3D Printing of Ti-6Al-4V-Based Porous-Channel Dental Implants: Computational, Biomechanical, and Cytocompatibility Analyses.

Objective: Loosening of dental implants due to resorption of the surrounding bone is one of the challenging clinical complications in prosthetic dentistry. Generally, stiffness mismatch between an implant and its surrounding bone is one of the major factors. In order to prevent such clinical consequences, it is essential to develop implants with customized stiffness. The present study investigates the computational and experimental biomechanical responses together with cytocompatibility studies of three-dimensional (3D)-printed Ti-6Al-4V-based porous dental implants with varied stiffness properties. Methods: Additive manufacturing (direct metal laser sintering, DMLS) was utilized to create Ti-6Al-4V implants having distinct porosities and pore sizes (650 and 1000 µm), along with a nonporous (solid) implant. To validate the compression testing of the constructed implants and to probe their biomechanical response, finite element models were employed. The cytocompatibility of the implants was assessed using MG-63 cells, in vitro. Results: Both X-ray microcomputed tomography (µ-CT) and scanning electron microscopy (SEM) studies illustrated the ability of DMLS to produce implants with the designed porosities. Biomechanical analysis results revealed that the porous implants had less stiffness and were suitable for providing the appropriate peri-implant bone strain. Although all of the manufactured implants demonstrated cell adhesion and proliferation, the porous implants in particular supported better bone cell growth and extracellular matrix deposition. Conclusions: 3D-printed porous implants showed tunable stiffness properties with clinical translational potential.

Design and manufacturing of patient-specific Ti6Al4V implants with inhomogeneous porosity.

Stress shielding remains a challenge in orthopaedic implants, including total hip arthroplasty. Recent development in printable porous implants offers improved patient-specific solutions by providing adequate stability and reducing stress shielding possibilities. This work presents an approach for designing patient-specific implants with inhomogeneous porosity. A novel group of orthotropic auxetic structures is introduced, and their mechanical properties are computed. These auxetic structure units were distributed at different locations on the implant along with optimized pore distribution to achieve optimum performance. A computer tomography (CT) based finite element (FE) model was used to evaluate the performance of the proposed implant. The optimized implant and the auxetic structures were manufactured using laser powder bed-based laser metal additive manufacturing. Validation was done by comparing FE results with experimentally measured directional stiffness and Poisson's ratio of the auxetic structures and strain on the optimized implant. The correlation coefficient for the strain values was within a range of 0.9633-0.9844. Stress shielding was mainly observed in Gruen zones 1, 2, 6, and 7. The average stress shielding on the solid implant model was 56%, reduced to 18% when the optimized implant was used. This significant reduction in stress shielding can decrease the risk of implant loosening and create an osseointegration-friendly mechanical environment on the surrounding bone. The proposed approach can be effectively applied to the design of other orthopaedic implants to minimize stress shielding.

Patient-specific femoral implant design using metamaterials for improving load transfer at proximal-lateral region of the femur.

Loading configuration of hip joint creates resultant bending effect on femoral implants. So, the lateral side of femoral implant which is under tension retracts from peri­implant bone due to positive Poisson's ratio. This retraction of implant leads to load shielding and gap opening in proximal-lateral region, thereby allowing entry of wear particle to implant-bone interface. Retraction of femoral implant can be avoided by introducing auxetic metamaterial to the retracting side. This allows the implant to push peri­implant bone under tensile condition by virtue of their auxetic (negative Poisson's ratio) nature. To develop such implants, a patient-specific conventional solid implant was first designed based on computed-tomography scan of a patient's femur. Two types of metamaterials (2D: type-1) and (3D: type-2) were employed to design femoral meta-implants. Type-1 and type-2 meta-implants were fabricated using metallic 3D printing method and mechanical compression testing was conducted. Three finite element (FE) models of the femur implanted with solid implant, type-1 meta-implant and type-2 meta-implant were developed and analysed under compression loading. Significant correlation (R2 = 0.9821 and R2 = 0.9977) was found between the experimental and FE predicted strains of the two meta-implants. In proximal-lateral region of the femur, an increase of 7.1% and 44.1% von-Mises strain was observed when implanted with type-1 and type-2 meta-implant over the solid implant. In this region, bone remodelling analysis revealed 2.5% bone resorption in case of solid implant. While bone apposition of 0.5% and 7.7% was observed in case of type-1 and type-2 meta-implants, respectively. The results of this study indicates that concept of introduction of metamaterial to the lateral side of femoral implant can prove to provide higher osseointegration-friendly environment in the proximal-lateral region of femur.

