Porous Implants Research Articles

Contemporary Treatment of Microtia-Atresia.

Microtia-atresia is a congenital deformity affecting the external ear and ear canal that can present with varying degrees of severity and morbidity. Treatment occurs along a spectrum and primarily centers on improving aesthetic appearance. Many cases of microtia will not be effectively treated with conservative measures and will require some form of reconstruction. There are several options available, including porous polyethylene implants, autologous rib grafting, and autologous chondrocyte frameworks. Equally significant is the treatment of hearing loss, as many patients with microtia-atresia will have a component of conductive hearing loss. This article aims to comprehensively review contemporary treatment modalities for microtia-atresia and discuss the advantages, disadvantages, and practicality of each. Treatment and reconstruction often take a multidisciplinary and multistaged approach to achieve optimal results, with ideal management determined by each patient's individualized needs.

Study of the biocompatibility of porous 3D-TiNi implants in vivo

Introduction. Porous TiNi alloys are widely used in medicine as osteoreplacement implants due to their unique properties of superelasticity and biocompatibility, but their clinical use is severely limited by time-consuming manual fabrication and the inability to create precise geometries. Reconstructive surgery for the replacement of bone defects requires biocompatible endoprostheses of individual shape and complex geometry. The use of porous 3D-TiNi implants can be a solution to many problems in traumatology and bone oncology.Aim: To evaluate the possibility of using porous 3D-TiNi implants in osteoplastic surgery based on a study of the structure and biocompatibility of the material under in vivo conditions.Material and Methods. Porous samples in the form of cones and a single implant for maxillofacial surgery were prepared from TiNi powder by selective laser melting. To print an individual implant for maxillofacial surgery, the personal data of the patient at the Oncology Research Institute were used. The macrostructure, elemental and phase composition of porous titanium nickelide samples were investigated using scanning microscopy and X-ray diffraction analysis. The biocompatibility of porous cone-shaped samples was evaluated in vivo using guinea pigs whose condition was analysed by CT scanning.Results. Structural studies of porous titanium nickelide samples showed that selective laser melting can be used to obtain a continuous porous structure with strong contact bridges between particles of a three-phase powder. In vivo testing of the cone-shaped implants showed no local inflammatory changes, rejection or deformation of the hind limb axes of the experimental animals. The basic feasibility of fabricating a custom implant of complex geometry from TiNi powder using selective laser melting according to a patient’s MSCT data was demonstrated.Conclusions. Porous 3D-TiNi implants obtained by selective laser melting showed high biocompatibility under in vivo conditions. An experimental study confirmed the efficacy and ease of use of 3D TiNi implants, their excellent self-fixation in bone tissue, and bone tissue augmentation at the interface with the implant. The macrostructure, chemical and phase composition of the implant material was found to be close to traditional porous TiNi alloys. It was shown that the method of selective laser melting makes it possible to create complex geometric defects in bone tissue from TiNi.

Determination mechanical properties and permeability of porous titanium alloy bone implants, including under conditions of their interaction with biological fluids

Additive manufacturing technologies make it possible to create porous implants with mechanical properties equivalent to natural bone. At the same time, a number of new problems arise, including determining the mechanical properties of such structures. This study is aimed at obtaining the mechanical parameters of porous titanium alloy for bone implants, including under conditions of their interaction with biological fluids. Mechanical properties were obtained for nine types of structures: three types of porosity for each of the three types of structure orientation. The considered porosity of the structures from 41–52 % lies in the porosity range of cancellous bone. Young's modulus was obtained from 10 to 22 GPa and Poisson's ratio was obtained from 0.136 to 0.337, as the results of uniaxial compression test. The Young's moduli of the standard 47 % porosity are closest to the moduli of the cortical bone 15–16 GPa. The structure configuration with the lowest Young's modulus is recommended for the manufacture of implants for patients with high porosity of bone tissue. The experiments considered the interaction of porous structures with biological fluids. Poroelastic effects were not found for structures with pore space filled by collagen under uniaxial compression up to 5000 N. Experiments to determine the permeability were carried out for three types of porosity with the orthogonal orientation of the structure. The permeability coefficient varied from 0.99∙10-10 to 3.6∙10-10 m2 for an aqueous solution of glycerol, simulating blood, and from 1.4∙10-10 to 2∙10-10 m2 for gelatin, simulating collagen formation during primary osteointegration. The results obtained will be useful in developing new approaches to modeling porous implants in biomechanics.

