Orthopedic Devices Research Articles

Mechanoregulation modelling of stretching versus bending dominated periodic cellular solids

With additive manufacturing advancements, the possibility of creating lattice-based 3D-printed implants can enhance the osseointegration of orthopedic devices. To this date, there is no study that characterizes Ti6Al4V lattice structure microscopic geometrical parameters based on mechano-regulatory theories. This research compared twenty-four different lattice topologies using bone ingrowth stimulations, at ten different relative densities (between 5 % and 50 %) subjected to four different pressures (0.5 MPa, 1 MPa, 1.5 MPa and 2 MPa). A total of 964 results from the numerical mechano-regulation analysis are presented. Sub-groups of Stretching-dominated lattice (SDL) and Bending-dominated lattice (BDL) topologies were compared. The analyzed topologies include AFCC, Auxetic, BCC, Diamond, FBCC, FCC, G7/ Octahedron, Kelvin cell, Vintile, Rhombic Dodecahedron, Cubic, Octet, Cuboctahedron, Rhombicuboctahedron, Iso-truss, Truncated Cube, Truncated Cuboctahedron, and BCCZ, FCCZ, FBCCXYZ and Cubic Center. Higher deformation and fluid flow were observed in BDL topologies leading to better mature bone growth stimulation compared to the SDL topologies. Topologies with lower Young’s Moduli were also leading to better growth stimulation. It is found that the most favourable BDL topologies include, BCC, Diamond, FBCC, G7, Octahedron. On the other hand, the most favourable SDL are Tetrahedron and Tesseract. Material selection design charts are created which will help in the design of novel Ti6Al4V lattice-based implants.

DISTAL RADIUS FRACTURES IN CHILDHOOD - OUR FIVE-YEAR EXPERIENCE

The most common fractures in children are those of the distal radius. There are relatively scanty publications devoted to this specific pathology in childhood. The timely diagnosis and proper treatment of the distal radius fractures are of undoubted significance. The purpose of the present communication is to share our recent practical experience with the management of the distal radius fractures in children. 2. Methodology. During the period between January 1, 2017 and December 31, 2021, 34 children at an average age of 10,85±3,00 years (between two and 17) with wrist joint injuries resulting in distal radius fractures were examined in the Clinic of Orthopedics and Traumatology, St. Anna Multiprofile Hospital of Varna. There were 21 boys at an average age of 11,43±3,39 years (between two and 17) and 13 girls at an average age of 9,92±2,38 years (between six and 12). Diagnosis was based on clinical and x-ray examinations. Therapeutic behavior included operative treatment, administration of analgesic means, immobilization, and, in some cases, subsequent rehabilitation. Surgery was accomplished under general anaesthesia in most cases. 3. Results. Mean age did not differ statistically reliably between both groups (t=1,524; p>0,05). The left radius fractures (13 in boys and 11 in girls) were statistically significantly more common than right radius ones (eight in boys and two in girls) (t=3,726; p<0,001). Most commonly, a closed reduction technique with or without internal fixation of the radius and ulna was made use of (in 15 boys and in seven girls) followed by reposition and fixation with one Kirschner wire (in one girl), with two Kirschner wires (in five boys and one girl), or with three ones (in five boys and two girls). An open reduction technique was applied in six boys and in six girls followed by reposition and fixation with one Kirschner wire (in one girl), with two Kirschner wires (in two boys and two girls), or with three ones (in two boys). It should be noted that internal fixation was not carried out in two boys and three girls. Control x-ray examination was performed in all the children. Cast immobilization for a period between 28 and 35 days, most often, for one month, was obligatorily done. Subsequently, Kirschner wires were removed in eight boys and in four girls. One complication was observed in a six-year old girl. It was caused by mechanical damage of the left wrist joint following the implantation of the internal orthopedic devices, i.e. three Kirschner wires. They were removed two months after the operation. Complete healing was achieved in all the children. 4. Conclusions. Based on these results of ours, the conclusion can be drawn that these surgical procedures along with the precise diagnosis and immobilization have proven to be safe and effective in the children with distal radius fractures. Obviously, modern strategies to successfully prevent the fractures in children should be developed.

