Porous Alloy Research Articles

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.

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.

Effect of Mn Content on the Microstructure, Mechanical, and Corrosion Properties of Porous Mg–1Zn–1Ca Scaffolds

Porous Mg alloys scaffolds are considered as an attractive strategy for bone repair due to their good biodegradability, biocompatibility, and suitable mechanical properties. In this study, porous Mg–1Zn–1Ca–xMn (x = 0, 0.2, 0.5, 0.8) scaffolds with cubic pore structure are prepared, and the size of main pore and interconnected pores of the scaffolds are predicted to be 355–450 and 30–50 μm, respectively. Among the four scaffolds, Mg–1Zn–1Ca–0.8Mn scaffold possesses good mechanical properties, with a maximum yield strength of 27.1 and an elastic modulus of 0.66 GPa. However, Mg–1Zn–1Ca–0.5Mn scaffold exhibits the optimal corrosion resistance with a corrosion rate 1.02 mm year−1 after 5 days immersion in Hank's solution. This is mainly attributed to α‐Mn phase, which is uniformly distributed on the substrate and uniformly degraded.

Porous high-entropy alloy coatings as highly efficient electrocatalysts for electrocatalytic water splitting

Developing highly efficient and stable non-noble metal electrocatalysts has always been a grand challenge for water splitting. Herein, the promising and highly efficient porous high entropy alloy (HEA) coatings is fabricated through the plasma spraying, which could be favorable to solve the above issues. Abased on the synergistic effect of different metals and the porous structure within the HEA coatings, it can provide the superior catalytic activities. Hence, the CoCrFeNiMo catalyst displays a low overpotential of 273 mV (for oxygen evolution reaction, OER) at 100 mA cm−2 in 1.0 M KOH electrolyte. As hydrogen evolution reaction (HER) catalysts, the CoCrFeNiMo presents a small overpotential. When the catalysts can be utilized to the overall water splitting, it delivers an excellent durable for 24 h. DFT result shows that CoCrFeNiMo is conducive to the hydrogen adsorption/desorption process, and it can enhance the transformation of *O to *OOH and improve the OER performance. This study not only offers a universal method to prepare high performance electrocatalysts, but also demonstrates the great potential of HEA coatings in energy conversion fields.

In-Plane Vibrations of Deep Sandwich Arches with Different End Conditions Based on a Logarithmic Shear Deformation Theory

This paper deals with the vibrational frequencies of deep sandwich arches to enhance their application domain and possibly use them for energy harvesting. The circular arch with porous nanocomposite core and titanium alloy face sheets having different end conditions is numerically analyzed. The middle core of the sandwich arch is made of a six-layered porous aluminum reinforced with graphene nanoplatelets. The kinematic equations are formulated in this study based on the higher-order shear deformation theory using a logarithmic function of radius. The effective properties of the nanocomposite media are modeled by employing the Halpin–Tsai modified rule. The equations of motion are determined by applying the principle of virtual displacement. The partial differential equations are reduced using the generalized differential quadrature technique to solving an algebraic eigenvalue problem. Novel numerical results are given to show the effects of geometrical parameters, material properties, and boundary conditions on the vibrations of deep sandwich arch.

A low-density polymer/CrMnFeCoNi composite with high strength and high damping capacity

A novel damping composite was successfully prepared by taking a porous CrMnFeCoNi high-entropy shape memory alloy as the skeleton and filling its pores with the composite composed of carbon nanotubes and polyurethane/epoxy interpenetrating polymer networks. When the porosity, pore size and CNT loading are 80 %, 1.2 mm and 2 wt%, respectively, the compressive strength, elastic modulus and energy absorption capacity of the composite are 35.7 MPa, 1.31 GPa and 23.1 MJ/m3 (ε = 65 %), respectively. Furthermore, it has a mere density of 2.525 g/cm3. Its loss factor is greater than 0.093 and can reach a maximum of 0.145 within the temperature and frequency range of 20 ∼ 150 ℃ and 0.1 ∼ 200 Hz. A triple-phase micromechanical model was utilized to explore the damping mechanism of composites. Results indicate the coupling of multiple damping mechanisms is the reason for the high ground-state damping of composites, and interface damping is the primary damping mechanism. The superposition of the ε → γ reverse martensite transformation peak of the CrMnFeCoNi HESMA skeleton and the glass transition peak of the CNTs/polymer composite matrix realizes the wide damping temperature range of the composite.

