Composite Bone Plates Research Articles

Structural design and evaluation of bone remodeling effect of fracture internal fixation implants with time-varying stiffness

The stiffness of an ideal fracture internal fixation implant should have a time-varying performance, so that the fracture can generate reasonable mechanical stimulation at different healing stages, and biodegradable materials meet this performance. A topology optimization design method for composite structures of fracture internal fixation implants with time-varying stiffness is proposed, considering the time-dependent degradation process of materials. Using relative density and degradation residual rate to describe the distribution and degradation state of two materials with different degradation rates and elastic modulus, a coupled mathematical model of degradation simulation mechanical analysis was established. Biomaterial composite structures were designed based on variable density method to exhibit time-varying stiffness characteristics. Taking the bone plate used for the treatment of tibial fractures as an example, a composite structure bone plate with time-varying stiffness characteristics was designed using the proposed method. The optimization results showed that material 1 with high stiffness formed a columnar support structure, while material 2 with low stiffness was distributed at the degradation boundary and inside. Using a bone remodeling simulation model, the optimized bone plates were evaluated. After 11 months of remodeling, the average elastic modulus of callus using degradable time-varying stiffness plates, titanium alloy plates, and stainless steel plates were 8 634 MPa, 8 521 MPa, and 8 412 MPa, respectively, indicating that the use of degradable time-varying stiffness plates would result in better remodeling effects on the callus.

Effect of matrix material property on the composite tibia fracture plate: a biomechanical study.

For the purpose of fixing tibia fractures, composite bone plates are suggested. Metal plates cause stress shielding, lessen the compression force at the fracture site, and have an impact on the healing process because they are significantly more rigid than bone. To prevent excessive shear strain and consequent instability at the fracture site, it is imperative to reduce stiffness in the axial direction without lowering stiffness in the transverse direction. Only a carefully crafted fiber reinforced composite with anisotropic properties will suffice to accomplish this. The purpose of the current study is to examine the impact of axial and shear movements at the fracture site on the fixing of metal and composite bone plates. After modeling the tibia with a 1 mm fracture gap, titanium plates, carbon/epoxy, carbon/PEEK, and carbon/UHMWPE composite bone plates were used to fix it. There are 6 holes on each of the 103 mm long plates. To determine the stresses and axial movement in the fracture site, anatomical 3D Finite Element (FE) models of the tibia with composite bone plates are built. The simulations that were run for various composite plate layouts and types give suggestions for selecting the best composite bone plate. Although the matrix material causes some variations in behaviors, most of the plates perform as well as or even better than metal plates. Thus, the appropriate composite combinations are recommended for a given fracture structure.

Jute Fiber Reinforced Biocomposite: Towards Developing Composite Bone Plate

Bone fractures are often treated with metallic bone plates which are inherited some fundamental issues such as stress shielding, bone atrophy, heavyweight, corrosion, and so on. This work aims to develop a jute epoxy composite to investigate its feasibility to use as a composite bone plate. In this work, the natural fiber-based composite made of jute extracted from the jute plant and epoxy resin obtained from LAPOX® METALAM - B is studied experimentally. The mechanical properties such as tensile, compressive, and bending strength of jute/epoxy composite were measured using the universal testing machine (UTM). Moisture absorption test and scanning electron microscope (SEM) image analysis were also performed. The preliminary results suggest that the jute/epoxy composite could be a potential material for a composite bone plate. However, further detailed studies are required to confirm its applicability as a composite bone plate.

A novel carbon‐flax bioepoxy hybrid composite bone plate with enhanced bio‐mechanical performance

AbstractThis study aimed to pioneer a transformative approach in orthopedic implant design by developing and analyzing a groundbreaking carbon‐flax reinforced bioepoxy hybrid composite bone plate. The primary objectives of the present research were to enhance the bio‐mechanical performance of orthopedic implants and explore the potential applications of the novel material for orthopedic implants. Hybrid composite plate was fabricated mimicking the human bone with the soft inner core and a rigid outer coating. Mechanical properties for the hybrid composite were obtained through material characterization studies as per ASTM standards. The hybrid composite bone plates were tested as per bio‐mechanical test standard and the results were correlated with the finite element simulations. The maximum stress value in the experiments for the biomechanical four‐point bending tests was 331.74 MPa, and the corresponding strain value was 0.0337. The maximum equivalent stress and strain values obtained from simulation were in line with the findings of the experiments. The current research signifies a paradigm shift in orthopedic implant technology. The carbon‐flax bioepoxy hybrid composite offers remarkable potential for orthopedic applications, promising safer and more durable solutions for patients in need of bone repair or replacement.

