Tantalum Implants Research Articles

VIABILITY OF BLOOD LEUKOCYTES OF RATS AFTER IMPLANTATION OF POLYPROPYLENE SURGICAL MESH WITH A TANTALUM-BASED COATING AND ITS DERIVATIVES

Aim. To investigate the viability and types of cell death of peripheral blood leukocytes in experimental animals after implantation of surgical meshes with a tantalum-based coating and its derivatives. Materials and methods. The experimental group included 40 male rats of the WAG population. Polypropylene surgical mesh was surgically implanted between the abdominal wall and sections of the large intestine with different types of coatings. After 28 days, collected blood was analyzed by a BD FACSCanto™ II flow cytometer. Results. It was determined that there were no significant changes in the viability of blood leukocytes between the animals of the intact group and the group of animals that underwent surgery without implantation. Analysis of leukocyte viability in groups of rats implanted with tantalum and tantalum oxide-coated meshes showed a slight decrease in viable cells compared with the results of the intact group. At the same time, the percentage of necrotic cells showed a slight increase. In the group of rats implanted with a mesh with tantalum nitride-coated, a decrease in viable leukocytes was determined in comparison with the results of the intact group by 12,9%, while the percentage of necrotic leukocytes was 3,8% higher. A 16,2% decrease in viable leukocytes was determined in the group of rats implanted with a non-coated mesh compared to the results of the intact group. At the same time, the percentage of necrotic cells was 6,9% higher. Conclusions. Implantation of uncoated and tantalum nitride-coated surgical meshes was found to decrease the percentage of viable blood leukocytes in rats compared to intact animals, while implantation of tantalum- and tantalum-oxide-coated surgical meshes did not significantly decrease viable white blood cells. leukocytes.

Elevated Blood Tantalum Concentrations in Patients Following Reconstruction of Severe Acetabular Defects in Total Hip Arthroplasty Using Modular Tantalum Augments in Combination With Uncemented Tantalum Cups

IntroductionThe reconstruction of acetabular defects in total hip arthroplasty (THA) can be challenging. An option to treat uncontained acetabular defects is to use modular tantalum augments in combination with cementless press-fit cups. However, modularity is associated with an increased risk of debonding and mechanical failure. In addition, metal wear particles can be released due to micromotions at the implant interface. Clinical data on the long-term results of this treatment strategy is limited. The purposes of this study were: (1) to evaluate the clinical and radiological outcome of complex THA using modular trabecular metal augments and uncemented revision cups; (2) to investigate the blood tantalum concentrations in these patients at mid-term (mean 4.5 year) follow-up; and (3) to report complications and mechanisms of failure related to this procedure. Materials and MethodsIn this single-center study, we retrospectively reviewed data from a consecutive cohort of 27 patients who underwent complex acetabular defect reconstruction using a modular tantalum acetabular augment in combination with an uncemented tantalum cup. We evaluated the implant survival, and the radiological and clinical outcomes after a mean follow-up of 4.5 years (SD 2.1; range 2.5 to 10.6 years) using patient-reported outcome scores (PROMs). Blood samples were analyzed regarding tantalum concentration and compared with a control group. ResultsThe cumulative survival rate at 4.5 years with the endpoint “revision of the acetabular component for aseptic loosening” was 94.4% (95% confidence interval (CI) 71.6 to 99.2) and 82.9% (95 % CI 60.5 to 93.3) for the endpoint “revision for any reason.” The PROMs improved significantly up to the latest follow-up, and radiographic data showed no signs of loosening or implant migration. Median blood tantalum concentrations were significantly higher in the study group (0.15 μg/L) compared to the control group (0.002 μg/L) (P < 0.001). ConclusionsThis study demonstrated acceptable clinical and radiological results of cementless revision THA using modular trabecular metal implants for the reconstruction of large acetabular defects. Tantalum concentrations were significantly higher in patients who had tantalum implants compared to the control group, however, the systemic and local effects of an increased tantalum exposure are not yet fully understood and have to be further investigated.

Stress distribution pattern in all-on-four maxillary restorations supported by porous tantalum and solid titanium implants using three-dimensional finite element analysis.

