Stress Shielding Of Bone Research Articles

Biomechanical Analysis of Axial Gradient Porous Dental Implants: A Finite Element Analysis.

The porous structure can reduce the elastic modulus of a dental implant and better approximate the elastic characteristics of the material to the alveolar bone. Therefore, it has the potential to alleviate bone stress shielding around the implant. However, natural bone is heterogeneous, and, thus, introducing a porous structure may produce pathological bone stress. Herein, we designed a porous implant with axial gradient variation in porosity to alleviate stress shielding in the cancellous bone while controlling the peak stress value in the cortical bone margin region. The biomechanical distribution characteristics of axial gradient porous implants were studied using a finite element method. The analysis showed that a porous implant with an axial gradient variation in porosity ranging from 55% to 75% was the best structure. Under vertical and oblique loads, the proportion of the area with a stress value within the optimal stress interval at the bone-implant interface (BII) was 40.34% and 34.57%, respectively, which was 99% and 65% higher compared with that of the non-porous implant in the control group. Moreover, the maximum equivalent stress value in the implant with this pore parameter was 64.4 MPa, which was less than 1/7 of its theoretical yield strength. Axial gradient porous implants meet the strength requirements for bone implant applications. They can alleviate stress shielding in cancellous bone without increasing the stress concentration in the cortical bone margin, thereby optimizing the stress distribution pattern at the BII.

Micromotion and stress shielding between taper fluted and cylindrical femoral stems for Paprosky bone deficiency type IIIB.

Taper fluted and cylindrical femoral stems have been commonly used for revision surgery with femoral bone loss. Shape and material differences between taper fluted and cylindrical confused surgeons whether superiority and inferiority in comparisons especially for type IIIB Paprosky bone deficiency. This study aims to investigate the micromotion between implant and bone interface and stress distribution around the implant in human cadaveric experiments. Paired comparisons of 7 cadavers between taper fluted stem and cylindrical stem were tested under dynamic cyclic loading. The results showed appropriate bone-implant micromotions for bone osteointegration could be observed between both taper fluted and cylindrical stems (85 ± 10μm and 113 ± 80μm respectively, p = 0.59). Taper fluted stem attained the load distribution from the proximal to distal surrounding bone (from 4.92 ± 2.87MPa to 2.14 ± 1.43MPa, p = 0.43), while the cylindrical stem type showed the proximal bone stress shielding (from 2.56 ± 0.76MPa to 5.23 ± 0.77MPa, p = 0.03). Both taper fluted and cylindrical femoral stems provided an adequate initial stability with a proper micromotions for bone-implant osteointegration for type IIIB Paprosky femoral bone loss. The taper fluted femoral stem had better biomechanical advantage in terms of greater stress transfer to periprosthetic bone.

Update on the research and development of magnesium-based biodegradable implants and their clinical translation in orthopaedics.

ABSTRACTBiodegradable magnesium (Mg) or its alloys are desirable materials for development into new-generation internal fixation devices or implants with high biocompatibility, adequate mechanical modulus, and osteopromotive properties, which may overcome some of the drawbacks of the existing permanent orthopaedic implants with regard to stress-shielding of bone and beam-hardening effects on radiographic images. This review summarises the current research status of Mg-based orthopaedic implants in animals and clinical trials. First, detailed information of animal studies including bone fracture repair and anterior cruciate ligament reconstruction with the use of Mg-based orthopaedic devices is introduced. Second, the repair mechanisms of the Mg-based orthopaedic implants are also reviewed. Afterwards, reports of recent clinical cases treated using Mg-based implants in orthopaedics are summarised. Finally, the challenges and the strategies of the use of Mg-based orthopaedic implants are discussed. Taken together, the collected efforts in basic research, translational work, and clinical applications of Mg-based orthopaedic implants over the last decades greatly contribute to the development of a new generation of biodegradable metals used for the design of innovative implants for better treatment of orthopaedic conditions in patients with challenging skeletal disorders or injuries.

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.

