistry for CD206, iNOS, and TGF-β. Our findings demonstrated that the density of lymphocytes and plasma cells was significantly higher in the BS group at 45, and 7 days compared to the BG group, respectively. Furthermore, a significant increase of foreign body giant cells (FBGCs) in the BG group at day 7, compared to BS was found, demonstrating early efficient recruitment of FBGCs against sol-gel-derived glass-ceramic particulate (BS group). According to macrophage profiles, CD206+ macrophages enhanced at the final periods of both groups, being significantly higher at 45 days of BS compared to the BG group. On the other hand, the density of transformation growth factor beta (TGF-β) positive cells on 21 days were the highest in BG, and the lowest in the BS group, demonstrating a differential synergy among groups. Noteworthy, TGF-β+ cells were significantly higher at 21 days of BG compared to the BS group. Glass-ceramic biomaterials can act differently in the biological process of bone remodeling due to their route production, being the sol-gel route more efficient to activate M2 macrophages and specific FBGCs compared to the traditional route. Altogether, these features lead to a better understanding of the effectiveness of inflammatory response for biomaterial degradation and provide new insights for further preclinical and clinical studies involved in bone healing.

The Use of Free Vascularized Fibula Graft in Spinal Reconstruction: A Comprehensive Systematic Review

Reconstructive surgeons frequently face large structural abnormalities after spine resection. Unlike defects in the mandible or long bone, where a free vascularized fibular graft (FVFG) is a popular alternative for segmental osseous reconstruction, data on the use of an FVFG in the spine are still limited. The purpose of this study was to comprehensively describe and analyze the outcome of spinal reconstruction utilizing FVFG.

Methods

The extensive search included the following databases: PubMed, ScienceDirect, Web of Science, Cumulative Index to Nursing and Allied Health Literature, and Cochrane for relevant studies published up to January 20, 2023, according to PRISMA 2020 guidelines. Demographic data, flap success, recipient vessels, and flap-related complications were evaluated.

Results

We identified 25 eligible studies involving 150 patients, consisting of 82 men and 68 women. Spinal reconstruction utilizing FVFG is mostly reported in the case of spinal neoplasm, followed by spinal infection (osteomyelitis and spinal tuberculosis) and spinal deformities. The cervical spine is the most common vertebral defect reported in the studies. All studies summarized in the present study reported successful spinal reconstruction, while wound infection was the most reported postoperative complication after spinal reconstruction utilizing FVFG.

Conclusions

The results of the current study highlight the ability and superiority of using FVFG in spinal reconstruction. Despite being technically challenging, this strategy provides enormous benefits to patients. However, a further additional large-scale study is required to corroborate these findings.

Craniofacial therapy: advanced local therapies from nano-engineered titanium implants to treat craniofacial conditions

Nano-engineering-based tissue regeneration and local therapeutic delivery strategies show significant potential to reduce the health and economic burden associated with craniofacial defects, including traumas and tumours. Critical to the success of such nano-engineered non-resorbable craniofacial implants include load-bearing functioning and survival in complex local trauma conditions. Further, race to invade between multiple cells and pathogens is an important criterion that dictates the fate of the implant. In this pioneering review, we compare the therapeutic efficacy of nano-engineered titanium-based craniofacial implants towards maximised local therapy addressing bone formation/resorption, soft-tissue integration, bacterial infection and cancers/tumours. We present the various strategies to engineer titanium-based craniofacial implants in the macro-, micro- and nano-scales, using topographical, chemical, electrochemical, biological and therapeutic modifications. A particular focus is electrochemically anodised titanium implants with controlled nanotopographies that enable tailored and enhanced bioactivity and local therapeutic release. Next, we review the clinical translation challenges associated with such implants. This review will inform the readers of the latest developments and challenges related to therapeutic nano-engineered craniofacial implants.

Comparison of retrograde anatomy iliac bone flap grafting versus anterograde anatomy iliac bone flap grafting for treatment of osteonecrosis of the femoral head

BACKGROUND

Iliac bone flap with deep circumflex iliac artery is a common option in the treatment of Osteonecrosis of the femoral head (ONFH), and dissection of iliac bone flap is the key step for successful operation. This paper aims to introduce a new operative technique for dissecting iliac bone flap with deep circumflex iliac artery based on analysis of its advantages.

METHODS

A total of 49 patients treated by retrograde anatomy and 52 patients treated by anterograde anatomy from January 2010 to December 2020 were recruited. The two groups were then compared in terms of the preoperative baseline conditions, intraoperative data, and postoperative Harris hip score (HHS).

RESULTS

Compared with the retrograde anatomy group, the anterograde anatomy group had a significantly longer operating time, a significantly heavier intraoperative blood loss, a significantly higher rate of donor complication morbidity, a significantly higher rate of donor-recipient delayed healing, a significantly higher failure rate of iliac bone flap resection, a significantly higher rate of lateral femoral cutaneous nerve (LFCN) injury, and a significantly higher rate of ectopic ossification. No difference was found in postoperative HHS score between the two groups.

CONCLUSION

As a new operative technique that can accurately locate the nutrient vessels of the iliac bone flap and quickly dissect the iliac bone flap with deep circumflex iliac artery while maintaining a comparable clinical effect, retrograde anatomy exhibited distinct advantages over anterograde anatomy in terms of simpler intraoperative operation, safer dissection, shorter operation time, lower blood loss, and fewer donor complications.

LEVEL OF EVIDENCE

III, Retrospective.