In situ growth of Ca-Zn-P coatings on the Zn-pretreated WE43 Mg alloy to mitigate corrosion and enhance cytocompatibility

Magnesium (Mg) alloys are potential materials for orthopedic fixation devices but rapid degradation of the materials restricts wider clinical applications. Herein, zinc-incorporated calcium phosphate (Ca-Zn-P) coatings are prepared on the Zn-pretreated WE43 Mg alloy by a hydrothermal technique under relatively stable and favorable conditions. The hydrothermal coating consists of a compact bottom layer of CaZn2(PO4)2∙2 H2O and ZnO granular crystals and a jagged upper layer of CaHPO4. The Zn coating reduces the corrosion current density of WE43 to (3.49 ± 1.60) × 10−5 A cm−2, whereas the Ca-Zn-P/Zn composite coating further reduces it by 3 orders of magnitude in the simulated body fluid (SBF). The charge transfer resistances of the Zn-coated and Ca-Zn-P/Zn-coated alloys increase by 49 and 7176 times to 835 and 1.22 × 105 Ω cm2, respectively. The 7-day immersion results reveal that the Zn coating cannot provide long-term protection to WE43 in SBF because of the formation of galvanic couples between the Zn coating and WE43. In contrast, Ca-Zn-P/Zn-coated WE43 remains intact after soaking for 7 days and furthermore, the Ca-Zn-P coating self-repairs and continues to grow despite dissolution. The compact and adherent Ca-Zn-P bottom layer plays a major role in mitigating corrosion of WE43 by hindering penetration of the aggressive medium and charge transfer of the corrosion reactions resulting in only slight corrosion of the Zn layer. Biologically, the Zn coating reduces attachment and proliferation of MC3T3-E1 pre-osteoblasts on WE43, but the composite coating fosters cell adhesion and proliferation which stems from the good biocompatibility of the hydrothermal layer and relatively stable surface conditions avoiding severe corrosion.

Early orthodontic treatment of malocclusion in the mixed dentition

Children in the mixed dentition grow rapidly, and various types of malocclusion often appear in this period. At the same time, there are many environmental factors affecting the development of the occlusion at this stage. Functional abnormalities related to lip, tongue, articulation and breathing, and impacted teeth should be actively intervened and blocked to avoid the continued development of the deformity. Appropriate orthopedic devices should be used in patients with skeletal malocclusion, if necessary, for growth modification and the influence of congenital factors and the prognosis of treatment should be fully evaluated. Over-intervention of the temporary malocclusions in the mixed dentition should be avoided. In conclusion, early orthodontic treatment in the mixed dentition requires a comprehensive assessment of the treatment need, risks, timing, cost and the ultimate benefit of the patient. The timing of orthodontic treatment is not the sooner the better. The indications must be strictly controlled, and the necessity and limitations must be carefully considered.

A Review of Anodized TiNbSn Alloys for Improvement in Layer Quality and Application to Orthopedic Implants.

Titanium alloys are useful for application in orthopedic implants. However, complications, such as prosthetic infections and aseptic loosening, often occur after orthopedic devices are implanted. Therefore, innovation in surface modification techniques is essential to develop orthopedic materials with optimal properties at the biomaterial–bone interface. In this review, we present recent research on the improvement in the osteoconductivity and antibacterial effect of the Ti-33.6% Nb-4% Sn (TiNbSn) alloy by anodic oxidation and other related studies. TiNbSn alloys are excellent new titanium alloys with a low Young’s modulus, high tensile strength, and with gradient functional properties such as a thermally adjustable Young’s modulus and strength. Titanium dioxide (TiO2), when obtained by the anodic oxidation of a TiNbSn alloy, improves bone affinity and provides antibacterial performance owing to its photocatalytic activity. The safety of TiO2 and its strong bonding with metal materials make its method of preparation a promising alternative to conventional methods for improving the surface quality of orthopedic implants. Implementing anodization technology for TiNbSn alloys may alleviate orthopedic surgery-related complications, such as loosening, stress shielding, and infection after arthroplasty.

