Artificial Hip Prosthesis Research Articles

Simulation of Design Optimization and Performance of CoCrMo Acetabular Hip Prosthesis Implants on Climbing Stairs Activity Using Finite Element Method

Damage or a loss of strength in this hip joint can occur as a result of calcification, aging, the development of illnesses such as osteoporosis, arthritis, and bone cancer, and it can also be permanently destroyed by accidents. As a result, an artificial hip prosthesis can be implanted to prevent undesirable outcomes. Throughout the jumping, running, and walking cycles, the hip joint is the most essential load-bearing and shock-absorbing component in the lower half body. As a result, using a finite element analysis technique, this work simulates the design of an Artificial Hip Joint with holes and thickness as variables, using CoCrMo acetabular implant material. ANSYS 19.1 software with transient structural characteristics will be used to simulate providing the load with the activity of climbing stairs. According to the findings of this study, the acetabular design with a thickness of 3 mm and 5 holes is the most optimal. This is due to the design's distribution of stress, strain, and total deformation being the most ideal and having a relatively low weight with appropriate usage period and safety factor forecasts.

Lifespan Enhancement of Stainless Steel 316L Artificial Hip Prosthesis by Novel Ti-6Al-4V-2ZrC Coating

Lifespan Enhancement of Stainless Steel 316L Artificial Hip Prosthesis by Novel Ti-6Al-4V-2ZrC Coating

Fabrication of TC4/TiCp New Hip Prosthesis by Laser Cladding

Artificial hip prostheses are commonly utilized in total hip replacement surgeries. However, current single materials like metal, polyethylene, and ceramic do not satisfy the comprehensive performance requirements of prostheses, such as biocompatibility, wear resistance, and toughness. To address these limitations, a new metal–ceramic hip prosthesis which can be prepared by laser cladding technique is proposed. By combining the advantages of metal and ceramic, this prosthesis aims to overcome existing product limitations. A TiCp bioceramic coating is prepared on the TC4 surface, and its microstructure, mechanical properties, and biological characteristics are systematically analyzed. The results show that the TiCp phase is uniformly distributed in the coating. Additionally, dendritic TiCp at the bonding interface results in metallurgical bond between the coating and substrate. The α‐Ti phase in the matrix of the TiCp coating helps to enhance its fracture toughness and fatigue strength, while the solid solution of trace C elements in the matrix provides solid solution strengthening. Mechanical tests reveal that the microhardness of the TiCp coating is 2.5 times greater than that of the substrate, and the wear mass is reduced by 89.4%. Finally, the TiCp bioceramic coating is verified to be biocompatible, demonstrating excellent potential for use in hip prostheses.

In vivo evaluation of osseointegration ability of sintered bionic trabecular porous titanium alloy as artificial hip prosthesis.

Hydroxyapatite (HA) coatings have been widely used for improving the bone-implant interface (BII) bonding of the artificial joint prostheses. However, the incidence of prosthetic revisions due to aseptic loosening remains high. Porous materials, including three-dimensional (3D) printing, can reduce the elastic modulus and improve osseointegration at the BII. In our previous study, we identified a porous material with a sintered bionic trabecular structure with in vitro and in vivo bio-safety as well as in vivo mechanical safety. This study aimed to compare the difference in osseointegration ability of the different porous materials and HA-coated titanium alloy in the BII. We fabricated sintered bionic trabecular porous titanium acetabular cups, 3D-printed porous titanium acetabular cups, and HA-coated titanium alloy acetabular cups for producing a hip prosthesis suitable for beagle dogs. Subsequently, the imaging and histomorphological analysis of the three materials under mechanical loading in animals was performed (at months 1, 3, and 6). The results suggested that both sintered bionic porous titanium alloy and 3D-printed titanium alloy exhibited superior performances in promoting osseointegration at the BII than the HA-coated titanium alloy. In particular, the sintered bionic porous titanium alloy exhibited a favorable bone ingrowth performance at an early stage (month 1). A comparison of the two porous titanium alloys suggested that the sintered bionic porous titanium alloys exhibit superior bone in growth properties and osseointegration ability. Overall, our findings provide an experimental basis for the clinical application of sintered bionic trabecular porous titanium alloys.

