Orthopedic Surgical Implants Research Articles

Development and Evaluation of an AZ31 Magnesium Alloy and Eggshell Powder Composite for Orthopedic Surgical Implants

This research investigates the development and evaluation of a novel composite material composed of AZ31 magnesium alloy and eggshell powder, designed for use in surgical bone implants. The primary objective is to enhance the mechanical properties and biocompatibility of AZ31 by incorporating eggshell powder, which is known for its hardness and strength. The composite is fabricated using the stir casting technique, where the molten magnesium is mixed with finely ground eggshell powder to achieve uniform dispersion. The resulting samples are subjected to rigorous mechanical testing, including tensile and compressive strength evaluations, as well as hardness measurements. Additionally, the internal structure and particle distribution of the composite are analyzed using scanning electron microscopy and X-ray diffraction, respectively. This study aims to provide a comprehensive understanding of the material properties and structural characteristics of the composite, with a focus on its potential applications in orthopedic load-bearing implants and fixation devices, such as bone plates, joint replacements, screws, rods, dental implants, and cardiac stents. The findings are expected to contribute to the development of improved biomaterials for medical applications, leveraging the unique benefits of both magnesium alloy and eggshell powder.

Comparison of percutaneous distractor and arthroscopic-assisted screw fixation with open reduction and plate fixation for Sanders II calcaneal fractures treatment: A single-center retrospective cohort study

BackgroundAlthough the numerous advancements in orthopedic surgical techniques and implants witnessed in recent decades, the management of calcaneus fractures remains among the most complex challenges in the field. This study introduced a percutaneous distractor and arthroscopic-assisted screw fixation (PDA-CRSF) technique and compared its wound-related complications and clinical efficacy with open reduction and plate fixation with sinus tarsi approach (STA-ORPF) for treating Sanders II calcaneal fractures. Patients and methodsThis retrospective cohort analysis evaluated two patient cohorts with Sanders II calcaneal fractures received either STA-ORPF or PDA-CRSF using clinical indicators time to operation, operation duration, blood loss volume, hospital stay, wound healing complications, nerve damage, American Orthopedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot score, Visual Analogue Scale (VAS) score, and imaging indicators Gissane's angle (GA), Böhler's angle (BA), varus angle (VA), the length, height and width of calcaneal fractures, respectively. ResultsBetween March 2019 and March 2022, 23 patients underwent PDA-CRSF and 49 under STA-ORPF. The STA-ORPF group had fewer wound complications and nerve damage compared to the PDA-CRSF group (P < 0.05). Furthermore, the PDA-CRSF group exhibited shorter time to operation, reduced operation duration, decreased blood loss volume, and shorter hospital stay (P < 0.01). Three months after surgery, patients treated with PDA-CRSF also showed better scores on AOFAS (P < 0.01) and VAS (P < 0.05). However, at the final follow-up, the difference was not statistically significant (P = 0.222; P = 0.118). Both groups regarding radiographic indices had comparable outcomes at different postoperative follow-up stages. ConclusionThe results demonstrate that PDA-CRSF effectively reduces the risk of wound complications, shortens the surgical duration, expedites the time to surgery, and enhances post-operative rehabilitation.

822. Structural Damage and Biofilm Accumulation on Patient-Ready Orthopaedic Implant (Least Used Cortical Screws), Acquired through Loaner System