ULTRA-PRECISION DIAMOND PROCESSING OF BIODEGRADABLE AZ31 ALLOY FOR ORTHOPEDIC APPLICATION

The biodegradable magnesium (Mg) alloys have been acknowledged amongst the top potential biomedical materials for developing different orthopedic devices. Indeed, the processed Mg alloys’ surface integrity shows a substantial contribution to the resulting biomedical applications’ performance. In this paper, the effect of various influential process parameters of an ultra-precision diamond turning (UPDT), such as rotational frequency of spindle, tool overhanging (TOH), feed rate (FR), and depth-of-cut (DOC) on the chip formation, shearing mechanism, and surface finish of the biodegradable Mg AZ31 alloy have been studied. The resulting chips’ analysis of the different processing parameters has been studied to investigate the involved shearing mechanism. Besides, a relationship between the resulting surface topography and the consequences of UPDT-parameters on skewness ([Formula: see text]) and kurtosis ([Formula: see text]) was studied. The statistical analysis highlighted that the FR and TOH significantly influenced the surface roughness of the Mg AZ31 alloys at a 95% confidence level. Therefore, being statistically dominating, the morphology of the formed chip has also been influenced by FR and TOH’s parametric levels. The UPDT-processed Mg-alloy possessed a nano-finished surface that acted as hydrophobic and could prevent the surface from corrosion. In the light of experimental findings, the UPDT-processed Mg-alloy can be used for orthopedic screws and plates applications.

Corrosion resistance improvement of the Ti6Al4V/UHMWPE systems by the assembly of ODPA molecules by dip coating technique

Living with degenerative diseases, such as arthritis and osteoporosis, is challenging if orthopedic devices manifest adverse effects caused by corrosion processes. Ti6Al4V alloy is used to manufacture orthopedic implants due to its excellent mechanical and osseointegration properties. Nonetheless, it has poor resistance to wear and corrosion by biological fluids and mechanical activity. This degradation process generates the need to improve the corrosion resistance of metallic biomaterials used as biomedical implants. Dip-coating technique is a wet coating method used to lessen wear damage on the metal surface and can produce coatings using a wide variety of molecules at a low cost. In this work, Ti6Al4V alloys were coated with ultra-high molecular weight polyethylene (UHMWPE) and Octadecylphosphonic Acid (ODPA) films forming a UHMWPE/ODPA bilayer coating by dip-coating method to improve protection efficiency against corrosion in phosphate-buffered isotonic saline solutions and proposed it as alternative coatings to delay the failure of medical implants. The optimization of individual coated systems were obtained with an immersion time of 40 s (Ti6Al4V/UHMWPE) and 30 h (Ti6Al4V/ODPA) with corrosion current densities of 1.51 × 10−9 A cm−2 and 6.8 × 10−8 A cm−2, respectively. The formation of bilayer coatings reduces the average roughness from 19.34 nm (Ti6Al4V/UHMWPE) to 12.67 nm (Ti6Al4V/UHMWPE/ODPA). ODPA deposition on UHMWPE films changes the corrosion rate by interfering with the anodic and cathodic reactions, reducing the corrosion rate to 7.46 × 10−4 μm y−1 and an estimated corrosion protection efficiency of about 99.99 %. The results show a superior performance as a protective barrier over the individual films (1.19 μm y−1 with 97.2 %, and 0.026 μm y−1 with 99.9 %, ODPA, and UHMWPE, respectively), improving the corrosion resistance of the Ti6Al4V alloys.

Dynamic hip screw versus intramedullary nailing for the treatment of A1 intertrochanteric fractures: A retrospective, comparative study and cost analysis.

Objectives This study aims to compare sliding hip screw and intramedullary nail perioperative results and costs in two-part femoral fractures.Patients and methods Between January 2015 and December 2019, a total of 85 patients (70 males, 15 females; mean age: 85.6±9.5 years; range, 33 to 99 years) who were treated for intertrochanteric two-part femoral fractures were retrospectively analyzed. The patients were stratified and divided into two groups according to type of implant used for surgical fixation: one group treated with intramedullary proximal femoral nail (EBA) and the other with sliding hip screw (DHS). Comorbidity, hemoglobin level (Hb), hematocrit (hct) level, number of transfusions, and days of hospitalization details were evaluated. Postoperative X-rays were analyzed to assess the quality of reduction and to identify non-union, malunion, mechanical failures, and heterotopic ossifications. The modified Harris Hip Score, fracture mobility score, and Parker Mobility Score were calculated. Cost analysis considered the orthopedic device, operating room, transfusion, and hospital costs for the primary hospital stay.Results Of the patients, 44 were treated with DHS and 41 were treated with EBA nail by a single surgeon. No significant differences were found in the baseline demographic data. There was a significant increased operative time (p<0.001) and decreased fluoroscopy X-ray exposure time (p=0.031) in the subgroup of patients who underwent DHS fixation. The patients who underwent EBA nail fixation had a significantly higher transfusion rate during hospitalization (p=0.001) and a significantly lower Hb level and hct level on postoperative Day 1 and Day 3 (p<0.05). There were no significant differences in the clinical and functional scores, radiographic outcomes and mortality (p>0.05). The patients who underwent intramedullary nail fixation had higher costs.Conclusion Sliding hip screws showed decreased postoperative anemization, lower transfusion rates, and similar clinical outcomes compared to the intramedullary nail for two-part femoral fractures. Sliding hip screws should be preferred for A1 intertrochanteric fractures.

