Screw Parameters Research Articles

Morphometric Characteristics of Sacral-2 Alar Iliac Screw Fixation in Pediatric Population.

A computed tomographic assessment. To establish morphometric data of sacral-2 alar iliac (S2AI) screw fixation in pediatric population. Studies on morphometric parameters of S2AI screw fixation are mostly based on adult population. The pediatric scoliosis also needs the S2AI screw fixation, however, without the previous morphometric information of among pediatric population. Computed tomography (CT) scans of 120 pediatric patients without spinal deformities are obtained and imported to Mimics software for 3D reconstruction. Then, a cylinder (radius of 3.25 mm) is drawn to imitate the screw trajectory of S2AI screw and adjusted to a maximum upward and downward angle to obtain the feasible region. Nine parameters of the S2AI screw are measured. Differences between age groups are compared and significant statistical correlations are carefully studied to determine the potentially important clinical relationships. The mean values and standard deviations (SD) for nine parameters at the maximum upward and downward angles were determined. With age increased, the S2AI screw trajectory becomes more caudal in the coronal (44.03 ± 4.43°-53.15 ± 4.68°) and sagittal planes (50.33 ± 5.89°-57.69 ± 4.21°) and more lateral in the transverse plane (49.40 ± 5.90°-54.44 ± 2.99°), and all of the distance parameters include max-length, sacral distance, iliac width, S2 midline, iliac wing, and skin distance increased. Age has a more significant effect on other parameters than transverse angle and skin distance (P < 0.05). The S2AI screw fixation could be used on pediatric population too, but the pediatric population had smaller size of pelvis than adults, surgeons should choose the smaller diameters and the shorter length of screws for pediatric population depends on their age. N/ A.

Temperature influence on chemical properties of jatropha curcas L. oil extracted with mechanical screw press

Pure plant J.curcas oil has been used in direct injection compression engines and plant oil stoves without any engine modification necessary. Oil quality information and preservation are essential knowledge to avoid the wear and breakdown of combustion engines. This study focused on investigating the generated temperature during mechanical extraction with a mechanical screw press type (Komet D85-1G) on J.curcas oil quality. Chemical properties of extracted J.curcas oil were analyzed and the results were compared with the chemical extraction method (soxhlet) and DIN 51605. Most of the characteristic chemical properties of J.curcas oil extracted with a mechanical extraction method did not exceed the threshold norm DIN 51605. The standard deviation and coefficient of variation between all experiments was very small. This means, that the characteristic oil quality was not influenced by temperatures generated when alternating different screw parameters. The analyzed variable chemical properties of J.curcas oil extracted by mechanical extraction (AV, FFA, TC, P, Ca, K and WC) were above the allowed limit described by standard norm DIN 51605, except CR and Na contents, which fulfill the standard norm. The standard deviation and coefficient of variation of analyzed experiments varied from 13 to 46%. These proved that oil extraction is influenced by temperature generation when using different screw press design parameters. The highest temperature was generated on point T3 and the best correlation values were achieved between temperature T3 and variable chemical properties. The temperature at the cohesion zone T3 is an indicator for oil quality determination. Mechanical extraction temperatures below 90 °C at the compression zone and 70 °C at the oil outlet would produce oil quality, which allows the direct use of the oil as fuel or for biodiesel production.

Optimal synthesis of parallel robots' actuators stiffness for given combinations of twist and wrench sets

Robot stiffness synthesis, with the goal of obtaining given instantaneous displacements for known loads, may result in a non-feasible stiffness matrix. This paper presents a stiffness synthesis scheme that generates a feasible stiffness matrix, which, for a known set of wrenches, results in optimized end-effector twists as close as possible to the given ones. This was achieved by minimizing the variance between the given and the actual motion screw parameters formulated as a non-linear optimization problem. This approach is demonstrated in an artificial spinal disc joint that consists of a passive parallel robot structure, designed to resemble the natural motion of adjacent spine vertebrae under a known set of loads.

Regularities of motion of a particle in the spiral–screwed device

The article describes the functional relationship between the geometric parameters of the spiral screw and the kinematic motion characteristics of the material being moved and its individual particles. The authors considered the movement of a particle in the cylindrical system of coordinates. Differential equations have been obtained, which describe the motion trajectory of a material particle along the inner surface of the casing of a spiral–helical device.

Risk Factors for Clinically Relevant Loosening of Percutaneous Pedicle Screws.