BackgroundThe acquisition of reusable medical devices through loaner system is a worldwide phenomenon. Single-use implants, such as orthopaedic screws, that remain in the surgical tray are subjected to multiple handling and reprocessing until they are implanted. Exposure to physical, chemical and biological agents may compromise their quality/safety and favor biofilm formation. The aim of this study was to assess the surface integrity and microbiological conditions of patient-ready orthopaedic surgical implants (least used cortical screws), provided through loaner system.MethodsAfter full reprocessing, clinical trays used for small fragment surgery (3,5) provided through loaner system to a large Brazilian teaching hospital were randomly selected between August to November 2019. Trays were opened in a biological safety cabinet and the least frequently used cortical screws (numbers 10 and 38), therefore, the ones most exposed to biological, chemical and physical agents, were randomly removed and subjected to bacterial culture (n = 3 screws/tray, 9 trays) and Scanning Electron Microscopy (SEM) (n= 1 screw/tray, 5 trays). The 27 screws were individually cultured in Tryptic Soy Broth (TSB), sonicated and vortexed, and incubated at 35oC for up to 28 days (screws were left in TSB). Positive cultures were plate out for automated bacteria identification.ResultsBacterial growth was identified in 2/27 screws. Three bacterial species were isolated, Staphylococcus hominis resistant to rifampicin and Kocuria rhizophila (screw A), and Micrococcus luteus (Screw B). Structural damage and soil were visualized on all screws subjected to SEM (5/5). Extensive biofilms were detected on three screws (3/5) (Figure 1).Figure 1. Scanning electron micrographs of patient-ready orthopaedic implants (screws), acquired through loaner system showing extensive biofilm, with incorporated bacilli/rods and/or cocci shape bacteria. ConclusionRecovery of bacteria, biofilm accumulation and structural damage were detected on patient-ready least frequently used orthopaedic cortical screws. Screws frequently remain in surgical trays for multiple reprocessing, thus, they are repeatedly exposed to contamination and possible damage. These findings point to the need to discuss and review the way these single-use implants are currently made available for surgery.Disclosures All Authors: No reported disclosures

A Newly Created Meso-, Micro-, and Nano-Scale Rough Titanium Surface Promotes Bone-Implant Integration.

Titanium implants are the standard therapeutic option when restoring missing teeth and reconstructing fractured and/or diseased bone. However, in the 30 years since the advent of micro-rough surfaces, titanium’s ability to integrate with bone has not improved significantly. We developed a method to create a unique titanium surface with distinct roughness features at meso-, micro-, and nano-scales. We sought to determine the biological ability of the surface and optimize it for better osseointegration. Commercially pure titanium was acid-etched with sulfuric acid at different temperatures (120, 130, 140, and 150 °C). Although only the typical micro-scale compartmental structure was formed during acid-etching at 120 and 130 °C, meso-scale spikes (20–50 μm wide) and nano-scale polymorphic structures as well as micro-scale compartmental structures formed exclusively at 140 and 150 °C. The average surface roughness (Ra) of the three-scale rough surface was 6–12 times greater than that with micro-roughness only, and did not compromise the initial attachment and spreading of osteoblasts despite its considerably increased surface roughness. The new surface promoted osteoblast differentiation and in vivo osseointegration significantly; regression analysis between osteoconductivity and surface variables revealed these effects were highly correlated with the size and density of meso-scale spikes. The overall strength of osseointegration was the greatest when the acid-etching was performed at 140 °C. Thus, we demonstrated that our meso-, micro-, and nano-scale rough titanium surface generates substantially increased osteoconductive and osseointegrative ability over the well-established micro-rough titanium surface. This novel surface is expected to be utilized in dental and various types of orthopedic surgical implants, as well as titanium-based bone engineering scaffolds.

What's New in Musculoskeletal Infection: Update on Biofilms.

Infections involving orthopaedic surgical implants present unique challenges when compared with infections that do not involve implants. Microorganisms have a high affinity for adhering to foreign materials commonly used in orthopaedics, including cobalt-chromium, titanium, polyethylene, and polymethylmethacrylate (PMMA) cement. When bacteria adhere to these surfaces, they can form a complex structure surrounded by a self-generated extracellular polymeric substance (EPS) matrix formed by multiplex agents of biopolymers consisting of proteins, polysaccharides, lipids, nucleic acids, and humic substances1-3. The term “biofilm” is commonly used to describe this network of microorganisms, a term popularized by Dr. J. William Costerton et al. in 19784. Biofilms are formed by a confluence of bacteria commonly encountered in orthopaedic infections. Up to 65% of bacterial infections are caused by biofilm-producing organisms5. Staphylococci, specifically Staphylococcus aureus ( S. aureus ) and Staphylococcus epidermidis ( S. epidermidis ), are the most common biofilm-forming bacteria found in orthopaedics, and, when combined with Pseudomonas aeruginosa ( P. aeruginosa ), they represent nearly 75% of biofilm infections observed in medical devices6. Propionibacterium acnes ( P. acnes ), an organism commonly found in shoulder infections, has also been shown to form biofilm. Biofilms can be composed of a single organism or can be polymicrobial; polymicrobial biofilms are more difficult to eradicate7. Once bacteria adhere to the surface of implants, they may replicate and may form a complex network of microorganisms that communicate with one another via cell-to-cell signaling that facilitates the participation of bacteria in quorum sensing7. Quorum sensing serves as an elementary endocrine system whereby bacteria sense the local cell population density and regulate gene expression by releasing extracellular molecules to facilitate synchronized changes in the bacteria within the biofilm. These transcriptional changes can occur with the exchange of plasmids between bacteria, which can confer genes …