Effect of elbow implant design parameters on loosening: A finite element analysis

Loosening of an implant is the main complication after total elbow arthroplasty. The design parameters of the implant are a factor that contributes to the loosening of the implant. In this study, the correlation of loosening and geometry of the elbow implant component was investigated using the finite element method. Image processing software was used to construct elbow bones. Humeral and ulnar components were modeled with various cross-sections and flanges using modeling computer-aided design software. Modeling of all stems was based on conventional cemented fixation. Axial torsion and Anterior-posterior force were applied to the articular surface. Zero-displacement was applied to the proximal humerus and distal ulna. Bone graft was used between the flange and distal humerus bone. The stress shielding of bones and micro-motion were obtained in cement-implant-bone interfaces. Results showed that humeral and ulnar stems with modified diamond cross-section observed less micro-motion in the cement-bone-implant interfaces and as well as the least stress shielding in the distal humerus and proximal ulna compared to others. Furthermore, the modified flange, concave, transferred the least micro-motion to the bone-cement-implant interface and less stress shielding in distal humerus in comparison with trapezium and rectangular ones. This computational analysis represented a step in quantifying the role of interface micro-motion stress shielding of bone in initiating elbow implant loosening. A reduction of micro-motion and stress shielding through design modifications may improve the clinical outcomes.

Control of crystallographic orientation by metal additive manufacturing process of β-type Ti alloys based on the bone tissue anisotropy

Variation in the scanning strategy for β-type Ti alloys during additive manufacturing (AM) enables the fabrication of a singlecrystal-like microstructure possessing a crystallographic texture, in which the low-Young’s modulus-<100> direction is aligned along a specific direction. Thus, metal biomaterial with low elasticity, comparable to the bone Young’s modulus, can be developed by AM, which will contribute to suppress the stress shielding of bone and prevent degradation of bone tissue anisotropy.

Stress analysis in a bone fracture fixed with topology-optimised plates

The design of commercially available fixation plates and the materials used for their fabrication lead to the plates being stiffer than bone. Consequently, commercial plates are prone to induce bone stress shielding. In this study, three-dimensional fixation plates are designed using topology optimisation aiming to reduce the risk of bone stress shielding. Fixation plate designs were optimised by minimising the strain energy for three levels of volume reduction (i.e. 25%, 45% and 75%). To evaluate stress shielding, changes in bone stress due to the different fixation plate designs were determined on the fracture plane of an idealised shaft of a long bone under a four-point bending load considering the effect of a patient walking with crutches of a transverse fractured tibia. Topology optimisation is a viable approach to design less stiff plates with adequate mechanical strength considering high volume reductions, which consequently increased the stress transferred to the bone fracture plane minimising bone stress shielding.

Prediction of stress shielding around implant screws induced by three-point and four-point bending

Implant screws failure commonly occurs due to the load that constantly generated by the patient’s body to the fracture area. Bending load is often encountered in femur bone due to lateral impact which affected the bone and also the implants installed. Consequently, the load will lead to the failure of implants that can cause loosening or tightening of implants. Henceforth, in this manner, it is significant to study the bending behavior of bone implant in femur bone. The aim of this study was to analyze the stress shielding of bone implant on the internal fixator. 3D technique is able to show the overall deformation and stress distribution. The lower the biomechanical compatibility, the lower the STP value obtained. In addition, the variation of elastic modulus (E) of the screws materials, 200GPa (Stainless Steel) and 113.8GPa (Titanium) resulted in the increase of the total stress transferred (STP) between screw and bone interface. In this work, strain energy density (SED) was determined as a good indicator of stress shielding.

Superior fixation and less periprosthetic stress-shielding of tibial components with a finned stem versus an I-beam block stem: a randomized RSA and DXA study with minimum 5 years’ follow-up