Screening and Characterization of Biofilm Forming Food Pathogens and their Biocontrol

Microorganisms grow as a complex aggregation on a solid substrate to form a biofilm. This film serves as a defensive tool for various pathogenic microorganisms at different stress conditions. A well developed biofilm forms a complex diverse structure of dormant and active bacterial colonies with their enzymes and its excretory products. The main features of biofilm forming bacteria are their ability for surface attachment, high population density and extracellular polymeric substances. Biofilm has positive effects on biotechnology but it is extremely harmful in industry and medicine. Numerous chronic infections are caused by bacterial biofilm. Besides, biofilm also causes various infections of biomaterial used in medicine such as intravascular urethral catheters, orthopedic devices, contact lenses, heart valves and vocal cord prosthesis. Biomaterials used in medicine such as intravascular urethral catheters, orthopedic devices, contact lenses, heart valves and vocal cord prosthesis also gets infected by biofilm. The proposed work was carried out to study the biofilm-forming ability of bacteria from different food items. These bacteria were isolated and tested for biofilm-forming ability using Congo red and microtiter plate assay. All strong biofilm producers were tested for antibiotic sensitivity. Enzyme profiling and molecular characterization were done. Morphological and biochemical characterization of isolates was also carried out.

Surface finishing of Nitinol for implantable medical devices: A review.

Nitinol (NiTi), a nickel-titanium alloy, has been used for various cardiovascular, orthopedic, fracture fixation, and orthodontic devices. As with most other metallic biomaterials, the corrosion resistance and biocompatibility of NiTi are primarily determined by the properties of the surface oxide layer such as thickness, chemical composition, structure, uniformity, and stability. Currently, a number of finishing methods are used to improve the properties of surface oxide of NiTi with an ultimate goal to produce a defect-free, impurity-free, thin homogeneous oxide layer that is stable and composed of only titanium dioxide (TiO2 ) with negligible amount of Ni species. This review discusses the effects of various surface finishing methods such as mechanical polishing, electropolishing, magnetoelectropolishing, heat treatments at different temperatures, passivation, chemical etching, boiling in water, hydrogen peroxide treatment, and sterilization techniques (steam autoclave, ethylene oxide, dry heat, peracetic acid, and plasma-based treatments) on the properties of a surface oxide layer and how it impacts the corrosion resistance of NiTi. Considering the findings of the literature review, a checklist has been provided to assist with choosing finishing/sterilization methods and relevant rationale and recommendations to consider when selecting a surface finishing process for NiTi used in implantable medical devices.

Evaluation of successful treatment of patients with unilateral functional crossbite

Purpose: Unilateral functional crossbite (UFCB) is one of the most common malocclusions in the deciduous and early mixed dentition stage. It is accompanied by lateral mandibular shift and mandibular midline deviation due to the narrow maxillary dental arch. The aim of this study was to assess the effects of early correction of UFCB with the Fränkel (FR–3) functional regulator.&#x0D; Methods: Ninety Caucasian subjects (32 boys and 58 girls) with UFCB in the early mixed dentition stage (mean age, 6 years and 8 months (SD±1.8)) were treated with the FR–3 functional regulator and monitored. The diagnosis was based on anamnestic data, clinical examinations, radiographs, and analyses of study cast models. Dental casts taken before and after treatment were used in the analysis of effects.&#x0D; Results: Treatment of UFCB involved expansion of the maxillary arch, removal of occlusal interferences, and elimination of the functional shift. The width of the maxilla increased by 2.90 mm (SD±1.63) in the canine region and by 2.78 mm (SD±1.60) in the molar region. Another advantage of early treatment was improvement of maxillary arch length deficiency secondary to maxillary constriction because the permanent incisors were afforded more space before or during eruption than if the crossbite was treated at a later age. At least one abnormal orofacial function was identified in 69 (76,67%) patients with UFCB. Aftertreatment, all crossbites were corrected, functional deviations were eliminated, and no relapses were observed during follow–up at 2 years and 8 months.&#x0D; Conclusion: The Fränkel functional regulator is a functional orthodontic–orthopedic device that is an effective alternative for the treatment of UFCB. Dental occlusion was significantly improved, and the prognosis for normal craniofacial growth and normal function of the stomatognathic system was enhanced.