Composite Coatings for Osteoblast Growth Attachment Fabricated by Matrix-Assisted Pulsed Laser Evaporation

The bioactive and biocompatible properties of hydroxyapatite (HAp) promote the osseointegration process. HAp is widely used in biomedical applications, especially in orthopedics, as well as a coating material for metallic implants. We obtained composite coatings based on HAp, chitosan (CS), and FGF2 by a matrix-assisted pulsed laser evaporation (MAPLE) technique. The coatings were physico-chemically investigated by means of X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Infrared Microscopy (IRM), and Scanning Electron Microscopy (SEM). Further, biological investigations were performed. The MAPLE-composite coatings were tested in vitro on the MC3T3-E1 cell line in order to endorse cell attachment and growth without toxic effects and to promote pre-osteoblast differentiation towards the osteogenic lineage. These coatings can be considered suitable for bone tissue engineering applications that lack toxicity and promotes cell adhesion and proliferation while also sustaining the differentiation of pre-osteoblasts towards mature bone cells.

Effect of Bone Morphogenetic Protein-2 in the Treatment of Long Bone Non-Unions

Background: Delayed fracture healing continues to cause significant patient morbidity and an economic burden to society. Biological stimulation of non-unions includes application of recombinant bone morphogenetic protein-2 (rhBMP-2). However, rhBMP-2 use continues to be a matter of controversy as literature shows scarce evidence for treatment effectiveness. Questions: The objective of this study was to evaluate the effectiveness of rhBMP-2 treatment on long bone non-unions measuring union rate and time to union. Furthermore, we assess risk factors for treatment failure. Methods and patients: A total of 91 patients with non-unions of long bones were treated with rhBMP-2 (n = 72) or standard care without BMP (n = 19) at our institution. Patient characteristics, comorbidities, nicotine consumption, and complications were recorded. Bone healing was assessed by plane X-rays and clinical examination. Patients were followed up with for 24 months. Results: Overall, there was significantly faster bone healing after rhBMP-2 application compared to the no-BMP group (p < 0.001; HR = 2.78; 95% CI 1.4–5.6). Union rates differed significantly between rhBMP-2 compared to the no-BMP group (89% vs. 47%; p < 0.001). At the humerus, there was neither a significantly higher union rate in the rhBMP-2 (83%) compared to the no-BMP group (50%) (p = 0.26; n = 12) nor a faster bone healing with a median time of 9 months in both groups (HR = 2.01; 95% CI 0.49–8.61; p = 0.315). The 33 femora treated using rhBMP-2 healed significantly faster than 9 femora in the no-BMP group (HR = 2.93; 95% CI 1.00–8.4; p = 0.023) with significant differences in union rate with 85% and 44%, respectively (p = 0.022). Regarding tibia non-unions, 25 out of 27 (93%) healed with a median of 9 months after rhBMP-2 application with no significant difference in the no-BMP group (33%) in time to union (p = 0.097) but a significantly higher union rate (p = 0.039). There was no effect of comorbidities, age, sex, soft tissue damage, or nicotine use on time to union, union rate, or secondary interventions. Conclusion: Consistent with the literature, overall, significantly higher union rates with reduced time to union were achieved after rhBMP-2 application. Femoral and tibial non-unions in particular seem to profit from rhBMP-2 application.

Patient-Reported Long-Term Outcomes After Free Vascularized Fibula Graft in Spinal Reconstruction: a 24-year Cohort

PURPOSE

The use of free vascularized fibula grafts (FVFG) in complex spinal deformity surgery intends to allow for life-long stability of the spine with good long-term clinical outcome. However, these long-term outcomes of this technique are still lacking. The objective of this study is to report the long-term postoperative outcomes and establish the long-term viability of this method for spinal reconstruction.

METHODS

A retrospective cohort study was conducted in all patients who underwent spinal reconstructive surgery utilizing a FVFG at a tertiary medical centre. Questionnaires taken from the participants were the Numeric Pain Rating Scale (NPRS), Oswestry Low Back Pain Disability (also known as Oswestry Disability Index (ODI)), Scoliosis Research Society 22r (SRS-22), the EQ-5D-5L and a self-assembled questionnaire regarding donor site comorbidities and patient satisfaction.

RESULTS

Over a period of 24 years (1995-2019), we used FVFG for spinal reconstruction in 31 patients. A total of 25 patients were included in this study, 8 patients were deceased at the time of this study, and sixteen patients responded to the questionnaires. Patient satisfaction was rated 6.8 out of 10, the average SRS-22r score was 3.6, EQ-5D-5L score was 0.725, and the ODI score showed a minimal disability (0-20%) postoperatively. Overall complication-free survival was 8.9 years. Nine patients underwent a re-operation in the spinal area; five for the removal of the spinal instrumentation.

CONCLUSION

Patients reported satisfied and good long-term outcomes following FVFG surgical procedure for complex spinal deformities. Therefore, considering the alternatives, this procedure provides a good long-term solution for complex spinal deformity surgery.

[Harvesting cancellous bone or composite corticocancellous bone grafts from the posterior iliac crest]

OBJECTIVE

Harvesting bone-either cancellous bone or composite corticocancellous bone grafts-from the iliac crest is an efficient method for filling or bridging bony defects commonly encountered in comminuted epimetaphyseal fractures (e.g., tibial head fractures), in nonunions or during reconstructive measures as in arthrodesis of major joints or spondylodesis, bone defects due to tumor resection or following eradication of chronic infection.

INDICATIONS

All bone defects with a maximum size of 4-5 cm.

CONTRAINDICATIONS

Rejection of surgery by the patient, infection or evidence of pathological bony changes in the posterior pelvic rim, inexperience of the surgeon with the procedure.

SURGICAL TECHNIQUE

Incision at the posterior iliac crest and removal of a structural or cancellous bone graft of predetermined length. Depending on the bleeding tendency, a suction drain can be inserted.

POSTOPERATIVE MANAGEMENT

After surgery supine positioning is favorable for wound compression to avoid bleeding as well as sufficient analgesia. Mobilization is dictated by the main operation. The pelvis is not compromised in its mechanical integrity and allows for full weight bearing on the operated side.

