Porous Bone Research Articles

Fabrication of hierarchically porous trabecular bone replicas via 3D printing with high internal phase emulsions (HIPEs)

Combining emulsion templating with additive manufacturing enables the production of inherently porous scaffolds with multiscale porosity. This approach incorporates interconnected porous materials, providing a structure that supports cell ingrowth. However, 3D printing hierarchical porous structures that combine semi-micropores and micropores remains a challenging task. Previous studies have demonstrated that using a carefully adjusted combination of light absorbers and photoinitiators in the resin can produce open surface porosity, sponge-like internal structures, and a printing resolution of about 150µm. In this study, we explored how varying concentrations of tartrazine (0, 0.02, 0.04, and 0.08 wt%) as a light absorber affect the porous structure of acrylate-based polymerized medium internal phase emulsions fabricated via vat photopolymerization. Given the importance of a porous and interconnected structure for tissue engineering and regenerative medicine, we tested cell behavior on these 3D-printed disk samples using MG-63 cells, examining metabolic activity, adhesion, and morphology. The 0.08 wt% tartrazine-containing 3D-printed sample (008 T) demonstrated the best cell proliferation and adhesion. To show that this high internal phase emulsion (HIPE) resin can be used to create complex structures for biomedical applications, we 3D-printed trabecular bone structures based on microCT imaging. These structures were further evaluated for cell behavior and migration, followed by microCT analysis after 60 days of cell culture. This research demonstrates that HIPEs can be used as a resin to print trabecular bone mimics using additive manufacturing, which could be further developed for lab-on-a-chip models of healthy and diseased bone.

All-Natural Ceramic Whitlockite/Wollastonite Fiber Composite Bone Scaffolds: DLP Additive Manufacturing, Microstructure, and Performance

In this study, we introduced a novel approach by using natural calcium phosphate-based ceramic whitlockite as the matrix, natural silicon-based ceramic wollastonite fiber as the secondary phase, and desktop-level DLP 3D printing as the fabrication method to develop an all-natural ceramic porous bone scaffold with excellent mechanical, degradable, biomineralization, and cell responses. The results demonstrated that, at a solid loading of 75 wt% and a sintering temperature of 1000°C, the compressive strength of the whitlockite porous scaffold reached 20.0 MPa. With the incorporation of wollastonite fiber, the compressive strength of the composite ceramic scaffold further increased to 31.0 MPa, achieving a top-tier level for desktop-level DLP-printed porous ceramic bone scaffolds. This mechanical enhancement effect was mainly attributed to the grain refinement effect of WF on whitlockite and the fiber reinforcement effect of WF. Additionally, the degradation rate of the composite ceramic scaffold increased with higher WF content, attributed to the rapid degradation rate of WF and the microstructural changes in the whitlockite matrix induced by WF doping. Furthermore, the biomineralization capability and cellular response of the composite ceramic scaffold were enhanced with WF doping, due to the improved degradation ability promoting the release of calcium, phosphate, and silicon ions. This study further validates the applicability of desktop-level DLP for fabricating ceramic bone scaffolds and provides evidence of the potential of all-natural ceramic whitlockite/WF as bone scaffold materials.

Periosteum-bone inspired hierarchical scaffold with endogenous piezoelectricity for neuro-vascularized bone regeneration

The development of scaffolds for repairing critical-sized bone defects heavily relies on establishing a neuro-vascularized network for proper penetration of nerves and blood vessels. Despite significant advancements in using artificial bone-like scaffolds infused with various agents, challenges remain. Natural bone tissue consists of a porous bone matrix surrounded by a neuro-vascularized periosteum, with unique piezoelectric properties essential for bone growth. Drawing inspiration from this assembly, we developed a periosteum-bone-mimicking bilayer scaffold with piezoelectric properties for regeneration of critical-sized bone defects. The periosteum-like layer of this scaffold features a double network hydrogel composed of chelated alginate, gelatin methacrylate, and sintered whitlockite nanoparticles, emulating the viscoelastic and piezoelectric properties of the natural periosteum. The bone-like layer is composed of a porous structure of chitosan and bioactive hydroxyapatite created through a biomineralization process. Unlike conventional bone-like scaffolds, this bioinspired bilayer scaffold significantly enhances osteogenesis, angiogenesis, and neurogenesis combined with low-intensity pulsed ultrasound-assisted piezoelectric stimulation. Such a scheme enhances neuro-vascularized bone regeneration in vivo. The results suggest that the bilayer scaffold could serve as an effective self-powered electrical stimulator to expedite bone regeneration under dynamic physical stimulation.