Background and purpose — The stem on the tibial component of total knee arthroplasty provides mechanical resistance to lift-off, shear forces, and torque. We compared tibial components with finned stems (FS) and I-beam block stems (IS) to assess differences in implant migration.Patients and methods — In a patient-blinded RCT, 54 patients/knees (15 men) with knee osteoarthritis at a mean age of 77 years (70–90) were randomly allocated to receive tibial components with either a FS (n = 27) or an IS (n = 27). Through 5 to 7 years’ follow-up, implant migration was measured with RSA, periprosthetic bone mineral density (BMD) was measured with DXA, and surgeons reported American Knee Society Score (AKSS).Results — At minimum 5 years’ follow-up, maximum total point motion (MTPM) was higher (p = 0.04) for IS (1.48 mm, 95% CI 0.81–2.16) than for FS (0.85 mm, CI 0.38–1.32) tibial components. Likewise, total rotation (TR) was higher (p = 0.03) for IS (1.51˚, CI 0.78–2.24) than for FS (0.81˚, CI 0.36–1.27). Tibial components with IS externally rotated 0.50° (CI –0.06 to 1.06) while FS internally rotated 0.09° (CI –0.20 to 0.38) (p = 0.03). Periprosthetic bone stress-shielding was higher (p < 0.01) up to 2 years’ follow-up for IS compared with FS in the regions medial to the stem (–13% vs. –2%) and posterior to the stem (–13% vs. –2%). Below the stem bone loss was also higher (p = 0.01) for IS compared with FS (–6% vs. +1%) up to 1-year follow-up. Knee score improved similarly in both groups up to 5 years’ follow-up.Interpretation — Periprosthetic bone stress-shielding medial and posterior to the stem until 2 years, and tibial component migration at 5 years, was less for a finned compared with an I-shaped block stem design.Trial registration: ClinicalTrials.gov identifier: NCT00175136.

On the Potential of Bulk Metallic Glasses for Dental Implantology: Case Study on Ti40Zr10Cu36Pd14.

Ti40Zr10Cu36Pd14 Bulk Metallic Glass (BMG) appears very attractive for future biomedical applications thanks to its high glass forming ability, the absence of toxic elements such as Ni, Al or Be and its good mechanical properties. For the first time, a complete and exhaustive characterization of a unique batch of this glassy alloy was performed, together with ISO standard mechanical tests on machined implant-abutment assemblies. The results were compared to the benchmark Ti-6Al-4V ELI (Extra-Low-Interstitial) to assess its potential in dental implantology. The thermal stability, corrosion and sterilization resistance, cytocompatibility and mechanical properties were measured on samples with a simple geometry, but also on implant-abutment assemblies’ prototypes. Results show that the glassy alloy exhibits a quite high thermal stability, with a temperature range of 38 °C between the glass transition and crystallization, a compressive strength of 2 GPa, a certain plastic deformation (0.7%), a hardness of 5.5 GPa and a toughness of 56 MPa.√m. Moreover, the alloy shows a relatively lower Young’s modulus (96 GPa) than the Ti-6Al-4V alloy (110–115 GPa), which is beneficial to limit bone stress shielding. The BMG shows a satisfactory cytocompatibility, a high resistance to sterilization and a good corrosion resistance (corrosion potential of −0.07 V/SCE and corrosion current density of 6.0 nA/cm2), which may ensure its use as a biomaterial. Tests on dental implants reveal a load to failure 1.5-times higher than that of Ti-6Al-4V and a comparable fatigue limit. Moreover, implants could be machined and sandblasted by methods usually conducted for titanium implants, without significant degradation of their amorphous nature. All these properties place this metallic glass among a promising class of materials for mechanically-challenging applications such as dental implants.

Stress shielding in periprosthetic bone following a total knee replacement: Effects of implant material, design and alignment

Periprosthetic bone strain distributions in some of the typical cases of total knee replacement (TKR) were studied with regard to the selection of material, design and the alignments of tibial components to examine which conditions are more forgiving than the others to stress shielding post a TKR. Four tibial components with two implant designs (cruciate sacrificing and cruciate retaining) and material properties (metal-backed (MB) and all-polyethylene (AP)) were considered in a specimen-specific finite element tibia bone model loaded in a neutral position. The influence of tibial material and design on the periprosthetic bone strain response was investigated under the peak loads of walking and stair descending/ascending. Two of the models were also modified to examine the effect of selected implant malalignment conditions (7° posterior, 5° valgus and 5° varus) on stress shielding in the bone, where the medio-lateral load share ratios were adjusted accordingly. The predicted increases of bone density due to implantation for the selected cases studied were also presented.For the cases examined, the effect of stress shielding on the periprosthetic bone seems to be more significantly influenced by the implant material than by the implant geometry. Significant stress shielding is found in MB cases, as opposed to increase in bone density found in AP cases, particularly in the bones immediately beneath the baseplate. The effect of stress shielding is reduced somewhat for the MB components in the malaligned positions compared with the neutral case. In AP cases, the effect of stress shielding is mostly low except in the varus position, possibly due to off-loading of lateral condyle. Increases in bone density are found in both MB and AP cases for the malaligned conditions.