Success/failure of dental implants depends on stress transfer and distribution at the bone-implant interface. This study aimed to assess the stress distribution pattern in all-on-four maxillary restorations supported by porous tantalum and solid titanium implants using three-dimensional (3D) finite element analysis (FEA). In this FEA, a geometric model of an edentulous maxilla, Zimmer screw-vent tantalum and solid titanium implants were modelled. Four models with the all-on-four concept were designed. The fifth model had 6 vertical implants (all-on-six). Two different implant types (porous tantalum and solid titanium) were modelled to yield a total of 10 models, and subjected to 200 N bilateral vertical load. Pattern of stress distribution and maximum von Mises stress values in cancellous and cortical bones around implants were analysed. In tantalum models, the effect of increasing the distal tilting of posterior implants was comparable to the effect of increasing the number of implants to 6 on von Mises stress values in cortical bone. However, in cancellous bone, the effect of increasing the tilting of posterior implants on stress was slightly greater than the effect of increasing the number of implants to 6. In solid titanium models, the effect of both of the abovementioned parameters was comparable on stress in cancellous bone; but in cortical bone, the effect of increasing the implant number was slightly greater on stress reduction. Despite similar pattern of stress distribution in bone around implants, higher maximum von Mises stress values around tantalum implants indicate higher stress transfer capacity of this type of implant to the adjacent bone, compared with solid titanium implants.

Microstructure Optimization for Design of Porous Tantalum Scaffolds Based on Mechanical Properties and Permeability.

Porous tantalum (Ta) implants have important clinical application prospects due to their appropriate elastic modulus, and their excellent bone growth and bone conduction ability. However, porous Ta microstructure designs generally mimic titanium (Ti) implants commonly used in the clinic, and there is a lack of research on the influence of the microstructure on the mechanical properties and penetration characteristics, which will greatly affect bone integration performance. This study explored the effects of different microstructure parameters, including the fillet radius of the middle plane and top planes, on the mechanics and permeability properties of porous Ta diamond cells through simulation, and put forward an optimization design with a 0.5 mm midplane fillet radius and 0.3 mm top-plane fillet radius in order to significantly decrease the stress concentration effect and improve permeability. On this basis, the porous Ta structures were prepared by Laser Powder Bed Fusion (LPBF) technology and evaluated before and after microstructural optimization. The elastic modulus and the yield strength were increased by 2.31% and 10.39%, respectively. At the same time, the permeability of the optimized structure was also increased by 8.25%. The optimized microstructure design of porous Ta has important medical application value.

Optimize the pore size-pore distribution-pore geometry-porosity of 3D-printed porous tantalum to obtain optimal critical bone defect repair capability

The treatment and reconstruction of large or critical size bone defects is a challenging clinical problem. Additive manufacturing breaks the technical difficulties of preparing complex conformation and anatomically matched personalized porous tantalum implants, but the ideal pore structure for 3D-printed porous tantalum in critical bone defect repair applications remains unclear. Guiding appropriate bone tissue regeneration by regulating proper pore size-pore distribution-pore geometry-porosity is a challenge for its fabrication and application. We fabricated porous tantalum (PTa) scaffolds with six different combinations of pore structures using powder bed laser melting (L-PBF) technology. In vitro biological experiments were conducted to systematically investigate the effects of pore structure characteristics on osteoblast behaviors, showing that the bionic trabecular structure with both large and small poress facilitated cell permeation, proliferation and differentiation compared to the cubic structure with uniform pore sizes. The osteogenesis of PTa with different porosity of trabecular structures was further investigated by a rabbit condyle critical bone defect model. Synthetically, T70% up-regulated the expression of osteogenesis-related genes (ALP, COLI, OCN, RUNX-2) and showed the highest bone ingrowth area and bone contact rate in vivo after 16 weeks, with the best potential for critical bone defect repair. Our results suggested that the bionic trabecular structure with a pore size distribution of 200–1200 μm, an average pore size of 700 μm, and a porosity of 70 % is the best choice for repairing critical bone defects, which is expected to guide the clinical application of clinical 3D-printed PTa scaffolds.