ZrC-Impregnated Titanium-Based Coating as an Effective Lubricating Barrier for Artificial Hip Prosthesis

Abstract The important properties of implant materials are extended component life, wear resistance, and biocompatibility. The wear characteristics depend, for implant materials, on the nature of the implant, movement of joints, and usage of the part. Hard ceramic Ti-6Al-4V-2ZrC (Titanium (Ti), Aluminium (Al), Vanadium (V), Zirconium Carbide (ZrC)) was coated over stainless steel (SS) 316L for analyzing the wear and mechanical properties against E-52100 steel balls sliding for artificial hip joints. The coating crystallography was examined by X-ray diffraction analysis and the topography was inspected by an Atomic Force Microscope (AFM). The coating thickness has been measured as 5–6 µm using a scanning electron microscope (SEM), and the smooth surface roughness of 0.03 µm was measured using AFM. The Ti-6Al-4V-2ZrC coated surface nanohardness has been enhanced three times higher than uncoated. The ball-on-disk wear was investigated with a load of 2–3 N, sliding distance 110 m, and sliding velocity 0.25–0.95 m/s. The investigated wear rates are mostly higher than 10−5 mm3/Nm, and the frictional coefficient reduces from 0.8 to 0.35. The morphology of worn surfaces was analyzed using SEM. Based on the improvement in nanohardness, it is concluded that the Ti-6Al-4V-2ZrC coated SS 316L is a good replacement for an artificial hip joint because of its better wear resistance and coefficient of friction.

Mechanical Performance of Artificial Hip Stems Manufactured by Hot Forging and Selective Laser Melting Using Biocompatible Ti-15Zr-4Nb Alloy.

We investigated the microstructures, tensile properties, fatigue strengths, and durability limits of hot-forged Ti-15Zr-4Nb (Ti-15-4) alloy artificial hip stems. These properties were compared with those of Ti-15Zr-4Nb-4Ta (Ti-15-4-4) and Ti-6Al-4V (Ti-6-4) alloy stems annealed after selective laser melting. The tensile and fatigue properties of test specimens cut from Ti-15-4 stems annealed after hot forging were excellent compared with those of the Alloclassic Zweymüller Stepless (SL) stem, which is used globally. The 0.2% proof stress (σ0.2%PS), ultimate tensile strength (σUTS), total elongation (TE) at breaking, and fatigue strength (σFS) after 107 cycles were 919 ± 10, 983 ± 9 MPa, 21 ± 1%, and 855 ± 14 MPa, respectively. The durability limit (PD) after 5 × 106 cycles of Ti-15-4 stems was excellent compared with that of the SL stem. The σUTS values of 90°- and 0°-direction-built Ti-15-4-4 rods were 1032 ± 1 and 1022 ± 2 MPa, and their TE values were 14 ± 1% and 16 ± 1%, respectively. The σFS values of annealed 90°-direction-built Ti-15-4-4 and Ti-6-4 rods were 640 ± 11 and 680 ± 37 MPa, respectively, which were close to that of the wrought Ti-15-4 rod (785 ± 17 MPa). These findings indicate that the hot forging and selective laser melting (SLM) techniques can also be applied to the manufacture of artificial hip prostheses. In particular, it was clarified that selective laser melting using Ti-15-4-4 and Ti-6-4 powders is useful for the low-cost manufacturing of custom-made artificial joint prostheses and other prosthetic implants.

Metal artifact reduction for improving quantitative SPECT/CT imaging.