Comparison of finite element modeling approaches for Ti6Al4V porous bone implants

Additive technologies have made it possible to make a significant breakthrough in the development and production of personalized porous implants, which have clear advantages over monolithic predecessors. At the same time, engineers are faced with a number of new tasks, one of which is correct and effective numerical modeling of porous implants in the process of solving optimization problems. The study compares approaches to numerical modeling of porous titanium for bone implants, taking into account differences in the mechanical parameters of the material and the geometry of the models. The detailed geometry of the structure of 9 models is considered, for which two variants of material parameters are specified: pure Ti6Al4V alloy and experimental ones obtained for specimens printed from Ti6Al4V powder. As a proposed approach to homogenizing the structure, a continuum model of a cylinder is considered, for which the experimental properties of the specimen’s material are specified. The numerically obtained values of Young's moduli for each approach are compared with those obtained in the experiment. It has been established that when setting the properties of a pure alloy, the calculated Young's modulus exceeds the experimental one by 83–92 %. The closest thing to experiment is detailed modeling of geometry with setting the experimental properties of the material structure, while the calculated Young's modulus does not exceed the experimental one by more than 10 %. However, in this case the calculation takes from 2 to 8 hours. In the case of continuum modeling, the calculated Young's moduli exceed the calculated moduli in detailed modeling by no more than 11 %, while the calculation lasts no more than 1 minute. Based on this, it is proposed to use a continuum approach to modeling implants in the process of calculating the optimization of their shape, as an initial iteration before detailed modeling of the structure. As material properties, it is necessary to use the mechanical parameters of the structures, previously obtained from uniaxial compression experiments. Using the properties of a pure alloy will lead to results that significantly exceed the actual ones when calculating the porous structure.

Porous titanium alloys for medical application: Progress in preparation process and surface modification research

Excellent mechanical properties and biocompatibility are the most sought-after attributes in biomedical materials for the regeneration of damaged tissues. However, conventional dense titanium alloys possess a modulus significantly higher than that of human tissues, leading to potential stress-shielding effects. Medical porous titanium alloys can reduce the elastic modulus of the material, promote tissue fixation and vascular regeneration, and improve the suitability for human tissue properties. With the continuous development of technology, the preparation process of porous titanium alloys has undergone a series of multifaceted transformations and improvements in the aspects of powder sintering, fiber preparation, and additive manufacturing processes, and its structural characteristics and mechanical properties are constantly evolving in a controllable direction. Alongside the enhancement of the material’s mechanical properties through porous design, optimization of the properties at the implant-tissue interface also leads to improved antimicrobial and osteogenic properties of porous titanium. Due to the complex internal structure of porous titanium alloys, surface modification is mainly carried out in fluid media, which is realized by morphological modification and the introduction of functional substances. Over time, the surface modification of porous titanium alloys for medical applications has progressed from morphological modification and introduction of chemical composition to the loading of bioactive substances. This evolution aims to enhance safety and efficiency in the use of these materials. This paper reviews the preparation and surface modification processes of porous titanium alloys for medical use and summarizes the advantages, disadvantages, and influencing factors among different processes, with a view to providing new ideas for the development of porous implants for medical use.

Interbody Fusion Device in the Treatment of Cervicobrachial Syndrome: A Prospective 5-Year Follow-Up Extension Study of Porous Titanium Cervical Cages