Evaluation of absorbable composite polylactide–hydroxyapatite bone fixation devices: a cohort study

BackgroundAt present, most bone fixation devices are made of metal, and are applied to prevent the postoperative dislocation of bone fragments. The major issues with such metal bone fixation devices are the necessity for secondary surgery to remove the devices, stress shielding of bone, stimulation and erosion of bone and soft tissue, and limited biocompatibility. To mitigate these problems, we aimed to assess use of a flexible absorbable polymer bone fixation devices. These devices were certified for use in China in September, 2015. MethodsIn this study, patients were treated at the First Hospital of Jilin University with absorbable fixation screws for fixation of non-weight-bearing bones (eg, metacarpal, phalange, talus, metatarsus, or inner ankle) or absorbable bone plates (eg, for hand, feet, ulna, or fibula fixation). Absorbable bone fixation devices were made from 90% by weight polylactide and 10% hydroxyapatite. Patients were followed up for at least 6 months, and evaluated clinically and radiographically at 3 months and 6 months after surgery. The ethics committee of the First Hospital of Jilin University gave ethical approval for the study and all patients provided written informed consent. FindingsBetween February, 2011, and July, 2014, 45 patients (62 screws; 33 men, 12 women; mean age 41·7 years [range 19–63; SD 12·5]) had absorbable fixation screws implanted and 45 patients (45 bone plates; 35 men, ten women; mean age 39·2 years [range 24–60; SD 10·4]) had absorbable bone plates. The flexural strength of the tested bone screw was ≥170 MPa and flexural modulus was ≥4000 MPa, and those of bone plate were ≥100MPa and ≥3000 MPa. The high mechanical properties met the requirements of clinical applications. No patients required revision surgery, and no device-related adverse events were observed during the 6 month follow-up period. 6 months after implantation, the fracture healing rates were both 100% for both absorbable bone fixation screw and plate. InterpretationAbsorbable polylactide–hydroxyapatite bone fixation screws and plates seemed safe and effective in this study. FundingNational Natural Science Foundation of China (grants 51303174, 51473165, and 51390484).

Lattice Ti structures with low rigidity but compatible mechanical strength: Design of implant materials for trabecular bone

The development of porous metals to alleviate the effects of stress shielding in bone will help improve the function of metallic biomaterials in orthopaedic applications. A critical step in advancing this technology is to design metallic structures with low rigidity that is comparable with bone tissue, but with good mechanical strength. In this study, porous titanium (Ti) structures with periodic cell topologies were designed to achieve tunable mechanical properties. The versatility of the design scheme was demonstrated by examining lattice designs with different stiffness properties achieved by using the Selective Laser Melting (SLM) technology. The fabricated porous Ti exhibited a low modulus of 1.05 GPa but a high compressive strength of 55 MPa. Large deformation analysis using digital image correlation (DIC) technique indicated uniform strain patterns at micro-trusses, suggesting the overall high quality of the structure with absence of local flaws. A functionally-graded stiffness design was further investigated by varying the diameters of micro-trusses within the structure. A stiffness graded material may be favourable for anatomical site that has strong depthdependent variations, such as in trabecular bone microstructures.

Stress shielding in bone of a bone-cement interface

Cementation is one of the main fixation methods used in joint replacement surgeries such as Total Knee Replacement (TKR). This work was prompted by a recent retrieval study [1,2], which shows losses up to 75% of the bone stock at the bone-cement interface ten years post TKR. It aims to examine the effects of cementation on the stress shielding of the interfacing bone, when the influence of an implant is removed.A micromechanics finite element study of a generic bone-cement interface is presented here, where bone elements in the partially and the fully interdigitated regions were evaluated under selected load cases. The results revealed significant stress shielding effect in the bone of all bone-cement interface regions, particularly in fully interdigitated region. This finding may be useful in the studies of implant fixation and other related orthopedic treatment strategies.