Development of thermally responsive composite bone plates for maxillofacial trauma treatment

Development of thermally responsive composite bone plates for maxillofacial trauma treatment

Simulation of the biodegradable behavior of composite bone plate under human body environment

The Young’s modulus degradation of a biodegradable composite based on the exposure time to phosphate-buffered saline (PBS) solution was simulated by estimating the material’s effective diffusion coefficient. The relationship between PBS uptake rate and material removal was investigated by comparing the finite element analysis and experimental results, and a criterion for the material removal of finite elements was proposed for an accurate material degradation simulation. The diffusion coefficient was calibrated to determine the best fit for the PBS uptake rate based on exposure time. The degradation behavior of a bone plate made of a fully biodegradable composite was analyzed using a calibrated diffusion coefficient; it was found that the screw hole parts were severely damaged owing to PBS uptake, which induced premature structural failure. To address this drawback, a hybrid bone plate composed of a nondegradable composite and a Mg wire/Polylactic acid (PLA) composite was introduced; its serviceability was verified using finite element analysis.

Thermoforming of partially biodegradable hybrid thermoplastic composites for bone plate applications

This study introduces a partially biodegradable composite of carbon fibre/Nylon and Magnesium alloy (Mg) wire/polylactic acid (PLA) for bone fracture healing, focusing on its mechanical properties, with Young's modulus, flexural strength, and interlaminar shear strength investigated under different forming conditions. The Mg wires were subjected to mechanical and chemical treatments (with 80 and 220 grit sandpapers and phytic acid) to improve mechanical performance. Optimal treatment conditions were determined, and material test results were compared with microscopic observations. Using the recommended forming conditions, a hybrid composite bone plate was thermoformed for potential medical use.

An insight into the mechanical and tribological behavior of carbon-flax reinforced bioepoxy hybrid composite bone plates for orthopedic applications

Femur fractures are often treated by fixing metallic bone plates in the fractured area. But metallic bone plates are subjected to stress shielding. To overcome stress shielding, a material with similar strength and stiffness to that of the human bone can be better suited. The present study focuses on the fabrication of carbon-flax/bioepoxy hybrid composite. The femur bone plate was modeled using SOLIDWORKS®2020 3D modeling software package. Hybrid composite laminates were developed using compression molding technique and material characterization studies viz. Tensile, shear, flexural and wear tests were conducted on the ASTM shaped specimens to estimate the strength and wear properties of the fabricated hybrid composite. The results of the tests indicate that the Carbon-flax reinforced hybrid composite have properties similar to that of human femur bone and seems to be a better option for the replacement of metallic bone plates.

Surrogate model assisted design optimization of composite bone plates to achieve selective stress shielding

ABSTRACT Optimal composite bone plate is designed for Periprosthetic Femoral Fracture (PFF) fixation using genetic algorithm (GA) by hybrid and varying fiber orientation. The bone plate should allow higher displacement in axial direction and minimum movement in shear direction. Composite material is considered for the bone plate, the most important constraint in this design problem is that the axial movement and shear movement are limited to 2 and 0.5 mm, respectively. The simulated data from the finite element analysis (FEA) are used for creating the artificial neural network (ANN) surrogate models for the bone displacements in both the directions, which act as the objective functions for the GA-driven optimization in the multi-objective fashion. FEA is used to validate the solutions derived through the design optimization process. The FE simulations have shown only 10% deviation in the simulation output when compared to the achieved optimum solutions.

Investigation of Compression and Hardness for UHMWPE Bio-composites as Internal Bone Plate Fixation

