Charnley wear model for validation of hip simulators' ball diameter versus polytetrafluoroethylene and polyethylene wear

1997 ◽  
Vol 211 (1) ◽  
pp. 25-36 ◽  
Author(s):  
I C Clarke ◽  
V Good ◽  
L Anissian ◽  
A Gustafson
Keyword(s):  
Femoral Head ◽  
Clinical Data ◽  
Polyethylene Wear ◽  
Test Duration ◽  
Cobalt Chromium ◽  
Wear Model ◽  
Wear Rates ◽  
Ball Diameter ◽  
Relationship Of

Wear rates of polytetrafluoroethylene (PTFE) and polyethylene cups were compared in 9-channel and 12-channel simulators, using serum lubrication and gravimetric techniques for wear assessment. Cobalt-chromium (CoCr) and alumina ceramic femoral heads in 22-42 mm diameter range were used to validate simulator wear rates against clinical data. This was also the first study of three femoral head sizes evaluated concurrently in a simulator (with three replicate specimens) and also the first report in which any wear experiments were repeated. Fluid absorption artefacts were within ± 1 per cent of wear magnitude for PTFE and ± 8 per cent for polyethylene and were corrected for. Wear rates were linear as a function of test duration. Precision within each set of three cups was within ±6 per cent. The wear rates from experiments repeated over 15 months were reproducible to within ± 24 per cent. However, the magnitudes of the simulator wear rates were not clinically accurate, the PTFE wear rates (2843 mm3/106 cycles; 22 mm diameter) were over three times higher than in vivo, the polyethylene 30 to 50 per cent on the low side (23 mm3/106 cycles; 22 mm diameter). Volumetric wear rate increased with respect to size of femoral head and a linearly increasing relationship of 7-8 per cent/mm was evident with respect to femoral head diameter for both PTFE and polyethylene. These data compared well with the clinical data.

Comparison of Polyethylene Wear between Highly Crosslinked and Annealed UHMWPE and Conventional UHMWPE against Ceramic Heads in Total Hip Arthroplasty

2012 ◽  
Vol 529-530 ◽  
pp. 279-284 ◽  
Author(s):  
Taishi Sato ◽  
Yasuharu Nakashima ◽  
Mio Akiyama ◽  
Takuaki Yamamoto ◽  
Taro Mawatari ◽  
...  
Keyword(s):  
Femoral Head ◽  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Polyethylene Wear ◽  
Wear Rates ◽  
Head Penetration ◽  
Total Hip ◽  
Patient Demographics ◽  
Ceramic Femoral Head ◽  
Implantation Period

The purpose of this study was to examine the effects of ceramic femoral head material on the wear of annealed, crosslinked ultra-high molecular weight polyethylene (UHMWPE) (XLPE) in total hip arthroplasty compared to non-crosslinked conventional UHMWPE (CPE). XLPE was fabricated by crosslinking with 60 kGy irradiation and annealing. Femoral heads made from zirconia and alumina ceramics, and cobalt-chrome (CoCr) of 22 mm or 26 mm diameter were used. In this study, the femoral head penetration into the cup was measured digitally on radiographs of 70 hips with XLPE and 50 hips with CPE. The average follow-up periods were 6.1 and 12.7 years, respectively. The steady wear rate of XLPE was significantly lower than those of CPE (0.002 versus 0.08 mm/year, respectively). Zirconia displayed increased wear rates compared to alumina in CPE; however, there was no difference among head materials in XLPE (0.0028, 0.011 and 0.009 mm/year for zirconia, alumina and CoCr, respectively). Neither head size or implantation period impacted XLPE wear. In contrast to CPE, XLPE displayed low wear rates surpassing the effects of varying femoral head material, size, implantation period and patient demographics.

scholarly journals Peri-implant cartilage and bone histological changes following treatment of focal osteochondral defects in the femoral head with polyether ether ketone implants versus cobalt chromium molybdenum alloy implants: assessment in a goat model

2020 ◽  
Author(s):  
Zhiguo Yuan ◽  
Wei Zhang ◽  
Xiangchao Meng ◽  
Jue Zhang ◽  
Teng TengLong ◽  
...  
Keyword(s):  
Femoral Head ◽  
Osteochondral Defect ◽  
Osteochondral Defects ◽  
Cobalt Chromium ◽  
Cocrmo Alloy ◽  
Polyether Ether Ketone ◽  
Histological Score ◽  
Ether Ketone ◽  
Cobalt Chromium Molybdenum