Probing the Influence of Hybrid Thread Design on Biomechanical Response of Dental Implants: Finite Element Study and Experimental Validation.

This study aimed to perform quantitative biomechanical analysis for probing the effect of varying thread shapes in an implant for improved primary stability in prosthodontics surgery. Dental implants were designed with square (SQR), buttress (BUT), and triangular (TRI) thread shapes or their combinations. Cone-beam computed tomography images of mandible molar zones in human subjects belonging to three age groups were used for virtual implantation of the designed implants, to quantify patient-specific peri-implant bone microstrain, using finite element analyses. The in silico analyses were carried out considering frictional contact to simulate immediate loading with a static masticatory force of 200 N. To validate computational biomechanics results, compression tests were performed on three-dimensional printed implants having the investigated thread architectures. Bone/implant contact areas were also quantitatively assessed. It was observed that, bone/implant contact was maximum for SQR implants followed by BUT and TRI implants. For all the cases, peak microstrain was recorded in the cervical cortical bone. The combination of different thread shapes in the middle or in the apical part (or both) was demonstrated to improve peri-implant microstrain, particularly for BUT and TRI. Considering 1500-2000 microstrain generates in the peri-implant bone during regular physiological functioning, BUT-SQR, BUT-TRI-SQR, TRI-SQR-BUT, SQR, and SQR-BUT-TRI design concepts were suitable for younger; BUT-TRI-SQR, BUT-SQR-TRI, TRI-SQR-BUT, SQR-BUT, SQR-TRI for middle-aged, and BUT-TRI-SQR, BUT-SQR-TRI, TRI-BUT-SQR, SQR, and SQR-TRI for the older group of human patients.

Simulation and experimental investigation of the surgical needle deflection model during the rotational and steady insertion process.

Needle insertion is executed in numerous medical and brachytherapy events. Exact needle insertion into inhomogeneous soft biological tissue is of useful importance due to its significance in clinical diagnosis (especially percutaneous) and treatments. The surgical needles used in such processes can deflect during the percutaneous process. Needle deflecting which affects needle - soft tissue interface and needle controllability have a crucial role in establishment precision. In this paper, we have analyzed a mechanics-based model both rotational and non-rotational needle insertion, and studied the deflection phenomenon in both insertion cases, we validated it with a real-time nonlinear Dassault Systèmes® ABAQUS simulation model. For definite contact force, the maximum the contact stiffness was, the minimum it inserted, the cohesive surface model was used to investigate the needle insertion analysis, where the fracture point was defined by a failure strain and with the help of the in, the fully failed components would be removed. Using living tissue comparable PVA gel materials, the needle insertion force model is developed from insertion experimentations with the help of two different processes (rotational and non-rotational needle insertion). In a rotational needle, deflection is less than in a non-rotational needle. The preliminary insertion was observed in the rotational needle at 1.261 mm (experiment), and 1.538 mm (simulation), and for non-rotational needle insertion, the initial insertion was noticed at 1.756 mm (experiment) and 1.982 mm (simulation). The main aim of this study is to navigate the surgical needle in an accurate way to reduce the erroneousness for a clinical diagnosis like anesthesia, brachytherapy, biopsy, and modern microsurgery operation.

