Alternate Bearing Materials: Metal-on-Metal

2005 ◽  
pp. 677-698 ◽  
Keyword(s):  
Alternate Bearing ◽  
Metal On Metal ◽  
Bearing Materials

Improving soil remediation through characterization

1995 ◽  
Vol 53 ◽  
pp. 386-387
Author(s):  
E. C. Buck ◽  
N. L. Dietz ◽  
J. K. Bates
Keyword(s):  
Dust Particles ◽  
Radiochemical Analysis ◽  
Solid Product ◽  
Uranium Contamination ◽  
Physical Separation ◽  
X Ray ◽  
Rocky Flats ◽  
Remediation Strategies ◽  
Bearing Materials ◽  
X Ray Absorption

Operations at former weapons processing facilities in the U. S. have resulted in a large volume of radionuclidecontaminated soils and residues. In an effort to improve remediation strategies and meet environmental regulations, radionuclide-bearing particles in contaminant soils from Fernald in Ohio and the Rocky Flats Plant (RFP) in Colorado have been characterized by electron microscopy. The object of these studies was to determine the form of the contaminant radionuclide, so that it properties could be established [1]. Physical separation and radiochemical analysis determined that uranium contamination at Fernald was not present exclusively in any one size/density fraction [2]. The uranium-contamination resulted from aqueous and solid product spills, air-borne dust particles, and from the operation of an incinerator on site. At RFP the contamination was from the incineration of Pu-bearing materials. Further analysis by x-ray absorption spectroscopy indicated that the majority of the uranium was in the 6+ oxidation state [3].

Eosinophilic Metallosis: A Newly Described Entity in Failed Metal-on-Metal Arthroplasty

2016 ◽  
Vol 26 (4) ◽  
pp. 341-346
Author(s):  
Brandon Levy ◽  
A. Hanflik ◽  
E. Bryk ◽  
V. J. Vigorita
Keyword(s):  
Metal On Metal

scholarly journals Properties of Journal Bearing Materials That Determine Their Wear Resistance on the Example of Aluminum-Based Alloys

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 535
Author(s):  
Alexander Mironov ◽  
Iosif Gershman ◽  
Eugeniy Gershman ◽  
Pavel Podrabinnik ◽  
Ekaterina Kuznetsova ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Journal Bearing ◽  
Tribological Behavior ◽  
Secondary Structures ◽  
Magnesium Content ◽  
Wear Rates ◽  
Relative Extension ◽  
Bearing Materials ◽  
Antifriction Alloys

Potential relations of tribological characteristics of aluminum antifriction alloys with their compositions and mechanical properties were investigated. In this regard, the properties of eight aluminum alloys containing tin from 5.4% to 11% doped with lead, copper, silicon, zinc, magnesium, and titanium were studied. Mechanical properties such as hardness, strength, relative extension, and impact strength were analyzed. Within the tribological tests seizure load and wear of material were evaluated and secondary structures were studied afterwards. The absence of a definitive correlation between tribological behavior and mechanical properties was shown. It was determined that doping tin over 6% is excessive. The seizure load of the alloys increases with the magnesium content. Secondary structures of the alloys with higher wear rates contain one order less magnesium and tin.

scholarly journals Whole blood chromium concentration is very rarely elevated independently of whole blood cobalt

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Olli Lainiala ◽  
Mari Karsikas ◽  
Aleksi Reito ◽  
Antti Eskelinen
Keyword(s):  
Whole Blood ◽  
Cost Savings ◽  
Chromium Concentration ◽  
Continuous Variables ◽  
Metal Debris ◽  
Screening Guidelines ◽  
Metal On Metal ◽  
Hip Replacements