Bone plates are essential for bone fracture healing because they modify the biomechanical microenvironment at the fracture site to provide the necessary mechanical fixation for fracture fragments. This paper addresses the use of composite bone plates in healing long-bone fractures such as transverse fractures of the femur. However, stress shielding in the bone due to metal plates can be reduced by designing implants with Bio-composites that involve Ultra high molecular polyethylene reinforced (UHMWPE) with Nano hydroxyapatite (n-HA) and Nano titanium dioxide (n-TiO2) particles at different weight fraction (0,1.5,2.5,3.5and 4. 5%) and 5% of carbon and Kevlar fibers. FRIT spectrum was used to identify the incorporation between the matrix and Nano particles, and the shifting in main peaks confirmed the good cross-linking within the composite structure. The specimens thus prepared were subjected to a compression test, hardness test, and density. The results indicated that UHMWPE+4.5%n-HA+CF hybrid biocomposite has the highest compressive strength and hardness properties. In contrast, UHMWPE+4.5%TiO2+CF has the highest density, which increased with increasing percentages of weight fraction of Nano-particles, where the compression strength 53 MPa, hardness property ranges 65.6 shore D, and density 1.09 (g/cm3). According to the current study's findings, it is possible to create bio-composites as internal fixation device with improved performance by placing different fiber reinforcements.

The influence of composite bone plates in Vancouver femur B1 fracture fixation after post-operative, and healed bone stages: A finite element study

Conventional stainless steel or titanium plates are used for bone fracture fixation to provide support at fracture location. Plates with high elastic modulus reduce the transfer of compressive load at the fracture location (due to stress shielding), causing failure. The objective of the study is to find for composite bone plates with different types of fibers and varied fiber orientations for post-operative (PO) and healed bone (HB) conditions which can reduce the stress shielding. Femur fracture fixation was constructed with 12 holes narrow type with metal and composite bone plates. The fracture gap was constructed with soft bone region for post-operative (PO) condition and harder bone for healed bone (HB). Composite bone plates with different configurations (fiber directions) and types (thickness and width) were analyzed to study the stress distribution and movement in the fracture location. The models were analyzed and the stresses in plate and callus, movement and strain in axial and shear direction in both metal and composite bone plates were studied. The metal and composite plates (carbon fiber/epoxy, fiberglass/epoxy, and flax/epoxy) used for most common Vancouver type B1 fracture to observe the biomechanical behavior of different models in PO and HB condition. The FE simulation on different configurations and types of composite plates provide in-depth idea about choosing the suitable composite bone plate. There are variations in behavior for varying types and configurations, but the performance of most of the plates are either better or similar to that of metal plate, except the plates with higher width.

Metal and composite bone plates for B1 periprosthetic femoral fracture in healthy and osteoporotic condition: A comparative biomechanical study.

The major concern after total hip arthroplasty (THA) is the incidence of periprosthetic fracture in the weaker bone, which can lead to subsequent revision surgery. Achieving the suitable fixation without affecting the stability of the well-fixed prosthesis remains controversial. Most of the studies examined the behavior of the Periprosthetic Fracture (PF) fixation (Vancouver "B1" type) through computational and experimentation on healthy bone condition with metal plates. The aim of the present study is to analyze the influences of the metal and composite bone plate PF fixation on the axial and shear movement at the fracture site. The PF fixation constructs were modeled with medical graded stainless-steel plate (construct A), titanium plate (construct B) and carbon/epoxy composite bone plate (construct C) with 12 holes and a 4 mm fracture gap. Analysis was carried out for all the stages (stage 1-Normal bone, stage 2-THA, stage 3-Immediate Post-Operative (IPO), stage 4-Post-Operative (PO) and, stage 5-Healed Bone (HB)) under various loadings for intact and osteoporosis conditions. The results showed higher stress in cortical bone for stage 3, whereas in all the other stages lower stresses were experienced in the cortical and cancelous bone under peak load in construct C for osteoporosis model compared with other constructs. The present study suggested the construct C may be suitable for osteoporosis bone conditions.

Finite element analysis of biodegradable Ti/polyglycolic acid composite bone plates based on 3D printing concept

Dense metallic bone plates often cause stress shielding, delayed healing, or bone non-unions. Therefore, three-dimensional models of partially biodegradable titanium/polyglycolic acid (Ti/PGA) composite cubes with strut thicknesses of 0.33–1.25 mm were designed to achieve different mechanical properties, and compressive simulations of these models were performed to construct stress–strain plots. Finite element models of these plates were assembled with tibial bone fractures using six bicortical screws. Callus volumes were predicted using a rejection coefficient algorithm, and a mechanoregulation algorithm based on deviatoric strain and fluid flow was employed to simulate the healing process. The effective Young’s moduli were 12.13–84.6 GPa during the first week and 4.4–80 GPa during the sixth week, while the callus volume increased after reducing the Young’s modulus of the bone plate. Thus, the additively manufactured design of biodegradable bone plates can be controlled to achieve the appropriate initial Young’s modulus and degradation rate.

