Total Hip Wear Assessment: A Comparison Between Computational and In Vitro Wear Assessment Techniques Using ISO 14242 Loading and Kinematics

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
George Matsoukas ◽  
Ryan Willing ◽  
Il Yong Kim
Keyword(s):  
Computational Model ◽  
Laser Scanning ◽  
Computational Simulation ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Wear Testing ◽  
Volumetric Wear ◽  
Wear Rates ◽  
Total Hip ◽  
Nonlinear Stress

In the present study a direct comparison was made between in vitro total hip wear testing and a computational analysis considering the effects of time and a nonlinear stress-strain relationship for ultrahigh molecular weight polyethylene (UHMWPE) at 37°C. The computational simulation was made correct through calibration to experimental volumetric wear results, and the predicted damage layout on the acetabular liner surface was compared with results estimated from laser scanning of the actual worn specimens. The wear rates for the testing specimens were found to be 17.14±1.23 mg/106 cycles and 19.39±0.79 mg/106 cycles, and the cumulative volumetric wear values after 3×106 cycles were 63.70 mm3 and 64.02 mm3 for specimens 1 and 2, respectively. The value of the calibrated wear coefficient was found to be 5.32(10−10) mm3/N mm for both specimens. The major difference between the computational and experimental wear results was the existence of two damage vectors in the experimental case. The actual location of damage was virtually the same in both cases, and the maximum damage depth of the computational model agreed well with the experiment. The existence of multiple wear vectors may indicate the need for computational approaches to account for multidirectional sliding or strain hardening of UHMWPE. Despite the limitation in terms of describing the overall damage layout, the present computational model shows that simulation can mimic some of the behavior of in vitro wear.

Wear and osteolysis outcomes for highly cross-linked polyethylene in primary total hip arthroplasty compared with conventional polyethylene: a 15- to 18-year single-centre follow-up study

2020 ◽  
pp. 112070001989697 ◽  
Author(s):  
Nam Hoon Moon ◽  
Won Chul Shin ◽  
Min Uk Do ◽  
Suk-Woong Kang ◽  
Sang-Min Lee ◽  
...  
Keyword(s):  
Wear Rate ◽  
Survival Rates ◽  
Reoperation Rate ◽  
Volumetric Wear ◽  
Wear Rates ◽  
Total Hip ◽  
Kaplan Meier ◽  
Long Term Result ◽  
Wear Reduction

Background: Although highly positive results for wear reduction of highly cross-linked polyethylene (HXLPE) have been reported around the 10-year follow-up, the long-term result related to reoperation and wear-related survival is still an issue. Therefore, this study aimed to compare the follow-up results of a single manufacture’s polyethylene liner for >15 years in terms of survival and wear rate. Methods: This retrospective cohort study included 134 primary total hip arthroplasties (THAs) who were followed up for at least 15 years. The mean age at the time of surgery was 50.7 years (conventional polyethylene [CPE] group = 22; HXLPE group = 112). Linear and volumetric wear rates of polyethylene were measured, and the reoperation rate and radiographic osteolysis were evaluated and Kaplan-Meier survival analysis was performed in both groups. Implant-related complications were also examined. Results: HXLPE group showed a significantly lower wear rate in both linear and volumetric wear. None of the hip radiographs showed evidence of loosening or osteolysis in the HXLPE group. The survival rates at 15- to 18-year follow-up were 90.9% and 95.5% in the CPE and HXLPE groups when all-cause reoperation was the endpoint, and 90.9% and 100.0% when the wear-related reoperation was the endpoint, respectively. Implant-related complications were not different between the 2 groups. Conclusions: Wear reduction and osteolysis showed a great advantage in HXLPE after a 15-year follow-up. Although the CPE and HXLPE showed excellent survival, wear and osteolysis were more frequent in the CPE; therefore, the high risk of reoperation in the future should be considered.

