Investigation of Protein Adsorption Mechanism and Biotribological Properties at Simulated Stem-Cement Interface

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Hongyu Zhang ◽  
Shaohua Zhang ◽  
Jianbin Luo ◽  
Yuhong Liu ◽  
Shanhua Qian ◽  
...  

Debonding of the stem–cement interface occurs inevitably for almost all stem designs under physiological loading, and the wear debris generated at this interface is showing an increasing significance in contributing to the mechanical failure of cemented total hip replacements. However, the influence of protein adsorption onto the femoral stem and the bone cement surfaces has not been well taken into consideration across previous in vitro wear simulations. In the present study, the protein adsorption mechanism and biotribological properties at the stem-cement interface were investigated through a series of frictional tests using bone cements and femoral stems with two kinds of surface finishes, lubricated by calf serum at body temperature. The friction coefficient was dependent on the surface finish of the samples, with an initial much lower value obtained for the polished contacting pairs followed by a sudden increase in the friction coefficient with regard to the tests performed at higher frequencies. The friction coefficient did not change much during the tests for the glass-bead blasted contacting pairs. In addition, proteins from the calf serum were found to adsorb onto both the femoral stem and the bone cement surfaces, and the thickness of the physically adsorbed proteins on the polished metallic samples was more than 10 μm, which was measured using an optical interferometer and validated through a vertical scanning methodology based on Raman spectroscopy. An initial protein adsorption mechanism and biotribological properties at the stem-cement interface were examined in this study, and it suggested that wear at the stem-cement interface may be postponed or reduced by tailoring physicochemical properties of the femoral components to promote protein adsorption.

Author(s):  
H. Zhang ◽  
L. Brown ◽  
L. Blunt

The long term stabilization and durability of cemented total hip replacement (THR) depends on not only the bulk properties of the components but also the interfaces through which they interact. The stem-cement interface has been consistently considered as a weak link in the stem-cement-bone system, being a transitional zone between two materials with significantly different mechanical properties. Previous research concerning this interface has been limited to investigation of interfacial shear strength through in vitro test and finite element analysis (FEA). Until now, a deep insight into the contact characteristics at this interface, especially the interaction between femoral stems with various surface finishes and bone cement, has not been established. In addition, it is still an area of debate whether a permanent fixation can be achieved by utilizing a matt femoral stem, and furthermore it is another matter of concern that a matt femoral stem would cause much more damage to the cement mantle, resulting in an acceleration of aseptic loosening of the femoral stem. This present study investigated the surface topography of stainless steel rods and Simplex P bone cement obtained from a series of pull out tests in order to gain a better understanding of the interaction at the stem-cement interface.


Author(s):  
Masaru Higa ◽  
Ikuya Nishimura ◽  
Kazuhiro Matsuda ◽  
Hiromasa Tanino ◽  
Yoshinori Mitamura

Though Total Hip Arthroplasty (THA) is being performed with greater frequency every year for patients with endstage arthritis of hip, mechanical fatigue of bone cement leading to damage accumulation is implicated in the loosening of cemented hip components. This fatigue failure of bone cement has been reported to be the result of high tensile and shear stresses at the bone cement. The aim of this study is to design the optimum shape of femoral component of a THA that minimizes the peak stress value of maximum principal stress at the bone cement and to validate the FEM results by comparing numerical stress with experimental ones. The p-version three-dimensional Finite Element Method (FEM) combined with an optimization procedure was used to perform the shape optimization. Moreover the strain in the cement mantle surrounding the cemented femoral component of a THA was measured in vitro using strain gauges embedded within the cement mantle adjacent to the developed femoral stem to validate the optimization results of FEM.


2020 ◽  
Vol 10 (18) ◽  
pp. 6528 ◽  
Author(s):  
Mayra Eliana Valencia Zapata ◽  
José Herminsul Mina Hernandez ◽  
Carlos David Grande Tovar ◽  
Carlos Humberto Valencia Llano ◽  
Blanca Vázquez-Lasa ◽  
...  

Acrylic bone cement (ABC) is one of the most used materials in orthopedic surgery, mainly for the fixation of orthopedic implants to the bone. However, ABCs usually present lack of biological activity and osseointegration capacity that leads to loosening of the prosthesis. This work reports the effect of introducing graphene oxide (GO) and chitosan (CS), separately or together, in the ABC formulation on setting performance, mechanical behavior, and biological properties. Introduction of both CS and GO to the ABC decreased the maximum temperature by 21% and increased the antibacterial activity against Escherichia coli by 87%, while introduction of only CS decreased bending strength by 32%. The results of cell viability and cell adhesion tests showed in vitro biocompatibility. The in vivo response was investigated using both subdermal and bone parietal implantations in Wistar rats. Modified ABCs showed absence of immune response, as confirmed by a normal inflammatory response in Wistar rat subdermal implantation. The results of the parietal bone implantation showed that the addition of CS and GO together allowed a near total healing bone–cement interface, as observed in the micrographic analysis. The overall results support the great potential of the modified ABCs for application in orthopedic surgery mainly in those cases where osseointegration is required.