Ten-Year Cephalometric Comparison of Patients With Cleft Palate who Received Treatment With Active or Passive Pre-surgical Orthopedic Devices.

Pre-surgical orthopedic (PSO) devices can be used in the management of patient with cleft lip/palate (CL/P) to narrow the alveolar gap (AG) prior to lip surgery. There are few studies comparing these 2 devices. The objective of this work was to compare the effects of active and passive PSO devices on facial growth in a single surgeon's cohort of patients with CL/P over a 10-year period. A retrospective review of all patients with CL/P in a single surgeon's practice from 2002 to 2018 was performed. Preoperative measurements of AG size were done using electronic calipers on patient molds. Patient radiographs were taken at 5 and 10 years of age and cephalometric landmarks were plotted using specialized software. Independent sample t-tests were used to compare means for maxillary, mandibular, vertical, and dento-alveolar growth parameters. Twenty patients with an active device and 23 patients with a passive device were included. No differences were observed in the basic demographic information between the two groups. At the time of lip repair, patients with a passive device had significantly larger horizontal AGs (P < .01), but by the time of palate repair, there was no difference between the two groups (P = .94). There was no significant difference in any growth measurements between the active and passive device groups at 5 and 10 years. Despite closing the AG more quickly, patients treated with an active device have no significant difference in facial growth at 10 years compared to patients treated with a passive device.

The FDA and Ensuring Safety and Effectiveness of Devices, Biologics, and Technology.

Orthopaedic devices account for nearly 20% of all devices on the market, with more than 600 novel orthopaedic devices cleared or approved by the FDA for marketing in the United States annually. Advances in technology and biologic therapies offer tremendous potential for patients with musculoskeletal ailments; however, it is important that the safety and effectiveness of these products be assessed to safeguard the public health. The FDA uses multiple different premarket pathways for devices, biologics, and combination products based on perceived risk of the novel product. More than 97% of orthopaedic devices go through the FDA's 510(k) pathway, which does not require clinical trials. The remaining high-risk devices must receive premarket approval and submit clinical trial data demonstrating safety and effectiveness. Similarly, high-risk biologics must obtain a biologics license application by submitting clinical trial data. Postmarketing surveillance strategies, including extended clinical trials or real-world evidence from registries, are increasingly being relied on by the FDA to expedite approval while also improving its capacity to identify problematic products.

Total Joint Arthroplasty Direct-to-Consumer Advertising by Medical Device Companies Lacks Patient Diversity

BackgroundObese and African American populations suffer from higher incidence of hip and knee osteoarthritis, yet African Americans are less likely to undergo total hip and knee arthroplasty (TJA). Patient interest in TJA is a necessary first step for surgery. Medical device company direct-to-consumer advertising for TJA represents 1 potential factor driving disparities in utilization. Here we analyze demographics of models represented in medical device company direct-to-consumer TJA advertisements to understand whether advertisement content correlates with the population in need. MethodsWe analyzed medical device company pamphlets, websites, and banner and video advertisements of the top 4 medical device companies in US arthroplasty sales, collected via ad-specific search engine and direct correspondence. Variables include model race, sex, age, and weight. Pearson likelihood ratio tests were used to compare categorical variables. ResultsOf the 116 advertisements collected, the model featured in the advertisement was white in 69.8%. The proportion of white models differed across medical device companies (company C, 75%) (P < .001) and advertisement type (video, 81.8%) (P < .001). Only 2.6% of advertisements featured obese models. Neither company C nor D, nor pamphlet or website advertisements used obese models. ConclusionsDirect-to-consumer advertising from the top 4 orthopedic US medical device companies does not represent the population in need: While TJA remains underutilized by African American/Hispanic patients, models were overwhelmingly white. While obese patients are known to need TJA, patients in the advertisements were overwhelmingly not obese. We advocate for medical device companies to refocus their advertising strategies to target diverse patients in need of TJA. Level of evidenceIII (retrospective cohort study).