The influence of shape and sliding distance of femoral head movement loci on the wear of acetabular cups in total hip arthroplasty

2002 ◽  
Vol 216 (6) ◽  
pp. 393-402 ◽  
Author(s):  
D Bennett ◽  
J F Orr ◽  
D E Beverland ◽  
R Baker
Keyword(s):  
Femoral Head ◽  
Aspect Ratio ◽  
Hip Joint ◽  
Wear Rates ◽  
Total Hip ◽  
Aspect Ratios ◽  
Average Aspect Ratio ◽  
Sliding Distance

Wear of the polyethylene acetabular component is the most serious threat to the long-term success of total hip replacements (THRs). Greatly reduced wear rates have been reported for unidirectional, compared to multidirectional, articulation in vitro. This study considers the multidirectional motions experienced at the hip joint as described by movement loci of points on the femoral head for individual THR patients. A three-dimensional computer program determined the movement loci of selected points on the femoral head for THR patients and normal subjects using kinematic data obtained from gait analysis. The sizes and shapes of these loci were quantified by their sliding distances and aspect ratios with substantial differences exhibited between individual THR patients. The average sliding distances ranged from 10.0 to 18.1 mm and the average aspect ratios of the loci ranged from 2.5 to 9.2 for the THR patients. Positive correlations were found between wear rate and average sliding distance, the inverse of the average aspect ratio of the loci and the product of the average sliding distance and the inverse of the average aspect ratio of the loci. Patients with a normal hip joint range of motion produce multidirectional motion loci and tend to experience more wear than patients with more unidirectional motion loci. Differing patterns of multidirectional motion at the hip joint for individual THR patients may explain widely differing wear rates in vivo.

Wear Evaluation of Ultra High Molecular Weight Polyethylene Using Pin-On-Flat and Hip Simulation Techniques

1995 ◽  
Vol 394 ◽  
Author(s):  
David W. Schroeder ◽  
Joel C. Higgins
Keyword(s):  
Wear Debris ◽  
Compression Molding ◽  
Wear Testing ◽  
Bacterial Degradation ◽  
Wear Rates ◽  
Hip Simulator ◽  
The Difference ◽  
Wear Evaluation ◽  
Isostatic Compression

AbstractReduction of wear and wear debris is one of the most important areas of research presently in the field of orthopedic devices. It is speculated that wear debris is one of the contributing factors in the cascade of events that lead to osteolysis. In this regard it is very important to be able to evaluate in vitro the wear of UHMWPE produced by various manufacturing methods. Presently the three most common methods of wear testing are: pin-on-flat, pin-on-disk, and hip simulator.Wear evaluation was performed on gamma irradiated UHMWPE that was manufactured by three different processes: extrusion, direct compression molding, and isostatic compression molding. The wear evaluation consisted of pin-on-flat and hip simulator testing.omparison of the results from these two different types of tests show that the two tests would rank the wear resistance of the UHMWPE in the same order. However, there is a variation in the difference of the wear rates between the two tests. The pin-on-flat results show that the direct and isostatic compression molded material had approximately 50% less wear than the extruded material whereas the hip simulator results show that the isostatic compression molded material had 16% less wear than the extruded material. The difference in the results of these two tests are the effects of a combination of factors including the mechanical and material properties of the UHN4WPE, modes of wear that are active, the state of stress (constant vs. cyclic) in the specimens, third body contamination of the lubricant, bacterial degradation of the bovine serum lubricant, etc. Both tests are very important and necessary in the evaluation of wear of orthopedic materials.