Comparison of the Mechanical and Osseointegrative Performance of Porous Tantalum and Titanium for Acetabular Implantation in Total Hip Arthroplasty: A Literature Review

Introduction: Stability of the acetabular component is a critical factor in the success of primary and revision total hip arthroplasty (THA) procedures. As such, the identification of implant surface characteristics that maximize stability of the acetabular cup is an important research objective. While titanium has historically been the most commonly used implant material, the proportion of THA procedures utilizing porous tantalum (PTa) implants has increased in recent years. The objective of this review is to examine the comparative mechanical and osseointegrative performance of PTa and porous titanium (PTi) and interpret these results in the context of primary and secondary stability of acetabular implants in THA, as characterized by strength of initial mechanical attachment and successful interlocking at the bone-implant interface, respectively. Methods: A literature search using a predetermined protocol and inclusion criteria yielded 7 articles presenting results of comparative testing of mechanical performance or osseointegration of PTa and PTi in the context of THA. Results: Neither PTa nor PTi presented consistently superior results in mechanical tests designed to correlate to primary stability at the metallo-biological surface nor in measures of osseointegration intended to represent secondary stability in THA. Discussion: In comparing PTa and PTi, it appears that the characteristics of the implant coating's pores may have a more significant impact on factors affecting the stability of an acetabular cup implant than the metal selected. However, determining the ideal pore morphology for this application is complex; pore characteristics that would suggest mechanical compatibility may conflict with those that would encourage more effective osseointegration. Conclusion: When extrapolated to be indicators of hypothetical clinical success, the results of this review are consistent with those of recently released macro-analyses of clinical outcomes: PTa and PTi acetabular cups, as they are currently manufactured, produce clinically equivalent outcomes. In the development and comparison of coating options, pore morphology and its complex effects on stability must be adequately accounted for; only then can we reach a faithful conclusion regarding the ideal porous adhesion surface for acetabular implant in THA.

Long-Term Results of Anodic and Thermal Oxidation Surface Modification on Titanium and Tantalum Implants

Tantalum and titanium are two of the most popular materials used in dental implants today. These materials are highly biocompatible, durable, and long-lasting, making them ideal for use in dental and maxillofacial implants. The ceramic oxide layer that covers the surface of titanium and tantalum implants (TiO2,TaO2) is formed through an electrochemical growth from the inside of the metal and subsequently altered through heat treatment. The aim of this retrospective study was to evaluate the long-term survival of the oxide ceramic-coated titanium dental implants. The secondary purpose was to evaluate the production process and the cost of the coated tantalum and titanium implants, and to complete these retrospective investigations with the results of our previous work concerning the titanium oxide coating. The structural, physical, and chemical properties as well as the corrosion resistance of the Ti/TiO2 surface were investigated; XPS, SIMS, and XRD techniques were used. Patients who received tantalum oxide-coated (Ta/TaO2) dental implants, titanium oxide-coated (Ti/TiO2) dental implants, or titanium oxide-coated (Ti/TiO2) osteosynthesis plates for rehabilitation at the Department of Oro-Maxillofacial Surgery and Stomatology, Semmelweis University between 1995 and 2005 were included in this retrospective study. Data collection was performed between June 2021 and December 2021. The cost of the tantalum implant was 25 times that of the titanium implant. Only 21 implants were inserted in 10 patients. The survival rate (min. 16 years) was 95%. Twelve patients with a total of sixty-four TiO2-coated implants were observed. The mean implant survival rate was 95%. Our conclusion was that, regardless of the shape of the implant, the Ti/TiO2 coating proved its excellent durability over the years. The “tantalum issue” is increasingly relevant nowadays, since instead of implants made of pure tantalum metal, implants with a porous tantalum surface have come to the fore.

Preparation, modification, and clinical application of porous tantalum scaffolds.

Porous tantalum (Ta) implants have been developed and clinically applied as high-quality implant biomaterials in the orthopedics field because of their excellent corrosion resistance, biocompatibility, osteointegration, and bone conductivity. Porous Ta allows fine bone ingrowth and new bone formation through the inner space because of its high porosity and interconnected pore structure. It contributes to rapid bone integration and long-term stability of osseointegrated implants. Porous Ta has excellent wetting properties and high surface energy, which facilitate the adhesion, proliferation, and mineralization of osteoblasts. Moreover, porous Ta is superior to classical metallic materials in avoiding the stress shielding effect, minimizing the loss of marginal bone, and improving primary stability because of its low elastic modulus and high friction coefficient. Accordingly, the excellent biological and mechanical properties of porous Ta are primarily responsible for its rising clinical translation trend. Over the past 2decades, advanced fabrication strategies such as emerging manufacturing technologies, surface modification techniques, and patient-oriented designs have remarkably influenced the microstructural characteristic, bioactive performance, and clinical indications of porous Ta scaffolds. The present review offers an overview of the fabrication methods, modification techniques, and orthopedic applications of porous Ta implants.