Introduction (1) To evaluate the influence of pedicle screw loosening on clinical outcomes; (2) to clarify the association between the pull-out length and screw loosening 1 year after surgery; and (3) to determine radiographically which screw parameters predominantly influence the pull-out resistance of screws. Methods We analyzed 32 consecutive patients who underwent minimally invasive lumbar or thoracic spinal stabilization by intraoperative three-dimensional computed tomography (CT)-guided navigation without anterior reconstruction and were followed up for 1 year. The screw pull-out length was measured on axial CT images obtained both immediately after screw insertion and postoperatively. Loosening of screws and clinical outcomes were evaluated radiographically, clinically, and by CT 1 year after surgery. Results There were no significant differences in the mean age, sex, bone mineral density, mean stabilized length, and smoking habits of patients with (+) or without (−) loosening. The Oswestry Disability Index and the lumbar visual analog scale 1 year after surgery were significantly higher in patients with loosening (+) than in those without (−). The overall pedicle screw pull-out rate was 16.2% (47/290) of screws and the overall screw loosening rate was 15.2% (44/290) of screws. Screws with loosening (+) had significantly lower (axial) trajectory angles and higher screw pull-out lengths than those without (−). Approximately 82% of loosened screws had been pulled out during rod connection. Conclusions A lower axial trajectory and an increased screw pull-out length after rod reduction are crucial risk factors for screw loosening.

Modeling of Solid Conveying Pressure Throughput Behavior of Single Screw Smooth Barrel Extruders under Consideration of Backpressure and High Screw Speeds

AbstractThe task of the solid conveying section is to collect the entering material and transfer it to the melt dominated sections. Therefore, its upstream interface is the hopper and its downstream interface is the section in which the first melting occurs. Beneath the hopper opening, the screw rotation collects and conveys the material forward. It is hereby assumed that the friction forces among the particles are higher than the transferring forces on the screw and barrel. For that reason commonly known models for describing the solid conveying in single screw extruders assume that the screw channel is always completely filled so that a plug flow occurs. At high screw speeds, however, these assumptions are no longer valid. To analyze and mathematically describe the solid conveying behavior at screw speeds up to 2000 rpm, simulations based on the Discrete Element Method have been executed in previous investigations. Based on this, a model for describing the solid conveying behavior was developed which enables a variation of general screw and hopper geometry parameters but neglects the backpressure that inhibits the solid movement. For that reason, further investigations based on the Discrete Element Method are presented in this paper, which enable a consideration of the backpressure and pressure build-up in the feeding zone. Astonishingly, at high screw speeds a low filling degree in the screw channel was observed which did not fulfill the expectations of an always fully filled channel due to a backpressure forced particle backlog. Based on the investigations, a mathematical model has been developed which now fully comprehends the effects occurring in the solid conveying section. The conducted simulations were subsequently validated by experimental investigations. Therefore, a test bench was designed which enables solid conveying analysis with adjustable backpressures. The results indicate a good agreement with the formulated model which now enables the calculation of solid conveying zones with consideration of the pressure build-up and filling degrees.

Electro mechanical linear actuator using roller screws

Electro Mechanical linear Actuators as the name suggests are linear actuators operated by electric motor. The linear motion is desirable to drive a high inertia weapon system in elevation axis. In this paper, design and development aspects of an Electromechanical linear actuator using Roller screw has been attempted. Initial Comparison with ball screw drive suggests that roller screws are favorable for high dynamic load application. Selection and functional parameters of roller screw had been evaluated to optimize the linear actuator based on roller screw. This paper studies in detail the design aspects of an electromechanical linear actuator. The variation of different parameters with respect to Lead of the roller screw has been studied.

Novel Placement of Cortical Bone Trajectory Screws in the Lumbar Spine: A Radiographic and Cadaveric Study.