Study of the surgical needle and biological soft tissue interaction phenomenon during insertion process for medical application: A Survey.

The insertion of the surgical needle in soft tissue has involved significant interest in the current time because of its purpose in minimally invasive surgery (MIS) and percutaneous events like biopsies, PCNL, and brachytherapy. This study represents a review of the existing condition of investigation on insertion of a surgical needle in biological living soft tissue material. As observes the issue from numerous phases, like, analysis of the cutting forces modeling (insertion), tissue material deformation, analysis of the needle deflection for the period of the needle insertion, and the robot-controlled insertion procedures. All analysis confirms that the total needle insertion force is the total of dissimilar forces spread sideways the shaft of the insertion needle for example cutting force, stiffness force, and frictional force. Various investigations have analyzed all these kinds of forces during the needle insertion process. The force data in several measures are applied for recognizing the biological tissue materials as the needle is penetrated or for path planning. The deflection of the needle during insertion and tissue material deformation is the main trouble for defined needle placing and efforts have been prepared to model them. Applying existing models numerous insertion methods are established that are discussed in this review.

Design of patient specific basal dental implant using Finite Element method and Artificial Neural Network technique.

The bone conditions of mandibular bone vary from patient to patient, and as a result, a patient-specific dental implant needs to be designed. The basal dental implant is implanted in the cortical region of the bone since the top surface of the bone narrows down because of aging. Taguchi designs of experiments technique are used in which 25 optimum solid models of basal dental implants are modeled with variable geometrical parameters, viz. thread length, diameter, and pitch. In the solid models the implants are placed in the cortical part of the 3D models of cadaveric mandibles, that are prepared from CT data using image processing software. Patient-specific bone conditions are varied according to the strong, weak, and normal basal bone. A compressive force of 200 N is applied on the top surface of these implants and using finite element analysis software, the microstrain on the peri-implant bone ranges from 1000 to 4000 depending on the various bone conditions. According to the finite element data, it can be concluded that weak bone microstrain is comparatively high compared with normal and strong bone conditions. A surrogate artificial neural network model is prepared from the finite element analysis data. Surrogate model assisted genetic algorithm is used to find the optimum patient-specific basal dental implant for a better osseointegration-friendly mechanical environment.

Probing combinational influence of design variables on bone biomechanical response around dental implant-supported fixed prosthesis.

This study aimed to understand the effect of physiological and dental implant-related parameter variations on the osseointegration for an implant-supported fixed prosthesis. Eight design factors were considered (implant shape, diameter, and length; thread pitch, depth, and profile; cantilever [CL] length and implant-loading protocol). Total 36 implantation scenarios were simulated using finite element method based on Taguchi L36 orthogonal array. Three patient-specific bone conditions were also simulated by scaling the density and Young's modulus of a mandible sample to mimic weak, normal, and strong bones. Taguchi method was employed to determine the significance of each design factor in controlling the peri-implant cortical bone microstrain. For normal bone condition, CL length had the maximum contribution (28%) followed by implant diameter (18%), thread pitch (14%), implant length (8%), and thread profile (5%). For strong bone condition, CL and implant diameter had equal contribution (32%) followed by thread pitch (7%) and implant length (5%). For weak bone condition, implant diameter had the highest contribution (31%) followed by CL length (30%), thread pitch (11%) and implant length (8%). The presence of distal CL in dental framework was found to be the most influential design factor, which can cause high strain in the cervical cortical bone. It was seen that implant diameter had more effect compared to implant length toward peri-implant bone biomechanical response. Implant-loading time had no significant effect towards peri-implant bone biomechanical response, signifying immediate loading is possible with sufficient mechanical retention.

Design of patient specific bone stiffness mimicking scaffold.