Nanomechanical tribological characterisation of nanostructured titanium alloy surfaces using AFM: A friction vs velocity study

Medical-grade titanium alloys used for orthopaedic implants are at risk from infections and complications such as wear and tear. We have recently shown that hydrothermally etched (HTE) nanostructures (NS) formed on the Ti6AlV4 alloy surfaces impart enhanced anti-bacterial activity which results in inhibited formation of bacterial biofilm. Although these titanium alloy nanostructures may resist bacterial colonisation, their frictional properties are yet to be understood. Orthopaedic devices are encapsulated by bone and muscle tissue. Contact friction between orthopaedic implant surfaces and these host tissues may trigger inflammation, osteolysis and wear. To address these challenges, we performed simulation of the contact behaviour between a smooth control Ti6Al4V alloy and HTE surfaces against a hardwearing SiO2 sphere using Atomic Force Microscopy (AFM) in Lateral Force Microscopy mode. The friction study was evaluated in both air and liquid environments at high (5 Hz) and low (0.5 Hz) scan velocities. Lower scan velocities demonstrated opposing friction force changes between the two mediums, with friction stabilising at higher velocities. The friction measured on the NS alloy surfaces was reduced by ~20% in air and ~80% in phosphate buffered saline, in comparison to the smooth control surface, displaying a non-linear behaviour of the force applied by the AFM tip. Changes in friction values and cantilever scan velocities on different substrates are discussed with respect to the Stribeck curve. Reduced friction on nanostructured surfaces may improve wear resistance and aid osseointegration.

Effectiveness of the Fixtoe Device® in plantar pressure reduction: a preliminary study

BackgroundMetatarsalgia is a common foot condition. The metatarsophalangeal stabilizing taping technique described by Yu et al. has shown good clinical results as a provisional treatment in propulsive metatarsalgia. 35 The Fixtoe Device®, a novel orthopedic device, intends to simulate stabilizing tape. However, to date, there is no evidence of its effectiveness. The aim of this study was to assess plantar pressure changes using the Fixtoe Device®, in comparison with the traditional method (stabilizing tape) in a young, healthy sample thorough a cross-sectional study.MethodsMaximal pressure (Kpa) and pressure–time integral (Kpa/s) in the second metatarsal head were measured in twenty-four healthy volunteers. Registers were taken in four different conditions: barefoot, traditional stabilizing tape, Fixtoe Device® without metatarsal pad, and Fixtoe Device® with metatarsal pad.ResultsMean second metatarsal head maximal pressure and mean pressure–time integral showed statistical difference among the four analyzed conditions (p < 0.0001 in both cases). The improvement in maximal pressure and pressure–time integral obtained in each intervention also showed significance (p < 0.0001 in both cases). Comparing the improvement of the Fixtoe Device® with and without metatarsal pad with that of tape condition showed a moderate to high and moderate effect size for both peak pressure and pressure–time integral reduction.ConclusionsThe Fixtoe Device® reduces median maximal pressure and median pressure–time integral under the second metatarsal head in healthy young individuals. The Fixtoe Device® shows higher effectiveness than the traditional second metatarsophalangeal joint stabilizing taping technique. To our knowledge, this is the first investigation proving the effectiveness of the recently developed Fixtoe Device® in terms of plantar pressure modification, which leads the way to its use in clinics.