Wear simulation of the ProDisc-L disc replacement using adaptive finite element analysis

2007 ◽  
Vol 7 (2) ◽  
pp. 165-173 ◽  
Author(s):  
Jeremy J. Rawlinson ◽  
Karan P. Punga ◽  
Kirk L. Gunsallus ◽  
Donald L. Bartel ◽  
Timothy M. Wright
Keyword(s):  
Finite Element ◽  
Wear Rate ◽  
Axial Load ◽  
Computational Simulation ◽  
Wear Test ◽  
Wear Testing ◽  
Adaptive Finite Element ◽  
Wear Rates ◽  
Specific Loading ◽  
Flexion Extension

Object. An understanding of the wear potential of total disc replacements (TDRs) is critical as these new devices are increasingly introduced into clinical practice. The authors analyzed the wear potential of a ProDisc-L implant using an adaptive finite element (FE) technique in a computational simulation representing a physical wear test. Methods. The framework for calculating abrasive wear, first validated using a model of a total hip replacement (THR), was then used to model the ProDisc-L polyethylene component that is fixed to the inferior endplate and articulates with the rigid superior endplate. Proposed standards for spine wear testing protocols specified the inputs of flexion–extension (6/−3°), lateral bending (± 2°), axial twist (± 1.5°), and axial load (200–1750 N or 600–2000 N) applied to the model through 10 million simulation cycles. The model was calibrated with a wear coefficient determined from an experimental wear test. Implicit FE analyses were then performed for variations in coefficient of friction, polyethylene elastic modulus, radial clearance, and polyethylene component thickness to investigate their effects on wear. Results. Using the initial loading protocol (single-peaked axial load profile of 300–1750 N) from the experimental wear test, the polyethylene wear rate was 9.82 mg per million cycles. When a double-peaked loading profile (600–2000 N) was applied, the wear rate increased to 11.77 mg per million cycles. Parametric design variations produced only small changes in wear rates for this simulation. Conclusions. The chosen design variables had little effect on the resultant wear rates. The comparable wear rate for the THR validation analysis was 16.17 mg per million cycles, indicating that, using this framework, the wear potential of the TDR was equivalent to, if not better, than the THR using joint-specific loading standards.

scholarly journals Clinical and radiological results with a 36-mm cobalt-chrome prosthetic head, cross-linked Durasul liners associated with Allofit cups: a more than 10-year follow-up period

2019 ◽  
Vol 30 (4) ◽  
pp. 446-451
Author(s):  
Pierre Georis ◽  
Thierry Thirion ◽  
Philippe Gillet
Keyword(s):  
Polyethylene Liner ◽  
Harris Hip Score ◽  
Volumetric Wear ◽  
Wear Rates ◽  
Head Penetration ◽  
Total Hip ◽  
Prosthetic Head ◽  
Clinical And Radiological Results

Background: Highly cross-linked polyethylene is currently a common articulation surface used for total hip arthroplasty (THA). Aim: The aim of the present study is in vivo assessment of highly cross-linked Durasul polyethylene linear and volumetric wear when associated with a 36-mm prosthetic femoral head. Methods: We retrospectively reviewed clinical and radiographic data of 78 patients (81 hips) having primary THAs using Durasul liner combined with a 36-mm CoCr prosthetic head. All of them were followed for more than 10 years. Patient outcome was assessed with the Harris Hip Score (HHS) preoperatively and at last follow-up. 2-D prosthetic head penetration into polyethylene, 3D wear rates and cup migration were evaluated. Results: The preoperative and last follow-up HHS were 50.43 +/− 10.42 and 97.44 +/− 5.51 respectively. The annual penetration of the prosthetic head into Durasul® liner was 0.029 +/− 0.003 mm. The annual linear penetration and volumetric wear extrapolation rates using Charnley and Ilchmann formulas were 37.84% and 57.76% respectively of that seen with conventional polyethylene liner. At last follow-up, the total loss of material in Durasul represents only 0.15% of the initial polyethylene mass. We did not observe any significant cup migration in the study group. Conclusions: Results are promising, and we believe that these data authorise the continued use of highly cross-linked polyethylene liner associated with a 36-mm prosthetic head for total hip arthroplasties in older patients. More long-term follow-up studies are mandatory before we feel comfortable with the project of using cross-linked polyethylene in young and active patients instead of ceramic-on-ceramic bearings.

