Investigation of contact behavior on a model of the dual-mobility artificial hip joint for Asians in different inner liner thicknesses.

BACKGROUND: The four components that make up the current dual-mobility artificial hip joint design are the femoral head, the inner liner, the outer liner as a metal cover to prevent wear, and the acetabular cup. The acetabular cup and the outer liner were constructed of 316L stainless steel. At the same time, the inner liner was made of ultra-high-molecular-weight polyethylene (UHMWPE). As this new dual-mobility artificial hip joint has not been researched extensively, more tribological research is needed to predict wear. The thickness of the inner liner is a significant component to consider when calculating the contact pressure. AIM: To make use of finite element analysis to gain a better understanding of the contact behavior in various inner liner thicknesses on a new model of a dual-mobility artificial hip joint, with the ultimate objective of determining the inner liner thickness that was most suitable for this particular type of dual-mobility artificial hip joint. METHODS: In this study, the size of the femoral head was compared between two diameters (28 mm and 36 mm) and eight inner liner thicknesses ranging from 5 mm to 12 mm. Using the finite element method, the contact parameters, including the maximum contact pressure and contact area, have been evaluated in light of the Hertzian contact theory. The simulation was performed statically with dissipated energy and asymmetric behavior. The types of interaction were surface-to-surface contact and normal contact behavior. RESULTS: The maximum contact pressures in the inner liner (UHMWPE) at a head diameter of 28 mm and 36 mm are between 3.7-13.5 MPa and 2.7-10.4 MPa, respectively. The maximum von Mises of the inner liner, outer liner, and acetabular cup are 2.4-11.4 MPa, 15.7-44.3 MPa, and 3.7-12.6 MPa, respectively, for 28 mm head. Then the maximum von Mises stresses of the 36 mm head are 1.9-8.9 MPa for the inner liner, 9.9-32.8 MPa for the outer liner, and 2.6-9.9 MPa for the acetabular cup. A head with a diameter of 28 mm should have an inner liner with a thickness of 12 mm. Whereas the head diameter was 36 mm, an inner liner thickness of 8 mm was suitable. CONCLUSION: The contact pressures and von Mises stresses generated during this research can potentially be exploited in estimating the wear of dual-mobility artificial hip joints in general. Contact pressure and von Mises stress reduce with an increasing head diameter and inner liner's thickness. Present findings would become one of the references for orthopedic surgery for choosing suitable bearing geometric parameter of hip implant.

Calcination-based direct extraction of hydroxyapatite from bovine bone waste.

The main chemical components of waste cow bones are apatite minerals, especially those containing calcium and phosphorus. This study investigated whether this bone could produce extracted hydroxyapatite through calcining at 900° C for different holding times (1-6 h). An average mass loss of 45% occurred in this experiment during the preparation of bone powders, which involved crushing and further calcining at this temperature. The quantitative XRD analysis showed that 99.97 wt.% hydroxyapatite and over 0.3 wt.% calcite were present in the raw and as-calcined bone powders, with trace amounts of CaFe3O5 (calcium ferrite) phases appearing in the calcined product. Depending on the holding calcining times, SEM images of the calcined bovine powders revealed aggregate sizes ranging from 0.5-3 µm and crystallite (grain) sizes ranging from 70 to 340 nm in all calcium-phosphate powder products. Following EDX analysis of all sample surfaces, possible calcium-deficient hydroxyapatite instead of hydroxyapatite formed, as evidenced by the calcined product's Ca/P ratio exceeding 1.67. Additionally, calcining cow bones for 5-6 h at 900° C yielded a high-purity nano-crystalline hydroxyapatite powder precursor in biomedical applications.

Performance of textured dual mobility total hip prosthesis with a concave dimple during Muslim prayer movements.

