Wear and deformation of ceramic-on-polyethylene total hip replacements with joint laxity and swing phase microseparation

Author(s):  
S Williams ◽  
M Butterfield ◽  
T Stewart ◽  
E Ingham ◽  
M Stone ◽  
...  

Wear of polyethylene and the resulting wear debris-induced osteolysis remains a major cause of long-term failure in artificial hip joints. There is interest in understanding engineering and clinical conditions that influence wear rates. Fluoroscopic studies have shown separation of the head and the cup during the swing phase of walking due to joint laxity. In ceramic-on-ceramic hips, joint laxity and microseparation, which leads to contact of the head on the superior rim of the cup, has led to localized damage and increased wear in vivo and in vitro. The aim of this study was to investigate the influence of joint laxity and microseparation on the wear of ceramic on polyethylene artificial hip joints in an in vitro simulator. Microseparation during the swing phase of the walking cycle produced contact of the ceramic head on the rim of the polyethylene acetabular cup that deformed the softer polyethylene cup. No damage to the alumina ceramic femoral head was found. Under standard simulator conditions the volume change of the moderately crosslinked polyethylene cups was 25.6 ± 5.3 mm3/million cycles and this reduced to 5.6 ± 4.2 mm3/million cycles under microseparation conditions. Testing under microseparation conditions caused the rim of the polyethylene cup to deform locally, possibly due to creep, and the volume change of the polyethylene cup when the head relocated was substantially reduced, possibly due to improved lubrication. Joint laxity may be caused by poor soft tissue tension or migration and subsidence of components. In ceramic-on-polyethylene acetabular cups wear was decreased with a small degree of joint laxity, while in contrast in hard-on-hard alumina bearings, microseparation accelerated wear. These findings may have significant implications for the choice of fixation systems to be used for different types of bearing couples.

Author(s):  
J Bell ◽  
J L Tipper ◽  
E Ingham ◽  
M H Stone ◽  
J Fisher

There is considerable interest in the wear of polyethylene and the resulting wear-debrisinduced osteolysis in artificial hip joints. Proteins play an important role as boundary lubricants in vivo in the pseudosynovial fluid, and these are reproduced in in vitro tests through the use of bovine serum. Little is known, however, about the effect of phospholipid concentrations within proteinaceous solutions on the wear of ultra-high molecular weight polyethylene (UHMWPE). The effects of protein-containing lubricants with 0.05, 0.5 and 5 per cent (w/v) phosphatidyl choline concentrations on the wear of ultra-high molecular weight polyethylene (UHMWPE) were compared with 25 per cent (v/v) bovine serum which had 0.01 per cent (w/v) lipid; the effects were compared in a hip joint simulator with smooth (n = 4) and scratched (n = 3) femoral heads. The control bovine serum lubricant produced UHWMPE wear of 55 and 115mm3/106 cycles on the smooth and rough heads respectively. The increased phospholipid concentration significantly reduced the wear rate. At the higher concentration (5% w/v phosphatidyl choline) the average wear was reduced to less than 2 mm3/106 cycles. Even with the relatively low concentrations of 0.05% w/v phosphatidyl choline the wear was reduced by at least threefold compared with the bovine serum tests for both the smooth and rough femoral heads. There may be considerable differences in the phospholipid concentrations in patients' synovial fluid and this is highly likely to produce considerable variation in wear rates. In vitro, differences in the phospholipid concentration of lubricants may also cause variation in wear rates between different simulator tests.


2003 ◽  
Vol 13 (2_suppl) ◽  
pp. 17-27 ◽  
Author(s):  
E. Ingham ◽  
J. Fisher ◽  
M.H. Stone

Polyethylene wear debris induced osteolysis is a major cause of failure in artificial hip joints. Sub micrometre size particles are taken up by macrophages which are stimulated to release osteolytic cytokines such as TNFα. This leads to bone resorption, loosening and failure. In vitro cell culture studies have shown particles in the size range 0.1 to 1 micrometre to be at least six times more reactive than larger particles. Studies of historically used gamma irradiated in air polyethylene show increased wear rate with damaged femoral heads and with aged and oxidised polyethylene. The aged and oxidised polyethylene also produced a greater percentage of smaller particles leading to increased osteolytic potential. Combined tribological and biological simulation models have been developed for pre-clinical assessment of osteolytic potential of artificial hip joints.


2000 ◽  
Vol 15 (6) ◽  
pp. 793-795 ◽  
Author(s):  
J. Nevelos ◽  
E. Ingham ◽  
C. Doyle ◽  
R. Streicher ◽  
A. Nevelos ◽  
...  

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3569
Author(s):  
Jessica Hembus ◽  
Lisa Rößler ◽  
Mario Jackszis ◽  
Annett Klinder ◽  
Rainer Bader ◽  
...  