Influence of porosity on osteogenesis, bone growth and osteointegration in trabecular tantalum scaffolds fabricated by additive manufacturing.

Porous tantalum implants are a class of materials commonly used in clinical practice to repair bone defects. However, the cumbersome and problematic preparation procedure have limited their widespread application. Additive manufacturing has revolutionized the design and process of orthopedic implants, but the pore architecture feature of porous tantalum scaffolds prepared from additive materials for optimal osseointegration are unclear, particularly the influence of porosity. We prepared trabecular bone-mimicking tantalum scaffolds with three different porosities (60%, 70% and 80%) using the laser powder bed fusing technique to examine and compare the effects of adhesion, proliferation and osteogenic differentiation capacity of rat mesenchymal stem cells on the scaffolds in vitro. The in vivo bone ingrowth and osseointegration effects of each scaffold were analyzed in a rat femoral bone defect model. Three porous tantalum scaffolds were successfully prepared and characterized. In vitro studies showed that scaffolds with 70% and 80% porosity had a better ability to osteogenic proliferation and differentiation than scaffolds with 60% porosity. In vivo studies further confirmed that tantalum scaffolds with the 70% and 80% porosity had a better ability for bone ingrowh than the scaffold with 60% porosity. As for osseointegration, more bone was bound to the material in the scaffold with 70% porosity, suggesting that the 3D printed trabecular tantalum scaffold with 70% porosity could be the optimal choice for subsequent implant design, which we will further confirm in a large animal preclinical model for better clinical use.

Effects of Unit Cell Topology on the Mechanical Properties of Porous Tantalum Structures via Laser Powder Bed Fusion

Additive manufacturing (AM) of porous tantalum scaffolds receives extensive attention because the demands for tantalum implants grow rapidly. Understanding the effects of unit cell topology on the mechanical properties of porous tantalum scaffold structures is critical for durable implant design, but it is still lacking. Herein, porous tantalum structures with two types of unit cells (body‐centered cubic [BCC] and body‐centered cubic deformation [BCC‐D]) are additively manufactured with laser powder bed fusion (LPBF). The geometric characteristics and mechanical properties of the manufactured structures are comparatively studied. It is found that the mechanical properties of BCC porous tantalum in the building and horizontal directions are discovered to be nearly identical, with elastic modulus and yield strength of nearly 1.9 GPa and 56 MPa, respectively. Unit cell topology dominates the mechanical anisotropy and compressive failure mode of porous tantalum. The mechanical properties of the BCC‐D topology are anisotropic, and the fracture morphology indicates that it is a cleavage fracture and a minor ductile fracture. The capacity to finely control the mechanical properties of porous tantalum structure through unit cell topology is prominent for optimizing implant structure for personalized medical care.

FEATURES OF BONE REMODELING AROUND SURFACE-MODIFIED TITANIUM AND TANTALUM IMPLANTS.

The aim: To study the osseointegrative properties of titanium and tantalum implants with different surface structures in animal experiments. Materials and methods: The histological and morphometric study was carried out on 60 male white rats after titanium implants with different surface structures made by 3D printed technology were inserted in the distal femur bone: presented by the multilayered layers of interlacing pores of 300 microns (series 1); rough (> 2 microns) (series 2); and tantalum implants with 300 microns pores and 80% porosity (series 3) as control material. Results: On the 30 days we found statistically significant differences in the bone-implant contact rate between the 2nd experiment series (44.77 ± 1.86)% and 1st (59.91 ± 2.86)% (p=0.000047) and 3rd (53.89 ± 2.11)% (р=0.000065), on the 90 days between the 2nd experiment series (51.26 ± 2.7)% and 1st (66.84 ± 2.63)% (p=0.000187) and 3rd (70.35 ± 4.32)% (p=0.000349). There was a difference between the indices of the bone-implant volume at day 90 between the 1st (48.43 ± 2.2)% and 2nd (36.88 ± 2.56)% series (p=0.000919), between the 2nd and 3rd series (51.2 ± 3.06)% (p=0.000107). There were no significant differences between the studied indices in the 1st and 3rd series of the experiment. Conclusions: Titanium implants with multilayered interlaced pore layers of 300 microns and tantalum with 300 microns pore size and 80% porosity may be promising. Rough-surface titanium also has osseointegrative qualities, but they are lower compared to other materials.