Fluid Composition Impacts Standardized Testing Protocols in Ultrahigh Molecular Weight Polyethylene Knee Wear Testing

2005 ◽  
Vol 219 (6) ◽  
pp. 457-464 ◽  
Author(s):  
T Schwenke ◽  
C Kaddick ◽  
E Schneider ◽  
M A Wimmer
Keyword(s):  
Molecular Weight ◽  
Weight Gain ◽  
Calf Serum ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Wear Testing ◽  
Fluid Composition ◽  
Wear Rates ◽  
Ultrahigh Molecular Weight ◽  
Total Knee ◽  
Joint Prostheses

Wear of total knee replacements is determined gravimetrically in simulator studies. A mix of bovine serum, distilled water, and additives is intended to replicate the lubrication conditions in vivo. Weight gain due to fluid absorption during testing is corrected using a load soak station. In this study, three sets of ultrahigh molecular weight polyethylene tibial plateau were tested against highly polished titanium condyles. Test 1 was performed in two different institutions on the same simulator according to the standard ISO 14243-1, using two testing lubricants. Test 2 and test 3 repeated both previous test sections. The wear and load soak rates changed significantly with the lubricant. The wear rate decreased from 16.9 to 7.9 mg weight loss per million cycles when switching from fluid A to fluid B. The weight gain of the load soak specimen submersed in fluid A was 6.1 mg after 5 × 106 cycles, compared with 31.6 mg for the implant in fluid B after the same time period. Both lubricants were mixed in accordance with ISO 14243 ( Implants for surgery - wear of total knee-joint prostheses), suggesting that calf serum should be diluted to 25 ± 2 per cent with deionized water and a protein mass concentration of not less than 17 g/1. The main differences were the type and amount of additives that chemically stabilize the lubricant throughout the test. The results suggest that wear rates can only be compared if exactly the same testing conditions are applied. An agreement on detailed lubricant specifications is desirable.

scholarly journals Wear Simulation of Ceramic-on-Crosslinked Polyethylene Hip Prostheses: A New Non-Oxide Silicon Nitride versus the Gold Standard Composite Oxide Ceramic Femoral Heads

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2917 ◽  
Author(s):  
Makiko Yorifuji ◽  
Saverio Affatato ◽  
Toshiyuki Tateiwa ◽  
Yasuhito Takahashi ◽  
Takaaki Shishido ◽  
...  
Keyword(s):  
Vitamin E ◽  
Silicon Nitride ◽  
Gold Standard ◽  
Wear Behavior ◽  
Wear Testing ◽  
Oxide Ceramic ◽  
Silica Layer ◽  
Wear Rates ◽  
Femoral Heads

The purpose of the present study was to compare the wear behavior of ceramic-on-vitamin-E-diffused crosslinked polyethylene (Vit-E XLPE) hip bearings employing the gold standard oxide ceramic, zirconia (ZrO2)-toughened alumina (Al2O3) (ZTA, BIOLOX®delta) and a new non-oxide ceramic, silicon nitride (Si3N4, MC2®). In vitro wear test was performed using a 12-station hip joint simulator. The test was carried out by applying the kinematic inputs and outputs as recommended by ISO 14242-1:2012. Vitamin-E-diffused crosslinked polyethylene (Vit-E XLPE) acetabular liners (E1®) were coupled with Ø28-mm ZTA and Si3N4 femoral heads. XLPE liner weight loss over 5 million cycles (Mc) of testing was compared between the two different bearing couples. Surface topography, phase contents, and residual stresses were analyzed by contact profilometer and Raman microspectroscopy. Vit-E XLPE liners coupled with Si3N4 heads produced slightly lower wear rates than identical liners with ZTA heads. The mean wear rates (corrected for fluid absorption) of liners coupled with ZTA and Si3N4 heads were 0.53 ± 0.24 and 0.49 ± 0.23 mg/Mc after 5 Mc of simulated gait, respectively. However, after wear testing, the ZTA heads retained a smoother topography and showed fewer surface stresses than the Si3N4 ones. Note that no statistically significant differences were found in the above comparisons. This study suggests that the tribochemically formed soft silica layer on the Si3N4 heads may have reduced friction and slightly lowered the wear of the Vit-E XLPE liners. Considering also that the toughness of Si3N4 is superior to ZTA, the present wear data represent positive news in the future development of long-lasting hip components.