Graded elastic modulus orthopedic implants made of graded metastable beta ti alloy

Event Abstract Back to Event Graded elastic modulus orthopedic implants made of graded metastable beta ti alloy Eder N. Lopes1, Alessandra Cremasco2 and Rubens Caram1 1 University of Campinas, School of Mechanical Engineering, Brazil 2 University of Campinas, School of Applied Sciences, Brazil If the human body undergoes a traumatic event, a bone fracture can take place and fracture fixation implants, like bone-plates, are used to stabilize the bone fracture, limiting movements at the fracture site, leading to alignment of the fractured bone parts and allowing osseous healing [1]. In general, bones are less rigid than the bone fixation plate and consequently, mechanical stress imposed on the bone will be shielded by the plate and bone remodeling will occur [2]. While low elastic modulus bone-plate reduces the stress shielding in the fractured bone segments, it does not provide enough stability at the fracture site. A critical problem is to design a bone-plate that considers simultaneously the restriction resulting from bone stress shielding and the requirements of stability at the fracture site. The mechanical stress in a fractured bone fixed by stiffness-graded plates was simulated and the results were compared with stress distribution in bone fixed by stainless-steel plates [3]. The results suggested that stiffness-graded plates minimizea the stress shielding. An efficient way of generating a compromise between the bone stress shielding and the stability at the fracture site is the use of a stiffness-graded plate made of a Ti alloy. Mechanical behavior of β Ti alloys is related to processing conditions [4]. Depending on processing route, a β Ti alloys can exhibit a wide range of mechanical behaviors. While solution heat-treated and water quenched Ti alloy allows obtaining metastable β phase, with low elastic modulus, aging heat treatments to solution heat-treated and water quenched Ti alloy can result in high elastic modulus. The aim of this study is to discuss a new concept of fracture bone-plate made of β Ti alloy with graded stiffness used to minimize bone stress shielding. Samples based on Ti-Nb alloy were synthetized in arc melting furnace under inert atmosphere. They were hot rolled at 900 °C, resulting in plates measuring 3 mm in thickness and 120 mm long. These plates were solution heat-treated at 900 °C for 30 min under inert atmosphere and water-quenched. Then, localized aging heat treatment using heating induction was performed. While the center sections were heat-treated for 2 h at approximately 500 °C, the end sections were kept at room temperature. The β Ti sample that was solution-heat-treated and water-quenched showed β phase only. The same sample after aging at 500 °C for 2 h showed α phase in the β matrix. X-ray diffraction indicates that the initial microstructure was formed by β phase, while the application of aging led to precipitation of α phase. Elastic modulus was measured and the results suggest that high elastic modulus in obtained in the center part of the sample, while low elastic modulus is found far from the fracture. Application of solution heat treatment, water-quenching, and aging to β Ti alloys is able to tailor their mechanical behavior, allowing producing a graded elastic modulus bone fracture plates. The results also show that bone fracture plates with an elastic modulus ranging from 60 GPa to 110 GPa can be produced. The authors acknowledge the Brazilian research funding agencies FAPESP and CNPq for their financial support of this work.

Femoral hip stem prosthesis made of graded elastic modulus metastable β Ti Alloy

Abstract Ti alloys are frequently used in the manufacture of femoral stems for total hip arthroplasty. Although low elastic modulus stems minimize bone stress shielding, they also may produce micromotions at the bone/implant interface, leading to excessive interfacial mechanical stress at the proximal region. This phenomenon may lead to the growth of fibrous tissues and, eventually, implant failure. To address both restrictions simultaneously, stems with adjustable rigidity may be used. Considering that the rigidity of β Ti alloys can be controlled by heat treatments, this paper introduces a new concept for a femoral stem with a graded elastic modulus using metastable β Ti alloy. The combination of solution heat treatment, water-quenching, and aging heat treatments allows the mechanical behavior of the metastable β Ti alloys to be tailored and, in particular, be used to construct a graded elastic modulus femoral hip stem. The results obtained revealed that it is feasible to design biomedical implants from metastable β Ti alloys with hybrid mechanical behavior. The specific mechanical behavior is obtained by focusing only on heat treatments. A stem with an elastic modulus varying from 65 GPa to 110 GPa was obtained.