Effect of pore on the deformation behaviors of NiTi shape memory alloys: A crystal-plasticity-based phase field modeling

Porous NiTi shape memory alloys (SMA) have been developed into important biomedical and damping materials. However, the effect of pore on the martensitic microstructure evolution, functional properties, and plastic deformation has not been fully clear yet. In this work, to reveal the functional properties including superelasticity (SE), elastocaloric effect (eCE), one-way shape memory effect (OWSME), and stress-assisted two-way shape memory effect (SATWSME), as well as plastic deformation of porous NiTi SMAs, the polycrystalline SMA system is considered as a composite containing the grain-interior (GI) and grain-boundary (GB) phases, a thermo-mechanically coupled, grain-size-dependent and crystal-plasticity-based phase field model is proposed for the GI phase, and an elasto-viscoplastic constitutive model is established for the GB phase. The effects of porosity, pore diameter, pore aspect ratio, pore orientation, and pore distribution, as well as the interaction between pore and grain size, are comprehensively revealed and discussed. The simulations demonstrate that the pores cause a heterogeneous stress field, and the interaction among pores and that between pores and grain boundaries can enhance such heterogeneity, which can promote the initiation of martensitic transformation and reorientation. Moreover, the geometrical constraints caused by the pores can significantly affect the morphology and evolution of martensite microstructures. However, due to the diverse microstructure evolutions during SE, OWSME, and SATWSME, their interactions with the pores are quite different, resulting in various dependencies of each functional property and plastic deformation on the pore, and such dependencies are strongly influenced by porosity, pore diameter, pore aspect ratio, pore orientation, and pore distribution. The simulated results in this work are helpful to comprehensively and deeply understand the pore effect and its microscopic mechanism.

Effect of process parameters on residual stresses in SLM-formed bionic porous titanium alloy structures

Bionic porous titanium alloy structures have demonstrated broad application prospects in the field of biomedicine, and selective laser melting (SLM) has become one of the main methods for preparing porous titanium alloy structures due to its high degree of forming freedom. Residual stress is a crucial indicator for evaluating the forming quality of SLM parts, thus its control methods have garnered significant attention. Therefore, it is important to understand the process parameters' influence on the generation and regulation of residual stresses in SLM-formed bionic porous titanium alloy parts. In this paper, finite elements and experiments are employed to research the relationship between process parameters and residual stresses in the SLM process, and a method for controlling residual stresses in the key sensitive areas is proposed. It is found that increasing the laser scanning speed is conducive to reducing the residual stress of the porous structure and alleviating the phenomenon of stress concentration. Appropriately increasing the laser power can reduce the residual stress in the Z direction of the porous structure, with the optimal range being from 200 W to 250 W. Using a medium laying powder thickness (0.03 mm∼0.04 mm) results in uniformly distributed residual stress on the surface of the porous structure, leading to the attainment of maximum residual compressive stress. Building upon this foundation, the experimental verification of forming quality established stability, while the derived parameter optimization method and forming mechanism offered theoretical support for process optimization in fabricating porous titanium alloy structures through SLM.

Mechanical and Magnetic Properties of Porous Ni50Mn28Ga22 Shape Memory Alloy

A porous Ni50Mn28Ga22 alloy was produced using powder metallurgy, with NaCl serving as the pore-forming agent. The phase structure, mechanical properties, and magnetic properties of annealed bulk alloys and porous alloys with different pore sizes were analyzed. Vacuum sintering for mixed green billets in a tube furnace was employed, which facilitated the direct evaporation of NaCl, resulting in the formation of porous alloys characterized by a complete sinter neck, uniform pore distribution, and consistent pore size. The study found that porous alloys within this size range exhibit a recoverable shape memory performance of 3.5%, as well as a notable decrease in the critical stress required for martensitic twin shear when compared to that of bulk alloys. Additionally, porous alloys demonstrated a 2% superelastic strain when exposed to 353 K. Notably, under a 1.5 T magnetic field, the porous Ni50Mn28Ga22 alloy with a pore size ranging from 20 to 30 μm exhibited a peak saturation magnetization of 62.60 emu/g and a maximum magnetic entropy of 1.93 J/kg·K.