Several retrieval studies have reported on metallic depositions on ceramic femoral heads, but the effect on the wear behavior of artificial hip joints has not been investigated in wear simulator studies. In the present study, retrieved ceramic heads with metallic depositions as third particles were tested against cross-linked ultra-high-molecular-weight polyethylene (UHMWPE) liners in a hip wear simulator. The amount of liner wear and expansion of metallic depositions on the heads were determined before and after wear testing with digital microscopy. The surface roughness of the heads was investigated in areas with and without metallic depositions by laser scanning microscopy. After five million load cycles, a non-significant reduction in the metallic formation on the retrieved heads was found. The metallic areas showed a higher surface roughness compared to unconcerned areas. The liners showed a higher wear rate of 1.57 ± 1.36 mg/million cycles for 28 mm heads and 2.42 ± 0.82 mg/million cycles for 36 mm heads with metallic depositions, in comparison with new ceramic heads with a 28 mm size ((−0.06 ± 0.89) mg/million cycles) and 36 mm size ((2.04 ± 0.46) mg/million cycles). Metallic transfer on ceramic heads can lead to an increased surface roughness and higher wear rates at the UHMWPE liners. Therefore, metallic contact of the ceramic femoral head should be avoided.


Biomaterials ◽  
2002 ◽  
Vol 23 (16) ◽  
pp. 3441-3448 ◽  
Author(s):  
J.L. Tipper ◽  
A. Hatton ◽  
J.E. Nevelos ◽  
E. Ingham ◽  
C. Doyle ◽  
...  

Lubricants ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 72 ◽  
Author(s):  
Alessandro Ruggiero ◽  
Alessandro Sicilia

The aim of this paper was to propose a novel in silico mixed elasto-hydrodynamic lubrication model with the purpose of wear prediction in Total Hip Replacements (THRs). The model considers the progressive wear contribution in the calculation of the meatus filled by the non-Newtonian synovial fluid. The results were referred to the gait cycle kinematics, calculated by using musculoskeletal multibody software, while the loading was assumed by literature in vivo measurements. The simulations allow evaluating the fluid and the contact pressure fields and the acetabular cup wear over the time. The results were obtained considering a Ultra High Molecular Weight PolyEthylene, UHMWPE, cup and were compared with results from the literature, showing a good agreement in terms of total volume wear of the cup.


2005 ◽  
Vol 127 (4) ◽  
pp. 729-739 ◽  
Author(s):  
F. C. Wang ◽  
Z. M. Jin

A general steady-state elastohydrodynamic lubrication model was developed for artificial hip joints, with particular reference to the effect of the anatomical position of the cup and the three-dimensional physiological loading and motion experienced during walking. Appropriate spherical coordinates and mesh grids were employed to facilitate the numerical solution. A specific hip implant employing an ultrahigh molecular-weight polyethylene acetabular cup against a metallic femoral head was chosen to demonstrate the general applicability of the lubrication model and the effects of both the cup inclination angle and the combined flexion-extension and internal-external rotation on the lubrication were analyzed.


Volume 1 ◽  
2004 ◽  
Author(s):  
Fengcai Wang ◽  
Zhongmin Jin

A full numerical methodology was developed for the mixed lubrication analysis of hip implants, covering a continuous spectrum from full fluid film to boundary (dry contact) lubrication regimes. The methodology was applied to a typical hip implant employing an ultra high molecular weight polyethylene (UHMWPE) acetabular cup in articulation with a metallic femoral head. It was shown that as the viscosity decreased, direct contact was initiated at the exit regions both in the entraining and side-leakage directions where the minimum film thickness occurred. As the viscosity decreased further, the direct contact area increased and until eventually became similar to the dry contact area.


Author(s):  
R M Streicher ◽  
M Semlitsch ◽  
R Schön ◽  
H Weber ◽  
C Rieker

As wear is inevitable with artificial joint replacement, it has to be minimized to avoid possible aseptic loosening following osteolysis due to particle-initiated foreign body reaction. Co-Cr-Mo-C alloys have a long history with only minimum wear when articulating with themselves. This investigation shows that the choice of the alloy has an effect on the wear rate of this articulation couple. Tribological studies in a screening device, a pendulum apparatus and a hip joint simulator showed a marked influence of the environment as well as the diameter of the implants with metal-on-metal articulation. A wear-resistant combination with low friction characteristics has been developed by using a wrought Co-Cr-Mo-C alloy and reducing the implant diameter to 28 mm. Clinical wear rates are comparable with laboratory data and demonstrate the potential of the metal-on-metal articulation to solve the problem of wear-induced osteolysis of hip joint endoprostheses.


Author(s):  
Sunny M. Jhurani ◽  
C. Fred Higgs

Improvements in surgical procedures, installation techniques and properties of materials have resulted in a remarkable reduction in the failure of artificial hip joints (AHJ) due to infection. However, the durability of these replacements is greatly limited by premature osteolysis and eventual joint loosening, caused by macrophage activity in response to the release of submicron particles of ultra-high molecular weight polyethylene (UHMWPE) cup material [1–4]. The wear debris is mainly due to wear between the bearing surfaces, and these wear rates are known to be accelerated by the third body action of polymethylmethacrylate (PMMA) bone cement particles and metallic fragments of the femoral head material scattered within the synovial fluid lubricant [5]. This study is focused on development of a model that simulates the motion of UHMWPE particles in the synovial fluid between the AHJ bearing surfaces during articulation.


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