Evaluation of the effect of bone plate modulus on the early bone healing of fractured tibia

Metallic implants with high Young's moduli are used to treat long-bone fractures; however, they cause stress shielding and prevent bones from attaining their original strength. Thus, flexible composite implants have been designed to enhance tissue development without stress shielding. Herein, 3D-printed composite bone plates with different Young's moduli were designed, and their effects on 3D models of long-bone fractures were analysed. A biphasic mechano-regulation algorithm, coupled with cell diffusion and tissue phenotype activities, was developed using a Python script to analyse bone-healing patterns for 112 days after surgery. A composite bone plate (Young's modulus, 40 GPa) showed the best healing performance (100%), compared with a stainless-steel bone plate (70%). Further, cell and tissue development using bone plates with different Young's moduli under different loading conditions are presented.

Optimization of 3D Printing Parameters of Biodegradable Polylactic Acid/Hydroxyapatite Composite Bone Plates.

The building parameters of three-dimensional (3D) printed polylactic acid/hydroxyapatite (HA) composite bone plates were optimized by an orthogonal experiment, and the effects of the layer thickness, printing speed, filament feeding speed, and HA content on the bending strengths of the specimens were analyzed. The deformation characteristics of the specimens were studied by 3D full-field strain analysis, and the internal defects of the specimens were analyzed. The effects of different combinations of the process parameters on the cross-sectional shape of the single deposited line, printing temperature, and pressure of the molten material were further analyzed. The results showed that the factors affecting the bending properties were the layer thickness, printing speed, filament feeding speed, and HA content, successively. The optimized process parameters were an HA content of 10%, a layer thickness of 0.1 mm, a printing speed of 30 mm/s, and a filament feeding speed of 0.8 mm/s, and the optimized specimen bending strength was 103.1 ± 5.24 MPa. The deposited line with a flat section shape and width greater than the print spacing helped to reduce the porosity of the specimens. The process parameters that resulted in large high-temperature areas and a high extrusion pressure could better promote material fusion.

Experimental study on magnesium wire–polylactic acid biodegradable composite implants under in vitro material degradation and fatigue loading conditions

This study investigated the fatigue life of biodegradable magnesium wire–polylactic acid (Mg/PLA) composite implants during the initial patient rehabilitation period under physiological loads through experimental and finite element methods. Under a simulated body fluid condition, the fatigue life was observed to be completely affected by material degradation, which accelerated the pitting corrosion of the composite bone plate. The mechanical behaviour of Mg/PLA composite bone plate was investigated under physiological loading conditions for the case of a tibial fracture with a 3 mm gap. A three-point bending fatigue test setup was employed to validate the fatigue characteristics of composite specimens. Finally, to alleviate the generated stress and enhance the fatigue resistance of fully biodegradable composites, a hybrid composite bone plate is proposed. At the screw section, the hybrid composite is partly composed of a comparatively more fatigue-safe non-degradable glass–polypropylene composite, which improves the healing performance of the fractured tibia.

Analysis of carbon fibre bone plate for “B1” type periprosthetic femoral fracture

Peri-prosthetic Fractures after Total Hip Arthroplasty (THA) are a dreaded complication which happen frequently due to aging and day to day normal activities of the patient. These fractures happen below the cemented/uncemented stem, either straight/oblique direction concerning the transverse plane. Treatment requires surgical stabilization using metal plates, screws, cables and/or clamps. However, stress shielding in bone due to metal plates can be reduced by designing implants with fibre reinforced polymer composites. The present study aims to study the stress distribution in a composite plate using carbon fibre for a B1 type periprosthetic femoral fracture fixation in immediate postoperative (IPO) condition and compared with metal plate by varying geometrical parameters, laminate stacking sequence and fibre orientation. To evaluate the axial stiffness and surface stress of composite plate fixation finite element (FE) analysis was done. Various parameters like axial movement, shear movement, strain and maximum stress are considered to measure the fracture stability and the healing process through FE method. The results showed that the proposed composite bone plate could be a potential candidate for replacement of metallic bone plates for periprosthetic fracture in the femur.

