Computational modelling of polyethylene wear and creep in total hip joint replacements: Effect of the bearing clearance and diameter

2012 ◽  
Vol 226 (6) ◽  
pp. 552-563 ◽  
Author(s):  
Feng Liu ◽  
John Fisher ◽  
Zhongmin Jin
Keyword(s):  
Wear Rate ◽  
Hip Joint ◽  
Contact Area ◽  
Polyethylene Wear ◽  
Computational Modelling ◽  
Total Hip ◽  
Bearing Clearance ◽  
Wear Modelling ◽  
Wear Law ◽  
Hip Joint Replacements

Computational wear modelling has been improved using a contact area dependent wear law for the conventional ultra-high molecular weight polyethylene used in total hip joint bearings. The current designs of polyethylene bearings tend to use larger diameter heads to achieve improved motion function for patients in clinical practice, but the wear of the bearing may also increase due to the increase in contact area associated with the larger bearings. Additionally, bearing clearance, which is the difference in diameter or radius between the cup and head bearing surfaces, may also play an important role in affecting the wear. This study particularly investigates the effect of bearing clearance on polyethylene wear, for different femoral head diameters, through a parametric study using the computational modelling method. The effect of creep of polyethylene on the contact area and wear was considered, since polyethylene creep can account for a significantly large proportion of volumetric change, particularly during the initial loading stage, and an increase in the contact area. The predicted wear rate was found to be comparable to the experimental wear rate found in independent simulator tests. The polyethylene bearing with decreased bearing clearances led to a substantial increase in the wear rate, particularly when combined with large diameters.

Distribution of polyethylene wear particles and bone fragments in periprosthetic tissue around total hip joint replacements

2010 ◽  
Vol 6 (9) ◽  
pp. 3595-3600 ◽  
Author(s):  
E. Zolotarevova ◽  
G. Entlicher ◽  
E. Pavlova ◽  
M. Slouf ◽  
D. Pokorny ◽  
...  
Keyword(s):  
Hip Joint ◽  
Polyethylene Wear ◽  
Wear Particles ◽  
Periprosthetic Tissue ◽  
Joint Replacements ◽  
Total Hip ◽  
Bone Fragments ◽  
Hip Joint Replacements

Clinical wear behaviour of ultra-high molecular weight polyethylene cups paired with metal and ceramic ball heads in comparison to metal-on-metal pairings of hip joint replacements

1997 ◽  
Vol 211 (1) ◽  
pp. 73-88 ◽  
Author(s):  
M Semlitsch ◽  
H G Willert
Keyword(s):  
Life Expectancy ◽  
Wear Rate ◽  
Hip Prosthesis ◽  
Polyethylene Wear ◽  
Wear Behaviour ◽  
Hip Prostheses ◽  
Ceramic Ball ◽  
Highly Active ◽  
Metal Metal ◽  
Hip Joint Replacements

In the course of 30 years of hip endoprosthetics, a number of material combinations for the cups and balls of total hip prostheses have proven successful under clinical conditions. Favourably priced hip prostheses with polyethylene cups and metal balls are available for older patients with a moderate range of activity. Polyethylene wear of 100-300 μm/year is to be expected with these models. Ceramic balls (aluminium oxide for diameters 32 and 28 mm and zirconium oxide for 22 mm) paired with polyethylene cups are recommended for patients with a life expectancy of 10 to 20 years, because the expected polyethylene wear rate with this material combination is only 50-150 μm/year. In other words, the life cycle of the polyethylene cup is doubled, when it is paired with a ceramic ball. A similar polyethylene wear rate is also to be expected with oxygen-deep-hardened TiAlNb metal balls, which are currently the subject of a clinical field study. Last but not least, CoCrMoC metal-metal and Al2O3 ceramic-ceramic pairings, which have the lowest wear rate of 2-20 μm/year, are available for highly active patients with a life expectancy of more than 20 years. As far as the cup-ball pairing is concerned and under the current pressure of costs, the surgeon should be able to select the optimum hip prosthesis model for every patient from these three categories.