The single mobility bearing as a previous bearing design of total hip prosthesis has severe mobility constraints that can result in dislocation during Muslim (people who follow the Islam as religion) prayer movements, specifically shalat that requires intense movement. There are five intense movements (i.e., bowing, prostration, sitting, transition from standing to prostration, and final sitting) during Muslim prayer that may generate an impingement problem for patients with total hip prosthesis. In this work, textured dual mobility total hip prosthesis with two textured cases (i.e., textured femoral head and textured inner liner) are presented and their performances are numerically evaluated against untextured surface model during Muslim prayer movement. The concave dimple design is chosen for surface texturing, while for simulating femoral head materials, SS 316L and CoCrMo is choosen. To represent the real condition, three-dimensional computational fluid dynamics (CFD) coupled with two-way fluid-structure interaction (FSI) methods are employed to analyze elastohydrodynamic lubrication problem with non-Newtonian synovial fluid model. The main aim of the present study is to investigate the tribological performance on dual mobility total hip prosthesis with applied textured surface with concave dimple in femoral head and inner liner surface under Muslim prayer movements. It is found that applying surface texturing has a beneficial effect on the lubrication performance for some intense movements. The textured femoral head model performs better than textured inner liner model and untextured model (both femoral head and inner liner). The numerical results also indicate superior performance of CoCrMo femoral head compared to SS 316L femoral head. These findings can be used as a reference for biomedical engineers and orthopedic surgeons in designing and choosing suitable total hip prosthesis for Muslims makes they can carry out Muslim prayer movements like humans in general who have normal hip joints.

In-depth knowledge of the low-temperature hydrothermal synthesis of nanocrystalline hydroxyapatite from waste green mussel shell (Perna Viridis).

ABSTRACTThis study presents the use of a low-temperature hydrothermal method for extracting calcium sources from green mussel shell (P. Viridis) wastes and converting them into synthetic nanosized hydroxyapatite (HA). In this study, raw mussel shells were washed, pulverised, and sieved to start producing a fine calcium carbonate-rich powder. XRD quantitative analysis confirmed that the powder contains 97.6 wt. % aragonite. This powder was then calcined for 5 h at 900 °C to remove water, salt, and mud, yielding a calcium-rich feedstock with major minerals of calcite (68.7 wt.%), portlandite (24.7 wt.%), and minor aragonite (6.5 wt.%). The calcined powders were dissolved in aqueous stock solutions of HNO3 and NH4OH before hydrothermally reacting with phosphoric acid [(NH4)2HPO4], yielding pure, nanoscale (16-18 nm) carbonated HA crystals, according to XRD, FT-IR, and SEM analyses. The use of a low-temperature hydrothermal method for a feedstock powder produced by the calcination of low-cost mussel shell wastes would be a valuable processing approach for the industry's development of large-scale hydroxyapatite nanoparticle production.

Optimisation of the machining time required by insole orthotic shoes for patients with clubfoot using the Taguchi and response surface methodology approach.

In this study, the application of the computer-aided reverse engineering system (CARE) to the novel design and manufacture of a comfortable insole for a clubfoot patient is presented. The Taguchi method (TM) and response surface methodology (RMS) were used to predict the machining time of the orthotic boot insole during both computer-aided manufacturing (CAM) simulation and computer numerical control (CNC) machining. Taguchi's experimental design, presented as a matrix orthogonal array L2736, was acquired for controlling parameters, namely tool path strategy (A), spindle speed (B), step-down (C), step-over of the cutter (D), cutter diameter (E), and dimensional tolerance (F) of the insole size. In this method, the model generated by the RMS method evaluates the six parameters influencing the machining time. The objective of this study is to develop a regression model that demonstrates the relationship between the cutting parameters and insole machining time. The optimal parameters are A1B1C3D2E1F2, where A1 denotes raster finishing, B1 denotes a spindle speed of 10,000 rpm, C3 denotes a step-down of 850 mm, D2 denotes a step-over of 0.25 mm, E1 denotes a cutter diameter of 20-35 mm, and F2 deontes a tolerance of 0.75 mm. The experimental and calculated machining time (tm) results were 236 and 125.4 min, respectively. However, the real machining results were 334 and 152.25 min with error values of 46.86% and 54.42%, respectively. Meanwhile, with the tm RMS method, the simulated and calculated machining time results were 189.22 and 236.35 min, whereas the real tm values were 236.52 and 334.86 min with error values of 19.94% and 29.37%, respectively. This research obtains improvements of 19.82% (simulation time) and 29.19% (real-time).