This is a radiographic and cadaveric study. The aim of this study was to conduct a detailed comparison about the parameters between the ideal cortical bone trajectory (CBT) and practical CBT screw. CBT screws have recently become popular in spinal surgery, mainly because of their improved fixation while minimizing soft tissue dissection. However, to our knowledge, no previous study has provided a detailed comparison on the parameters between the ideal CBT and practical CBT screws. The 3-dimensional computed tomography scans of 126 spinal vertebrae separated from 40 lumbar spines were studied. After determining the CBT, the maximal screw length, maximal screw diameter, lateral angle (LA), and cephalad angle (CA) were calculated. Thereafter, CBT screws were inserted into these cadaveric lumbar spines. Subsequently, the lateral angle of screw (LAs) and cephalad angle of screw (CAs) of the screws were measured using 3-dimensional computed tomography. As for the ideal CBT, the maximal screw length gradually increased from L1 (32.0 mm) to L4 (35.3 mm) and then decreased at L5 (34.8 mm). Moreover, the maximal screw diameter increased from L1 (4.5 mm) to L5 (7.5 mm). The LA from L1 to L5 were 9.2, 9.4, 9.9, 11.2, and 12.0 degrees, respectively. The CA from L1 to L5 were 25.8, 25.8, 26.3, 26.8, and 26.0 degrees, respectively. As for the actual CBT screw, the LAs from L1 to L5 were 12.7, 14.1, 13.2, 12.4, and 13.0 degrees, respectively. The CAs from L1 to L5 were 25.4, 27.5, 29.2, 30.1, and 30.5 degrees, respectively. Significant differences were observed between the angles of the ideal trajectory and the actual screw. Parameters of the actual CBT screw are slightly larger than the optimal trajectory measurements. The CAs and LAs are ∼25-30 and 10-16 degrees, respectively. L1 and L2 should be given considerable attention when using the CBT technique. And the trajectory measurements can only be used as a guide in clinical practice.

Substantiation of the design parameters of a screw for the variable pitch of a press extruder in the preparation of a loose sunflower meal

The purpose of the study is to reduce the energy consumption of extruding sunflower seed waste when obtaining a sunflower meal in loose form on the basis of planning a multifactor experiment. Before the beginning of the experiment, the factors were encoded by performing a linear transformation of the factor space with the transfer of the origin to the center of the experiment and the introduction of new units of measurement along the axes. The natural value of the factor variation interval was determined. Taking into account the review of literature sources, theoretical studies and scientific and technical information, factors of variation were chosen to calculate the density of sunflower meal in the loose form obtained after treating the waste of seeds on a press extruder KMZ-2. After calculating the regression coefficients, a regression equation was obtained describing the density of the sunflower meal in the loose form. A study was made of the homogeneity of the variances of the experimental responses obtained by the Cochran test, and also checked the adequacy of the obtained mathematical model with the help of the Fisher criterion. The angle of conicity of the screw, the pitch of the auger of the 2nd coiling and, to a lesser extent, the 1st coiling, including the pair interaction between the taper angle and the pitch of the screw of the 1st winding, influence the obtaining of the sunflower meal in loose form in the extruder KMZ-2. Based on the results of the three-factor experiment, the optimum design parameters of the variable-pitch screw of the KMZ-2 press-extruder were determined, which have the following values: the cone angle is 30 °, the pitch of the screw of the 2nd coiling is 28 mm, the pitch of the screw of the 1st coiling - 36 mm, which make it possible to obtain a loose sunflower meal with a density of 2139,4 kg / m3 and reduce the energy consumption of extruding sunflower seeds.

Identification of Drilling Parameters during the Flow Drill Screw Driving Process

The automobile manufacturing industry, until recent years, has been using steel for car body components and the main method for joining these components has always been Resistance Spot Welding. However, since the global trends toward CO2 reduction and resource efficiency have significantly increased, the importance and usage of lightweight materials has enhanced as well. New lightweight materials such as aluminum and magnesium alloys, carbon-fiber-reinforced plastics, etc., have become a reality, thanks to the new fastening technologies. Flow drill screw driving (FDS) is a one–sided thermomechanical assembly process based on heat generation by frictional force and plastic deformation. A special screw, known as hole forming and self-tapping screw, is used in this process as both fastener and tool. Moreover, rotational and translation movements are applied to the screw to create special friction conditions with the workpiece. Furthermore, unlike traditional drilling and thread milling processes, there is no chip or waste of material in FDS and the machining operations are realized through plastic deformation. This paper explores flow drilling steps and the parameters which influence heating and local softening of the aluminum sheet 5182-0. An experimental study has been carried out by varying process parameters (rotational speed, drilling force), coating and geometry of the screw. As a result, an increase of rotational speed and drilling force allows significant reduction in drilling time and introduce an important variation of the torque installation. In addition, a strong dependence is observed between drilling time and torque on the one hand, and related to the screw parameters geometry and coating on the other hand. Finally, an evaluation of the heating effect on the thread forming operation is also undertaken.