Operative management of metastatic disease of the acetabulum: review of the literature and prevailing concepts.

Metastatic disease of the periacetabular region is a common problem in orthopaedic oncology, associated with severe pain, decreased mobility, and substantial decline of the quality of life. Conservative management includes optimisation of pain management, activity modification, and radiation therapy. However, patients with destructive lesions affecting the weight-bearing portion of the acetabulum often require reconstructive surgery to decrease pain and restore mobility. The goal of surgery is to provide an immediately stable and durable construct, allowing immediate postoperative weight-bearing and maintaining functional independence for the remaining lifetime of the patient. A variety of surgical techniques have been reported, most of which are based upon cemented total hip arthroplasty, but also include porous tantalum implants and percutaneous cementoplasty. This review discusses the various reconstructive concepts and options, including their respective indications and outcome. A reconstructive algorithm incorporating different techniques and strategies based upon location and quality of remaining bone is also presented.

Outcomes of Hip Reconstruction for Metastatic Acetabular Lesions: A Scoping Review of the Literature

(1) Background: Management of metastatic periacetabular lesions remains a challenging area of orthopaedics. This study aims to evaluate and summarize the currently available reconstructive modalities, including their indications and outcomes. (2) Methods: A scoping review was carried out in accordance with PRISMA guidelines. Medline, EMBASE, and Cochrane were searched for relevant articles. (3) Results: A total of 18 papers met inclusion criteria encompassing 875 patients. The most common primary malignancy was breast (n = 230, 26.3%). Reconstruction modalities used were total hip arthroplasty (n = 432, 49.1%), the Harrington procedure (n = 374, 42.5%), modular hemipelvic endoprotheses (n = 63, 7.2%) and a reverse ice-cream cone prosthesis (n = 11, 1.25%). (4) Conclusions: Advances in implant design including use of dual mobility or flanged cups, tantalum implants, and modular hemipelvic endoprostheses allow for larger acetabular defects to be addressed with improved patient outcomes. This armamentarium of reconstruction options allows for tailoring of the procedure performed depending on patient factors and extent of periacetabular disease.

Emerging Concepts in the Surgical Management of Peri-Acetabular Metastatic Bone Disease.

The pelvis is a common site of metastatic bone disease. Peri-acetabular lesions are particularly challenging and can cause severe pain, disability and pathologic fractures. Surgical management of these lesions has historically consisted of cementoplasty for contained lesions and Harrington reconstructions for larger, more destructive lesions. Due to the limitations of these procedures, a number of novel procedures have been developed to manage this challenging problem. Percutaneous techniques—including acetabular screw fixation and cementoplasty augmented with screws—have been developed to minimize surgical morbidity. Recent literature has demonstrated a reliable reduction in pain and improvement in function in appropriately selected patients. Several adjuncts to the Harrington procedure have been utilized in recent years to reduce complication rates. The use of constrained liners and dual mobility bearings have reduced the historically high dislocation rates. Cage constructs and porous tantalum implants are becoming increasingly common in the management of large bony defects and destructive lesions. With novel and evolving surgical techniques, surgeons are presented with a variety of surgical options to manage this challenging condition. Physicians must take into account the patients’ overall health status, oncologic prognosis and anatomic location and extent of disease when developing an appropriate surgical plan.

Osseointegration of porous titanium and tantalum implants in ovariectomized rabbits: A biomechanical study.