Analysis of contact pressure in a 3D model of dual-mobility hip joint prosthesis under a gait cycle.

Hip joint prostheses are used to replace hip joint function in the human body. The latest dual-mobility hip joint prosthesis has an additional component of an outer liner that acts as a cover for the liner component. Research on the contact pressure generated on the latest model of a dual-mobility hip joint prosthesis under a gait cycle has never been done before. The model is made of ultrahigh molecular weight polyethylene (UHMWPE) on the inner liner and 316L stainless steel (SS 316L) on the outer liner and acetabular cup. Simulation modeling using the finite element method is considered static loading with an implicit solver for studying the geometric parameter design of dual-mobility hip joint prostheses. In this study, simulation modeling was carried out by applying varying inclination angles of 30°, 40°, 45°, 50°, 60°, and 70° to the acetabular cup component. Three-dimensional loads were placed on femoral head reference points with variations of femoral head diameter used at 22 mm, 28 mm, and 32 mm. The results in the inner surface of the inner liner, the outer surface of the outer liner, and the inner surface of the acetabular cup showed that the variations in inclination angle do not have a major effect on the maximum contact pressure value on the liner component, where the acetabular cup with an inclination angle of 45° can reduce contact pressure more than the other studied inclination angle variations. In addition, it was found that the 22 mm diameter of the femoral head increases the contact pressure. The use of a larger diameter femoral head with an acetabular cup configuration at a 45° inclination can minimize the risk of implant failure due to wear.

Adopted walking condition for computational simulation approach on bearing of hip joint prosthesis: review over the past 30 years.

Bearing on artificial hip joint experiences friction, wear, and surface damage that impact on overall performance and leading to failure at a particular time due to continuous contact that endangers the user. Assessing bearing hip joint using clinical study, experimental testing, and mathematical formula approach is challenging because there are some obstacles from each approach. Computational simulation is an effective alternative approach that is affordable, relatively fast, and more accessible than other approaches in examining various complex conditions requiring extensive resources and several different parameters. In particular, different gait cycles affect the sliding distance and distribution of gait loading acting on the joints. Appropriate selection and addition of gait cycles in computation modelling are crucial for accurate and reliable prediction and analysis of bearing performance such as wear a failure of implants. However, a wide spread of gait cycles and loading data are being considered and studied by researchers as reported in literature. The current article describes a comprehensive literature review adopted walking condition that has been carried out to study bearing using computational simulation approach over the past 30 years. Many knowledge gaps related to adoption procedures, simplification, and future research have been identified to obtain bearing analysis results with more realistic computational simulation approach according to physiological human hip joints.

Application of fused deposition modeling (FDM) on bone scaffold manufacturing process: A review.

Some of the health issues that are becoming more prevalent each year include bone disease and fractures. Because the natural healing process of bones takes a long time, a bone grafting procedure is required so that the patient's condition can improve rapidly. Because bone grafting procedures such as autographs, allographs, and xenografts have limits, bone replacement is constructed by employing biomaterials in the form of a bone scaffold via additive manufacturing. As a result, fused deposition modeling (FDM) is a proposed technology for the manufacturing process because it is straightforward, capable of producing complex parts and adjustable shapes, and has minimal operational expenses. However, implementing this technique is challenging because of the scarcity of biocompatible and bioactive materials that are suited. This technology has a number of limitations, including a limited variety of biocompatible and bioactive materials, the most appropriate microarchitecture of bone scaffold, and the establishment of printing parameters that can produce bone scaffold with the strongest mechanical properties. This article discusses current advancements in the use of FDM technologies for bone scaffold production.

Practical insights into the recycling of green mussel shells (Perna Viridis) for the production of precipitated calcium carbonate.