Process Mapping of the Sol-Gel Transition in Acid-Initiated Sodium Silicate Solutions.

Fabricating large-scale porous bioactive glass bone scaffolds presents significant challenges. This study aims to develop formable, in situ setting scaffolds with a practical gelation time of about 10 min by mixing 45S5 bioactive glass with sodium silicate (waterglass) and an acid initiator. The effects of pH (2-11), waterglass concentration (15-50 wt.%), and acid initiator type (phosphoric or boric acid) were examined to optimize gelation kinetics and microstructure. A 10 min gelation time was achieved with boric acid and phosphoric acid at various pH levels by adjusting the waterglass concentration. Exponential and polynomial models were proposed to predict gelation times in basic and acidic environments, respectively. The optical properties of the gels were studied qualitatively and quantitatively, providing insights into gelation kinetics and structure. Acidic gels formed smaller particles in a dense network (pores < 550 nm) with higher light transmittance, while basic gels had larger aggregates (pores ~5 µm) and lower transmittance. As the waterglass concentration decreased, pore size and transmittance converged in both groups. The onset of gelation was detected around 8 min using the derivative of light transmittance. This work identifies the key factors controlling waterglass gelation and their impact on gel structure, enabling the tailored creation of formable, in situ setting bioactive glass bone scaffolds.

Additive manufacturing and in vitro study of biological characteristics of sulfonated polyetheretherketone-bioactive glass porous bone scaffolds

Polyetheretherketone (PEEK), a high-performance special engineering plastic, has gradually been used in bone substitutes due to its wear resistance, acid and alkali resistance, non-toxicity, radiolucency, and modulus close to that of human bone. However, its stable biphenyl structure determines strong biological inertness, thus artificial interventions are required to improve the biological activity of fabricated PEEK parts for better clinical applications. This study developed a novel strategy for grafting bioactive glass (BAG) onto the surface of PEEK through sulfonation reaction with concentrated sulfuric acid (H2SO4), aiming to improve the bioactivity of printed porous bone scaffolds manufactured by fused deposition modeling (FDM) to meet clinical individual needs. In vitro biological study was conducted on sulfonated polyetheretherketone-bioactive glass (SPEEK-BAG) scaffolds obtained by this strategy. The results demonstrated that the optimal modification condition was a 4-hour sulfonation reaction with 1 mol/L concentrated H2SO4 at high temperature and high pressure. The scaffold obtained under this condition showed minimal cytotoxicity, and the Ca/P molar ratio, yield compressive strength, and compressive modulus of this scaffold were 2.94 ± 0.02, 62.78 MPa, and 0.186 GPa respectively. The hydrophilicity and the biomineralization ability of PEEK modified by the proposed strategy were substantially improved. The SPEEK-BAG bone scaffolds exhibited excellent biocompatible properties, suggesting that the sulfonation reaction and BAG effectively enhanced the proliferation and differentiation of osteoblasts. The presented method provides an innovative, highly effective, and customized strategy to improve the biocompatibility and bone repair ability of printed PEEK bone scaffolds for virous biomedical applications.

A comprehensive study of LPBF parameter influence in 316L stainless steel mechanical properties, macrostructure, and printability

Additive manufacturing, particularly using Laser Powder Bed Fusion (LPBF) technologies with 316L stainless steel, has proven highly promising in biomedical engineering due to the material’s exceptional mechanical properties and biocompatibility. This study, which is a foundational step towards developing porous bone implants, focuses on assessing the influence of a broad range of parameters - spot size, scanning speed, laser power, and energy density - on the mechanical performance and structural integrity of 316L stainless steel parts across three distinct specimen geometries: fully dense parallelepipedic, fully dense cubic, and cellular (lattice) specimens. By analysing 17 different parameter sets and producing over 150 specimens, a thorough series of experimental tests were conducted, including flexural tests, compression tests, hardness tests, macroscopic evaluation of the surface of fully dense specimens, and macroscopic evaluation of the lattice structures.e in powder accumulation within the pores of cellular structures, with higher energy densities (100 J/mm3) leading to a significantly greater retention compared to lower energy densities (66 J/mm3). This underexplored phenomenon has significant implications for the selection of parameters in the fabrication of bone implants. Further research is needed to refine LPBF printing parameters and enhance the quality of porous bone implants.