Calvarial Reconstruction Following Massive Tissue Loss: A Feasible Treatment Strategy and Surgical Technique

BACKGROUND

Severe cranial injuries require reconstructive surgeries to protect the underlying brain and to restore cranial contour and scalp integrity, as well as avoid complications such as neurocognitive decline. In cases of full-thickness cranial tissue damage, adept surgical skill in both bone and soft tissue reconstruction is critical for a minimally invasive surgery and successful bone integration without endangering previous soft tissue efforts. Different surgical techniques and materials are beset with various problems.

OBJECTIVE

To present a surgical procedure intended for the reconstruction of complex calvarial and associated tissue defects with reduced invasiveness and improved soft tissue healing compared to the existing gold standard. Both soft tissue and bone reconstruction techniques are described in detail due to their intertwined importance for successful full thickness skull and scalp reconstruction.

METHODS

During initial medical care, aseptic wound treatment and temporary wound closure are performed. Two weeks postinjury, extensive necrotic tissue debridement and soft tissue reconstruction lay the foundation for well-vascularized tissue regeneration. Soft tissue healing is followed by minimally invasive cranioplasty using autologous split-rib transplants after approximately 6 mo.

RESULTS

With consideration of the established gold standards for treatment, soft tissue regenerated without complications. The minimally invasive insertion of autologous rib grafts underneath the healed soft tissue allowed for quick recovery without requiring further follow-up treatments.

CONCLUSION

We optimized initial scalp wound healing and bone regeneration by making use of minimally invasive procedures and autologous materials, offering a viable treatment alternative to existing methods for treating large cranial bone injuries.

Adapting the Pore Size of Individual, 3D-Printed CPC Scaffolds in Maxillofacial Surgery

Three dimensional (3D) printing allows additive manufacturing of patient specific scaffolds with varying pore size and geometry. Such porous scaffolds, made of 3D-printable bone-like calcium phosphate cement (CPC), are suitable for bone augmentation due to their benefit for osteogenesis. Their pores allow blood-, bone- and stem cells to migrate, colonize and finally integrate into the adjacent tissue. Furthermore, the pore size affects the scaffold’s stability. Since scaffolds in maxillofacial surgery have to withstand high forces within the jaw, adequate mechanical properties are of high clinical importance. Although many studies have investigated CPC for bone augmentation, the ideal porosity for specific indications has not been defined yet. We investigated 3D printed CPC cubes with increasing pore sizes and different printing orientations regarding cell migration and mechanical properties in comparison to commercially available bone substitutes. Furthermore, by investigating clinical cases, the scaffolds’ designs were adapted to resemble the in vivo conditions as accurately as possible. Our findings suggest that the pore size of CPC scaffolds for bone augmentation in maxillofacial surgery necessarily needs to be adapted to the surgical site. Scaffolds for sites that are not exposed to high forces, such as the sinus floor, should be printed with a pore size of 750 µm to benefit from enhanced cell infiltration. In contrast, for areas exposed to high pressures, such as the lateral mandible, scaffolds should be manufactured with a pore size of 490 µm to guarantee adequate cell migration and in order to withstand the high forces during the chewing process.

Proximal Humerus Reconstruction after Tumor Resection: An Overview of Surgical Management

Proximal humerus is one of the anatomical sites that are most frequently involved by bone and soft tissue malignant tumors. Alone or in association with adjuvant treatments, surgery represents the main therapeutic option to treat and eradicate these diseases. Once the first-line option, in the last decades, amputation lost its role as treatment of choice for the large majority of cases in favor of the modern limb sparing surgery that promises to preserve anatomy and-as much as possible-upper limb functionality. Currently, the main approaches used to replace proximal humerus after a wide resection in oncologic surgery can be summarized in biological reconstructions (allografts and autografts), prosthetic reconstructions (anatomic endoprostheses, total reverse shoulder prostheses), and graft-prosthetic composite reconstructions. The purpose of this overview is to present nowadays surgical options for proximal humerus reconstruction in oncological patients, with their respective advantages and disadvantages.

In Vitro and In Vivo Evaluation of Nanostructured Biphasic Calcium Phosphate in Granules and Putty Configurations

Synthetic biphasic calcium phosphate (BCP) granules and powder are biocompatible biomaterials with a well-known capacity for osteoconduction, presenting very satisfactory clinical and histological results. It remains unanswered if the putty configuration impacts the biological response to the material. In this study, we aimed to compare the cytocompatibility and biocompatibility of nanostructured BCP in the putty configuration (moldable nanostructured calcium phosphate, MnCaP) on the healing of critical-sized bone defects (8 mm) in rat calvaria. Cytocompatibility was determined through the viability of fibroblast cells (V-79) to the extracts of different concentrations of MnCaP. Forty-five Wistar rats were randomly divided into three groups (n = 15)-clot, MnCaP, and commercial biphasic calcium phosphate in granules configurations (Nanosynt®)-and subdivided into three experimental periods (1, 3, and 6 months). Histological, histomorphometric, and microtomographic analyses allowed the evaluation of newly formed bone, residual biomaterial, and connective tissue. The in vitro evaluation showed that MnCaP was cytocompatible. The histomorphometric results showed that the Nanosynt® group granted the highest new-formed bone values at six months (p < 0.05), although the biomaterial volume did not differ between groups. The putty configuration was easier to handle, and both configurations were biocompatible and osteoconductive, presented similar biosorption rates, and preserved the calvaria architecture.

TGF-β Activity of a Demineralized Bone Matrix

Allografts consisting of demineralized bone matrix (DBM) are supposed to retain the growth factors of native bone. However, it is not clear if transforming growth factor β1 (TGF-β1) is maintained in the acid-extracted human bone. To this aim, the aqueous solutions of supernatants and acid lysates of OraGRAFT^® Demineralized Cortical Particulate and OraGRAFT^® Prime were prepared. Exposing fibroblasts to the aqueous solution caused a TGF-β receptor type I kinase-inhibitor SB431542-dependent increase in interleukin 11 (IL11), NADPH oxidase 4 (NOX4), and proteoglycan 4 (PRG4) expression. Interleukin 11 expression and the presence of TGF-β1 in the aqueous solutions were confirmed by immunoassay. Immunofluorescence further confirmed the nuclear translocation of Smad2/3 when fibroblasts were exposed to the aqueous solutions of both allografts. Moreover, allografts released matrix metalloprotease-2 activity and blocking proteases diminished the cellular TGF-β response to the supernatant. These results suggest that TGF-β is preserved upon the processing of OraGRAFT^® and released by proteolytic activity into the aqueous solution.