The study presented a powder processing method involving calcination and subsequent carbonation in the synthesis of precipitated calcium carbonate (PCC) for recycling green mussel shells, which contain a high calcium carbonate content. The purity of portlandite [Ca(OH)2] as a result of calcination and subsequent moisture absorption during storage was verified using the XRD-Rietveld method. Further quantitative XRD Rietveld analysis of the PCC product confirmed the presence of vaterite (55.20 wt.%) and calcite (44.80 wt.%) minerals after carbonation process of the calcined powder product. The SEM examination of this product revealed particle aggregates of non-uniform polyhedral and cubical grains of varying small and large sizes. The FTIR analysis also confirmed that calcination and subsequent hydration of mussel shell powder yielded pure portlandite, whereas the carbonation yielded PCC polymorphism. As a result, this powder processing method is simple to scale and reduces the cost of PCC synthesis, which is critical for practical applications. The current study demonstrated that the powder processing method for recycling green mussel shells as starting materials in biomedical applications is technically feasible.

Computational Contact Pressure Prediction of CoCrMo, SS 316L and Ti6Al4V Femoral Head against UHMWPE Acetabular Cup under Gait Cycle.

Due to various concerns about the use of metal-on-metal that is detrimental to users, the use of metal as acetabular cup material was later changed to ultra high molecular weight polyethylene (UHMWPE). However, the wear on UHMWPE releases polyethylene wear particles, which can trigger a negative body response and contribute to osteolysis. For reducing the wear of polyethylene, one of the efforts is to investigate the selection of metal materials. Cobalt chromium molybdenum (CoCrMo), stainless steel 316L (SS 316L), and titanium alloy (Ti6Al4V) are the frequently employed materials. The computational evaluation of contact pressure was carried out using a two-dimensional axisymmetric model for UHMWPE acetabular cup paired with metal femoral head under gait cycle in this study. The results show Ti6Al4V-on-UHMWPE is able to reduce cumulative contact pressure compared to SS 316L-on-UHMWPE and CoCrMo-on-UHMWPE. Compared to Ti6Al4V-on-UHMWPE at peak loading, the difference in cumulative contact pressure to respective maximum contact pressure is 9.740% for SS 316L-on-UHMWPE and 11.038% for CoCrMo-on-UHMWPE.

Short communication: Running-in behavior on single-mobility total hip arthroplasty.

Total hip arthroplasty is a short-term solution for replacing a damaged hip joint with synthetic biomaterials. Total hip arthroplasty comes in two flavors: single and dual mobility. Mechanical and biological factors may degrade the quality of biomaterials over time. This may lead to implant failure and second surgical treatment. Wear is the crucial element leading to damaged bone and debris release throughout the body over time. Running-in is the initial wear phase between two surfaces before the steady-state phase. The stage of running-in is critical for understanding hip joint wear. Running-in and wear behavior have been extensively studied in single-mobility total hip arthroplasty, but aseptic loosening is the leading reason for restoration in arthroplasty registries. This paper seeks to summarize running-in behavior on single mobility hip implants, emphasizing its key aspects and recent developments.

Effect of Short-Term Deep-Pressure Portable Seat on Behavioral and Biological Stress in Children with Autism Spectrum Disorders: A Pilot Study.

Children with autism spectrum disorder (ASD) have challenging behaviors, which are associated with difficulties in parenting. Deep pressure is a therapeutic modality in occupational therapy, and it was reported to produce a calming effect. This study aimed to determine whether the short-term use of an autism hug machine portable seat (AHMPS) improves behavioral and neurobiological stress in children with ASD, and to determine whether AHMPS with an inflatable wrap or manual pull is more effective. This study enrolled children with ASD who were administered with the inflatable wrap (group I) and manual pull (group II) for 20 min twice a week for 3 weeks. Conners' Parent Rating Scale-48 (CPRS-48) was used to rate behavioral improvements, and galvanic skin response (GSR) was used to measure sympathetic stress response. A total of 20 children with ASD (14 boys and 6 girls; aged 7-13 years) were included. CPRS-48 presented conduct problems: behavior was significantly decreased in the inflatable group (p = 0.007) compared to the manual pull group. The GSR captured a significant reduction in sympathetic response (p = 0.01) only in group I. Neurobiological stress was reduced in children who were wearing the AHMPS inflatable wrap; therefore, AHMPS inflatable wrap is an effective method to reduce emotional arousal.