Abstract Objective: This study aimed to quantitatively investigate the peri-implant histology of applying defect-size polyether ether ketone (PEEK) implant for the treatment of localized osteochondral defects in the femoral head and compared it with cobalt chromium molybdenum (CoCrMo) alloy implant.Methods: A femoral head osteochondral defect model was created in the left hips of goats (n=12). Defects were randomly treated by immediate placement of a PEEK (n=6) or CoCrMo implant (n=6). The un-operated right hip joints served as a control. Goats were sacrificed at 12 weeks. Periprosthetic cartilage quality was semi-quantitatively analyzed macroscopically and microscopically. Implant osseointegration was measured by micro-CT and histomorphometry.Results: The modified macroscopic articular evaluation score in the PEEK group was lower than that in the CoCrMo group (p<0.05), and the histological score of the periprosthetic and acetabular cartilage in the PEEK group was lower than that in the CoCrMo group (P<0.05). The mean bone-implant contact for PEEK implants was comparable with that for CoCrMo alloy implants at 12 weeks.Conclusions: A PEEK implant for the treatment of local osteochondral defect in the femoral head demonstrated effective fixation and superior in vivo cartilage protection compared with an identical CoCrMo alloy implant.

A dynamic contact wear model of ball bearings without or with distributed defects

2020 ◽  
Vol 234 (24) ◽  
pp. 4827-4843
Author(s):  
Xi Zhang ◽  
Hua Xu ◽  
Wei Chang ◽  
Hui Xi ◽  
Shiyuan Pei ◽  
...  
Keyword(s):  
Dynamic Contact ◽  
Ball Bearings ◽  
Wear Model ◽  
Wear Rates ◽  
Contact Wear ◽  
Body Dynamics ◽  
Ball Diameter ◽  
Dynamic Wear ◽  
Multi Body ◽  
The Ideal

A dynamic contact wear model of ball bearings consisting of wear degree and position distribution is proposed by integrating the developed contact wear model, multi-body dynamics and raceway waviness or ball diameter differences. Subsequently, the dynamic wear characteristics, not only for the ideal bearing under different axial and radial loads, but also for the bearing with above defects are analysed. The influences of load, typical waviness orders and amplitude on the wear of each ball against both raceways are evaluated and qualitatively validated. Finally, the dynamic characteristics of ball bearings with one ball larger are discussed, and then vibration frequency and wear rates distinction are verified by the experiment with working-surface roughness measurement as a way for wear rate assessment.

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.

scholarly journals In Vivo Femoral Head Damage and Its Effect on Polyethylene Wear

2010 ◽  
Vol 25 (2) ◽  
pp. 302-308 ◽  
Author(s):  
Hiroshi Ito ◽  
Caitlin M. Maloney ◽  
Roy D. Crowninshield ◽  
John C. Clohisy ◽  
Douglas J. McDonald ◽  
...  
Keyword(s):  
Femoral Head ◽  
Polyethylene Wear

Material loss at the femoral head taper

2018 ◽  
Vol 100-B (10) ◽  
pp. 1310-1319 ◽  
Author(s):  
D. J. Langton ◽  
S. R. Wells ◽  
T. J. Joyce ◽  
J. G. Bowsher ◽  
D. Deehan ◽  
...  
Keyword(s):  
Femoral Head ◽  
Multiple Regression ◽  
Clinical Success ◽  
Published Data ◽  
Material Loss ◽  
Wear Rates ◽  
Regression Modelling ◽  
Median Period ◽  
Hip Arthroplasties

Aims There are limited published data detailing the volumetric material loss from tapers of conventional metal-on-polyethylene (MoP) total hip arthroplasties (THAs). Our aim was to address this by comparing the taper wear rates measured in an explanted cohort of the widely used Exeter THA with those measured in a group of metal-on-metal (MoM) THAs. Patients and Methods We examined an existing retrieval database to identify all Exeter V40 and Universal MoP THAs. Volumetric wear analysis of the taper surfaces was conducted using previously validated methodology. These values were compared with those obtained from a series of MoM THAs using non-parametric statistical methodology. A number of patient and device variables were accounted for using multiple regression modelling. Results A total of 95 Exeter MoP and 249 MoM THAs were examined. The median volumetric loss from the MoM cohort was over four times larger than that from the MoP cohort (1.01 mm3 vs 0.23 mm3, p < 0.001), despite a significantly shorter median period in vivo for the MoM group (48 months vs 90 months, p < 0.001). Multiple regression modelling indicated that the dominant variables leading to greater female taper material loss were bearing diameter (p < 0.001), larger female taper angles (p < 0.001), and male titanium stem tapers (p < 0.001). Conclusion Consistent with the long-term clinical success of the device, the volumetric material loss from Exeter femoral head tapers was, in general, small compared with that from larger-diameter MoM head tapers. Cite this article: Bone Joint J 2018;100-B:1310–9.

scholarly journals Articular cartilage and bone changes following treatment of focal osteochondral defects in the femoral head with polyether ether ketone implants versus cobalt chromium molybdenum alloy implants: assessment in a goat model