1995 ◽  
Vol 5 (3-4) ◽  
pp. 124-130 ◽  
Author(s):  
A. J. Ward ◽  
E. J. Smith ◽  
J. W. Barlow ◽  
A. Powell ◽  
M. Halawa ◽  
...  

Two differing cementation methods were investigated in an in vitro simulation of hip arthroplasty. The bone-cement interface pressures were recorded during cement injection and stem insertion in matched pairs of fresh cadaveric femora. Reduced viscosity cement injected with a cement gun and proximal seal was compared with injection of high viscosity cement and finger-packing in each pair. The resultant shear strength of the bone-cement interface was measured by push-out tests. Results were analysed using the Wilcoxon ranked sum test for paired samples. The Exeter method of cementation produced significantly higher mean and maximum pressures above the bleeding pressure of femoral bone at all interface levels during cement injection. This was associated with significantly greater mean shear strengths. The authors conclude that the Exeter pressurization system for cementation overcomes the effect of femoral bone bleeding and improves the quality of the bone-cement interface. This may contribute to reduction in the incidence of loosening in cement hip arthroplasty.


Author(s):  
L Brown ◽  
H Zhang ◽  
L Blunt ◽  
S Barrans

The stem-cement interface experiences fretting wear in vivo due to low-amplitude oscillatory micromotion under physiological loading, as a consequence it is considered to play an important part in the overall wear of cemented total hip replacement. Despite its potential significance, in-vitro simulation to reproduce fretting wear has seldom been attempted and even then with only limited success. In the present study, fretting wear was successfully reproduced at the stem-cement interface through an in-vitro wear simulation, which was performed in part with reference to ISO 7206-4: 2002. The wear locations compared well with the results of retrieval studies. There was no evidence of bone cement transfer films on the stem surface and no fatigue cracks in the cement mantle. The cement surface was severely damaged in those areas in contact with the fretting zones on the stem surface, with retention of cement debris in the micropores. Furthermore, it was suggested that these micropores contributed to initiation and propagation of fretting wear. This study gave scope for further comparative study of the influence of stem geometry, stem surface finish, and bone cement brand on generation of fretting wear.


2002 ◽  
Vol 30 (3) ◽  
pp. 265-270 ◽  
Author(s):  
O Rodop ◽  
A Kiral ◽  
O Arpacioglu ◽  
I Akmaz ◽  
C Solakoglu ◽  
...  

The necrotizing effects of the heat, particularly at more than 50 °C, produced by the exothermic polymerization process associated with the acrylic implant cement polymethylmethacrylate (PMMA) are well documented. The temperature changes that occur are dependent on the thickness of the PMMA. The current study investigates the hypothesis that the heat produced by the bone cement may be reduced by the choice of stem design and by pre-cooling the hip prosthesis. The thermal alterations at the bone-cement interface were measured in an in vitro model. The results indicated that a temperature decrease of approximately 7 °C could be achieved by pre-cooling the prosthesis, and by changing the shape of the prosthesis stem from flat and wide to round.


2008 ◽  
Vol 130 (2) ◽  
Author(s):  
N. P. Zant ◽  
P. Heaton-Adegbile ◽  
J. G. Hussell ◽  
J. Tong