The difference in stiffness of a patient's bone and bone implant causes stress shielding. Thus, implants which match the stiffness of bone of the patient result in better bone growth and osseointegration. Variation in porosity is one of the methods to obtain implants with different stiffness values. This study proposes a novel method to design biomimetic bone graft implant based on computed tomography (CT) scan data, that creates similar pre- and post-implant mechanical environment on peri-implant bone. The design methodology is demonstrated by taking three different sections of human femur bone, greater trochanter, diaphysis and epicondyle, with two different implant materials, Ti-6Al-4V and Ti-Mg. Bones from these three sections were replaced with porous implants of effective stiffness of replaced bone, as would have been required after a resection surgery. Models were simulated with physiological loading condition using finite element (FE) method. Variation of maximum von Mises stress and average strain on peri-prosthetic bone were found to be in the range of -6% to 10.7% and -7% to -17.9% for porous implants and 26% to 50% and -36% to -59% for solid implant respectively compared to natural bone. The results revealed that the porous implants, which have been designed based on CT scan data, can effectively produce mechanical response at peri-implant bone, which is very close to pre-implanted condition. Following this methodology, more osseointegration friendly mechanical environment can be achieved at peri-implant bone for any anatomical location independent of implant materials.

Finite element and experimental analysis to select patient's bone condition specific porous dental implant, fabricated using additive manufacturing.

BACKGROUND: Differences in patients' bone conditions lead to variations in the bio-mechanical environment at the peri-implant bone after implantation. It is therefore imperative to design patient-specific dental implants with customized stiffness to minimize stress shielding and better osseointegration. METHOD: Nine Ti-6Al-4V implants with pore sizes of 500, 700, 900 µm and 10, 20, 30% porosity each and one non-porous (solid) implant were modelled for experimental and finite element (FE) analysis. Using computed tomography (CT) data of the mandible, five different bone conditions were considered by varying bone density. Implants were fabricated using additive manufacturing, and micro-CT analysis was performed for assessing accuracy of fabricated implants and further modelling for FE analyses. The FE results were also compared with experimental results. RESULTS: Under a 200 N static load, the average difference between the experimental and FE observations of deformation was 9.7%. The peri-implant bone micro-strain revealed statistically significant interactions between percentage porosity (%porosity) and bone condition, as well as between pore size and %porosity (p < 0.05). In contrast, no statistically significant interaction between pore size and bone condition (p > 0.05) was observed. Together, %porosity and bone conditions contributed about 45.22% of the overall peri-implant bone micro-strain. CONCLUSIONS: Considering 1500-2000 as the maximum generated peri-implant bone micro-strain during regular physiological functioning, implants with 700 and 900 µm pore size and 10% porosity were deemed suitable for a 'very weak' bone condition. Contrarily, implants with 900 µm pore size and 30% porosity generated the highest peri-implant bone micro-strain for a 'normal' bone condition. Overall, the study establishes the necessity for considering the patient's bone condition as an important factor for the design of dental implants.

Design of Patient Specific Spinal Implant (Pedicle Screw Fixation) using FE Analysis and Soft Computing Techniques.

BACKGROUND: This work uses genetic algorithm (GA) for optimum design of patient specific spinal implants (pedicle screw) with varying implant diameter and bone condition. The optimum pedicle screw fixation in terms of implant diameter is on the basis of minimum strain difference from intact (natural) to implantation at peri-prosthetic bone for the considered six different peri-implant positions. METHODS: This design problem is expressed as an optimization problem using the desirability function, where the data generated by finite element analysis is converted into an artificial neural network (ANN) model. The finite element model is generated from CT scan data. Thereafter all the ANN predictions of the microstrain in six positions are converted to unitless desirability value varying between 0 and 1, which is then combined to form the composite desirability. Maximization of the composite desirability is done using GA where composite desirability should be made to go up as close as possible to 1. If the composite desirability is 1, then all 'strain difference values in 6 positions' are 0. RESULTS: The optimum solutions obtained can easily be used for making patient-specific spinal implants.