Stress distribution by parafunctional loading on tooth–implant, implant–implant, and tooth–tooth-supported prosthesis: A comparative three-dimensional finite element analysis

Aim: The study’s objective was to evaluate the stress distribution in tooth-implant, implant-implant, and tooth-tooth supported prostheses under parafunctional loading in axial and oblique directions employing a 3D finite element analysis in the mandibular posterior region which had D3 bone (porous cortical bone and fine trabecular bone). Setting and Design: In vitro study, Finite element analysis. Meterials and Methods: Cone-beam computed tomography data was used by Mimics software (Materialize Mimics 19) to create a three-dimensional finite element simulation of the jaw. Solid Works 2018 (Dassault Systems) was used to produce a geometric 3D model of the three systems. Each model consisted of a bone, an implant, and teeth (Model I tooth-tooth supported, Model II tooth-implant supported and Model III implant-implant supported). The three models’ geometrical models were transferred to Ansys Workbench (19.2 software) for the analysis portion. A load that mimicked masticatory force was delivered in both axial and oblique directions. Statistical Analysis Used: In the present study, statistical analysis was not required because 3D finite element analysis uses deterministic numerical methods to simulate physical behavior and stress distribution patterns. Result: The results demonstrated that under the parafunctional combined loading process, the implant- implant supported prosthesis showed significantly higher stress concentrations in the bone. It was found that the cortical bone around the crestal region had the highest stresses. Conclusion: Within the constraints of this investigation, we could draw the following conclusion: Of the three models, the tooth-tooth supported prosthesis exhibited the least amount of stress distribution, which was also least when functional loading was applied in the axial direction.

Physical and histological comparison of three-dimensional interconnected porous carbonate apatite bone graft fabricated with cylindrical and spherical granules

Three-dimensional interconnected porous carbonate apatite (3D-CO3Ap) bone grafts facilitate rapid bone replacement because of their structure, which supports cellular infiltration. Existing 3D-CO3Ap grafts have demonstrated limited mechanical strength, with a maximum compressive strength of 3 MPa. By fusing polymer-bound CaCO3 granules, followed by the debinding and compositional transformation of the granules via a dissolution–precipitation reaction, we successfully fabricated 3D-CO3Ap grafts that exhibited remarkably enhanced compressive strengths, which were recorded at 14.9 ± 3.7 MPa. The use of spherical granules, which provide more uniform and effective intergranular contacts than cylindrical granules, was key to achieving higher mechanical strength and superior bone formation. 3D-CO3Ap developed with spherical granules not only exhibited higher compressive strength, but also enhanced new bone formation compared with those fabricated with cylindrical granules. This study underscores the significance of porous microstructure design in 3D-CO3Ap, highlighting its critical role in optimizing both mechanical properties and bone regeneration capabilities.

Successful Treatment of Nasopalatine Duct Cyst After Maxillary Anterior Implant Surgery: A Case Report.

Sporadic studies have reported the occurrence of nasopalatine duct cysts after maxillary anterior implant surgery, and the treatment methods still have clinical uncertainty. We report a potential therapy method that successfully treated a nasopalatine duct cyst that developed and expanded 1 year after maxillary anterior implant placement following periodontally hopeless teeth extraction. The nasopalatine cyst was treated surgically without removing implants. During flap surgery, the cyst was removed intact, and the exposed implant's surface was debrided thoroughly by hydrogen peroxide (H2O2) rinsing, glycine air polishing, and saline rinsing. To deal with the significant bone defect caused by the cyst, a bovine porous bone mineral injected platelet-rich fibrin (BPBM-i-PRF) complex was applied to fill the defect, following a resorbable collagen membrane to cover. Seven years after surgery, no cyst recurrence was observed, and bone regeneration in the bone graft area was stable. The implants functioned well without mobility. For nasopalatine duct cysts associated with dental implant placement, complete surgical debridement and longitudinal stable bone regeneration are possibly accessible by regenerative surgery without implant removal.