Background: To assess long-term clinical and radiological data of porous titanium cervical interbody cages. Methods: We recruited 34 out of 49 patients previously enrolled in the EFFECT trial on 3D printed titanium cages, for 5 years follow-up. Objectives were the evaluation of Neck Disability Index, Visual Analog Scale of arm pain and neck pain, Likert self-reported perceived recovery, EQ-5D, fusion status and subsidence. Fusion was defined as rotation ≤ 4° and ≤ 1.25 mm translation at the index level, using flexion-extension radiograph. Results: All patients had good outcomes in terms of NDI (12.5±15.4), VAS neck pain (23.5±24.1), VAS arm pain (18.7±20.2) and EuroQol (0.77±0.24). 88.6% of the patients experienced complete or nearly complete recovery. NDI improved significantly at 5 years compared to 1 year, all other outcome measures did not significantly differ from the 12 months results. The fusion rate at the index level increased from 91.5% at 12 months to 100% at 5 years. Conclusion: 3D printed stand-alone porous titanium cervical implants are effective in terms of clinical and radiological outcome with 88.6% complete or nearly complete recovery and fusion rate of 100% at 5 years follow-up. Moreover, solid single level anterior cervical fusion can be achieved without additional plating. Trial Registration: The study has been registered in The Netherlands Trial Register (NTR 1289) and approved by the Medical Ethical Committee (NL76079.058.20).

Tantalum Particles Promote M2 Macrophage Polarization and Regulate Local Bone Metabolism via Macrophage-Derived Exosomes Influencing the Fates of BMSCs.

In this study, the regulatory role and mechanisms of tantalum (Ta) particles in the bone tissue microenvironment are explored. Ta particle deposition occurs in both clinical samples and animal tissues following porous Ta implantation. Unlike titanium (Ti) particles promoting M1 macrophage (Mϕ) polarization, Ta particles regulating calcium signaling pathways and promoting M2 Mϕ polarization. Ta-induced M2 Mϕ enhances bone marrow-derived mesenchymal stem cells (BMSCs) proliferation, migration, and osteogenic differentiation through exosomes (Exo) by upregulating miR-378a-3p/miR-221-5p and downregulating miR-155-5p/miR-212-5p. Ta particles suppress the pro-inflammatory and bone resorption effects of Ti particles in vivo and in vitro. In a rat femoral condyle bone defect model, artificial bone loaded with Ta particles promotes endogenous Mϕ polarization toward M2 differentiation at the defect site, accelerating bone repair. In conclusion, Ta particles modulate Mϕ polarization toward M2 and influence BMSCs osteogenic capacity through Exo secreted by M2 Mϕ, providing insights for potential bone repair applications.

Porous versus solid shoulder implants in humeri of different bone densities: A finite element analysis.

Porous metallic prosthesis components can now be manufactured using additive manufacturing techniques, and may prove beneficial for promoting bony ingrowth, for accommodating drug delivery systems, and for reducing stress shielding. Using finite element modeling techniques, 36 scenarios (three porous stems, three bone densities, and four held arm positions) were analysed to assess the viability of porous humeral stems for use in total shoulder arthroplasty, and their resulting mechanobiological impact on the surrounding humerus bone. All three porous stems were predicted to experience stresses below the yield strength of Ti6Al4V (880 MPa) and to be capable of withstanding more than 10 million cycles of each loading scenario before failure. There was an indication that within an 80 mm region of the proximal humerus, there would be a reduction in bone resorption as stem porosity increased. Overall, this study shows promise that these porous structures are mechanically viable for incorporation into permanent shoulder prostheses to combat orthopedic infections.

Mechanical properties of hierarchical porous lattices with microscopic porosity fabricated by combination of lattice design and HSSH process

The hierarchical porous lattice implant with microscopic porosity, which resembles the original human bone structure, has significant potential application value. The microscopic porosity in the hierarchical porous lattice implant plays a crucial role in transporting nutrients and promoting tissue regeneration. However, it is difficult to fabricate microscopic pores smaller than 200 μm by powder bed fusion (PBF) processes due to the limitations of the laser spot size. In this study, the preparation of a hierarchical porous lattice implant with microscopic porosity is proposed by coupling structure design with the high scanning speed - short hatch spacing (HSSH) process formation. The structure-versus-process relationship is used to control the size and distribution of the microscopic pores, which meets the requirements of modulus and high biocompatibility. This proposed process breaks the inherent law where the higher the porosity, the higher the modulus of the lattice for the same lattice type. The modulus and porosity of the hierarchical porous implants could be flexibly tuned over a wide range (0.1–1.8 GPa and 63–84 %, respectively). The microscopic porosity is mainly distributed near the contour of the core rod, and the macroscopic porosity and microscopic porosity are approximately 73.70 % and 8.22 %, respectively. The problem of large errors in fitting the hierarchical porous lattice modulus calculation model according to the Gibson-Ashby equation has been solved. The mechanism of microscopic porosity formation was also analyzed. Furthermore, this method has the advantage of universal applicability, providing a feasible way for the development and application of porous materials.