Fatigue performance of beta titanium alloy topological porous structures fabricated by laser powder bed fusion

The performance of porous β-titanium alloys is crucial for their diverse applications, with fatigue characteristics playing a pivotal role in shaping the design of these porous structures. While topological configurations have exhibited exceptional property, a systematic understanding of their fatigue performance is lacking in recent literature. This study reveals that at a porosity level of ∼75%, designed topologically optimized (TO) structures surpass rhombic dodecahedron (RD) structures in compressive yield strength by ∼4 times (149 ± 3 MPa vs. 38 ± 1 MPa). Furthermore, post-heat treatment further enhances the yield strength of TO structures by ∼15%, reaching 172 ± 3 MPa due to grain refinement and β phase stabilization. Moreover, the as-printed TO structure exhibits exceptional compressive fatigue endurance, enduring stress approximately ∼5 times higher than the as-printed RD structure at a cycle count of 106. Microstructure analysis after fatigue testing reveals a reduction in the α" martensitic phase and an increase in stress-induced ω phase in the heat-treated TO structure, contributing to a slight improvement in fatigue strength compared to the as-printed TO structure. The exceptional fatigue performance observed in LPBF-built beta-type titanium alloy within TO structures highlights the complex relationship between porous structure design, microstructure, compressive strength, and fatigue performance.

Porous Nickel-Molybdenum Phosphide Alloy Electrodes for Alkaline Hydrogen Evolution Reaction at the High-Current Density

Porous Nickel-Molybdenum Phosphide Alloy Electrodes for Alkaline Hydrogen Evolution Reaction at the High-Current Density

Effect of defocusing distance on interfacial reaction and mechanical properties of dissimilar laser Al/steel joints with a porous high entropy alloy coating

Aluminum alloy and low carbon steel were successfully laser weld-brazed when using a porous high entropy alloy (HEA) transient layer. It is shown that the joint wettability increased with the decreasing defocusing distance and the best wettability was obtained at 0 mm defocusing distance with the contact angle of 59.8° and wetting length of 5.57 mm. A fine and dense layer of τ5-(Fe,Co,Cr,Ni)1.8Al7.2Si phase was observed wrapping around the HEA spheres, and its thickness changed in a pronounced way with the defocusing distance, where a maximum thickness of 3.20 μm was obtained at 0 mm. A non-coherent interface and a composite-like structure was formed between the τ5 phase and the HEA spheres. However, the τ5 phase, consisting of a large number of nano-grains, aided in realizing the residual stresses at the joint interface through dislocation slip, leading to an enhanced interfacial bonding and joints failure near the fusion zone. An outstanding fracture load and displacement were achieved, with 333.9 N/mm and 4.07 mm respectively, at the optimized condition of 0 mm defocusing distance. And the mechanism of diffusion and metallurgical evolution was also revealed by thermodynamic calculations and diffusion kinetic analysis.

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.

Biodegradation-affected fatigue behavior of extrusion-based additively manufactured porous iron–manganese scaffolds

Additively manufactured (AM) biodegradable porous iron-manganese (FeMn) alloys have recently been developed as promising bone-substituting biomaterials. However, their corrosion fatigue behavior has not yet been studied. Here, we present the first study on the corrosion fatigue behavior of an extrusion-based AM porous Fe35Mn alloy under cyclic loading in air and in the revised simulated body fluid (r-SBF), including the fatigue crack morphology and distribution in the porous structure. We hypothesized that the fatigue behavior of the architected AM Fe35Mn alloy would be strongly affected by the simultaneous biodegradation process. We defined the endurance limit as the maximum stress at which the scaffolds could undergo 3 million loading cycles without failure. The endurance limit of the scaffolds was determined to be 90 % of their yield strength in air, but only 60 % in r-SBF. No notable crack formation in the specimens tested in air was observed even after loading up to 90 % of their yield strength. As for the specimens tested in r-SBF, however, cracks formed in the specimens subjected to loads exceeding 60 % of their yield strength appeared to initiate on the periphery and propagate toward the internal struts. Altogether, the results show that the extrusion-based AM porous Fe35Mn alloy is capable of tolerating up to 60 % of its yield strength for up to 3 million cycles, which corresponds to 1.5 years of use of load-bearing implants subjected to repetitive gait cycles. The fatigue performance of the alloy thus further enhances its potential for trabecular bone substitution subjected to cyclic compressive loading. Statement of significanceFatigue behavior of extrusion-based AM porous Fe35Mn alloy scaffolds in air and revised simulated body fluid was studied. The Fe35Mn alloy scaffolds endured 90 % of their yield strength for up to 3 × 106 loading cycles in air. Moreover, the scaffolds tolerated 3 × 106 loading cycles at 60 % of their yield strength in revised simulated body fluid. The Fe35Mn alloy scaffolds exhibited a capacity of withstanding 1.5-year physiological loading when used as bone implants.