Migration and retention of human osteosarcoma cells in bioceramic graft with open channel architecture designed for bone tissue engineering

The microstructure of a porous bioceramic bone graft, especially the pore architecture, plays a crucial role in the performance of the graft. Conventional bioceramic grafts typically feature a random, closed-pore structure, limiting biological activity to the periphery of the graft. This can lead to delay in full integration with the host site. Bioceramic forms with open through pores can perform better because their inner regions are accessible for natural bone remodeling. This study explores the influence of open through pores in a bioceramic graft on the migration and retention of the local cellsin vitro, which will correlate to the rate of healingin vivo.Hydroxyapatite ceramic forms with aligned channels were fabricated using slip casting technique, employing sacrificial fibers. The sorption characteristics across the graft were evaluated using human osteosarcoma cell line. Seven-day cultures showed viable cells within the channels, confirmed by live/dead assay, scanning electron microscope analysis, and cytoskeletal staining, indicating successful cell colonization. The channel architecture effectively enhances cell migration and retention throughout its entire structure, suggesting potential applications in bone tissue engineering based on the results obtained.

Indirect sinus lift with implant placement in maxillary right molar region

The maxilla has one of the least dense bone masses in the oral cavity and is composed of porous bone. Due to considerable alveolar bone resorption brought on by periodontal disease-induced tooth loss, there is an emphasis on bone reduction in both height and width. Pneumatization of the maxillary sinus, post-extraction bone resorption, and low-quality remaining alveolar bone all contribute to the difficulty in bone remodelling.Indirect sinus augmentation is an effective solution for this problem. This case report presents the rehabilitation of maxillary right first molar by using indirect sinus lift with implant placement where the bone height and bone width was compromised.

Advanced biomimetic design strategies for porous structures promoting bone integration with additive-manufactured Ti6Al4V scaffolds

The natural bone structure exhibits a radial gradient with dense cortical bone externally and porous cancellous bone internally. However, previous studies proposing scaffold designs have predominantly focused on homogeneous porous structures. Moreover, no consensus exists on the optimal structure for gradient porous scaffolds. Our scaffold closely imitated the natural bone structure by incorporating a gradient of pillar diameters. Additionally, we introduced a inverse gradient structure and three uniform diameter pillar structures (400 μm, 600 μm, and 1000 μm) for comparative analysis. Mechanical testing revealed that the compressive strength and elastic modulus of the Ti6Al4V porous scaffolds gradually increased with an increase in pillar diameter. In vitro experiments demonstrated that both the biomimetic gradient and inverse gradient scaffolds promoted osteogenic differentiation, with higher ALP activity (alkaline phosphatase) and osteogenesis-related gene expression compared to the uniform pillar structure scaffolds. The in vivo experiments confirmed these results, highlighting the superior ability of the biomimetic gradient Ti6Al4V porous scaffold to induce new bone formation. Based on our findings, we suggest that the optimal porous structure should have fine-diameter pillars (approximately 400 μm) internally to enhance cell penetration, while coarse-diameter pillars (approximately 800 μm) should be used externally to increase the cell attachment area and enhance mechanical strength. Overall, our study contributes to the field of bone tissue engineering by providing a biomimetic scaffold design that closely imitates the structure of natural bone and promotes osteogenic activity.

Multi-omics analyses reveal aberrant differentiation trajectory with WNT1 loss-of-function in type XV osteogenesis imperfecta.