Porous Titanium/SF Sponge Composite Scaffold with Loads of Gentamicin and Small Extracellular Vesicles to Improve Antibacterial and Osteogenesis Properties

AbstractAdditive manufacturing has been widely used for producing porous titanium orthopedic implants. However, the higher surface area inherent to porous structures increases the risk of bacterial colonization. In this work, composite scaffolds with dual functions of the antibacterial and osteogenesis promotion properties are developed. The porous titanium is fabricated using a selective laser melting process to provide mechanical support. Silk fibrin (SF) sponge‐loading gentamicin and extracellular vesicles (EVs) are prepared in the pores of the porous titanium. The developed composite scaffolds are investigated for their antibacterial and osteogenesis effects. The samples exhibit well antibacterial activity against Escherichia coli. The samples also show good cytocompatibility, effectively promoting the adhesion and proliferation of the bone marrow mesenchymal stem cells (rBMSCs). EVs significantly promote the expression of osteogenesis‐related genes in rBMCSs and the superior extracellular matrix mineralization reveals that EVs have a remarkable role in enhancing osteogenic differentiation. Therefore, the composite scaffolds with dual functions of antibacterial and osteogenesis promotion properties have excellent potential for orthopedic implant applications.

3D Printed Porous Zirconia Biomaterials based on Triply Periodic Minimal Surfaces Promote Osseointegration In Vitro by Regulating Osteoimmunomodulation and Osteo/Angiogenesis.

The triply periodic minimal surface (TPMS) is a highly useful structure for bone tissue engineering owing to its nearly nonexistent average surface curvature, high surface area-to-volume ratio, and exceptional mechanical energy absorption properties. However, limited literature is available regarding bionic zirconia implants using the TPMS structure for bone regeneration. Herein, we employed the digital light processing (DLP) technology to fabricate four types of zirconia-based TPMS structures: P-cell, S14, IWP, and Gyroid. For cell proliferation, the four porous TPMS structures outperformed the solid zirconia group (P-cell > S14 > Gyroid > IWP > ZrO2). In vitro assessments on the biological responses and osteogenic properties of the distinct porous surfaces identified the IWP and Gyroid structures as promising candidates for future clinical applications of porous zirconia implants because of their superior osteogenic capabilities (IWP > Gyroid > S14 > P-cell > ZrO2) and mechanical properties (ZrO2 > IWP > Gyroid > S14 > P-cell). Furthermore, the physical properties of the IWP/Gyroid surface had more substantial effects on bone immune regulation by reducing macrophage M1 phenotype polarization while increasing M2 phenotype polarization compared with the solid zirconia surface. Additionally, the IWP and Gyroid groups exhibited enhanced immune osteogenesis and angiogenesis abilities. Collectively, these findings highlight the substantial impact of topology on bone/angiogenesis and immune regulation in promoting bone integration.

Custom-Made Implant Fabrication for Chin Augmentation Using Piled-Up Expanded Polytetrafluoroethylene Sheets: An Innovative Surgical Technique and Literature Review