BACKGROUNDToday, biological fixation of uncemented press-fit acetabular components plays an important role in total hip arthroplasty. Long-term stable fixation of these implants depends on the osseointegration of the acetabular cup bone tissue into the acetabular cup implant, and their ability to withstand functional loads.AIMTo compare the strength of bone-implant osseointegration of four types of porous metal implants in normal and osteoporotic bone in rabbits.METHODSThe study was performed in 50 female California rabbits divided into non-ovariectomized (non-OVX) and ovariectomized groups (OVX) at 6 mo of age. Rabbits were sacrificed 8 wk after the implantation of four biomaterials [TTM, CONCELOC, Zimmer Biomet's Trabecular Metal (TANTALUM), and ATLANT] in a 5-mm diameter defect created in the left femur. A biomechanical evaluation of the femur was carried out by testing implant breakout force. The force was gradually increased until complete detachment of the implant from the bone occurred.RESULTSThe breakout force needed for implant detachment was significantly higher in the non-OVX group, compared with the OVX group for all implants (TANTALUM, 194.7 ± 6.1 N vs 181.3 ± 2.8 N; P = 0.005; CONCELOC, 190.8 ± 3.6 N vs 180.9 ± 6.6 N; P = 0.019; TTM, 186.3 ± 1.8 N vs 172.0 N ± 11.0 N; P = 0.043; and ATLANT, 104.9 ± 7.0 N vs 78.9 N ± 4.5 N; P = 0.001). In the OVX group, The breakout forces in TANTALUM, TTM, and CONCELOC did not differ significantly (P = 0.066). The breakout force for ATLANT in the OVX group was lower by a factor of 2.3 compared with TANTALUM and CONCELOC, and by 2.2 compared with TTM (P = 0.001). In the non-OVX group, the breakout force for ATLANT was significantly different from all other implants, with a reduction in fixation strength by a factor of 1.9 (P = 0.001).CONCLUSIONTANTALUM, TTM, and CONCELOC had equal bone-implant osseointegration in healthy and in osteoporotic bone. ATLANT had significantly decreased osseointegration (P = 0.001) in healthy and in osteoporotic bone.

The increased oxygen content in tantalum leads to decreased bioactivity and osteogenic ability of tantalum implants.

Tantalum (Ta) implants fabricated by current processing techniques inevitably contain more or less oxygen impurities due to the extremely high melting point and high affinity of oxygen for Ta. Therefore, in this study we investigated whether oxygen impurities cause any effects on the bioactivity of Ta. EDS analysis demonstrated the surface oxygen content difference among different fabricated Ta samples, and the surface water contact angle (WCA) of Ta with high oxygen content (HO-Ta) was significantly higher than that of Ta with medium (MO-Ta) and low (LO-Ta) oxygen content. The in vitro cellular experiments showed that MC3T3-E1 cells on Ta with lower oxygen content exhibited better adhesion, growth, morphological development and in vitro osteogenic ability. Similarly, the in vivo animal experiments indicated the better bone regeneration and ingrowth performances of Ta with lower oxygen content. In addition, the highest ROS production was detected in the HO-Ta group, while the lowest in the LO-Ta group. This study suggests that the oxygen content within Ta, which occurs unavoidably due to technical limitations, negatively affects the bioactivity of Ta in a dose-dependent manner, indicating the need to develop techniques to produce orthopedic all-Ta implants.

Porous tantalum rod implantation is associated with low survival rates in patients with type C2 osteonecrosis of the femoral head but has no effect on the clinical outcome of conversion total hip arthroplasty: a retrospective study with an average 8-year follow-up

BackgroundOur study aimed to investigate the clinical outcomes and survival rates following porous tantalum rod surgery (PTRS) and conversion total hip arthroplasty (THA) subsequent to failed PTRS.MethodsA total of 38 subjects (40 hips) with osteonecrosis of the femoral head (ONFH) were included in this retrospective study between January 2008 and December 2011. All subjects were evaluated before surgery by using the Association Research Circulation Osseous (ARCO) classification system, the Japan Investigation Committee (JIC) classification and the Harris hip score (HHS). The endpoint of this study was set as final follow-up (including the survival time of PTRS and conversion THA). The rates of radiological progression were also evaluated. Patients who received conversion THA were further followed and compared to a control group of 58 patients with ONFH who underwent primary THA.ResultsThe mean follow-up time was 120.7 ± 9.2 (range, 104–143) months, and the overall survival rate was 75% at 96 months (ARCO stage II: 81.5%; stage III: 38.5%; JIC type C1: 83.3%; C2: 30%). The HHS before surgery was 59 (55–61), in contrast to 94 (91–96) at 96 months follow-up (P < 0.01). HHS in stage III show a significant poorer result compared to stage II at 24 months. HHS in Type C2 group show no significant difference compared to HHS before surgery at 24 and 60 months follow up (P = 0.91, P = 0.30). Twelve hips requiring secondary THA were followed for 66.9 ± 31.7 months, and control hips that underwent primary THA was followed for 75.4 ± 14.9 months. The HHS in the conversion group was 89 (86–93) and that in the primary THA group was 92 (79–95, P = 0.09) at the 5-year follow-up.ConclusionIn the mid-term follow-up, porous tantalum implants showed an encouraging survival rate in symptomatic patients in early stages (ARCO stage II) or with limited necrotic lesions (JIC type C1). In addition, our results did not demonstrated any difference between primary THA and conversion THA.