Osteogenesis imperfecta (OI) is a group of severe genetic bone disorders characterized by congenital low bone mass, deformity, and frequent fractures. Type XV OI is a moderate to severe form of skeletal dysplasia caused by WNT1 variants. In this cohort study from southern China, we summarized the clinical phenotypes of patients with WNT1 variants and found that the proportion of type XV patients was around 10.3% (25 out of 243) with a diverse spectrum of phenotypes. Functional assays indicated that variants of WNT1 significantly impaired its secretion and effective activity, leading to moderate to severe clinical manifestations, porous bone structure, and enhanced osteoclastic activities. Analysis of proteomic data from human skeleton indicated that the expression of SOST (sclerostin) was dramatically reduced in type XV patients compared to patients with COL1A1 quantitative variants. Single-cell transcriptome data generated from human tibia samples of patients diagnosed with type XV OI and leg-length discrepancy, respectively, revealed aberrant differentiation trajectories of skeletal progenitors and impaired maturation of osteocytes with loss of WNT1, resulting in excessive CXCL12+ progenitors, fewer mature osteocytes, and the existence of abnormal cell populations with adipogenic characteristics. The integration of multi-omics data from human skeleton delineates how WNT1 regulates the differentiation and maturation of skeletal progenitors, which will provide a new direction for the treatment strategy of type XV OI and relative low bone mass diseases such as early onset osteoporosis.

GO/Cu Nanosheet-Integrated Hydrogel Platform as a Bioactive and Biocompatible Scaffold for Enhanced Calvarial Bone Regeneration.

The treatment of craniofacial bone defects caused by trauma, tumors, and infectious and degenerative diseases is a significant issue in current clinical practice. Following the rapid development of bone tissue engineering (BTE) in the last decade, bioactive scaffolds coupled with multifunctional properties are in high demand with regard to effective therapy for bone defects. Herein, an innovative bone scaffold consisting of GO/Cu nanoderivatives and GelMA-based organic-inorganic hybrids was reported for repairing full-thickness calvarial bone defect. In this study, motivated by the versatile biological functions of nanomaterials and synthetic hydrogels, copper nanoparticle (CuNP)-decorated graphene oxide (GO) nanosheets (GO/Cu) were combined with methacrylated gelatin (GelMA)-based organic-inorganic hybrids to construct porous bone scaffolds that mimic the extracellular matrix (ECM) of bone tissues by photocrosslinking. The material characterizations, in vitro cytocompatibility, macrophage polarization and osteogenesis of the biohybrid hydrogel scaffolds were investigated, and two different animal models (BALB/c mice and SD rats) were established to further confirm the in vivo neovascularization, macrophage recruitment, biocompatibility, biosafety and bone regenerative potential. We found that GO/Cu-functionalized GelMA/β-TCP hydrogel scaffolds exhibited evidently promoted osteogenic activities, M2 type macrophage polarization, increased secretion of anti-inflammatory factors and excellent cytocompatibility, with favorable surface characteristics and sustainable release of Cu2+. Additionally, improved neovascularization, macrophage recruitment and tissue integration were found in mice implanted with the bioactive hydrogels. More importantly, the observations of microCT reconstruction and histological analysis in a calvarial bone defect model in rats treated with GO/Cu-incorporated hydrogel scaffolds demonstrated significantly increased bone morphometric values and newly formed bone tissues, indicating accelerated bone healing. Taken together, this BTE-based bone repair strategy provides a promising and feasible method for constructing multifunctional GO/Cu nanocomposite-incorporated biohybrid hydrogel scaffolds with facilitated osteogenesis, angiogenesis and immunoregulation in one system, with the optimization of material properties and biosafety, it thereby demonstrates great application potential for correcting craniofacial bone defects in future clinical scenarios.

Dosimetric impact of stopping power for human bone porosity with dual-energy computed tomography in scanned carbon-ion therapy treatment planning

Few reports have documented how the accuracy of stopping power ratio (SPR) prediction for porous bone tissue affects the dose distribution of scanned carbon-ion beam therapy. The estimated SPR based on single-energy computed tomography (SECT) and dual-energy CT (DECT) were compared for the femur of a Rando phantom which simulates the porosity of human bone, NEOBONE which is the hydroxyapatite synthetic bone substitute, and soft tissue samples. Dose differences between SECT and DECT were evaluated for a scanned carbon-ion therapy treatment plan for the Rando phantom. The difference in the water equivalent length was measured to extract the SPR of the examined samples. The differences for SPR estimated from the DECT-SPR conversion were small with − 1.8% and − 3.3% for the Rando phantom femur and NEOBONE, respectively, whereas the differences for SECT-SPR were between 7.6 and 70.7%, illustrating a 1.5-mm shift of the range and a dose difference of 13.3% at maximum point in the evaluation of the dose distribution. This study demonstrated that the DECT-SPR conversion method better estimated the SPR of the porosity of bone tissues than SECT-SPR followed by the accurate range of the carbon-ion beams on carbon-ion dose calculations.