BackgroundAlloplastic chin augmentation is the most common esthetic surgical treatment to reshape the chin. However, factory-made chin implants are typically standardized rather than custom-made and have potential to cause complications. Although the fabrication of custom-made implants by using computer-assisted planning and 3D-printing technology has become widespread, the process has several disadvantages, including long preoperative prosthesis preparation times, high costs, and unsuitability for patients with asymmetric chins or those who undergo combined mandibuloplasty before implant placement. The present study developed an innovative chin augmentation technique involving stacked expanded polytetrafluoroethylene (e-PTFE) sheets that is suitable for most patients and has minimal side effects.Materials and MethodsA retrospective review of a single surgeon’s experience was performed over a 2 year period for patients who underwent a procedure involving piled-up e-PTFE sheets for alloplastic chin augmentation. This study analyzed the outcomes, complications (temporary nerve numbness, wound infection, hematoma formation, and implant displacement), and patient satisfaction during follow-up.ResultsBetween January 2018 and December 2020, 38 patients underwent the procedure involving piled-up e-PTFE sheets for alloplastic chin augmentation. Six patients (15.8%) experienced nerve-related temporary numbness, and one (2.6%) experienced wound infection. None had developed major complications such as implant displacement or wound infection at follow-up. Moreover, the patients demonstrated a high level of satisfaction with the surgical results.ConclusionPiled-up e-PTFE sheets can be used to produce custom-fit porous polyethylene chin implants that result in minimal complications and a very high satisfaction rate.Level of Evidence IVThis journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Dual-energy computed tomography and micro-computed tomography for assessing bone regeneration in a rabbit tibia model

To gain a more meaningful understanding of bone regeneration, it is essential to select an appropriate assessment method. Micro-computed tomography (Micro-CT) is widely used for bone regeneration because it provides a substantially higher spatial resolution. Dual-energy computed tomography (DECT) ensure shorter scan time and lower radiation doses during quantitative evaluation. Therefore, in this study, DECT and Micro-CT were used to evaluate bone regeneration. We created 18 defects in the tibial plateau of the rabbits and filled them with porous polyetheretherketone implants to promote bone regeneration. At 4, 8, and 12 weeks, Micro-CT and DECT were used to assess the bone repair in the defect region. In comparison to Micro-CT (152 ± 54 mg/cm3), the calcium density values and hydroxyapatite density values obtained by DECT [DECT(Ca) and DECT(HAP)] consistently achieved lower values (59 ± 25 mg/cm3, 126 ± 53 mg/cm3). In addition, there was a good association between DECT and Micro-CT (R = 0.98; R2 = 0.96; DECT(Ca): y = 0.45x–8.31; DECT(HAP): y = 0.95x–17.60). This study highlights the need to use two different imaging methods, each with its advantages and disadvantages, to better understand the bone regeneration process.

Otolaryngology Implants Usage and their Material Adverse Event Profile - A Narrative Review

Objectives:The objective of this study is to review various biomaterials or implants used in ENT and their adverse effects on events that were noticed from the initial days to the present era.Methods:Relevant articles were searched from the databases. PubMed, Scopus, Web of Science, and Google were used to search for the data.Results:Cochlear implant (CI) adequacy depends on biocompatibility, anti-inflammatory treatment, and reduction of fibrosis. Silicone is used in the otologic field, and its allergy is a rare cause of CI extrusion. Nitinol pistons are used in stapedotomy, and polyethylene (Teflon) grafts are used in partial ossicular replacement prosthesis (PORP) or total ossicular replacement prosthesis (TORP). Their complications include graft extrusion and residual perforation. Chronic sphenoid sinusitis is associated with Medpor porous polyethylene implants used for sellar reconstruction in skull-based surgeries. In vocal cord paralysis, injectable collagen preparations form submucosal deposits and dysphonia. Montgomery T-tubes are used in subglottic stenosis, and they produce granulation tissue. Metallic tracheostomy tubes cause the formation of secondary foreign bodies, and biofilms appear in double-lumen tracheostomy tubes.Conclusion:Even though several research studies have been carried out, still a modification of implant design is needed to minimize the complications and to further promote the quality of life of patients.