Control of Mechanical Properties of Three-Dimensional Ti-6Al-4V Products Fabricated by Electron Beam Melting with Unidirectional Elongated Pores

Aligned, unidirectional, elongated pores were incorporated in Ti-6Al-4V products fabricated by electron beam melting in order to control the mechanical properties of the products such that they became suitable for biomedical applications. Unidirectional pores were successfully produced when the scan spacing of the electron beam was greater than the diameter of the beam. By changing the scan spacing of the electron beam, the size of the unidirectional pores could be varied. As a result, both the Young’s moduli and the yield stresses of the products with unidirectional pores decreased linearly with an increase in their porosity, owing to the stress concentration coefficient being 1 in the equation representing the relation between strength and porosity for porous materials. Further, low (<35 GPa) Young’s moduli were obtained when the scan spacing was 1 mm or higher, with these values being were close to the typical Young’s modulus of human cortical bone. This suggested that these porous materials could be used to fabricate customized bone implants that exhibited desired mechanical properties and suppressed the stress shielding of bone that is normally noticed when implants made of Ti alloys are used.

Dual Plating of Humeral Shaft Fractures: Orthogonal Plates Biomechanically Outperform Side-by-Side Plates

Single large-fragment plate constructs currently are the norm for internal fixation of middiaphyseal humerus fractures. In cases where humeral size is limited, however, dual small-fragment locking plate constructs may serve as an alternative. The mechanical effects of different possible plate configurations around the humeral diaphysis may be important, but to our knowledge, have yet to be investigated. We used finite element analysis to compare the simulated mechanical performance of five different dual small-fragment locking plate construct configurations for humeral middiaphyseal fracture fixation in terms of (1) stiffness, (2) stress shielding of bone, (3) hardware stresses, and (4) interfragmentary strain. Middiaphyseal humeral fracture fixation was simulated using the finite element method. Three 90° and two side-by-side seven-hole and nine-hole small-fragment dual locking plate configurations were tested in compression, torsion, and combined loading. The configurations chosen are based on implantation using either a posterior or anterolateral approach. All three of the 90° configurations were more effective in restoring the intact compressive and torsional stiffness as compared with the side-by-side configurations, resulted in less stress shielding and stressed hardware, and showed interfragmentary strains between 5% to 10% in torsion and combined loading. The nine-hole plate anterior and seven-hole plate lateral (90° apart) configuration provided the best fixation. Our findings show the mechanical importance of plate placement with relation to loading in dual-plate fracture-fixation constructs. The results presented provide novel biomechanical information for the orthopaedic surgeon considering different treatment options for middiaphyseal humeral fractures.

Prediction of stress shielding around an orthopedic screw: Using stress and strain energy density as mechanical stimuli

Using finite element analysis, a parametric study was developed to compare stress and strain energy density (SED), in order to determine which stimuli might be better for predicting stress shielding in bone–screw models. Defined stimuli transfer parameters demonstrated that stress and SED (strong candidates for initiating the bone remodeling process) are transferred distinctively between an implant and bone. While small diameter angled threads increased transfer of both stimuli, reducing the screw's elastic modulus resulted in an increased transfer of stress; and unexpected decrease in SED, indicating that SED should be carefully examined in the context of future bone–screw models.

TAPERED FRACTURE FIXATION PLATE REDUCES BONE STRESS SHIELDING: A COMPUTATIONAL STUDY

Rigid fracture fixation plates offer stability to the fractured bone, but are known to result in stress shielding of the bone. This stress shielding results in bone resorption; which in-turn results in re-fracture of the bone after the bone-plate is removed. The aim of this research was to design a stiffness graded bone-plate to reduce the stress shielding effect. Stiffness grading of bone plate model was achieved by tapering the bone-plate along its length. A 3D finite element model of human femoral diaphysis and bone-plates with traditional design and tapered design were constructed using commercial finite element software Abaqus. These models were loaded in combined compression and bending, similar to the loads during walking. Stress distribution and the location of neutral axis were obtained for (a) Bone (b) Bone with traditional bone-plate and (c) Bone with tapered bone-plate. Results showed that tapered bone-plate results in substantial reduction in stress shielding in bone when compared to traditional bone-plate. The taper was optimized for reduction in stress shielding and adequate mechanical strength. We recommend tapered bone-plate instead of traditional uniform bone-plate for fracture fixation.