Fatigue performance of medical Ti6Al4V alloy after mechanical surface treatments.

Mechanical surface treatments have a long history in traditional engineering disciplines, such as the automotive or aerospace industries. Today, they are widely applied to metal components to increase the mechanical performance of these. However, their application in the medical field is rather rare. The present study aims to compare the potential of relevant mechanical surface treatments on the high cycle fatigue (R = 0.1 for a maximum of 10 million cycles) performance of a Ti6Al4V standard alloy for orthopedic, spinal, dental and trauma surgical implants: shot peening, deep rolling, ultrasonic shot peening and laser shock peening. Hour-glass shaped Ti6Al4V specimens were treated and analyzed with regard to the material’s microstructure, microhardness, residual stress depth profiles and the mechanical behavior during fatigue testing. All treatments introduced substantial compressive residual stresses and exhibited considerable potential for increasing fatigue performance from 10% to 17.2% after laser shock peening compared to non-treated samples. It is assumed that final mechanical surface treatments may also increase fretting wear resistance in the modular connection of total hip and knee replacements.

&lt;italic&gt;In Vivo&lt;/italic&gt; Monitoring of Orthopaedic Implant Wear Using Amorphous Ribbons

The wearing process of an ultrahigh molecular weight polyethylene (UHMWPE) bearing surface in orthopaedic surgical implants cannot be tracked at present; hence, implant failure only becomes apparent when the patient experiences some discomfort. In exploring the integration of wireless stress sensors into UHMWPE, this paper describes the first step in achieving in vivo monitoring of implant wear using magnetostrictive amorphous ribbons.

Transparency to Reduce Surgical Implant Waste.

BackgroundRising health care costs and emphasis on value have placed the onus of reducing healthcare costs on the surgeon.MethodsFinancial data from 3,973 hip, knee, and shoulder arthroplasties performed at a physician owned orthopedic hospital was retrospectively reviewed over a two-year period. A wasted implant financial report was posted starting the second year of the study. Each surgeon's performance could be identified by his peers.ResultsAfter posting of the financial report, 1.11% of all hip and knee arthroplasty cases had a waste event compared to 1.50% during the control year. Shoulder arthroplasty waste events occurred twice as often than that observed in hip and knee arthroplasty during the study period. A decrease in waste events was observed but was not statistically significant (p = 0.30).ConclusionsPosting a non-blinded wasted implant data sheet was associated with a reduction in the number of wasted orthopedic surgical implants in this series, although the reduction was not statistically significant.

Characterization of HDH Titanium Powder for Biomaterial Applications

Several materials have been used as surgical implants since the 16th century. Materials can be implanted in the human body; however, the choice of the appropriate material is based on the required mechanical, physical, chemical, and biological properties. Until now two classes of metals namely stainless steel and cobalt-chromium-molybdenum alloys became known as materials for implant applications. They were considered suitable for surgical implant procedures but many researchers and surgeons were not completely satisfied with their performance. The main problem of the modern science is to find a material that perfectly restores tissues damaged after accidents or diseases. The trend of the current research in orthopedic prosthesis is based on the development of titanium alloys composed of non-toxic elements with low modulus of elasticity. Powder metallurgy techniques have beenused to produce controlled porous structures such as the porous coating applied for dental and orthopedic surgical implants which allows bone tissue grown within the implant surface, improving fixation. The development of porous metallic biomaterials associated with their biomedical applications is an important research area. To obtain a good one implant successful therapy the composition, size, form and topography of the alloys are extremely important.