Novel Vacuum-Assisted Method for Harvesting Autologous Cancellous Bone Graft and Bone Marrow From the Proximal Tibial Metaphysis

Background:

Autogenous cancellous bone graft and bone marrow aspirate are commonly used in lower extremity fusion procedures to enhance fusion potential, and frequently in revision situations where bone loss and osteolysis may be a feature. The tibial metaphysis is a common donor site for bone graft, with the procedure typically performed using a curette or trephine to harvest the cancellous bone. Some limitations of this technique include suboptimal harvest of the marrow portion in particular, incomplete graft harvest, and loss of graft material during the harvest process. We describe a novel vacuum-assisted bone harvesting device to acquire cancellous bone and marrow from the proximal tibia.

Methods:

This is a retrospective study of a single surgeon’s consecutive patients who underwent foot and ankle arthrodesis procedures using proximal tibia autograft obtained using a vacuum-assisted bone harvesting device. Descriptive statistics were used to summarize patient and operative characteristics and outcomes. We identified 9 patients with a mean age of 51 years, 4 of whom were female.

Results:

On average, the skin incision was slightly more than 2 cm, and 27 mL of solid graft and 16 mL of liquid phase aspirate were collected. At 6 weeks after the procedure, there was minimal to no pain at the donor site, and we did not observe any fractures or other complications.

Conclusions:

We report the use of a novel vacuum-assisted curette device to harvest bone graft from the proximal tibial metaphysis for use in foot and ankle fusions. This device has been reliable and efficient in clinical practice.

Level of Evidence:

Level IV, retrospective case series.

Effects of icariin on the proliferation and osteogenic differentiation of human amniotic mesenchymal stem cells

Background

Tissue engineering technology has been applied extensively for clinical research and human amnion mesenchymal stem cells (hAMSCs) could cause mesenchymal stem cells to differentiate into the bone tissue. However, it is necessary to develop and identify the safer appropriate amount of osteogenic inducer. The objective of this study is to investigate the effect of icariin (ICA) on the proliferation and osteogenic differentiation of hAMSCs.

Methods

The morphology and phenotype of hAMSCs were discovered by flow cytometry and immunocytochemical staining. The osteogenic differentiation of hAMSCs under the influence of different concentrations of ICA were assessed by alkaline phosphatase (ALP) activity substrate assay and alizarin red staining.

Results

MTT assay revealed that the hAMSCs pretreated with ICA exhibited increased proliferation when compared with the control group, and the most optimum concentration of ICA was 1 × 10^− 6 mol/L. The combined analysis of ALP activity and ARS staining showed that ICA could significantly promote the osteogenic differentiation of hAMSCs, and the effect was most significant when the concentration of ICA was 1 × 10^− 6 mol/L.

Conclusion

All the above results implied that ICA could significantly increase proliferation and enhance the osteogenic differentiation of hAMSCs, especially when the concentration of ICA was 1 × 10^− 6 mol/L.

Harvesting of Autogenous Bone Graft from the Ascending Mandibular Ramus Compared with the Chin Region: a Systematic Review and Meta-Analysis Focusing on Complications and Donor Site Morbidity

Objectives

The aim of this systematic review was to test the hypothesis of no difference in complications and donor site morbidity following harvesting of autogenous bone graft from the ascending mandibular ramus compared with the chin region.

Material and Methods

MEDLINE (PubMed), Embase and Cochrane Library search in combination with a hand-search of relevant journals was conducted including human studies published in English through June 26, 2020. Randomized and controlled trials were included. Outcome measures included pain, infection, mucosal dehiscence, altered sensation or vitality of adjacent tooth/teeth, neurosensory disturbances and patient-reported outcome measures. Risk of bias was assessed by Cochrane risk of bias tool and Newcastle-Ottawa Scale.

Results

Ten controlled trials of high-quality fulfilled inclusion criteria. Risk of infection and mucosal dehiscence seems to be comparable with the two treatment modalities. However, harvesting from the chin seems to be associated with increased risk of pain, altered sensation or loss of tooth vitality, and neurosensory disturbances. Willingness to undergo the same treatment again was reported with both treatment modalities, but significant higher satisfaction, lower discomfort and acceptance of the surgical procedure was reported following harvesting from the ascending mandibular ramus.

Conclusions

The hypothesis was rejected due to higher prevalence and severity of complications and donor site morbidity following harvesting of autogenous bone graft from the chin region. Dissimilar evaluation methods and various methodological confounding factors posed serious restrictions for literature review in a quantitative systematic manner. Conclusions drawn from results of this systematic review should therefore be interpreted with caution.

Cell Scaffolds for Bone Tissue Engineering

Currently, well-known surgical procedures for bone defects are classified into four types: (1) autogenous bone graft transplantation, (2) allogeneic bone graft transplantation, (3) xenogeneic bone graft transplantation, and (4) artificial bone graft transplantation. However, they are often risky procedures and related to postoperative complications. As an alternative, tissue engineering to regenerate new bone often involves the use of mesenchymal stem cells (MSCs), derived from bone marrow, adipose tissues, and so on, which are cultured into three-dimensional (3D) scaffolds to regenerate bone tissue by osteoinductive signaling. In this manuscript, we provide an overview of recent treatment of bone defects and the studies on the creation of cell scaffolds for bone regeneration. Bone regeneration from bone marrow-derived mesenchymal stem cells using silica nonwoven fabric by the authors' group were provided. Potential application and future direction of the present systems were also described.