Reconstruction of the artificial knee joint using a reverse engineering approach based on computer-aided design.

A greater flexion angle in total knee arthroplasty (TKA) is desirable for replacing the human knee joint damage of people living in the Middle East and Asian regions. This flexion angle is a significant clinical factor affecting the range of motion for patients. Therefore, this study aims to optimise the flexion angle in the design of the Artificial Knee Joint (AKJ) by tailoring the Posterior tibial slope (PTS) and thickness of the Posterior Femoral Condyle (PFC). The 3D CAD model of AKJ was obtained from the reverse engineering (RE) process. Furthermore, the physical model used as a standard implant produced by DePuy, Cruciate Substituting (CS)-Revision type. The obtained 3D models were subsequently converted into CAD for the reconstruction process. Reconstruction of the CAD Model with the customised PTS and FPC components provided the flexion angle in the range of 149.9°-166.7°, which is required for the motion suitable for Middle Eastern and Asian people. The results may be used as a reference standard for doctors in hospitals or industries to design AKJ with Asian ergonomics.

Tresca Stress Simulation of Metal-on-Metal Total Hip Arthroplasty during Normal Walking Activity.

The selection of biomaterials for bearing in total hip arthroplasty is very important to avoid various risks of primary postoperative failure for patients. The current investigation attempts to analyze the Tresca stress of metal-on-metal bearings with three different materials, namely, cobalt chromium molybdenum (CoCrMo), stainless steel 316L (SS 316L), and titanium alloy (Ti6Al4V). We used computational simulations using a 2D axisymmetric finite element model to predict Tresca stresses under physiological conditions of the human hip joint during normal walking. The simulation results show that Ti6Al4V-on-Ti6Al4V has the best performance to reduce Tresca stress by 45.76% and 39.15%, respectively, compared to CoCrMo-on-CoCrMo and SS 316L-on-SS 316L.

The Effect of Bottom Profile Dimples on the Femoral Head on Wear in Metal-on-Metal Total Hip Arthroplasty.

Wear and wear-induced debris is a significant factor in causing failure in implants. Reducing contact pressure by using a textured surface between the femoral head and acetabular cup is crucial to improving the implant's life. This study presented the effect of surface texturing as dimples on the wear evolution of total hip arthroplasty. It was implemented by developing finite element analysis from the prediction model without dimples and with bottom profile dimples of flat, drill, and ball types. Simulations were carried out by performing 3D physiological loading of the hip joint under normal walking conditions. A geometry update was initiated based on the patient's daily routine activities. Our results showed that the addition of dimples reduced contact pressure and wear. The bottom profile dimples of the ball type had the best ability to reduce wear relative to the other types, reducing cumulative linear wear by 24.3% and cumulative volumetric wear by 31% compared to no dimples. The findings demonstrated that surface texturing with appropriate dimple bottom geometry on a bearing surface is able to extend the lifetime of hip implants.

Advanced design and manufacturing of custom orthotics insoles based on hybrid Taguchi-response surface method.

Herein, a machining strategy to fabricate custom orthotic insoles with high surface finish and wide fit tolerance is presented. CNC milling was used to machine ethylene-vinyl acetate (EVA) foam for insoles with various surface hardness, and the Taguchi-response surface method (TM-RSM) was adopted to optimize the parameters of the CNC milling process (cutting speed, feed rate, tool path strategy, and step over). EVA foam with varying surface hardness and the tolerance of the wide fit insoles corresponding to the surface roughness were analyzed. Subsequently, a mathematical model was established to determine the optimal CNC milling parameters for a standard milling cutter under dry coolants. The results of the six parameters corresponding to the mean values of surface roughness were initially examined using the signal-to-noise ratio of the Taguchi method (TM). The surface roughness obtained with the TM-RSM was up to 4.13% higher than that obtained with the TM. The EVA foam insole with a surface hardness of 50-60 HRC and a wide fit tolerance of 0.75 mm provided the ideal level of comfort and support for patients with diabetes. The results of this study demonstrated that CNC milling provided a better surface finish of orthotic shoe insoles than other methods, which can serve as guidance in the development of machining strategies for insoles made from EVA foam.