This study aimed to evaluate the effect of the metal artifact reduction (MAR) method on quantitative single-photon emission computed tomography (SPECT)/computed tomography (CT) to reveal the usefulness of MAR in patients with metal implants. We performed a phantom experiment simulating patients with artificial hip prostheses using SPECT/CT equipped with the iterative MAR (iMAR). The phantom was filled with Tc-99m solution (29.5kBq/mL). For the CT scan conditions, tube current time products were applied to obtain volume CT dose indexes (CTDIvols) of 1.4, 2.8, and 5.6mGy. Six types of quantitative SPECT images were reconstructed using data from different doses of CT processed with and without iMAR for CT attenuation correction. Thirty circular regions of interest (ROIs) were placed in each of the dark-band artifactareas, the white-streak artifactareas, and the non-artifact areas. We calculated radioactivity concentrations from quantitative SPECT images with and without iMAR to evaluate the quantitative accuracy. The differences of the effect of iMAR with different CT doses were also evaluated. The results obtained using CT data with a CTDIvol of 2.8mGy are described below. For quantitative SPECT data without iMAR, we observed the underestimation of radioactivity concentration in the dark-band artifactareas and overestimation in the white-streak artifactareas. We observed quantification errors ranging from - 41.1% to + 20.0% without iMAR, depending on the ROI localization. When iMAR was used, these errors were reduced to a range of - 22.8% to + 14.2%. The mean absolute error from the true value in the artifact regions was also significantly reduced from 4.00 to 1.74kBq/mL. In the non-artifact areas, the radioactivity concentrations obtained from the quantitative SPECT data with and without iMAR were equivalent to the true value and did not differ significantly between the two conditions. Similar results were observed for procedures with CTDIvols of 1.4 and 5.6mGy. This study indicated that iMAR could improve the quantitative accuracy of SPECT/CT independent of the CT dose. iMAR can serve as a practicable technique for quantitative SPECT/CT in patients with metal implants.

Tailor-made design, fabrication and validation of SrO doped nanostructured ZTA ceramic Femoral head – Acetabular socket liner assembly

An established commercial grade SrO doped ZTA composition has been considered to design, fabrication through uniaxial pressing followed by sintering and polishing, validation of dimension, 3D surface profile, 3D microstructure, and compressive load bearing capacity of femoral head – acetabular socket liner prototypes for the hip prosthesis. While design and dimensions are concerned, both the steel (HRC60) molds were designed and machined to achieve precious dimensions of femoral head (FH; OD – 30 ± 0.01 mm) and acetabular socket liner (ASL; ID – 30.15 ± 0.01 mm). A close variation in the range of ±0.01 mm was confirmed the precision geometry of polished FH and ASL with consideration of 22 points coordinate measuring method (CMM). 3D surface profile ensures the surface characteristics of Ra = 0.2 ± 0.01 μm and Rq = 0.5 ± 0.01 μm for outer surface of FH and an inner surface of ASL, respectively. Structure integrity and fabrication defects including cracks and pores free bulk structures were confirmed by Micro CT. The compressive load resistance known as burst strength for independent FH and FH-ASL assembly were measured 16.2 KN and 17.6 KN, respectively. The developed ceramic prototypes have an economic advantage and can be adopted as artificial hip prosthesis after extensive in-vitro and in-vivo analysis.

Probabilistic design strategy for improved Austin-Moore stem used in artificial cementless hip prosthesis considering material property uncertainty

Introduction. The use of probabilistic analysis is important when the input data are random, that leads to stochastic results. This paper describes the integration of a probabilistic design strategy of the solid and hollow stems implanted in a proximal femur in order to compare their advantages. The used hollow stem is called “Improved Austin-Moore” (IAM) model. Materials and Methods. Probabilistic methods allow variations in factors which control the biomechanical effects of the implanted femur to be taken into account while determining its performance. Different material properties were generated randomly using Monte Carlo simulation (MCS). Monte Carlo sampling techniques were applied, and different von Mises stresses of the layers (bone and metal) were chosen as a performance indicator. Results. A simple 2D implant-bone study of solid and IAM stem design was carried out with a high level of confidence, 99.87%, which corresponds to a target reliability index with regard to statistical uncertainties. The probabilistic design results show that the input and output parameters for the IAM stem are highly correlated relative to those for the solid stem. Discussion and Conclusions. The sensitivity analysis shows that the input parameters for the IAM stem play a much larger part in the output parameters relative to the solid stem. The IAM stem is much more advantageous than the solid stem which causes an increase in the performance of the hip prosthesis.