Although hip simulators for in vitro wear testing of prosthetic materials used in total hip arthroplasty (THA) have been available for a number of years, similar equipment has yet to appear for endurance testing of fixation in cemented THA, despite considerable evidence of late aseptic loosening as one of the most significant failure mechanisms in this type of replacements. An in vitro study of fatigue behavior in cemented acetabular replacements has been carried out, utilizing a newly developed hip simulator. The machine was designed to simulate the direction and the magnitude of the hip contact force under typical physiological loading conditions, including normal walking and stair climbing, as reported by Bergmann et al. (2001, Hip 98, Freie Universitaet, Berlin). A 3D finite element analysis has been carried out to validate the function of the hip simulator and to evaluate the effects of boundary conditions and geometry of the specimen on the stress distribution in the cement mantle. Bovine pelvic bones were implanted with a Charnley cup, using standard manual cementing techniques. Experiments were carried out under normal walking and descending stairs loading conditions with selected load levels from a body weight of 75–125kg. Periodically, the samples were removed from the test rigs to allow CT scanning for the purpose of monitoring damage development in the cement fixation. The hip simulator was found to be satisfactory in reproducing the hip contact force during normal walking and stair climbing, as reported by Bergmann et al. Finite element analysis shows that the stress distributions in the cement mantle and at the bone-cement interface are largely unaffected by the geometry and the boundary conditions of the model. Three samples were tested up to 17×106cycles and sectioned post-testing for microscopic studies. Debonding at the bone-cement interface of various degrees in the posterior-superior quadrant was revealed in these samples, and the location of the failures corresponds to the highest stressed region from the finite-element analysis. Preliminary experimental results from a newly developed hip simulator seem to suggest that debonding at the bone-cement interface is the main failure mechanism in cemented acetabular replacements, and descending stairs seem to be more detrimental than normal walking or ascending stairs with regard to fatigue integrity of cement fixation.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Azadeh Ghouchani ◽  
Gholamreza Rouhi ◽  
Mohammad Hosein Ebrahimzadeh

AbstractThe distal femur is the predominant site for benign bone tumours and a common site for fracture following tumour removal or cementation. However, the lack of conclusive assessment criterion for post-operative fracture risk and appropriate devices for cement augmentation are serious concerns. Hence, a validated biomechanical tool was developed to assess bone strength, depending on the size and location of artificially created tumorous defects in the distal femora. The mechanics of the bone–cement interface was investigated to determine the main causes of reconstruction failure. Based on quantitative-CT images, non-linear and heterogeneous finite element (FE) models of human cadaveric distal femora with simulated tumourous defects were created and validated using in vitro mechanical tests from 14 cadaveric samples. Statistical analyses demonstrated a strong linear relationship (R2 = 0.95, slope = 1.12) with no significant difference between bone strengths predicted by in silico analyses and in vitro tests (P = 0.174). FE analyses showed little reduction in bone strength until the defect was 35% or more of epiphyseal volume, and reduction in bone strength was less pronounced for laterally located defects than medial side defects. Moreover, the proximal end of the cortical window and the most interior wall of the bone–cement interface were the most vulnerable sites for reconstruction failure.


2021 ◽  
Vol 103-B (2) ◽  
pp. 309-320
Author(s):  
Matilda F. R. Powell-Bowns ◽  
Erlend Oag ◽  
Nathan Ng ◽  
Hemant Pandit ◽  
Matthew Moran ◽  
...  

Aims The aim of this study was to determine whether fixation, as opposed to revision arthroplasty, can be safely used to treat reducible Vancouver B type fractures in association with a cemented collarless polished tapered femoral stem (the Exeter). Methods This retrospective cohort study assessed 152 operatively managed consecutive unilateral Vancouver B fractures involving Exeter stems; 130 were managed with open reduction and internal fixation (ORIF) and 22 with revision arthroplasty. Mean follow-up was 6.5 years (SD 2.6; 3.2 to 12.1). The primary outcome measure was revision of at least one component. Kaplan–Meier survival analysis was performed. Regression analysis was used to identify risk factors for revision following ORIF. Secondary outcomes included any reoperation, complications, blood transfusion, length of hospital stay, and mortality. Results Fractures (B1 n = 74 (49%); B2 n = 50 (33%); and B3 n = 28 (18%)) occurred at median of 4.2 years (interquartile range (IQR) 1.2 to 9.2) after primary total hip arthroplasty (THA) (n = 138) or hemiarthroplasty (n = 14). Rates of revision and reoperation were significantly higher following revision arthroplasty compared to ORIF for B2 (p = 0.001) and B3 fractures (p = 0.050). Five-year survival was significantly better following ORIF: 92% (95% confidence interval (CI) 86.4% to 97.4%) versus 63% (95% CI 41.7% to 83.3%), p < 0.001. ORIF was associated with reduced blood transfusion requirement and reoperations, but there were no differences in medical complications, hospital stay, or mortality between surgical groups. No independent predictors of revision following ORIF were identified: where the bone-cement interface was intact, fixation of B2 or B3 fractures was not associated with an increased risk of revision. Conclusion When the bone-cement interface was intact and the fracture was anatomically reducible, all Vancouver B fractures around Exeter stems could be managed with fixation as opposed to revision arthroplasty. Fixation was associated with reduced need for blood transfusion and lower risk of revision surgery compared with revision arthroplasty. Cite this article: Bone Joint J 2021;103-B(2):309–320.


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