Short Term Clinical Outcome of a Porous Tantalum Implant for the Treatment of Advanced Osteonecrosis of the Femoral Head

Osteonecrosis of the hip mostly affects young individuals and often progresses to a debilitating disease. Several treatment modalities exist, but none are completely satisfactory. This study evaluates the clinical outcome of patients treated with core decompression and insertion of a porous tantalum implant in the femoral head. This procedure is similar to commonly performed procedures, but has the additional advantages of providing structural support to the necrotic femoral head while having no donor-site morbidity. We evaluated 15 patients with 18 osteonecrotic hips with Steinberg stage III (3 hips) and IV (15 hips) disease. The mean age of the patients was 42 years-old (eldest 66), and the mean time for follow-up was 23 months. The outcome measure was hip function, evaluated with the Harris hip score, and the end point was total hip arthroplasty, or referral for this procedure. The success rate at twelve months postoperatively was 77.8%, and the overall success rate was 44.5%. Failures occurred at a mean time of 11.7 months, and one complication, a periprosthetic fracture, occurred 4 months postoperatively. On average, patients who did well improved their Harris hip scores by 21.7 points, and patients who eventually required arthroplasty decreased their scores by 14 points. Core decompression with porous tantalum implants showed encouraging success rates and early clinical results in patients with advanced stage osteonecrosis, but further larger scale studies are required to identify the population best suited for this procedure.

Additively Manufactured Tantalum Implants for Repairing Bone Defects: A Systematic Review

Tantalum has unique advantages as a biomaterial for repairing bone defects due to its outstanding bioactivity, excellent corrosion resistance, and mechanical properties. Ideal implants for bone repair should be of good biocompatibility and bioactivity, as well as ability to simulate the microstructure and mechanical environment of human bone tissues. Additive manufacturing can facilitate freedom of design for the macrostructure/microstructure of bone implants with controlled mechanical properties; thus, this method has great potential. Additively manufactured tantalum implants provide a novel alternative for bone repair and are gaining increasing attention. This systematic review aims to comprehensively summarize the subsistent evidence from physicochemical, cellular, animal, and clinical studies on additively manufactured tantalum implants in repairing bone defects, for the first time. This work may provide researchers an essential grasp on the advances of additively manufactured tantalum implants. Impact statement Tantalum has unique advantages as a biomaterial. Additive manufacturing facilitates design freedom and additively manufactured tantalum is a novel alternative for bone repair. Studies on additively manufactured tantalum progress greatly, while no review summarizing the progresses was published.

Hydrothermal calcification surface modification of biomedical tantalum

Tantalum (Ta) as a new type of medical metal is now utilized in several orthopedic applications due to its excellent fracture toughness and workability, high corrosion resistance, good biocompatibility and X-ray visibility, but it lacks bioactivity. Therefore, pure Ta was hydrothermally calcified in CaHPO4 solution at 120–200 °C here for bioactive surface modification. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Raman spectroscopy analyses show that thin tantalum oxide film with a few calcium phosphate precipitates is formed at the surface after the treatment at 200 °C. The hydrothermally treated sample has good hydrophilicity and corrosion resistance evidenced by the water contact angle measurement and the potentiodynamic polarization test, respectively, and it can induce the formation of apatite layer after soaked in the simulated body fluid for 1 week. The present method would be applicable for bioactive surface modification of tantalum implants with irregular shapes and even porous structure.