Amine plasma polymers deposited on porous hydroxyapatite artificial bone with bipolar pulsed discharges

A recent in vivo study [Kodama et al., Sci. Rep. 11, 1 (2021)] showed that porous artificial bones coated with amine-containing polymers deposited by plasma-enhanced chemical vapor deposition (PECVD) significantly enhanced bone regeneration. This article reports the chemical and physical properties of amine plasma polymers (PPs) formed under the same deposition conditions, including the film stability for up to two months, the effects of sterilization on the chemical compositions of the films, and the penetration of amine PPs into the inner surfaces of interconnected microscopic pores of the amine PP-coated porous artificial bone. It was found that, immediately after the plasma polymerization process, approximately 20% of nitrogen atoms on the surface of the deposited amine PP formed primary amines. However, the value decreased to approximately 5% over one month if the sample was exposed to ambient air. The relative concentration of primary amines also decreased to a similar value after the sample was sterilized by autoclaving or ethylene oxide gas. Molecular dynamics simulations were used to examine possible formation mechanisms of nitriles in deposit films under the PECVD conditions and found that ion impact can significantly reduce the nitrile content.

Hierarchically porous bone scaffold fabricated via direct foam writing with TCP/ZrO2 composite ink

Customizing bone scaffolds to mimic the hierarchically porous structure of natural bone presents a promising strategy for treating critical bone defects. Although low-cost direct ink writing (DIW) is often used to customize bone scaffolds, the limited print resolution made it difficult to print microporous structures. In this study, DIW was combined with the direct foam method to construct bone scaffolds with hierarchical and interconnected macro-micro porous structures. The foam stabilization mechanism of pure TCP was investigated to prepare TCP-enhanced ZrO2-based composite foam inks. Incorporating TCP endowed a richer interconnection structure to the composite foam. The printed bone scaffolds feature three scales of pore structure: interconnected macropores of 400–500 μm, bubble template pores of 50 μm, and open pores of <20 μm. The scaffold exhibited properties comparable to cancellous bone, such as 90 % porosity, 3.1 MPa compressive strength, and 1.0 GPa elastic modulus. In vitro experiments have demonstrated that cells can grow into the interior of the scaffold by following the connecting pores. And, incorporating TCP significantly enhances osteogenic protein and gene expression in bionic bone scaffolds. This facile and controllable approach offers an alternative solution to addressing the challenge of clinical implant shortages.

Anatomic total shoulder arthroplasty using hybrid glenoid fixation with a porous-coated titanium post. Two- to ten-year follow-up of 256 cases with primary glenohumeral osteoarthritis