2020 ◽  
Author(s):  
Zhiguo Yuan ◽  
Wei Zhang ◽  
Xiangchao Meng ◽  
Jue Zhang ◽  
Teng TengLong ◽  
...  
Keyword(s):  
Femoral Head ◽  
Osteochondral Defect ◽  
Osteochondral Defects ◽  
Cobalt Chromium ◽  
Hip Joints ◽  
Cocrmo Alloy ◽  
Polyether Ether Ketone ◽  
Ether Ketone ◽  
Cobalt Chromium Molybdenum

Abstract Objective : This study aimed to investigate the feasibility of applying defect-size polyether ether ketone (PEEK) implant for the treatment of localized osteochondral defects in the femoral head and compared it with cobalt chromium molybdenum (CoCrMo) alloy implant. Methods : A femoral head osteochondral defect model was created in the left hips of goats (n=12). Defects were randomly treated by immediate placement of a PEEK (n=6) or CoCrMo implant (n=6). The un-operated right hip joints served as a control. Goats were sacrificed at 12 weeks. The hip joints were evaluated by gross appearance, computed tomography (CT), and magnetic resonance imaging(MRI). Periprosthetic cartilage quality and the opposing cartilage (at the acetabular) quality were analyzed macroscopically and microscopically. Implant osseointegration was measured by micro-CT and histomorphometry. Results : Radiography revealed that all implants had good overall placement, without loosening of the implant. The modified macroscopic articular evaluation score in the PEEK group was lower than that in the CoCrMo group (p<0.05), and the histological score of the periprosthetic and acetabular cartilage in the PEEK group was lower than that in the CoCrMo group (P<0.05). The mean bone-implant contact for PEEK implants was comparable with that for CoCrMo alloy implants at 12 weeks. Conclusions : A PEEK implant for the treatment of local osteochondral defect in the femoral head demonstrated effective fixation and superior in vivo cartilage protection compared with an identical CoCrMo alloy implant.

Wear Simulation of Metal on Metal Hip Replacements: An Analytical Approach

2012 ◽  
Author(s):  
Lorenza Mattei ◽  
Francesca Di Puccio ◽  
Enrico Ciulli
Keyword(s):  
Hip Replacement ◽  
Experimental Tests ◽  
Wear Model ◽  
Wear Rates ◽  
Metal On Metal ◽  
Hip Replacements ◽  
Wear Law ◽  
Implant Wear

Hip replacement failure is mainly attributable to the implant wear. Consequently preclinical wear evaluations are extremely important. As experimental tests are attractive but highly cost/time demanding, several predictive models have been proposed mainly based on finite element simulations and for metal on plastic (MoP) implants. The aim of this study is to develop a mathematical wear model of metal on metal prostheses, revision of the previous one for MoP implants, developed by the same authors. The model, based on the Archard wear law and on the Hertzian theory, was applied to compare a total (THR) and a resurfacing (RHR) hip replacement under both in vivo and in vitro gait conditions. The results were in agreement with the literature predicting wear rates significantly higher for the RHR than for the THR. The effect of the boundary conditions on wear rates/maps was also investigated and the model limitations discussed.

scholarly journals A COMPARATIVE STUDY ON WEAR BEHAVIOR OF HIP PROSTHESIS BY FINITE ELEMENT SIMULATION

2002 ◽  
Vol 14 (04) ◽  
pp. 139-148 ◽  
Author(s):  
JUI-PIN HUNG ◽  
JAMES SHIH-SHYN WU
Keyword(s):  
Hip Prosthesis ◽  
Polyethylene Wear ◽  
Wear Behavior ◽  
Numerical Approach ◽  
Analysis Model ◽  
Wear Rates ◽  
Femoral Heads ◽  
Artificial Hip Joints ◽  
Pin On Disk

A numerical approach was proposed to investigate the wear behavior occurred in the artificial hip joints in this paper. In the numerical simulations, the wear coefficients taken from pin-on-disk tests were introduced into the wear analysis model to assess the wear rates of polyethylene acetabular cups against metallic or ceramic femoral heads. For the established material combinations, different values of polyethylene wear rates were obtained respectively, which were not necessarily the realistic one as expected in vivo but could be confirmed after further discussion on the wear mechanism involved in wear tests. Current results indicated that the polyethylene/ceramic couples represented better wear performances than the polyethylene/metal couples. Furthermore, the ratio of wear rates for polyethylene cups against alumina and the metallic femoral heads was 0.5, which agreed well with that deduced from clinical studies or laboratory hip simulators. It is obvious that these comparable wear behaviors observed from clinics or laboratory studies also can be found by means of the numerical simulation.

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