Biomechanical Performance of the Cemented Hip Stem with Different Surface Finish

The integrity of the cemented fixation interface is responsible for the long-term longevity of artificial hip prostheses. Metallic stems with roughened surfaces are considered to provide stronger adhesion with cement. However, clinical studies have reported that roughened stems show a lower survival rate than polished stems. These studies clearly reveal that the causes of artificial stem loosening are very complicated and multifaceted. Therefore, this study was conducted to investigate the mechanical effect of stem surface finish in cemented hip replacement. To accomplish this, a series of cement–metal specimens were tested configurations to assess the mechanical characteristics of the cement–metal interface specimens. A finite elemental model of cemented femoral prostheses was then created, in which the cement–stem interface was assumed to be in different bonding states according to the experimentally measured interface properties. The failure probabilities of the cement mantle and cemented interface under physiological loadings were evaluated. Experimental results indicate that the polished metal produced higher interfacial tensile and lower shearing strengths than the roughened metal. The polished stems were predicted to induce a lower failure probability of cement mantle and higher integrity of the cement–stem interface when compared to the roughened stem. Overall, current results provide significant evidence to support the clinical outcomes of cemented hip prostheses with different stem surface finishes.

Micromotion analysis of the head-neck interface of a PEEK artificial hip prosthesis

PEEK has been gradually recommended in recent years as a metal substitute for artificial joint replacement. However, the risk of fretting of the PEEK artificial hip prosthesis in the head-neck interface cannot be ignored. In this study, PEEK was used as the head material, CoCrMo as the contrast material, Ti6Al4V as the neck material, and XLPE as the liner material. The micromotion analysis of the head-neck interface was carried out by a finite element method. The results show that the PEEK artificial hip prosthesis is more likely than the traditional metal artificial hip prosthesis to produce a large micromotion (62 μm) in the head-neck interface and therefore requires a greater impaction load. The PEEK artificial hip prosthesis is more suitable for patients with lighter weight, and a proper reduction in the walking stride can significantly reduce the micromotion of the head-neck interface. Flexion/extension has the greatest effect on micromotion in the hip motion, while inward/outward rotation has the least effect. Inserting the CoCrMo taper sleeve into the neck of the PEEK artificial hip prosthesis can effectively reduce the micromotion of the head-neck interface.

Discussion on Clinical Trial Design of Artificial Hip Prosthesis

Recently, the registration of artificial hip prosthesis products increased year by year. In the new version of the provisions for medical device registration, the domestic or import of such products in the registration declaration may need to complete a clinical trial in the country. How to carry out scientific clinical trials of the product design is the common concern of enterprises and clinical trial institutions. To review the guideline and literature concerning registration for artificial hip prosthesis, the focus on clinical trial design of artificial hip prosthesis include clinical inclusion, evaluation standard, sample size. Through the discussion, we hope to provide advice and guidance for clinical trials of this kind of products.