Biomechanical Analysis to Probe Role of Bone Condition and Subject Weight in Stiffness Customization of Femoral Stem for Improved Periprosthetic Biomechanical Response.

Stress shielding due to difference in stiffness of bone and implant material is one among the foremost causes of loosening and failure of load-bearing implants. Thus far, femoral geometry has been given priority for the customization of total hip joint replacement (THR) implant design. This study, for the first time, demonstrates the key role of bone condition and subject-weight on the customization of stiffness and design of the femoral stem. In particular, internal hollowness was incorporated to reduce the implant stiffness and such designed structure has been customized based on subject parameters, including bone condition and bodyweight. The primary aim was to tailor these parameters to achieve close to natural strain distribution at periprosthetic bone and to reduce interfacial bone loss over time. The maintenance of interfacial bone density over time has been studied here through analysis of bone remodeling (BR). For normal bodyweight, the highest hollowness exhibited clinically relevant biomechanical response, for all bone conditions. However, for heavier subjects, consideration of bone quality was found to be essential as higher hollowness induced bone failure in weaker bones and implant failure in stronger bones. Moreover, for stronger bone, thinner medial wall was found to reduce bone resorption over time on the proximo-lateral zone of stress shielding, while lateral thinning was found advantageous for weaker bones. The findings of this study are likely to facilitate designing of femoral stems for achieving better physiological outcomes and enhancement of the quality of life of patients undergoing THR surgery.

Measurement of strain in the rod for lumbar pedicle screw fixation: An experimental and finite element study.

Spinal fusion with pedicle-screw-rod is being used widely for treating spinal deformities diseases. Several biomechanical studies on screw rod based implant failure through screw pullout, bending, screw breakage have been performed. But few studies are available regarding the effect of strain for breakage of rod. So, the purpose of the present study is to observe strain at the rod connected with the pedicle screw for different loading condition. The strain in stainless steel (SS) connecting rods for pedicle screw fixation were measured using strain gauge. In order to investigate the bio-mechanical response of lumbar spine with reference to strain in the rod, a simple experimental setup was developed using a specimen of L1-S spine segment. SS rods were used for pedicle screw implant on prototyped lumbar Spine. Prior to testing with pedicle screw, the lumbar spine specimen was also compared with FE results. The strain measured using strain gauges at L3-L4 level on SS rod were within a range of 85 to 310 microstrain under 6, 8, 10 Nm flexion and extension, and for L4-L5 level, these values were within a range of 95 to 440 microstrain. It was found that FE result was higher than the strain gauge result and the error varied between 10.5% to 33% with average error of 22.8%. However similar stain behavior was observed by the FE analysis. The proposed method, as well as the qualitative data, might be helpful for the researchers to understand biomechanical behavior of pedicle-screw implanted spine.

Computational intelligence based design of implant for varying bone conditions.

The objective is to make the strain deviation before and after implantation adjacent to the femoral implant as close as possible to zero. Genetic algorithm is applied for this optimization of strain deviation, measured in eight separate positions. The concept of composite desirability is introduced in such a way that if the microstrain deviation values for all eight cases are 0, then the composite desirability is 1. Artificial neural network (ANN) models are developed to capture the correlation of the microstrain in femur implants using the data generated through finite element simulation. Then, the ANN model is used as the surrogate model, which in combination with the desirability function serves as the objective function for optimization. The optimum achievable deviation was found to vary with the bone condition. The optimum implant geometry varied for different bone condition, and the findings act as guideline for designing patient-specific implant.

Artificial Intervertebral Disc Replacement to Provide Dynamic Stability to the Lumbar Spine: A Finite Element Study.