Failure Analysis of Titanium-Based Dental Implant

Metallic materials designed for applications in orthopedic or dental surgical implants must show a group of properties, including biocompatibility, mechanical strength and resistance to degradation (by wear or corrosion) outstand. In order to assure that the properties are achieved, the implant materials must fulfill certain requirements, usually specified in standards. The standards also include chemical composition, microstructure and even macrographic aspects. The main aim of this work was to perform a failure analysis on a titanium-based dental implant and connect the possible causes of failure with the associated material requirements which were previously mentioned. Evaluation techniques included metallographic analysis by optical microscopy and fractographic analysis by scanning electron microscopy (SEM). The results of the examinations suggested that, in spite of their adequate microstructures, the implants fractured due to the overload generated by stress raisers which were found in the implants.

Treating natural disaster victims is dealing with shortages: An orthopaedics perspective

During natural disasters such as earthquakes or tsunamis, most of the casualties are known to suffer from musculoskeletal injuries. This leads to an enormous need of orthopaedic (surgical) implants such as osteosynthesis plates, which are difficult to provide in developing countries that rely on imported ones. One of the alternatives is utilization of local resources, but only after they have been proven safe to use, and meet the international standards set. Through this paper we would like to urge the international community to include locally produced biomedical products, like osteosynthesis plates in their scientific evaluations and communications. When the quality of local products is proven, the reluctance to use local products also by surgeons from developing countries will disappear and larger scale production can be initiated. This in its turn solves many problems that come after natural disasters and stimulates the national economy in an efficient and effective way.

Orthopädisch-chirurgische Implantate und Allergien

Orthopädisch-chirurgische Implantate und Allergien

Mechanical properties of metals for biomedical applications using powder metallurgy process: A review

The uses of biomaterials have been revolutionizing the biomedical field in deployment as implants for humans. During the past five decades, many implant materials made of metals have been put into practical use. Powder metallurgy techniques have been used to produce controlled porous structures, such as porous coatings applied for dental and orthopedic surgical implants, which allow bony tissue ingrowth within the implant surface, thereby improving fixation. This paper examines various important metals using powder metallurgy technology to produce elements of a total hip replacement. These alloys are 316L stainless steel alloy, Co−Cr−Mo alloy, and Ti−6Al−4V alloy. Also, this paper examines current information on the mechanical properties. Mechanical properties are discussed as a function of type of materials and process of fabrication. This article addresses the engineering aspects concerning the advantages and disadvantages of each type of material.

Coating analysis of implant materials used in orthopaedic surgery.

Biocompatibility of orthopaedic surgical implants with bone tissue allows adequate osseointegration between the bone and implant. To achieve this, implants are coated with biocompatible materials. The costly plasma spray procedure is routinely used to coat implants but uses high temperatures (over 16,000 degrees C), which affect the surface quality and microstructure of the implant. We analysed the effect of sintering temperature, time and rate on coated and uncoated implants using a dipping method. The effectiveness of synthetic hydrated calcium silicate compound as an interlayer was also investigated, using the dipping method and electrophoretic deposition. Sintering temperature, time and rate all affected the quality of the bond with the coating, but the interlayer bonded effectively with both implant and biocompatible coating. Electrophoretic deposition resulted in imperfect bonding and some irregularity on the substrate surface was seen. This technique may be improved by using coating particles of a smaller size.

Porous Structure Characterization in Titanium Coating for Surgical Implants

Powder metallurgy techniques have been used to produce controlled porous structures, such as the porous coatings applied for dental and orthopedic surgical implants, which allow bony tissue ingrowth within the implant surface improving fixation. This work presents the processing and characterization of titanium porous coatings of different porosity levels, processed through powder metallurgy techniques. Pure titanium sponge powders were used for coating and Ti-6Al7Nb powder metallurgy rods were used as substrates. Characterization was made through quantitative metallographic image analysis using optical light microscope for coating porosity data and SEM analysis for evaluation of the coating/substrate interface integrity. The results allowed optimization of the processing parameters in order to obtain porous coatings that meet the requirements for use as implants.