Comparison of Two Bone Grafting Techniques Applied During Posterior C1-C2 Screw-Rod Fixation and Fusion for Treating Reducible Atlantoaxial Dislocation

BACKGROUND

Several bone grafting techniques for posterior atlantoaxial arthrodesis have been reported. The techniques of placing a cancellous morselized bone graft (MBG) on decorticated surfaces of the atlantoaxial complex and securing a structural iliac bone graft (SBG) between C1 and C2 have been used widely. The aim of the present study was to compare the outcomes of these 2 bone grafting techniques for atlantoaxial arthrodesis.

METHODS

The data from 64 patients with reducible atlantoaxial dislocation treated using posterior C1-C2 screw-rod fixation and fusion were retrospectively reviewed. The MBG technique had been used in 32 patients and the SBG technique in 32 patients. The time required for bone fusion was recorded. The outcomes were evaluated using the Japanese Orthopaedic Association scale score, Neck Disability Index, visual analog scale (VAS) score for neck pain, patient satisfaction, and neck stiffness and compared between the 2 groups. The donor site complications were also compared, and donor site pain was assessed using a VAS.

RESULTS

At the final follow-up, the bone fusion rate was 100% in both groups. No significant differences were found in the bone fusion time or donor site pain between the 2 groups (P > 0.05). Postoperatively, The Japanese Orthopaedic Association scale scores, Neck Disability Index, and VAS score for neck pain had improved significantly within both groups (P < 0.05), with no statistically significant differences between the 2 groups (P > 0.05). Additionally, no differences were found between the 2 groups in patient satisfaction and neck stiffness postoperatively (P > 0.05).

CONCLUSIONS

The MBG and SBG techniques were both effective for atlantoaxial arthrodesis, with the advantages of reducing the potential risk of catastrophic bleeding of the epidural venous plexus and C2 nerve root injury.

Mandibular reconstruction using single piece zygomatic implant in conjunction with a reinforcing Fibular Graft Union: A case report

Presenting to our knowledge, for the first time in literature, a case report on the long term follow-up of an implant retained fixed prosthesis on free fibular reconstruction with a single piece zygomatic implant and single piece bicortical implant via a flapless approach and immediate functional rehabilitation. The technique involved the concept of "Remote Bone Anchorage" in conjunction with the union of grafted free fibula flap with the native mandible. It was facilitated with a single piece zygomatic implant engaged in the mandible and splinted with single piece implants on the grafted fibula as needed for prosthetic functional reconstruction. The author has reported a unique concept of immediate functional rehabilitation in the fibular graft therefore providing additional splinting of the vascularized free fibula to the mandible by splinting them with single piece zygomatic cortical implant.

Use of Human Dental Pulp and Endothelial Cell Seeded Tyrosine-Derived Polycarbonate Scaffolds for Robust in vivo Alveolar Jaw Bone Regeneration

The ability to effectively repair craniomaxillofacial (CMF) bone defects in a fully functional and aesthetically pleasing manner is essential to maintain physical and psychological health. Current challenges for CMF repair therapies include the facts that craniofacial bones exhibit highly distinct properties as compared to axial and appendicular bones, including their unique sizes, shapes and contours, and mechanical properties that enable the ability to support teeth and withstand the strong forces of mastication. The study described here examined the ability for tyrosine-derived polycarbonate, E1001(1K)/β-TCP scaffolds seeded with human dental pulp stem cells (hDPSCs) and human umbilical vein endothelial cells (HUVECs) to repair critical sized alveolar bone defects in an in vivo rabbit mandible defect model. Human dental pulp stem cells are uniquely suited for use in CMF repair in that they are derived from the neural crest, which naturally contributes to CMF development. E1001(1k)/β-TCP scaffolds provide tunable mechanical and biodegradation properties, and are highly porous, consisting of interconnected macro- and micropores, to promote cell infiltration and attachment throughout the construct. Human dental pulp stem cells/HUVECs seeded and acellular E1001(1k)/β-TCP constructs were implanted for one and three months, harvested and analyzed by micro-computed tomography, then demineralized, processed and sectioned for histological and immunohistochemical analyses. Our results showed that hDPSC seeded E1001(1k)/β-TCP constructs to support the formation of osteodentin-like mineralized jawbone tissue closely resembling that of natural rabbit jaw bone. Although unseeded scaffolds supported limited alveolar bone regeneration, more robust and homogeneous bone formation was observed in hDPSC/HUVEC-seeded constructs, suggesting that hDPSCs/HUVECs contributed to enhanced bone formation. Importantly, bioengineered jaw bone recapitulated the characteristic morphology of natural rabbit jaw bone, was highly vascularized, and exhibited active remodeling by the presence of osteoblasts and osteoclasts on newly formed bone surfaces. In conclusion, these results demonstrate, for the first time, that E1001(1K)/ β-TCP scaffolds pre-seeded with human hDPSCs and HUVECs contributed to enhanced bone formation in an in vivo rabbit mandible defect repair model as compared to acellular E1001(1K)/β-TCP constructs. These studies demonstrate the utility of hDPSC/HUVEC-seeded E1001(1K)/β-TCP scaffolds as a potentially superior clinically relevant therapy to repair craniomaxillofacial bone defects.

First Human Leucocyte Antigen (HLA) Response and Safety Evaluation of Fibrous Demineralized Bone Matrix in a Critical Size Femoral Defect Model of the Sprague-Dawley Rat

Treatment of large bone defects is one of the great challenges in contemporary orthopedic and traumatic surgery. Grafts are necessary to support bone healing. A well-established allograft is demineralized bone matrix (DBM) prepared from donated human bone tissue. In this study, a fibrous demineralized bone matrix (f-DBM) with a high surface-to-volume ratio has been analyzed for toxicity and immunogenicity. f-DBM was transplanted to a 5-mm, plate-stabilized, femoral critical-size-bone-defect in Sprague-Dawley (SD)-rats. Healthy animals were used as controls. After two months histology, hematological analyses, immunogenicity as well as serum biochemistry were performed. Evaluation of free radical release and hematological and biochemical analyses showed no significant differences between the control group and recipients of f-DBM. Histologically, there was no evidence of damage to liver and kidney and good bone healing was observed in the f-DBM group. Reactivity against human HLA class I and class II antigens was detected with mostly low fluorescence values both in the serum of untreated and treated animals, reflecting rather a background reaction. Taken together, these results provide evidence for no systemic toxicity and the first proof of no basic immunogenic reaction to bone allograft and no sensitization of the recipient.