Currently, intervertebral disc prostheses that are designed to restore mobility to a vertebral segment are possible for the lumbar spine. The ball-and-socket joint is a constrained design, wherein the rotational axis of the intervertebral joint is forced to pass through the center of the spherical surfaces that form the joint. One advantage of ball-and-socket joints versus unconstrained designs includes better shear stability, which results in sufficient flexibility. In this study, finite element analyses were performed in preimplanted and implanted (intervertebral disc replacement [IDR]) lumbar spine (L1-S) models to examine range of motion (ROM) and the resulting mechanical responses in the implant and the adjacent bones. Four physiological loading conditions including flexion, extension, and left and right lateral bending were analyzed to observe the effect on ROM under a 10-Newton meter moment. In terms of mechanical response, this study shows that disc replacement is an viable alternative to fusion surgery. The added advantage of IDR over fusion for degenerative discs is the reduced chance of disc degeneration at the adjacent segment of spinal vertebral column; with fusion surgery, chances of degeneration are increased.

Effect of Plate Geometry Modifications to Reduce Stress Shielding during Healing Stages for Tibial Fracture Fixation.

The goal of this finite element study is to reduce the stress shielding effect in tibial fracture fixation. Five different plates with modified geometry have been modeled. The fracture gap is assumed to be filled with callus, which is new born healing tissue. The effect of different plate modifications in four different healing stages has been compared to the nonmodified plate. It has been observed that all the modified models have higher callus stress than the nonmodified model, and the best modified plate has reduced the stress shielding effect by 117% for the first healing stage. It has also been observed that the effect of different plate modification is prominent during only the first and second healing stages.

Factors Affecting Diffuse Axonal Injury under Blunt Impact and Proposal for a Head Injury Criteria: A Finite Element Analysis.

Diffuse axonal injury (DAI) is the most common pathological feature of brain injury which accounts for half of the traumatic lesions in the United States. Although direct shear strain measures indicate DAI, it is localized and varies greatly in the brain. It has limitations when correlated with the possibility and severity of DAI in different brain regions along different planes for variable factors. Rather, a statistical strain measure such as peak shear strain possibility (PSSP) is proposed as a head injury criteria. In this study, computer tomography (CT) was used to derive a finite element model of the skull-brain complex including viscoelastic behavior for brain material. It was simulated under blunt impact for variable factors such as five impact directions, four impact velocities, and four head sizes. Nodal shear strain measures were obtained for seven brain regions along three planes. Proposed PSSPs for different shear strain level (10%90%) were calculated. Considering 30% shear strain as the critical level, PSSPs were 0.49 for corpus callosum and 0.71 for the brain stem along the sagittal plane, and 0.63 for frontal impact. Among eighty simulation cases (240 strain measures), the corpus callosum and brain stem have the highest possibility (30%) of DAI. Frontal impact is the most dangerous direction, followed by side-back and back impact. For all impact directions, the highest PSSP along the sagittal plane indicates the predominance of rotational motion of the brain for causing DAI. Head size variation has the least effect on DAI possibility. At higher impact velocities, DAI possibility increases nonlinearly. Hence, these proposed criteria are expected to predict DAI under variable factors.

Effect of two-level pedicle-screw fixation with different rod materials on lumbar spine: A finite element study.