Комбинированные матрицы и тканевые инженерные конструкции из биополимеров в реконструктивно-восстановительной хирургии ЛОР-органов

Microtia is a combined congenital malformation with the prevalence of one case per 10,000–15,000 newborns, which accounts for 50% of all congenital malformations. Treatment of microtia is a challenging task. Numerous solutions have been proposed, however, none of these options guarantee good functional and aesthetic outcome. High hopes for solving the problem are placed on advances in reconstructive surgery. The study was aimed to determine the possibility of using advanced biocompatible endoprostheses manufactured using the tissue engineering technologies. Two closely related male 2-year-old minipigs of the Sus salvanius breed underwent implantation of bioengineered implants manufactured by combined 3D bioprinting with application of the collagen solution containing autologous cartilage tissue cells under the temporal fascia. The samples were collected 3 months later. Histological examination and immunohistochemistry showed that the implanted endoprosthesis initiated the development of regenerated connective tissue and its own vasculature in 100% of cases, thereby ensuring cell viability and integrity of biological structures; furthermore, no facts of the endoprosthesis rejection or resorption were reported. We have concluded that the developed implant manufacturing method is promising and can provide the basis for creation of domestic porous ear implants based on biocompatible polymeric materials, hydrogels, and autologous cellular material. It is necessary to further test the auricular implant using biological models.

Parametric Design of Porous Structure and Optimal Porosity Gradient Distribution Based on Root-Shaped Implants.

Porous structures can reduce the elastic modulus of implants, decrease stress shielding, and avoid bone loss in the alveolar bone and aseptic loosening of implants; however, there is a mismatch between yield strength and elastic modulus as well as biocompatibility problems. This study aimed to investigate the parametric design method of porous root-shaped implants to reduce the stress-shielding effect and improve the biocompatibility and long-term stability and effectiveness of the implants. Firstly, the porous structure part was parametrically designed, and the control of porosity gradient distribution was achieved by using the fitting relationship between porosity and bias and the position function of bias. In addition, the optimal distribution law of the porous structure was explored through mechanical and hydrodynamic analyses of the porous structure. Finally, the biomechanical properties were verified using simulated implant-bone tissue interface micromotion values. The results showed that the effects of marginal and central porosity on yield strength were linear, with the elastic modulus decreasing from 18.9 to 10.1 GPa in the range of 20-35% for marginal porosity, with a maximum decrease of 46.6%; the changes in the central porosity had a more consistent effect on the elastic modulus, ranging from 18.9 to 15.3 GPa in the range of 50-90%, with a maximum downward shift of 19%. The central porosity had a more significant effect on permeability, ranging from 1.9 × 10-7 m2 to 4.9 × 10-7 m2 with a maximum enhancement of 61.2%. The analysis showed that the edge structure had a more substantial impact on the mechanical properties. The central structure could increase the permeability more effectively. Hence, the porous structure with reasonable gradient distribution had a better match between mechanical properties and flow properties. The simulated implantation results showed that the porous implant with proper porosity gradient distribution had better biomechanical properties.

Evaluation and Management of Acetabular Bone Loss in Revision Total Hip Arthroplasty: A 10-year Update.

Acetabular bone loss continues to be one of the most complex and challenging scenarios facing the orthopaedic surgeon. Preoperative planning and classification systems essentially have remained the same, with the Paprosky classification still being the most commonly used. Careful radiological assessment with well-defined criteria can accurately diagnose acetabular bone loss patterns with an associated chronic pelvic discontinuity before surgery. The use of cemented reconstruction techniques has declined, and contemporary practice trends have involved the increasing use of highly porous hemispherical shells in conjunction with modular porous metal augments, which can successfully treat most acetabular revisions. Noncemented treatment options for the management of acetabular bone loss during revision include conventional porous/modular highly porous hemispherical implants, nonmodular highly porous implants with cementable acetabular liners, cup-cage reconstruction, oblong cups, and triflange reconstruction. These options can be combined with modular porous metal augments, structural allografts, impaction grafting, or reconstruction cages. Acetabular distraction is a newer technique for chronic pelvic discontinuity, which is used in conjunction with off-the-shelf revision acetabular shells and modular porous metal augments. This review is an update over the past decade, highlighting studies with mid to long-term follow-up, and presents the advantages, disadvantages, and principles associated with each of the most commonly used reconstructive techniques.