Estimating the osteolysis-free life of a total hip prosthesis depending on the linear wear rate and head size

2018 ◽  
Vol 232 (8) ◽  
pp. 753-758 ◽  
Author(s):  
Reinhard Elke ◽  
Claude B Rieker
Keyword(s):  
Sensitivity Analysis ◽  
Wear Rate ◽  
Head Size ◽  
Wear Volume ◽  
Linear Wear ◽  
Volumetric Wear ◽  
Wear Rates ◽  
Linear Wear Rate ◽  
Total Hip ◽  
The Impact

We present a model to estimate the osteolysis-free life of total hip arthroplasty, depending on linear wear rate and femoral head size. An estimate of the radiologic osteolysis threshold was calculated, which was based on volumetric wear. The osteolysis-free life of the cup was estimated from the quotient of the osteolysis threshold and volumetric wear rate, which was calculated from the linear wear rate. The impact of the direction of linear wear was determined by sensitivity analysis. From our review, we calculated a weighted mean polyethylene volume of approximately 670 mm3 as osteolysis threshold. Osteolysis-free life of less than 20 years was estimated for linear wear rates of 50 µm/year for head sizes of 32 mm or more, or for linear wear rates of 100 µm/year for any head size. For head sizes of 36 and 40 mm with a linear wear rate of 50 µm/year, the osteolysis-free period is estimated to be only 14.10 and 11.42 years, respectively. Sensitivity analysis showed reasonably robust results. With the aim of osteolysis-free life of more than 20 years, our study presents a viable model to determine maximum possible head size for articulations. Osteolysis-free period for 36 and 40 mm head sizes are far too low for conventional polyethylenes. As the threshold wear volume for highly crosslinked polyethylene is, as of yet, unknown, more research is warranted before our model can be generalized to XLPE.

scholarly journals Can Pin-on-Disk Testing Be Used to Assess the Wear Performance of Retrieved UHMWPE Components for Total Joint Arthroplasty?

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Steven M. Kurtz ◽  
Daniel W. MacDonald ◽  
Sevi Kocagöz ◽  
Mariya Tohfafarosh ◽  
Doruk Baykal
Keyword(s):  
Wear Behavior ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Volumetric Wear ◽  
Wear Properties ◽  
Wear Rates ◽  
Ultrahigh Molecular Weight ◽  
Aging Conditions ◽  
Novel Method ◽  
Pin On Disk

The objective of this study was to assess the suitability of using multidirectional pin-on-disk (POD) testing to characterize wear behavior of retrieved ultrahigh molecular weight polyethylene (UHMWPE). The POD wear behavior of 25 UHMWPE components, retrieved after 10 yearsin vivo, was compared with 25 that were shelf aged for 10–15 years in their original packaging. Components were gamma sterilized (25–40 kGy) in an air or reduced oxygen (inert) package. 9 mm diameter pins were fabricated from each component and evaluated against CoCr disks using a super-CTPOD with 100 stations under physiologically relevant, multidirectional loading conditions. Bovine serum (20 g/L protein concentration) was used as lubricant. Volumetric wear rates were found to vary based on the aging environment, as well as sterilization environment. Volumetric wear rates were the lowest for the pins in the gamma inert, shelf aged cohort. These results support the utility of using modern, multidirectional POD testing with a physiologic lubricant as a novel method for evaluating wear properties of retrieved UHMWPE components. The data also supported the hypothesis that wear rates of gamma-inert liners were lower than gamma-air liners for both retrieved and shelf aging conditions. However, this difference was not statistically significant for the retrieved condition.

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