Effect of 3D-Printed Porous Titanium Alloy Pore Structure on Bone Regeneration: A Review

As a biomedical material, porous titanium alloy has gained widespread recognition and application within the field of orthopedics. Its remarkable biocompatibility, bioactivity, and mechanical properties establish it as a promising material for facilitating bone regeneration. A well-designed porous structure can lower the material’s modulus while retaining ample strength, rendering it more akin to natural bone tissue. The progression of additive manufacturing (AM) technology has significantly propelled the advancement of porous implants, simplifying the production of such structures. AM allows for the customization of porous implants with various shapes and sizes tailored to individual patients. Additionally, it enables the design of microscopic-scale porous structures to closely mimic natural bone, thus opening up avenues for the development of porous titanium alloy bone implants that can better stimulate bone regeneration. This article reviews the research progress on the structural design and preparation methods of porous titanium alloy bone implants, analyzes the porous structure design parameters that affect the performance of the implant, and discusses the application of porous medical titanium alloys. By comparing the effects of the parameters of different porosity, pore shape, and pore size on implant performance, it was concluded that pore diameters in the range of 500~800 μm and porosity in the range of 70%–90% have better bone-regeneration effects. At the same time, when the pore structure is a diamond, rhombohedral, or cube structure, it has better mechanical properties and bone-regeneration effects, providing a reference range for the application of clinical porous implants.

Fabrication and characterisation of CrMnFeCoNi high entropy alloy electrocatalyst for oxygen evolution reaction

Water electrolysis is attracting increasing attention in becoming the main method for green energy production, which has long been hindered by the sluggish kinetics of oxygen evolution reaction (OER) and high cost of noble-metal (NM) containing electrodes. Template replication technique has been employed to fabricate porous CrMnFeCoNi high entropy alloy (HEA) bulk foams with > 95 % porosity. High entropy led to the formation of a single-phase solid solution of transition metals in the as-fabricated porous HEA bulk foam, and the lattice distortion brings about the outstanding OER performance that is close to that of the RuO2 reference sample. Effective electrochemically active surface area and amount of exposed active sites are increased by grinding into nanoparticles, which produced superior OER performance with a near-record low overpotential of ∼ 245 mV to drive a current density of 10 mA/cm2, a low Tafel slope of 73.6 mV/dec, a double layer capacitance of 102.3 mF, and excellent long-term stability over 24 h. This work demonstrates a cost-effective way to fabricate NM-free HEA electrocatalyst with complex structure and excellent stability in OER, which could help in advancing the research for alkaline water electrolysis.

Enhancement in mechanical properties, antimicrobial properties and osseointegration ability of porous TC4-5Cu alloys prepared via additive manufacturing

The aim of this study was to address insufficient load-bearing capacity, and lack of antibacterial properties of porous Ti6Al4V (TC4) alloy, porous TC4-5Cu alloy with designed honeycomb structure were prepared by additive manufacturing technology. The effects of wall thickness (100–300 μm) on the microstructure, mechanical properties, antimicrobial properties and osseointegration ability of porous TC4-5Cu alloys were systematically investigated. Results indicated that the porous TC4-5Cu alloy was composed of α'/α, β and Ti2Cu phases. With the increase of wall thickness, the elastic modulus, yield strength, and Vickers hardness of the porous alloys increased. The yield strength increased slightly especially for the wall thicknesses of over 200 μm. Compared with the other porous TC4 alloy with various structures, the porous TC4-5Cu alloy with the wall thicknesses of 200–300 μm exhibited high yield strength (702.0–711.1 MPa), considerable elastic modulus (23.6–25.4 GPa) and high Vickers hardness (415.4–421.2 HV). Porous TC4-5Cu alloy revealed excellent antimicrobial rate 100% against both S. aureus and E. coli. Moreover, the porous TC4-5Cu alloy with the wall thickness of 200 μm displayed osseointegration ability and lower concentration of TNF-α during in vivo test. Therefore, the designed porous TC4-5Cu alloy exhibited immense potential of clinical application.

Effect of Sintering Temperature on Microstructure Characteristics of Porous NiTi Alloy Fabricated via Elemental Powder Sintering.