BACKGROUND: Pedicle-screw-rod fixation system is very popular surgical remedy for degenerative disc disease. It is important to observe load vs. spinal motion characteristic for better understanding of clinical problems and treatment of spinal instability associated with low-back pain. OBJECTIVE: The objective of this study is to understand the effect [range of motion (ROM) and intervertebral foramen height] of pedicle-screw fixation with three rod materials on lumbar spine under three physiological loading conditions. METHOD: A three-dimensional finite element (FE) model of lumbar to sacrum (L1-S) vertebrae with pedicle-screw-rod fixation at L3-L5 level is developed. Three rod materials [titanium alloy (Ti6Al4V), ultra-high molecular weight poly ethylene (UHMWPE) and poly-ether-ether-ketone (PEEK)] are used for two-level fixation and the FE models are simulated for axial rotation, lateral bending and flexion-extension under ±10 Nm moment and 500 N compressive load and compared with the intact (natural) model. RESULT & DISCUSSION: For axial rotation, lateral bending and flexion, ROM increased 2.8, 4.5 and 1.83 times respectively for UHMWPE, and 3.7, 7.2 and 2.15 times respectively for PEEK in comparison to Ti6Al4V. As ROM is 49, 29 and 31% of the intact model during axial rotation, lateral bending and flexion respectively, PEEK rod produced better motion flexibility than Ti6Al4V and UHMWPE rod. Foramen height increased insignificantly by 2.21% for the PEEK rod with respect to the intact spine during flexion. For the PEEK rod, maximum stress of 40 MPa during axial rotation is much below the yield stress of 98 MPa. CONCLUSION: Ti6Al4V pedicle-screw-rod fixation system highly restricted the ROM of the spine, which is improved by using UHMWPE and PEEK, having lower stiffness. The foramen height did not vary significantly for any implant materials. In terms of ROM and maximum stress, PEEK rod may be considered for a better implant design to get better ROM and thus mobility.

Optimization of spinal implant screw for lower vertebra through finite element studies.

The increasing older population is suffering from an increase in age-related spinal degeneration that causes tremendous pain. Spine injury is mostly indicated at the lumbar spine (L3-L5) and corresponding intervertebral disks. Finite element analysis (FEA) is now one of the most efficient and accepted tools used to simulate these pathological conditions in computer-assisted design (CAD) models. In this study, L3-L5 spines were modeled, and FEA was performed to formulate optimal remedial measures. Three different loads (420, 490.5, and 588.6 N) based on three body weights (70, 90, and 120 kg) were applied at the top surface of the L3 vertebra, while the lower surface of the L5 vertebra remained fixed. Models of implants using stainless steel and titanium alloy (Ti6Al4V) pedicle screws and rods with three different diameters (4, 5, and 6 mm) were inserted into the spine models. The relative strengths of bone (very weak, weak, standard, strong, and very strong) were considered to determine the patient-specific effect. A total of 90 models were simulated, and von Mises stress and strain, shear stress, and strain intensity contour at the bone-implant interface were analyzed. Results of these analyses indicate that the 6-mm pedicle screw diameter is optimal for most cases. Experimental and clinical validation are needed to confirm these theoretical results.

Hip fracture and anthropometric variations: dominance among trochanteric soft tissue thickness, body height and body weight during sideways fall.

BACKGROUND: Hip fracture depends on various anthropometric parameters such as trochanteric soft tissue thickness, body height and body weight. The objective was to evaluate the responses to the variations in anthropometric parameters during sideways fall, and to identify the most dominant parameter among them. METHOD: Seven finite element models were developed having anthropometric variations in trochanteric soft tissue thickness (5-26 mm), body height (1.70-1.88 m), and body weight (63-93.37 kg). These were simulated for sideways fall with ANSYS-LS-DYNA® code. FINDINGS: Significant effect of trochanteric soft tissue thickness variation was found on 'normalized peak impact force with respect to the body weight' (p=0.004, r²=0.808) and strain ratio (p=0.083, r²=0.829). But, variation in body height was found to be less significant on normalized peak impact force (p=0.478, r²=0.105) and strain ratio (p=0.292, r²=0.217). Same was true for the variation in body weight on normalized peak impact force (p=0.075, r²=0.456) and strain ratio (p=0.857, r²=0.007). The risk factor for fracture was also well correlated to the strain ratio for the inter-trochanteric zone (p<0.0007, r²=0.917) where the most fractures are clinically observed to happen. INTERPRETATIONS: Trochanteric soft tissue thickness was found likely to be the most dominant parameter over body height and body weight, signifying that a slimmer elderly person, taller or shorter, with less trochanteric soft tissue thickness should be advised to take preventive measures against hip fracture under sideways fall.