Comparison of the effects and complications of biotype and cement-based artificial hip prosthesis in the treatment of femoral neck fracture in the elderly

Objective To compare the effects and complications of biotype and cement-based artificial hip prosthesis in the treatment of femoral neck fracture in the elderly. Methods Seventy elderly patients with femoral neck fractures were selected as the subjects and were randomly divided into the bone-cement group(35 cases) and the biomaterials group(35 cases), the bone-cement group received cement-based artificial hip prosthesis, the biomaterials group received biotype artificial hip prosthesis, the perioperative clinical indicators and follow - up indicators of both group were compared. Results The operative time of the bone-cement group was (61.2±11.3) min, longer than that in the biomaterials group ((53.3±10.4) min), the difference was statistically significant (P<0.05), while the postoperative partial load bearing time was (4.0±1.6) d, the postoperative full load bearing time was (30.3±6.8) d and the hospital stay time was (18.2±2.4) d, significantly shorter than that in the biomaterials group ((20.7±2.2) d), the differences were statistically significant (P<0.05), the intraoperative blood loss ((175.3±40.3) ml) and the postoperative bleeding volume ((120.4±33.2) ml) were less than those in the biomaterials group ((213.3±30.4) ml, (185.5±26.6) ml) (P<0.05). The total incidence rate of bone cement complication of the bone-cement group was 11.43%, which were lower than that of the biomaterials group (34.29%), the difference was statistically significant (P<0.05). The Harris score and Barthel life index score of the bone-cement group were significantly higher than those of the biomaterials group (P<0.05), The rate of hip function recovery was significantly higher than that of the biomaterials group (P<0.05). Conclusion Compared with the biotype artificial hip prosthesis, the cement-based artificial hip prosthesis has advantages of rapid clinical improvement, good prognosis and less complication, especially suitable for the treatment of femoral neck fracture in the elderly. Key words: Biotype Artificial Hip Prosthesis; Cement-based Artificial Hip Prosthesis; Femoral Neck Fracture; the Elderly; Efficacy; Complication

The current approach to research and design of the artificial hip prosthesis: a review

The current approach to research and design of the artificial hip prosthesis: a review

Total hip replacement and surface replacement for the treatment of pain and disability resulting from end-stage arthritis of the hip (review of technology appraisal guidance 2 and 44): systematic review and economic evaluation.

Total hip replacement and surface replacement for the treatment of pain and disability resulting from end-stage arthritis of the hip (review of technology appraisal guidance 2 and 44): systematic review and economic evaluation.

Strain-induced martensitic transformation near twin boundaries in a biomedical Co–Cr–Mo alloy with negative stacking fault energy

Biomedical Co–Cr–Mo (CCM) alloys have been commonly used for artificial hip and knee joint prostheses, but a need to improve their biomedical inertness and wear resistance has become widely recognized. The mechanical behavior of CCM alloys is dominated by strain-induced martensitic transformation (SIMT), which causes crack initiation during plastic deformation but dramatically enhances the wear resistance in practical use. To develop more reliable CCM alloys it is essential to clarify the factors affecting the occurrence of SIMT. In the present study we have focused on the effect of annealing twin boundaries (ATBs) on SIMT behavior. We have analyzed in detail the substructures near a parallel pair of ATBs after deformation under a stress preferential for slip parallel to the ATBs. Preferential formation of ε-hexagonal close-packed (HCP) phase at ATBs in metastable γ-face-centered cubic (FCC) phase was found by both scanning electron microscopy with electron backscattered diffraction (EBSD) analysis and transmission electron microscopy (TEM). High resolution TEM images indicated that thickening of the ε-HCP phase does not proceed regularly on every second atomic plane, which would form perfect ε-phase HCP structure, but irregularly leaving a high density of stacking faults. Furthermore, the thickness of the ε-HCP phase was found to be different at ATBs on the two sides of the twin. The difference was attributed to the internal stress due to strain incompatibility at the ATBs on the basis of residual stress analysis by the EBSD–Wilkinson method and phase-field simulation of solute segregation at ATBs.