Regeneration of segmental defects in metatarsus of sheep with vascularized and customized 3D-printed calcium phosphate scaffolds

Although autografts are considered to be the gold standard treatment for reconstruction of large bone defects resulting from trauma or diseases, donor site morbidity and limited availability restrict their use. Successful bone repair also depends on sufficient vascularization and to address this challenge, novel strategies focus on the development of vascularized biomaterial scaffolds. This pilot study aimed to investigate the feasibility of regenerating large bone defects in sheep using 3D-printed customized calcium phosphate scaffolds with or without surgical vascularization. Pre-operative computed tomography scans were performed to visualize the metatarsus and vasculature and to fabricate customized scaffolds and surgical guides by 3D printing. Critical-sized segmental defects created in the mid-diaphyseal region of the metatarsus were either left empty or treated with the 3D scaffold alone or in combination with an axial vascular pedicle. Bone regeneration was evaluated 1, 2 and 3 months post-implantation. After 3 months, the untreated defect remained non-bridged while the 3D scaffold guided bone regeneration. The presence of the vascular pedicle further enhanced bone formation. Histology confirmed bone growth inside the porous 3D scaffolds with or without vascular pedicle inclusion. Taken together, this pilot study demonstrated the feasibility of precised pre-surgical planning and reconstruction of large bone defects with 3D-printed personalized scaffolds.

The Use of Electrospun Organic and Carbon Nanofibers in Bone Regeneration

There has been an increasing amount of research on regenerative medicine for the treatment of bone defects. Scaffolds are needed for the formation of new bone, and various scaffolding materials have been evaluated for bone regeneration. Materials with pores that allow cells to differentiate into osteocytes are preferred in scaffolds for bone regeneration, and porous materials and fibers are well suited for this application. Electrospinning is an effective method for producing a nanosized fiber by applying a high voltage to the needle tip containing a polymer solution. The use of electrospun nanofibers is being studied in the medical field, and its use as a scaffold for bone regeneration therapy has become a topic of growing interest. In this review, we will introduce the potential use of electrospun nanofiber as a scaffold for bone regenerative medicine with a focus on carbon nanofibers produced by the electrospinning method.

Sustained delivery of PlGF-2123-144*-fused BMP2-related peptide P28 from small intestinal submucosa/polylactic acid scaffold material for bone tissue regeneration

Bone morphogenetic protein 2 (BMP-2) is one of the most important factors for bone tissue formation. However, its use over the past decade has been associated with numerous side effects. This is due to the fact that recombinant human (rh) BMP-2 has several biological functions, as well as that non-physiological high dosages were commonly administered. In this study, we synthesized a novel BMP-2-related peptide (designated P28) and fused a mutant domain in placenta growth factor-2 (PlGF-2123-144*) that allowed for the "super-affinity" of extracellular matrix proteins to P28, effectively controlling the release of low dosage P28 from small intestinal submucosa/polylactic acid (SIS/PLA) scaffolds. These have been shown to be excellent scaffold materials both in vivo and in vitro. The aim of this study was to determine whether these scaffolds could support the controlled release of P28 over time, and whether the composite materials could serve as structurally and functionally superior bone substitutes in vivo. Our results demonstrated that P28 could be released slowly from SIS/PLA to promote the adhesion, proliferation, and differentiation of bone marrow stromal cells (BMSCs) in vitro. In vivo, radiographic and histological examination showed that SIS/PLA/P28/PlGF-2123-144* completely repaired critical-size bone defects, compared to SIS/PLA, SIS/PLA/PlGF-2123-144*, or SIS/PLA/P28 alone. These findings suggest that this controlled release system may have promising clinical applications in bone tissue engineering.

Biodegradable Polymers as Drug Delivery Systems for Bone Regeneration

Regenerative medicine has been widely researched for the treatment of bone defects. In the field of bone regenerative medicine, signaling molecules and the use of scaffolds are of particular importance as drug delivery systems (DDS) or carriers for cell differentiation, and various materials have been explored for their potential use. Although calcium phosphates such as hydroxyapatite and tricalcium phosphate are clinically used as synthetic scaffold material for bone regeneration, biodegradable materials have attracted much attention in recent years for their clinical application as scaffolds due their ability to facilitate rapid localized absorption and replacement with autologous bone. In this review, we introduce the types, features, and performance characteristics of biodegradable polymer scaffolds in their role as DDS for bone regeneration therapy.

Ganoderal A effectively induces osteogenic differentiation of human amniotic mesenchymal stem cells via cross-talk between Wnt/β-catenin and BMP/SMAD signaling pathways

Osteogenic inducers play central roles in effective stem cell-based treatment of bone defects/losses. However, the current routine osteogenic inducer is a cocktail comprising three components that must be improved due to low induction efficiency and side effects. Therefore, there is an urgent need to develop safer and more effective osteoinducers. Herein, we demonstrated the osteogenic effect of Ganoderal A (GD-A), a tetracyclic triterpenoid compound from Ganoderma lucidum. GD-A showed no cytotoxicity toward human amniotic mesenchymal stem cells (hAMSCs) at doses of 0.001-10 μM; furthermore, 0.01 μM GD-A significantly induced the generation of osteoblast-specific markers, such as alkaline phosphatase, and calcium deposition in hAMSCs. At molecular levels, GD-A promoted the expression of multiple osteoblast differentiation markers, such as RUNX2, OSX, OPN, ALP, OCN, and COL1α1. Both Wnt/β-catenin and BMP/SMAD signaling were shown as active during hAMSC osteodifferentiation. Furthermore, specific blocking of both signals by KYA1797K and SB431542 significantly inhibited alkaline phosphatase secretion and RUNX2 and ALP expression when used alone or in combination. Meanwhile, both signals were also blocked. These findings suggest that GD-A induces hAMSC differentiation into osteoblasts through signaling cross-talk between Wnt/β-catenin and BMP/SMAD. Taken together, GD-A is a safe, effective, and novel osteoinducer and might be used for stem cell-based therapy for bone defects/losses.