To investigate the effect of the sintering temperature on the microstructure characteristics of porous NiTi alloys, two types of porous NiTi alloys with equal atomic ratios were fabricated via elemental powder sintering at 950 °C and 1000 °C. Afterwards, optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were collectively applied to investigate the pore characteristics and microstructure of the fabricated porous NiTi alloy. The results show that when the sintering temperature increases from 950 °C to 1000 °C, the average pore size increases from 36.00 μm to 181.65 μm, owing to the integration of these newly formed small pores into these pre-existing large-sized pores. The measured density increases from 2.556 g/cm3 to 3.030 g/cm3, while the porosity decreases from 60.4% to 51.8%. This is due to the occurrence of shrinkage after the sufficient diffusion of atoms. Furthermore, the characterization results confirm that a change in the sintering temperature would not change the phase types within a porous NiTi alloy; namely, the matrix consists primarily of B2 NiTi, with a significant amount of Ni4Ti3 precipitates and a small amount of Ni3Ti precipitates and Ti2Ni precipitates. However, as the sintering temperature increases, the number of Ni4Ti3 precipitates decreases significantly. The formation of a Ni4Ti3 phase in the present study is closely related to the enrichment of Ni content in the matrix owing to the diffusion rate difference between Ni atoms and Ti atoms and the absence of a transient liquid phase (TLP) during the sintering process owing to the relatively low sintering temperature (lower than the eutectic temperature). Moreover, the increasing sintering temperature speeds up the atom diffusion, which contributes to a reduction in the enrichment of Ni as well as the number of formed Ni4Ti3 precipitates.

Engineered three-dimensional bioactive scaffold for enhanced bone regeneration through modulating transplanted adipose derived mesenchymal stem cell and stimulating angiogenesis.

Titanium alloy materials are commonly used in orthopedic clinical treatments. However, conventional titanium implants usually lead to insufficient bone regeneration and integration because of mismatched biomechanics and poor bioactivities. To tackle these challenges, a porous titanium alloy scaffold with suitable mechanical properties was prepared using three-dimensional (3D) printing, and then an adipose-derived mesenchymal stem cell (ADSC) loaded platelet-rich plasma (PRP) gel was placed into the pores of the porous scaffold to construct a bioactive scaffold with dual functions of enhancing angiogenesis and osteogenesis. This bioactive scaffold showed good biocompatibility and supported cell viability proliferation and morphology of encapsulated ADSCs. Osteogenic and angiogenic growth factors in the PRP gel promoted the migration and angiogenesis of human umbilical vein endothelial cells (HUVECs) in vitro and enhanced osteogenic-related gene and protein expression in ADSCs, thus promoting osteogenic differentiation. After implantation into the femoral defects of rabbits, the bioactive scaffold promoted vascular network formation and the expression of osteogenesis-related proteins, thus effectively accelerating bone regeneration. Therefore, the osteogenic and angiogenic bioactive scaffold comprising a 3D printed porous titanium alloy scaffold, PRP, and ADSCs provides a promising design for orthopedic biomaterials with clinical transformation prospects and an effective strategy for bone defect treatment.

The application of custom 3D-printed prostheses with ultra-short stems in the reconstruction of bone defects: a single center analysis

Objective: Considering the advantages and widespread presence of 3D-printing technology in surgical treatments, 3D-printed porous structure prostheses have been applied in a wide range of the treatments of bone tumor. In this research, we aimed to assess the application values of the 3D-printed custom prostheses with ultra-short stems for restoring bone defects and maintaining arthrosis in malignant bone tumors of lower extremities in children.Methods: Seven cases of pediatric patients were included in this study. In all cases, the prostheses were porous titanium alloy with ultra-short stems. MSTS 93 (Musculoskeletal Tumor Society) scores were recorded for the functional recovery of the limbs. VAS (Visual analogue scale) scores were utilized to assess the degree of painfulness for the patients. X-ray and MRI (magnetic resonance imaging) were applied to evaluate the bone integration, prostheses aseptic loosening, prostheses fracture, wound healing, and tumor recurrence during follow-up.Results: During follow-up, none of the patients developed any postoperative complications, including prostheses aseptic loosening, prostheses fracture, or tumor recurrence. Radiological examinations during the follow-up showed that prostheses implanted into the residual bone were stably fitted and bone defects were effectively reconstructed. The MSTS 93 scores were 24.9 ± 2.9 (20–28). VAS scores were decreased to 5.8 ± 1.2 (4.0–7.0). No statistically significant differences in leg length discrepancy were observed at the time of the last follow-up.Conclusion: 3D-printing technology can be effectively applied throughout the entire surgical treatment procedures of malignant bone tumors, offering stable foundations for the initial stability of 3D-printed prostheses with ultra-short stems through preoperative design, intraoperative precision operation, and personalized prosthesis matching. With meticulous postoperative follow-up, close monitoring of postoperative complications was ensured. These favorable outcomes indicate that the utilization of 3D-printed custom prostheses with ultra-short stems is a viable alternative for reconstructing bone defects. However, further investigation is warranted to determine the long-term effectiveness of the 3D-printing technique.