BackgroundAnatomic total shoulder arthroplasty is one of the recommended surgical treatments for severe glenohumeral osteoarthritis, providing good pain relief and function. Aseptic loosening of the glenoid component, however, is a major cause for revision. Hybrid components have been introduced, combining traditional cemented fixation with porous titanium bone ingrowth to improve fixation. The purpose of this study was to report our midterm to longterm experience using such a component, including clinical outcomes and implant survival. MethodsWe reviewed all patients who were operated for primary osteoarthritis during the period 2011-19, leaving a minimum of 2-year follow-up. The severity of the osteoarthritis was graded using Samilson-Prieto score, while glenoid morphology was graded using the modified Walch classification. Clinical outcomes included Western Ontario Osteoarthritis of the Shoulder (WOOS) index, EQ-5D-5L, and Constant-Murley score. Postoperative radiographs were analyzed for radiolucent lines. Patient records were studied for complications including revisions. Supplementary data for revision and outcome were obtained from the Danish Shoulder Arthroplasty Registry. Kaplan-Meier estimates for implant survival were calculated. ResultsA total of 256 arthroplasties in 224 patients were included (mean age: 69 years ± 9 years, 149 females). 81% of cases were graded radiographically as severe osteoarthritis, according to Samilson-Prieto. Walch type B1 was most commonly followed by B2 (29% and 28% respectively). The mean follow-up time was 49 months (range 24-127). The response rate for patient reported outcomes was 91%. The median WOOS index was 94% (81%-99%), the median EQ-5D-5L was 0.87 (0.69-0.95), and the mean Constant-Murley score was 75 (SD 17.7). 13 cases (6%) had a WOOS index below 50%. 8.2% had complications related to surgery. A radiolucent line had developed around the central post in six cases and at the bone-cement interface in three cases at follow-up. Six cases had been revised (2.3%); three due to aseptic loosening of the glenoid. The 10-year survival estimate was 95.6 % (95% CI: 87.9%-98.5%). ConclusionAnatomic total shoulder arthroplasty with hybrid glenoid fixation provides excellent clinical outcome with a low complication rate in patients, with primary glenohumeral osteoarthritis. The 10-year survival rate is high and comparable to that reported for the best- performing all-polyethylene components. Longer observation is needed to see if hybrid fixation will outperform standard all-cemented components.

Effect of Additive Manufactured Gyroid Porous Structure of Hybrid Gradients on Mechanical and Failure Properties

In bone tissue engineering, good structural and forming qualities are prerequisites for the long-term implantation of scaffolds. To mitigate the stress-shielding effect between porous bone scaffolds and the human skeleton, this study proposes a method for designing non-linear gradient gyroid porous structures with radial-axial hybrid gradients that are precisely controlled by multivariate polynomial functions to simulate human bone characteristics. The influence of the volumetric energy density on the forming quality of the porous structures was evaluated by characterizing the internal strut morphology and measuring the strut width and porosity. Finite element analysis combined with experimental observations revealed that during compression, the thin struts at the top and bottom of the hybrid-gradient porous structure deformed first, and the compressive stress and shear stress were gradually transferred from the thin struts at the upper and lower ends of the structure to the thicker struts in the middle. Compared with the axial gradient, the edge struts of the hybrid-gradient porous structures can withstand higher shear and compressive stresses. Furthermore, owing to the variation in the radial gradient, compared to structures with 20 % axial porosity variation, the hybrid-gradient porous structure with 40 % radial porosity variation and 20 % axial porosity variation exhibited an 18.10 % increase in elastic modulus and a 4.29 % increase in yield strength. Additionally, its effective energy absorption was 20.39 % higher than that of the homogeneous structures. Compared to radial-gradient porous structures, the hybrid-gradient porous structure showed a lower sensitivity of the elastic modulus and yield strength to the volumetric energy density.

Customized 3D printed porous titanium scaffolds with nanotubes loading antibacterial drugs for bone tissue engineering

Abstract Due to the uncertainty of trauma or infection, customized bone substitutes are often required in clinic. Meanwhile, excessive use of antibiotics may lead to drug resistance. Therefore, the design of anti-infection bone tissue engineering scaffold is of very important. In this study, porous titanium alloy bone tissue engineering scaffolds were designed and fabricated by 3D printing. TiO2 nanotubes were further constructed on the scaffolds through electrochemical anodic oxidation, achieving the drug loading and anti-infection functions. The micron-level bionic pores were fabricated by the 3D printing process, and the secondary nanoscale-level nanotubes were achieved through the anodic oxidation process. Thereafter, the micro–nano structured porous bone tissue engineering scaffolds are presented. This structure features that the drug release rate can be regulated by loading the anti-infection drug minocycline and coating them with poly(lactic-co-glycolic acid) (PLGA) in the nanotubes. According to the results, the micro–nano composite porous scaffold showed uniform and controllable micro–nano pores, it may load anti-infection drugs and shown anti-infection ability. In addition, the PLGA coating may delay the drug release and maintain a sustained anti-infection function for the scaffold in a week. This study provides new ideas for designing antibacterial bone tissue engineering scaffold.