Preparation of osteogenic matrices from cultured cells

Bone is a composite material consisting primarily of cells, extracellular matrices, accessory proteins and the complex calcium phosphate salt hydroxyapatite. Collectively, the extracellular network of proteins and accessory molecules that provide the organic component of bone tissue is referred to as the osteogenic extracellular matrix (OECM). OECM provides tensile strength and increases the durability of bone, but the OECM also serves as an attachment site and regulatory substrate for cells and a repository for growth factors and cytokines. Increasingly, purified OECM generated by osteogenic cells in culture has attracted interest because it has the capacity to improve the growth and viability of attached cells, enhances the osteogenic program in vitro and in vivo, and shows great promise as a therapeutic tool for orthopedic tissue engineering. This chapter will describe fundamental protocols for the selection and culture of osteogenic cells and conditions for their osteogenic differentiation, and the synthesis, purification and characterization of OECM. Some examples of immobilization to surfaces for the purpose of two- and three-dimensional culture will also be described.

Histological Criteria that Distinguish Human and Mouse Bone Formed Within a Mouse Skeletal Repair Defect

The effectiveness of autologous cell-based skeletal repair continues to be controversial in part because in vitro predictors of in vivo human bone formation by cultured human progenitor cells are not reliable. To assist in the development of in vivo assays of human osteoprogenitor potential, a fluorescence-based histology of nondecalcified mineralized tissue is presented that provides multiple criteria to distinguish human and host osteoblasts, osteocytes, and accumulated bone matrix in a mouse calvarial defect model. These include detection of an ubiquitously expressed red fluorescent protein reporter by the implanted human cells, antibodies specific to human bone sialoprotein and a human nuclear antigen, and expression of a bone/fibroblast restricted green fluorescent protein reporter in the host tissue. Using low passage bone marrow-derived stromal cells, robust human bone matrix formation was obtained. However, a striking feature is the lack of mouse bone marrow investment and osteoclasts within the human bone matrix. This deficiency may account for the accumulation of a disorganized human bone matrix that has not undergone extensive remodeling. These features, which would not be appreciated by traditional decalcified paraffin histology, indicate the human bone matrix is not undergoing active remodeling and thus the full differentiation potential of the implanted human cells within currently used mouse models is not being realized.

Use of Recombinant Human Bone Morphogenetic Protein-2 at the C1-C2 Lateral Articulation without Posterior Structural Bone Graft in Posterior Atlantoaxial Fusion in Adult Patients

BACKGROUND

Posterior atlantoaxial fusion is an important armamentarium for neurosurgeons to treat several pathologies involving the craniovertebral junction. Although the potential advantages of recombinant human bone morphogenetic protein-2 (rhBMP-2) are well documented in the lumbar spine, its indication for C1-C2 fusion has not been well characterized. In our institution, we apply rhBMP-2 to the C1-C2 joint either alone or with hydroxyapatite, locally harvested autograft chips, and/or morselized allogenic bone graft for selected cases-without conventional posterior structural bone graft. We report the clinical outcomes of the surgical technique to elucidate its feasibility.

METHODS

We performed a single-center, retrospective review of data from 2008 to 2016 and identified 69 patients who had undergone posterior atlantoaxial fusion with rhBMP-2. The clinical records of these patients were reviewed, and the baseline characteristics, operative data, and postoperative complications were collected and statistically analyzed.

RESULTS

The average age of the 69 patients was 60.8 ± 4.5 years, and 55.1% were women. With an average follow-up period of 21.1 ± 4.2 months, the C1-C2 fusion rate was 94.3% (65 of 69), and the average time to fusion was 11.4 ± 2.6 months (range, 5-23). The overall reoperation rate was 10.1% (7 of 69), with instrumentation failure in 7 patients (10.1%), adjacent segment disease in 2 (2.9%), and postoperative dysphagia and dyspnea in 2 patients (2.9%). No ectopic bone formation or soft tissue edema developed.

CONCLUSIONS

Although retrospective and from a single center, our study has shown that rhBMP-2 usage at the C1-C2 joint without posterior structural bone grafting is a safe and reasonable surgical option.

The legacy effects of electromagnetic fields on bone marrow mesenchymal stem cell self-renewal and multiple differentiation potential

Background

The effects of electromagnetic fields (EMF) on bone nonunion have been reported for many years. Many studies and randomized controlled trials have demonstrated that EMF exhibited benefits in curing delayed union and nonunion of long bone fractures. Most of them focused on the immediate effects, while the legacy effects of EMF remain poorly investigated.

Methods

In this study, rat bone marrow mesenchymal stem cells (BMSCs) were treated with EMF, and after a period of time the BMSC proliferation and differentiation were detected. Additionally, BMSC sheets with or without EMF treatment were transplanted into the rat tibia fracture nonunion models. The bone formation was evaluated after 2, 4, and 6 weeks.

Results

Our results showed that the proliferation capacity of BMSCs was heightened after EMF pretreatment. Over a period of time of EMF pretreatment, the capacities of osteogenic and chondrogenic differentiation were enhanced, while adipogenic differentiation was weakened. BMSC sheets pretreated with EMF could better promote the healing of tibia fracture in rats, compared to BMSC sheets alone. Furthermore, significantly higher values of radiographic grading scores were observed in the EMF group.