Study on the nailing path of S3 ala-iliac screw in adult spinal pelvis fixation

Objective The screw insertion and parameters of S3 ala-iliac screw fixation were introduced by 3D printing spinal pelvis model and computer software-assisted navigation. Methods Determine the nailing space of the S3 segment by 3D printing model and computer software related data, and select the position of the iliac screw into the needle point. Twenty of the male and female adult patients who had undergone three-dimensional pelvic CT reconstruction scans were randomly selected. The screw point O was selected, the horizontal section X was the coronal or sacral horizontal cross-section. Spherical probe into the minimum angle of the needle angle range A, the maximum angle range B and the optimal range of nailing angle Z was measured, and the needle point screwed into the screw pin length and width. The accuracy and safety of this new method of nailing were confirmed in the corresponding adult 3D printing model. Results The needle angle is within the range of the minimum angle OA to the maximum angle OB. If the narrowest diameter is more than 7 mm, the fixation can be safely done with a universal Iliac screw (average length 80-90 mm). The range of needle angle was (47.1±1.9)°-(56.7±1.4)° for the male X-OA-OB plane and (52.3±1.1)° for the optimal angle. The X-OA-OB plane for women was 49.6±0.8)°-(59.9±1.1)°, the best angle X-OZ range (53.7±0.8)°. The range of nail path length was (91.4±2.3) mm for OA, (89.5±4.6) mm for OB and (94.2±2.1) mm for OZ. The OA level of female was (90.4±1.9) mm, (85.6±2.3) mm, OZ plane range (96.4±1.7) mm. The statistical results showed that in the best setting angle OZ, nail angle differences (F=4.276, P 0.05). OB, male and female, nail angle differences (F=8.153, P 0.05). Conclusion The iliac bone screw can be safely and effectively inserted into the iliac bone via the S3 block. In theory, the iliac bone screw is safe and stable through the O-Z needle entry point. The O-Z angle is also the best in Spinal pelvis fixation. Key words: Spinal pelvic fixation; Iliac screw; Spiral computer navigation; 3D printing and 3D reconstruction

Identification and compensation of friction for a novel two-axis differential micro-feed system

Abstract Non-linear friction in a conventional drive feed system (CDFS) feeding at low speed is one of the main factors that lead to the complexity of the feed drive. The CDFS will inevitably enter or approach a non-linear creeping work area at extremely low speed. A novel two-axis differential micro-feed system (TDMS) is developed in this paper to overcome the accuracy limitation of CDFS. A dynamic model of TDMS is first established. Then, a novel all-component friction parameter identification method (ACFPIM) using a genetic algorithm (GA) to identify the friction parameters of a TDMS is introduced. The friction parameters of the ball screw and linear motion guides are identified independently using the method, assuring the accurate modelling of friction force at all components. A proportional-derivate feed drive position controller with an observer-based friction compensator is implemented to achieve an accurate trajectory tracking performance. Finally, comparative experiments demonstrate the effectiveness of the TDMS in inhibiting the disadvantageous influence of non-linear friction and the validity of the proposed identification method for TDMS.

On generalized inverses of dual matrices

Generalized inverses of real dual matrices are classified according to the set of Moore–Penrose conditions satisfied.The present paper offers theoretical and numerical insights regarding the types of dual generalized inverses that can be computed from a recently proposed formula. Moreover, the usefulness of the formula is demonstrated solving different kinematic problems. In particular, thanks to the dual matrix generalized inverse formula availability, the computation of infinite and infinitesimal screw parameters motion from redundant point and line features is obtained within a unified theoretical treatment. Numerical examples and comparison with the results from previous investigations are provided.

Fracture Gap Reduction With Variable-Pitch Headless Screws.