scholarly journals IMPACT OF VARIOUS FACTORS ON THE POLYETHYLENE WEAR RATE IN TOTAL HIP ARTHROPLASTY

2018 ◽  
Vol 24 (1) ◽  
pp. 18-28 ◽  
Author(s):  
R. M. Tikhilov ◽  
M. I. Shubnyakov ◽  
A. A. Boyarov ◽  
A. O. Denisov ◽  
I. I. Shubnyakov
Keyword(s):  
Total Hip Arthroplasty ◽  
Wear Rate ◽  
Hip Arthroplasty ◽  
Polyethylene Wear ◽  
Total Hip

Local Head Roughening as a Factor Contributing to Variability of Total Hip Wear: A Finite Element Analysis

2002 ◽  
Vol 124 (6) ◽  
pp. 691-698 ◽  
Author(s):  
Thomas D. Brown ◽  
Kristofer J. Stewart ◽  
John C. Nieman ◽  
Douglas R. Pedersen ◽  
John J. Callaghan
Keyword(s):  
Wear Rate ◽  
Adhesive Wear ◽  
Polyethylene Wear ◽  
Bearing Surface ◽  
Third Body ◽  
Element Analysis ◽  
Wear Factor ◽  
Total Hip ◽  
Key Factor ◽  
Sliding Distance

Large inter-patient variability in wear rate and wear direction have been a ubiquitous attribute of total hip arthroplasty (THA) cohorts. Since patients at the high end of the wear spectrum are of particular concern for osteolysis and loosening, it is important to understand why some individuals experience wear at a rate far in excess of their cohort average. An established computational model of polyethylene wear was used to test the hypothesis that, other factors being equal, clinically typical variability in regions of localized femoral head roughening could account for much of the variability observed clinically in both wear magnitude and wear direction. The model implemented the Archard abrasive/adhesive wear relationship, which incorporates contact stress, sliding distance, and (implicitly) bearing surface tribology. Systematic trials were conducted to explore the influences of head roughening severity, roughened area size, and roughened area location. The results showed that, given the postulated wear factor elevations, head roughening variability (conservatively) typical of retrieval specimens led to approximately a 30° variation in wear direction, and approximately a 7-fold variation in volumetric wear rate. Since these data show that randomness in head scratching can account for otherwise-difficult-to-explain variations in wear direction and wear rate, third-body debris may be a key factor causing excessive wear in the most problematic subset of the THA population.

A general axisymmetric contact mechanics model for layered surfaces, with particular reference to artificial hip joint replacements

2000 ◽  
Vol 214 (5) ◽  
pp. 425-435 ◽  
Author(s):  
Z M Jin
Keyword(s):  
Contact Mechanics ◽  
Hip Joint ◽  
Joint Replacements ◽  
Total Hip ◽  
Mechanics Model ◽  
Artificial Hip Joint ◽  
Metal On Metal ◽  
Artificial Hip ◽  
Hip Joint Replacements ◽  
Joint Prostheses

A general axisymmetric contact mechanics model for layered surfaces is considered in this study, with particular reference to artificial hip joint replacements. The indenting surface, which represents the femoral head, was modelled as an elastic solid with or without coating, while the other contacting surface, which represents the acetabular cup, was modelled as a two-layered solid. It is shown that this model is applicable to current total hip joint prostheses employing ultra-high molecular weight polyethylene (UHMWPE) acetabular cups against metallic, metallic with coating or ceramic femoral heads as well as metal-on-metal combinations. The effect of cement is also investigated for these prostheses using this model. The use of a metallic bearing surface bonded to a UHMWPE substrate for acetabular cups is particularly examined for metal-on-metal hip joint replacements. Both the contact radius and the contact pressure distribution are predicted for examples of these total hip joint replacements, under typical conditions. Application of contact mechanics to the design of artificial hip joint replacements employing various material combinations is discussed.

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