Conclusions

EMF has lasting effects on the proliferation and differentiation of BMSCs, and together with cell sheet technology can provide a new method for the treatment of fracture nonunion.

Chest-wall reconstruction with a customized titanium-alloy prosthesis fabricated by 3D printing and rapid prototyping

BACKGROUND

As 3D printing technology emerge, there is increasing demand for a more customizable implant in the repair of chest-wall bony defects. This article aims to present a custom design and fabrication method for repairing bony defects of the chest wall following tumour resection, which utilizes three-dimensional (3D) printing and rapid-prototyping technology.

METHODS

A 3D model of the bony defect was generated after acquiring helical CT data. A customized prosthesis was then designed using computer-aided design (CAD) and mirroring technology, and fabricated using titanium-alloy powder. The mechanical properties of the printed prosthesis were investigated using ANSYS software.

RESULTS

The yield strength of the titanium-alloy prosthesis was 950 ± 14 MPa (mean ± SD), and its ultimate strength was 1005 ± 26 MPa. The 3D finite element analyses revealed that the equivalent stress distribution of each prosthesis was unifrom. The symmetry and reconstruction quality contour of the repaired chest wall was satisfactory. No rejection or infection occurred during the 6-month follow-up period.

CONCLUSION

Chest-wall reconstruction with a customized titanium-alloy prosthesis is a reliable technique for repairing bony defects.

Preparation and characterization of cockle shell aragonite nanocomposite porous 3D scaffolds for bone repair

The demands for applicable tissue-engineered scaffolds that can be used to repair load-bearing segmental bone defects (SBDs) is vital and in increasing demand. In this study, seven different combinations of 3 dimensional (3D) novel nanocomposite porous structured scaffolds were fabricated to rebuild SBDs using an extraordinary blend of cockle shells (CaCo₃) nanoparticles (CCN), gelatin, dextran and dextrin to structure an ideal bone scaffold with adequate degradation rate using the Freeze Drying Method (FDM) and labeled as 5211, 5400, 6211, 6300, 7101, 7200 and 8100. The micron sized cockle shells powder obtained (75 µm) was made into nanoparticles using mechano-chemical, top-down method of nanoparticles synthesis with the presence of the surfactant BS-12 (dodecyl dimethyl bataine). The phase purity and crystallographic structures, the chemical functionality and the thermal characterization of the scaffolds’ powder were recognized using X-Ray Diffractometer (XRD), Fourier transform infrared (FTIR) spectrophotometer and Differential Scanning Calorimetry (DSC) respectively. Characterizations of the scaffolds were assessed by Scanning Electron Microscopy (SEM), Degradation Manner, Water Absorption Test, Swelling Test, Mechanical Test and Porosity Test. Top-down method produced cockle shell nanoparticles having averagely range 37.8±3–55.2±9 nm in size, which were determined using Transmission Electron Microscope (TEM). A mainly aragonite form of calcium carbonate was identified in both XRD and FTIR for all scaffolds, while the melting (Tm) and transition (Tg) temperatures were identified using DSC with the range of Tm 62.4–75.5 °C and of Tg 230.6–232.5 °C. The newly prepared scaffolds were with the following characteristics: (i) good biocompatibility and biodegradability, (ii) appropriate surface chemistry and (iii) highly porous, with interconnected pore network. Engineering analyses showed that scaffold 5211 possessed 3D interconnected homogenous porous structure with a porosity of about 49%, pore sizes ranging from 8.97 to 337 µm, mechanical strength 20.3 MPa, Young's Modulus 271±63 MPa and enzymatic degradation rate 22.7 within 14 days.

•

An innovative mixture of nano-CaCo₃ (aragonite), gelatin, dextrin and dextran.

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Scaffold 5211 reached a tipping point in terms of ideal morphology, optimal physiochemical properties, and great mechanical strength.

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Scaffold 5211 may guarantee the achievement of the developed scaffold purposes in true biological system.

Structural allograft reconstruction of the foot and ankle after tumor resections

BACKGROUND

Structural allografts have been used to correct deformities or to fill bone defects secondary to tumor excisions, trauma, osteochondral lesions, or intercalary arthrodesis. However, the quality of published evidence supporting the use of allograft transplantation in foot and ankle surgery has been reported as fair. The purpose of this study was to report the overall survival of structural allograft in the foot and ankle after tumor resection, and the survival according to the type of allograft and the complication rates in the medium to long term.

MATERIALS AND METHODS

From January 1989 to June 2011, 44 structural allograft reconstructions of the foot and ankle were performed in 42 patients (28 men and 14 women) due to musculoskeletal tumor resections. Mean age at presentation was 27 years. Mean follow-up was 53 months. Demographic data, diagnosis, site of the neoplasm, operations performed, operative complications, outcomes after surgery, date of last follow-up evaluation, and local recurrences were reviewed for all patients. Regarding the type of 44 allograft reconstructions, 16 were hemicylindrical allografts (HA), 12 intercalary allografts (IA), 10 osteoarticular allografts (OA), and 6 were total calcaneal allograft (CA).

RESULTS

The overall allograft survival rate, as calculated with the Kaplan-Meier method, at 5 and 10 years was 79 % (95 % CI 64-93 %). When allocated by type of allograft reconstruction the specific allograft survival at 5 and 10 years was: 83 % for CA, 80 % for HA, 77 % for OA, and 75 % for IA. The complications rate for this series was 36 % including: articular failure, local recurrence, infection, fracture and nonunion.

CONCLUSION

This study showed that structural allograft reconstruction in the foot and ankle after tumor resection may be durable with a 79 % survival rate at 5 and 10 years. The two types of allografts that showed better survival rate were hemicylindrical allografts (80 %) and calcaneus allografts (83 %). The highest complication rates occurred after calcaneus allografts and osteoarticular allografts.

LEVEL OF EVIDENCE

IV.