Fully threaded, variable-pitch, headless screws are used in many settings in surgery and have been extensively studied in this context, especially in regard to scaphoid fractures. However, it is not well understood how screw parameters such as diameter, length, and pitch variation, as well as technique parameters such as depth of drilling, affect gap closure. Acutrak 2 fully threaded variable-pitch headless screws of various diameters (Standard, Mini, and Micro) and lengths (16-28 mm) were inserted into polyurethane blocks of "normal" and "osteoporotic" bone model densities using a custom jig. Three drilling techniques (drill only through first block, 4 mm into second block, or completely through both blocks) were used. During screw insertion, fluoroscopic images were taken and later analyzed to measure gap reduction. The effect of backing the screw out after compression was evaluated. Drilling at least 4 mm past the fracture site reduces distal fragment push-off compared with drilling only through the proximal fragment. There were no significant differences in gap closure in the normal versus the osteoporotic model. The Micro screw had a smaller gap closure than both the Standard and the Mini screws. After block contact and compression with 2 subsequent full forward turns, backing the screw out by only 1 full turn resulted in gapping between the blocks. Intuitively, fully threaded headless variable-pitch screws can obtain compression between bone fragments only if the initial gap is less than the gap closed. Gap closure may be affected by drilling technique, screw size, and screw length. Fragment compression may be immediately lost if the screw is reversed. We describe characteristics of variable-pitch headless screws that may assist the surgeon in screw choice and method of use.

Investigation of the Changes of the Screw Parameters Used in the Treatment of Tibial Fractures

Investigation of the Changes of the Screw Parameters Used in the Treatment of Tibial Fractures

The Effects of Geometrical Parameters of the Pedicle Screw on Its Pullout Strength: In-Vitro Animal Tests

Background: Pedicle screw instrumentation is one of the most commonly used forms of stabilization. Achieving solid screw fixation within the bone presents a significant challenge to spinal surgeons. Although pure pullout is not the mode of failure seen in clinical situations, pullout testing is thought to be a good predictor of pedicle screw fixation strength for spinal fusion.Objectives: To investigate the effects of varying lengths and thread depths of pedicle screws, as well as its insertion angle relative to the sagittal line on pullout strength, and stiffness of the pedicle screws and adjacent bone.Methods: Six fresh-frozen bovine lumbar vertebrae (L5) were examined. Pedicle screws with the lengths of 35, 40, and 45 mm, and the pedicle screws with thread depths of 0.9, 1.1, and 1.15 mm were inserted in pedicles by an orthopedic surgeon. Axial pullout tests were performed by a pullout apparatus and force-displacement curves were plotted.Results: The 45 mm length screw showed the maximum pullout strength (1746 N) and stiffness (564.7 N/mm) in the case of constant thread depth of 0.9 mm. The 1.15 mm thread depth screw showed the maximum pullout strength (1719 N) and stiffness (646.4 N/mm) in the case of constant length of 40 mm, and the screw insertion angle of 25° resulted in maximum pullout strength (1251 N) and stiffness (249.6 N/mm) in the case of constant thread depth of 0.9 mm and constant length of 35 mm.Conclusions: Increasing the length and the thread depth of the screws leads to an increase in the pullout strength, as well as the bone-screw construct stiffness. Pedicle screw pullout strength and the bone-screw construct stiffness were also affected by the insertion angle of the screw. There are other factors such as the insertion technique employed by the surgeon, and bone mineral density, which affect the pullout strength.

Optimal Screw Fixation in Treating Jones Fractures

Category: Midfoot/Forefoot Introduction/Purpose: Jones fractures are among the most common fractures in the foot, mainly occurring in athletes. In order to facilitate return to sport and good functional outcomes, management with intramedullary screw fixation is often recommended [1-3]. While optimal screw dimension and location parameters have varied in the literature, it is clear that maximizing pull-out strength, providing adequate compression across the fracture, and minimizing irritation to surrounding soft tissue structures are of paramount importance. The aim of this study was to improve our guidelines regarding optimal insertion trajectory and screw parameters of Jones fractures by more accurately defining the bony and soft tissue anatomy of the fifth metatarsal bone and its intramedullary canal. Methods: 21 fifth metatarsal bones were harvested from cadaveric feet. Three reference screws were placed on each bone for registration. 3D CT model of each bone with outer cortex, intramedullary canal and the articular cortex was created (Figure A). The insertions of the PB and PF and the reference screws of each bone were carefully digitized and mapped onto corresponding 3D model. The anatomic insertions and the surface areas were determined. Based on the length of the bone, the shape of the intramedullary canal, and the diameter of the canal at its narrowest point, the perceived ideal screw and placement was then modulated for each bone model. Also, the fracture zone where Jones fractures occur was determined (Figure B) based on Lawrence/Botte classification [1]. Screw and thread length were calculated in this position, and the impact of screw placement on the insertion sites of both the PB and PF were recorded. Results: The mean length of the bones was 74.4±3.6 mm, with the narrowest diameter of the intramedullary canal being 4.3±0.7 mm. Ideal screw position was identified as parallel to the cuboid and coaxial with the intramedullary cortex; this placement, however, was found to partially sacrifice the PB and PF insertions in 62% (13/21) and 33% (7/21) of cases, respectively; with an average of 1.6±0.8 mm of the PB and 1.3±0.8 mm of the PF insertion. The mean ideal screw length in this position was found to be 47.8±5.8 mm, with a minimal thread length of 28±6.8 mm and a minimal diameter of 4.5 mm (Figure B). The ratio of screw length to the total bone length was 0.64 (range 0.50-0.72). Conclusion: In order to maximize compression and pull-out strength and minimize sacrifice of the adjacent soft tissue structures during screw placement, Jones fractures should be fixed with hardware parallel to the cuboid and collinear with the intramedullary cortex—which mitigates but does not avoid injury to the peroneal tendon and plantar fascia. Average optimal length of the screw should be 64% of the length of the bone, with a minimum 4.5 mm diameter and 50% thread length (relative to bone length). Given variability in metatarsal anatomy, screw choice should be tailored to the individual.