Study of an Additional Layer of Cement Mantle Hip Joints for Reducing Cracks.

Failure of the cement mantle in total hip arthroplasty is not a simple phenomenon. Cracking, which can be caused by crack initiation and repeated loading, can cause loosening of the acetabular liner component. A previous study showed that addition of a metal layer between the liner and acetabular could reduce the stress at the contact surface of the cement mantle. This study elaborates on the performance of the additional layer. Several material properties of the layer were simulated using finite element analysis for maximum performance. A static contact analysis was used to simulate the stresses at the contact surface of the cement mantle. The results show that an additional layer of cobalt chrome produced the best performance.

Initial Response of Human Bone Marrow-Derived Stem Cells after Contact with Ultrahigh-Molecular-Weight Polyethylene (UHMWPE) Material: An In Vitro Study on Cell Viability and Interleukin-6 Expression.

INTRODUCTION: Ultrahigh-molecular-weight polyethylene (UHMWPE) is a thermoplastic polymer useful in biomaterial applications, especially in orthopedic field. Yet, little is known concerning its initial effect on human bone marrow stem cells (hBMSCs) after implantation. MATERIALS AND METHODS: A cytotoxicity analysis was performed with a 3-(4,5-dimethylthiazol 2-yl)-2,5-diphenyltetrazolium assay after 24, 48, and 72h of incubation of hBMSC culture. Expression of interleukin-6 (IL-6) was measured using enzyme-linked immunosorbent assay. Cell viability was measured with Inhibitory concentration 50% (IC50) formula. RESULTS: All treatment groups showed a cell viability of >50% ranging from 78% to >100%. Lower expression of IL-6 of hBMSC compared to control group was found in 48h of incubation period. CONCLUSION: hBMSC showed high cell viability after initial contact with UHMWPE material. Modulation of IL-6 expression was present at the initial stage as a response to foreign material.

Human Bone Marrow-Derived Mesenchymal Cell Reactions to 316L Stainless Steel: An in Vitro Study on Cell Viability and Interleukin-6 Expression.

Purpose: Human bone marrow-derived mesenchymal cell (hBMC) reactions to 316L stainless steel (316L-SS) have never been evaluated. The objective of this study was to assess cell viability and interleukin-6 expression of hBMC cultures upon treatment with a 316L-SS implant. Methods: A cytotoxicity analysis was conducted with a 3-(4,5-dimethylthiazol 2-yl)-2,5-diphenyltetrazolium (MTT) assay after a period of 24, 48 and 72 hours of incubation. Expression of interleukin-6 was measured using enzyme-linked immunosorbent assay (ELISA). Results: Cell viability measurement was performed via IC50 formula. All treatment group showed a > 50 % cell viability with a range of 56,5 - 96,9 % at 24 hours, 51,8-77,3% at 48 hours and 70,1- 120 % at 72 hours. Interleukin-6 expression was downregulated subsequent to treatment with 316L-SS compared to the control group. Conclusion: We found that 316L-SS did not exhibit toxicity towards hBMC culture.

Range of Motion Simulation of Hip Joint Movement During Salat Activity.

BACKGROUND: Impingement of an artificial hip joint because of limited range of motion (RoM) during human activity is one of the main sources of hip joint failure. The aim of this article is to simulate the RoMs of hip joints during salat, the practice of formal worship in Islam. METHODS: Salat consists of several stages which can be represented with a cycle (raka'ah). Every raka'ah consists of standing, bowing (ruku'), straightening up (i'tidal), transition of standing toward prostrating, prostrating (sujud), and sitting. A virtual skeleton model was used to analyze the motion during salat for the possibility of the impingement occurrence. RESULTS: The results of the simulation were presented in terms of maximum flexion, abduction, and internal or external rotation. The results also showed that the prostration position is similar in RoM with the Japanese zarei position and similar in RoM to pick up an object while sitting on a chair. CONCLUSION: Specific aspects of salat such as the difference in position of the 2 legs at the last sitting position create an extreme RoM which in turn results in a high risk of impingement.