A biomechanical study on the laminate stacking sequence in composite bone plates for vancouver femur B1 fracture fixation

Background and objectivesComposite bone plates are proposed for fracture fixation in periprosthetic femoral fracture. Metallic plates, having high stiffness compared to bone lead to stress shielding, reduce the compression force in the fracture site, affectthe healing process. Reduction of stiffness in the axial direction due to above reason without lowering the stiffness in transverse to avoid much of shear strain and thus avoiding instability at the fracture site leads to selective stress shielding. This can only be achieved through meticulously designed fiber reinforced composite. In the present work varied fiber orientations in the stacked laminates with varied fiber types are employed in a post-operative femur fixation for the in-silico analyses of their effectiveness using finite element analysis. MethodsIn this study a Total Hip Arthroplasty (THA) model is constructed with composite bone plates. Three-dimensional narrow type metal plate is modeled with 12 holes and length of 194 mm. Three different types of composite bone plates are modeled with 12 holes of different size for the analysis i.e. Type 1 (5.6 mm thickness and 16 mm width), Type 2 (6 mm thickness and 16 mm width) and Type 3(6 mm thickness and 18 mm width). Anatomical 3D FE models of THA with composite bone plates are constructed to find out the interfacial stresses and strains. The finite element software ANSYS is used to perform the analysis. ResultsA three-dimensional FE model of immediately post-operative femur fixation is developed and studied the maximum stress distribution, strain and movement in axial/shear direction in the metal and composite bone plate near to the fracture site. In the present study, the metal and composite plate (carbon/epoxy, glass/epoxy and flax/epoxy) used for most common Vancouver type B1 fracture to observe the biomechanical behavior of different models in IPO condition using FEA. ConclusionsOptimizing the fiber orientations of composite bone plates of Total Hip Arthroplasty (THA) model by controlling the biomechanical stresses could be a favorable approach. The finite element analysis approach gives a viable solution to design the composite bone plate and for designing future models that preserves the biomechanical function of THA with composite bone plate.

Comparative study of healing fractured tibia assembled with various composite bone plates

This study introduces innovative hybrid-type (Magnesium wire/poly-lactic acid–glass/polypropylene composite (Mg/PLA–Twintex[0]2nT) and bio glass fibers/poly-lactic acid–glass/polypropylene composite (BGF/PLA–Twintex[0]2nT)) partially biodegradable composites for comparison with conventional metallic stainless steel (SS) and fully biodegradable composite bone plates (i.e. Mg/PLA and BGF/PLA), as well as for analyzing their effect towards the healing of fractured healthy and diseased bones. Two different diffusion coefficients are introduced as the biological parameter (0.01 and 0.04 mm2/day) to mimic the blood supply of the diseased and healthy bones. The time-dependent tainted mechanical properties of the degradable composites are implemented to the degradable parts of the bone plates. As hypothesised, we found stress alleviations of 72.36%, 58.82%, 64.82%, and 59.71% in the screws with the diseased bones and alleviations of 84.64%, 72.67%, 77.26%, and 70.8% with the healthy bones in the BGF/PLA, Mg/PLA, BGF/PLA–Twintex[0]2nT, and Mg/PLA–Twintex[0]2nT composite bone plates, respectively. These results were then compared with those for the SS plates on the 28th day of healing. The maximum healing performance was predicted for the hybrid composites as opposed to the degradable and SS implants, thereby confirming the superiority of the proposed composites.

Evaluation of unidirectional BGF/PLA and Mg/PLA biodegradable composites bone plates-scaffolds assembly for critical segmental fractures healing

This novel study presents the application of biodegradable bio-glass fibers (BGF)/polylactic acid (PLA) composite and magnesium (Mg) wires (fluoride-coated)/PLA composite bone plates, and stainless steel (SS) bone plate were assembled with PLA and titanium scaffolds (40%, 60%, 80% porous and functionally graded porous) to investigate the healing of critical segmental fractures. BGF/PLA composite bone plate (Young’s modulus 27.45 GPa) exhibited a high degradation rate that favored the healing for the first three weeks but poor final healing, however, the fluoride-coated Mg/PLA (Young’s modulus 13.27 GPa) composite bone plate showed lower degradation rate with enhanced final healing. About the calluses' healing status in case of fluoride-coated Mg/PLA composite bone plate, the average Young’s modulus of tissue phenotypes was 10.61%, 35.95%, and 20.16% higher with 80%, 60%, and 40% porous scaffolds, respectively, in comparison with the worst case of SS bone plate on day 60. These results revealed the potential applications of biodegradable composites in healing of critical bone fractures.