Functional characterization of biomechanical loading and biocorrosion resistance properties of novel additively manufactured porous CoCrMo implant: Comparative analysis with gyroid and rhombic dodecahedron

Notably, successful clinical outcomes of additively manufactured porous metallic implants require careful consideration of factors such as porosity, pore size, and pore interconnectivity. Applying the SLM technique in Cobalt chrome molybdenum (CoCrMo) alloy fabrication has shown excellent results for prosthetic restorations. However, the corrosion performance of 3D-printed interpenetrating lattices or a combination of minimal surface and strut lattices such as BD.05 (both based on TPMS and struts lattice cells) remains unexplored. This study explores additively manufactured BD.05 structures using CoCrMo as a bulk biomaterial to address the stiffness mismatch, a common cause of stress shielding between implants and bones. Comparative characterization of TPMS-based gyroid and stress lattice-based Rhombic dodecahedron (RH) shows a distinct deformation pattern under quasi-compressive loading. The gyroid exhibits higher yield stress (126.05 MPa), followed by BD-0.5 (25.46 MPa) and RH (9.36 MPa). BD.05 shows an impact strength of 3.17 ± 0.03J/cm2 and a microhardness of 556HV1. Electrochemical measurements demonstrate the inherent corrosion resistance of the fabricated structures. This indicates the appropriate and successful promise of these lightweight interpenetrating-based lattice metamaterial implants in orthopedic applications.

On‐Demand Magnetically‐Activated Drug Delivery from Additively Manufactured Porous Bone Implants to Tackle Antibiotic‐Resistant Infections

AbstractThis study proposes a new concept for an on‐demand drug releasing device intended for integration into additively manufactured (i.e., 3D printed) orthopedic implants. The system comprises a surface with conduits connected to a subsurface reservoir used for storage and on‐demand release of antimicrobial agents, covered with a cap that prevents the antibacterial agents from being released until alternating magnetic field (AMF) raises the temperature of the cap, thus, releasing the stored drug. To demonstrate this concept, Ti6Al4V specimens are directly 3D printed using selective laser melting and their surface, reservoirs, and drug releasing properties are characterized. A new synthetic antimicrobial peptide, SAAP‐148, is thereafter tested for its cytotoxic, osteogenic, and immunomodulatory effects at concentrations relevant for its minimal bactericidal concentration (MBC) and is compared with its natural analogue, LL‐37. The results showed that AMF successfully activated the release from the 3D printed loaded samples. Both peptides demonstrated to be non‐cytotoxic within the MBC levels for macrophages and preosteoblasts and did not influence their osteoimmunomodulatory behavior. The findings of this study indicate that the proposed concept is technically feasible and has the potential to be used for the development of bone implants with on‐demand delivery systems to fight IAI without systemic or continuous local release of antibiotics.

Hierarchical zeolite coatings featuring a spatial gradient architecture for sequentially-controlled bisphosphonate release in the modulation of osteogenic–osteoclastic balance

Osteogenic–osteoclastic microenvironment imbalance impairs osseointegration between joint prostheses and the marrow cavity, which is a crucial contributor to the high incidence of complications such as implant loosening and periprosthetic fractures in osteoporosis (OPs). Previously, we employed hydrogel-based bisphosphonate (BPs) coatings on 3D-printed porous titanium alloy implants (pTi) to modulate the OPs microenvironment through controlled release. However, challenges persisted, including the limited duration of BPs release and associated organic material degradation-induced toxicity. To address these issues, we modified pTi surfaces by introducing chemically stable zeolites and BPs. In this study, we applied Ca2+-functionalized hierarchical zeolite coating on pTi for the first time. By combining mesoporous adsorption and Ca2+ chelation, we achieved efficient encapsulation of zoledronate (ZOL), creating a bioactive interface characterized by a spatial gradient structure with a “microporous-mesoporous-macroporous” morphology. The coating achieves the release of ZOL through the mesoporous structure and facilitates the gradual release of chelated ZOL via ion exchange, resulting in hierarchical drug delivery. Moreover, the spatial gradient structure of the coatings significantly influenced cell extension. Simultaneously, we constructed a bioactive coating with a drug concentration gradient, achieving graded drug release within the microenvironment, which facilitated the accurate regulation of osteogenesis and bone resorption. This coating has the potential to substantially enhance the management of postoperative complications in OPs patients undergoing prosthetic replacement surgery by achieving a balanced osteogenic-osteoclastic response.