Analysis of different geometrical features to achieve close-to-bone stiffness material properties in medical device: A feasibility numerical study

Background and objectiveIn orthopedic medical devices, elasto-plastic behavior differences between bone and metallic materials could lead to mechanical issues at the bone-implant interface, as stress shielding. Those issue are mainly related to knee and hip arthroplasty, and they could be responsible for implant failure. To reduce mismatching-related adverse events between bone and prosthesis mechanical properties, modifying the implant's internal geometry varying the bulk stiffness and density could be the right approach. Therefore, this feasibility study aims to assess which in-body gap geometry improves, by reducing, the bulk stiffness. MethodsUsing five finite element models, a uniaxial compression test in five cubes with a 20 mm thickness was simulated and analyzed. The displacements, strain and Young Modulus were calculated in four cubes, each containing internal prismatic gaps with different transversal sections (squared, hexagonal, octagonal, and circular). Those were compared with a fifth full-volume cube used as control. ResultsThe most significant difference have been achieved in displacement values, in cubes containing internal gaps with hexagonal and circular transversal sections (82 µm and 82.5 µm, respectively), when compared to the full-volume cube (69.3 µm). ConclusionsThis study suggests that hexagonal and circular shape of the gaps allows obtaining the lower rigidity in a size range of 4 mm, offering a starting approach to achieve a “close-to-bone” material, with a potential use in prosthetic devices with limited thickness.

A coupled computational framework for bone fracture healing and long-term remodelling: Investigating the role of internal fixation on bone fractures.

In this study, a coupled computational modelling framework for bone fracture repair is presented that enables predictions of both healing and remodelling phases of the fracture region and is used to investigate the role of an internal fixation plate on the long‐term healing performance of a fracture tibia under a range of different conditions. It was found that introduction of a titanium plate allowed the tibia to undergo successful healing at higher loading conditions and fracture gaps, compared with the non‐plated versions. While these plated cases showed faster rates of repair in the healing phase, their performance was substantially different once they entered the remodelling phase, with substantial regions of stress shielding predicted. This framework is one of the few implementations of both fracture healing and remodelling phases of bone repair and includes several innovative approaches to smoothing, time‐averaging and time incrementation in its implementation, thereby avoiding any unwanted abrupt changes between tissue phenotypes. This provides a better representation of tissue development in the fracture site when compared with fracture healing models alone and provides a suitable platform to investigate the long‐term performance of orthopaedic fixation devices. This would enable the more effective design of permanent fixation devices and optimisation of the spatial and temporal performance of bioabsorbable implants.

Liquid Phase 3D Printing: How This New Technology Can Help Bring 3D Printing to the Operating Room.

The purpose of this review is to discuss the state of technology in liquid phase three-dimensional (3D) metal printing, how this has affected the field of orthopedic surgery, and changes that we can expect in the future with the rise of this printing technology. We will also discuss how liquid phase metal printing can possibly bring three-dimensional printing to the operating room. The use of liquid phase 3D metal printing may become commonplace for manufacturing orthopedic implants and devices. Traditional metal printing involved powder-based metals and high-energy beam technologies that are expensive, time-consuming, and potentially wasteful. This unfortunately leaves them out of reach for most end consumers such as orthopedic surgeons. Liquid phase metal printing is less expensive and faster. However, there is still major work required to bring this technology to the operating room and benefit patients. While major strides have been made in the field of liquid phase metal three-dimensional printing, there are still significant developments in the pipeline. These could lead to future production of personalized orthopedic implants and devices with optimal material properties for patients.

TiO2 Nanotubes Functionalized with Icariin for an Attenuated In Vitro Immune Response and Improved In Vivo Osseointegration.

Due to their superior mechanical and chemical properties, titanium (Ti) and its alloys have been widely used as orthopedic implantable devices. However, their bioinertness represents a limitation, which can be overcome by employing various surface modifications, such as TiO2 nanotube (TNT) fabrication via electrochemical anodization. Anodic TNTs present tunable dimensions and unique structures, turning them into feasible drug delivery platforms. In the present work, TNTs were loaded with icariin (Ica) through an adhesive intermediate layer of polydopamine (DP), and their in vitro and in vivo biological performance was evaluated. The successful fabrication of the modified surfaces was verified by scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), and contact angle measurements (CA), while the in vitro release of Ica was evaluated via UV-VIS spectrophotometry. In terms of in vitro behaviour, comparative studies on RAW 264.7 macrophages demonstrated that the TNT substrates, especially TNT-DP-Ica, elicited a lower inflammatory response compared to the Ti support. Moreover, the in vivo implantation studies evinced generation of a reduced fibrotic capsule around this implant and increased thickness of the newly formed bone tissue at 1 month and 3 months post-implantation, respectively. Overall, our results indicate that the controlled release of Ica from TNT surfaces could result in an improved osseointegration process.