In-situ electrochemical study of interaction of tribology and corrosion in artificial hip prosthesis simulators

The second generation Metal-on-Metal (MoM) hip replacements have been considered as an alternative to commonly used Polyethylene-on-Metal (PoM) joint prostheses due to polyethylene wear debris induced osteolysis. However, the role of corrosion and the biofilm formed under tribological contact are still not fully understood. Enhanced metal ion concentrations have been reported widely from hair, blood and urine samples of patients who received metal hip replacements and in isolated cases when abnormally high levels have caused adverse local tissue reactions. An understanding of the origin of metal ions is really important in order to design alloys for reduced ion release. Reciprocating pin-on-plate wear tester is a standard instrument to assess the interaction of corrosion and wear. However, more realistic hip simulator can provide a better understanding of tribocorrosion process for hip implants. It is very important to instrument the conventional hip simulator to enable electrochemical measurements. In this study, simple reciprocating pin-on-plate wear tests and hip simulator tests were compared. It was found that metal ions originated from two sources: (a) a depassivation of the contacting surfaces due to tribology (rubbing) and (b) corrosion of nano-sized wear particles generated from the contacting surfaces.

Artificial Hip Prosthesis and Biomechanics

Artificial Hip Prosthesis and Biomechanics

PR52P TO ASSESS THE EFFECTIVENESS OF TOPICAL NEGATIVE PRESSURE (TNP) COMBINED WITH LOCAL INSTILLATION OF BIOCIDES AGAINST STAPHYLOCOCCUS EPIDERMIDIS AND PSEUDOMONAS AERUGINOSA BIOFILM IN VITRO

Introduction: S epidermidis is a recognised major biofilm pathogen and has been implicated in medical device contamination ranging from artificial hip prostheses to breast implants. Pseudomonas aeruginosa is a known pathogen in chronic wounds. Within biofilms, bacteria are enclosed in a polymeric matrix or EPS which cements the bacteria to each other and to the surface. Biofilms act to protect the bacteria from the environment increasing resistance to host immunity, antibiotics and biocides. More recently, we have shown that biofilm occurs on the surface of chronic wounds and that this may have aetiological implications. Method: Staph spp and pseudomonas spp biofilm were grown on glass coupons using the CDC biofilm reactor for 48 hrs and the coupons randomly inserted into the wound model and for 24 hrs subjected to: 1 No instillation plus TNP 2 0.1% w/v formulated hypocholorous acid instillation plus TNP 3 Saline instillation (no biocide) plus TNP 4 Betadine instillation plus TNP Betadine and saline instillations were for 30 minutes every 8, 4 and 2 hours per day in separate experiments. NVC instillation was for 3 minutes, every 8, 4 and 2 hours per day in separate experiments. Following treatment, the coupons were carefully extracted to avoid damaging the biofilms. The effect of TNP on the biofilms was then assessed by colony forming units and electron microscopy. Results: The results show that lower frequency of instillation did not have significant effect on bacterial load for both types of bacteria. Increase in frequency of instillations resulted in no growth of pseudomonas while increase in frequency of instillations resulted in a significant decrease in staph spp.

Tribo-corrosion analysis of wear and metal ion release interactions from metal-on-metal and ceramic-on-metal contacts for the application in artificial hip prostheses

Osteolysis induced by polyethylene wear debris from metal-on-polyethylene total joint replacements is one of the major reasons for the renewed interest in metal-on-metal (MoM) bearings for total hip arthroplasty. However, long-term clinical performance is as yet unknown for the second generation MoM hip prostheses. The main concerns are the released metal ions and metallic wear debris from the artificial joints. It is well known that the metal ion release processes (corrosion) are electrochemical in nature. When two contacted components are in relative motion, wear can occur and it can accelerate corrosion. The role of corrosion in the generation of metallic wear debris is still not well understood. This paper addresses this point and makes a comparison of MoM and ceramic-on-metal (CoM) contacts. In this paper, tests were conducted on a pin-on-plate tester with an integrated electrochemical cell in 25 per cent bovine serum to determine the effects of pin rotation on the wear and metal ion release of two different combinations (metal pins with metal plates and metal pins with medical grade Alumina plates). The overall wear and released metallic ions were reduced with rotational movement of the pin in addition to the reciprocating action of the plate. For the CoM combination, a reduction of wear was associated with a more noble open circuit potential compared with the MoM combination.