Evaluation of mechanical and corrosion biocompatibility of TiTa alloys.

As-received and heat-treated Ti40Ta and Ti50Ta alloys were evaluated to determine their corrosion as well as mechanical performances and compared to Ti6A14V, a common material utilized for orthopedic (surgical) implants. Anodic potentiodynamic tests performed in Plasmalyte showed that all samples, except for the Ti50Ta specimen aged at 400 degrees C for 3 h gave a curve similar to that of Ti6A14V. Optical and TEM microscopy was performed to determine as-received and heat-treated microstructures. As-received materials showed an alpha precipitate in an alpha+beta and martensite matrix. Samples that were aged at 400 degrees C increased in the density and the length of the alpha precipitate. Vickers hardness measurements were performed to get an approximation of the tensile strengths. Aged Ti40Ta and Ti50Ta specimens produced the highest tensile values when compared to the Ti6A14V material, representing a 31% and 56% increase for the 3 h samples and an 18% and 58% increase for the 10 h samples. Of all the materials studied the Ti50Ta specimen aged for 10 h exhibited the best biocompatibility showing excellent corrosion resistance combined with the highest tensile strength (1089 MPa and 58% harder/stronger than Ti6A14V).

Survivorship Analysis of Pedicle Spinal Instrumentation

Between 1985 and 1989, the senior author performed 120 consecutive pedicle instrumentation cases--78 Steffee (VSP) procedures and 42 procedures using Cotrel-Dubousset instrumentation. Posterolateral or posterior fusions using autogenous iliac bone graft were performed across the instrumented vertebrae in all cases. Survivorship analysis was used to calculate a predicted cumulative rate of success for this series of patients over 10 years postoperative follow-up. The criteria of failure of pedicular instrumentation or "death" of an implant were defined as 1) screw bending, 2) screw breakage, 3) infection, 4) loosening of implants, 5) any rod or plate hardware problems, or 6) removal of hardware due to a neurologic complication. Out of 526 pedicle screws (175 Cotrel-Dubousset screws, 351 VSP screws) there were 22 problem screws (22/526 = 4.18%). Six screws had bent, none were infected, 16 screws had broken, and none were loose. The 22 problem screw events occurred in 12 patients. In seven patients, the instrumentation failure was an incidental radiographic finding, in that patients had a solid posterolateral fusion. The remaining five patients had screw breakage in association with a pseudarthrosis. Life table calculations predicted the survivorship of instrumentation without complications would be 80% at 10 years postoperative follow-up. Actuarial analysis predicted the survivorship of solid posterolateral fusion at 90% at 10 years follow-up. This survivorship rate is similar to those predicted at 10 years follow-up for other more widely used orthopedic surgical implants such as total hip arthroplasty components.

Quartz and graphite filament reinforced polymer composites for orthopedic surgical application.

AbstractMaterials conventionally used for orthopedic surgical implants are primarily metallic alloys such as stainless steel 316L, Cr‐Co‐Mo alloys and recently titanium and Ti‐6A1‐4V alloy. Modulus of elasticity of these (E = 15 to 30 × 106 psi) is an order of magnitude higher than that of bone (approximately 3 × 106 psi). Quartz filament reinforced composites were formulated with E = 6 × 106 psi and flexural stress at rupture (modulus of rupture) of approximately 200,000 psi. Similarly graphite filament reinforced epoxy composites were formulated with E = 16 × 106 psi and flexural stress at rupture (modulus of rupture) of approximately 200,000 psi. Specimens of these materials were implanted in white rats subcutaneously. At sacrifice 90 days after implantation there was no evidence of any inflammatory process, although the implants were completely encapsulated. (Similar in vivo compatibility tests in rabbit muscle tissue are currently in progress.) No significant changes in mechanical properties could be measured in the implants after the 90‐day period of implantation. By adjusting the volume fraction of fibers in a given composite, the modulus of elasticity can be adjusted (with concomittant variations in strength) to meet the biomechanical and dynamic requirements of the appliance. A continuing program to investigate other biocompatible resins and other reinforcement is planned.