3D printing\u2013assisted preoperative plan of pedicle screw placement for middle-upper thoracic trauma: a cohort study

BackgroundThis study aimed to evaluate the application of 3D printing in assisting preoperative plan of pedicle screw placement for treating middle-upper thoracic trauma.MethodsA preoperative plan was implemented in seven patients suffering from middle-upper thoracic (T3–T7) trauma between March 2013 and February 2016. In the 3D printing models, entry points of 56 pedicle screws (Magerl method) and 4 important parameters of the pedicle screws were measured, including optimal diameter (ϕ, mm), length (L, mm), inclined angle (α), head-tilting angle (+β), and tail-tilting angle (−β). In the surgery, bare-hands fixation of pedicle screws was performed using 3D printing models and the measured parameters as guidance.ResultsA total of seven patients were enrolled, including five men and two women, with the age of 21–62 years (mean age of 37.7 years). The position of the pedicle screw was evaluated postoperatively using a computerized tomography scan. Totally, 56 pedicle screws were placed, including 33 pieces of level 0, 18 pieces of level 1, 4 pieces of level 2 (pierced lateral wall), and 1 piece of level 3 (pierced lateral wall, no adverse consequences), with a fine rate of 91.0%.Conclusions3D printing technique is an intuitive and effective assistive technology to pedicle screw fixation for treating middle-upper thoracic vertebrae, which improve the accuracy of bare-hands screw placement and reduce empirical errors.Trial registrationThe trial was approved by the Ethics Committee of the Fujian Provincial Hospital. It was registered on March 1st, 2013, and the registration number was K2013–03-001.

Feasibility Study of the Method Choice of Manufacturing Screw Cleaning Elements with the Development and Use of Software

Abstract computer simulation of a curved profile formation on a helical spiral was carried out. A feasibility study was conducted in order to choose the method suitable for manufacturing of L-shaped helical spirals using specially developed software for calculating of the costs of helical spiral formation processes. The tables presenting technological characteristics of the design parameters of screw coiling working bodies manufactured by different methods are provided. The production costs for 1 meter of helical spiral with a curved profile manufactured by different methods are calculated. Theoretical and experimental investigations proved that the most cost-effective method of L-shaped helical spiral manufacturing is to coil it along the inner face from rectangular pieces with simultaneous or subsequent shelve formation.

Introduction of Maximum Stress Parameter for the Evaluation of Stress Shielding Around Orthopedic Screws in the Presence of Bone Remodeling Process

The current study introduces a novel parameter called maximum stress parameter (MSP) which supersedes the conventional parameter known as stress transfer parameter (STP). It also incorporates the bone remodeling algorithm into the finite element analysis. The results from MSP can be approved by those of STP; however, MSP is preferable due to its benefits, which is discussed in this study. The current study simulates a 48 months healing process and investigates the effect of screw parameters using a two-dimensional finite element model in the presence of bone remodeling process. Lower MSP values demonstrate a more homogeneous stress distribution between the screw and bone, which results in less stress shielding. However, the reciprocal of MSP, shown as RMSP is defined in order to enable the comparison between MSP and STP. The results of current study demonstrate that increasing the number of threads and outer diameter, and decreasing pitch and Young’s modulus of screw improve the performance of screw and reduce the possibility of screw loosening. The results also show that MSP is a promising parameter, which can supersede STP in future studies, and increase the reliability of results.