AbstractDue to the risk of adverse reactions to metal debris resulting from increased wear of the arthroplasty more than one million metal-on-metal (MoM) hip replacements worldwide are in active follow-up. Follow-up usually includes measurement of both whole blood cobalt (Co) and chromium (Cr) concentrations. Our experience is that Cr is seldom independently elevated. We wanted to ascertain whether blood Cr measurements could be omitted from follow-up protocols without lowering the quality of follow-up. We identified 8438 whole blood Co and Cr measurements performed without or prior to revision surgery. When the cut-off levels 5 µg/L and 7 µg/L were used, Cr was independently elevated in only 0.5% (95% confidence interval, CI, 0.3 to 0.6) and 0.2% (CI 0.1 to 0.3) of the measurements. The models with continuous variables showed that the higher the blood metal concentrations are the lower the percentage of measurements with Cr higher than Co. Our results suggest that whole blood Cr is very rarely independently elevated and therefore the authorities should consider omitting Cr measurements from their screening guidelines of MoM hip replacements. We believe this change in practice would simplify follow-up and lead to cost savings without decreasing the quality of follow-up.

scholarly journals Uncemented versus cemented arthroplasty after metal-on-metal total hip replacement in patients with femoral neck fractures: a retrospective study

2021 ◽  
Vol 49 (5) ◽  
pp. 030006052110122
Author(s):  
Wenlu Liu ◽  
Huanyi Lin ◽  
Xianshang Zeng ◽  
Meiji Chen ◽  
Weiwei Tang ◽  
...  
Keyword(s):  
Femoral Neck ◽  
Clinical Outcomes ◽  
Total Hip Replacement ◽  
Hip Replacement ◽  
Femoral Neck Fractures ◽  
Harris Hip Score ◽  
Complication Rates ◽  
Total Hip ◽  
Metal On Metal

Objective To compare the clinical outcomes of primary metal-on-metal total hip replacement (MoM-TR) converted to uncemented total hip replacement (UTR) or cemented total hip replacement (CTR) in patients with femoral neck fractures (AO/OTA: 31B/C). Methods Patient data of 234 UTR or CTR revisions after primary MoM-TR failure from March 2007 to January 2018 were retrospectively identified. Clinical outcomes, including the Harris hip score (HHS) and key orthopaedic complications, were collected at 3, 6, and 12 months following conversion and every 12 months thereafter. Results The mean follow-up was 84.12 (67–100) months for UTR and 84.23 (66–101) months for CTR. At the last follow-up, the HHS was better in the CTR- than UTR-treated patients. Noteworthy dissimilarities were correspondingly detected in the key orthopaedic complication rates (16.1% for CTR vs. 47.4% for UTR). Statistically significant differences in specific orthopaedic complications were also detected in the re-revision rate (10.3% for UTR vs. 2.5% for CTR), prosthesis loosening rate (16.3% for UTR vs. 5.9% for CTR), and periprosthetic fracture rate (12.0% for UTR vs. 4.2% for CTR). Conclusion In the setting of revision of failed primary MoM-TR, CTR may demonstrate advantages over UTR in improving functional outcomes and reducing key orthopaedic complications.

scholarly journals Small-head metal on metal total hip arthroplasty is associated with a high rate of complication and reoperation at mid-term follow-up

2021 ◽  
Vol 9 ◽  
pp. 205031212110147
Author(s):  
Nobuhiko Sumiyoshi ◽  
Kazuhiro Oinuma ◽  
Yoko Miura
Keyword(s):  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Adverse Reactions ◽  
Small Diameter ◽  
High Rate ◽  
Metal Debris ◽  
Total Hip ◽  
Metal On Metal ◽  
Small Head

Background: Adverse reactions to metal debris are significant complications after metal-on-metal total hip arthroplasty. Recently, late appearances of adverse reactions to metal debris and subsequent need for reoperations have been reported with small-diameter head metal-on-metal devices. We retrospectively investigated mid-term clinical outcomes of small-head metal-on-metal total hip arthroplasty. Methods: We reviewed 159 hips in 139 patients who had a small-head metal-on-metal total hip arthroplasty (M2a Taper; Biomet, Warsaw, IN) with a minimum 5-year follow-up and documented postoperative complications. Results: Focal osteolysis in either the femur or acetabulum was observed in 12 hips (7.5%, 44 months after surgery on average), with pseudotumor observed in 8 hips (5%, 120 months after surgery on average). Four hips (2.5%) had dislocations (84 months after surgery on average) and six hips (3.8%, 122 months after surgery on average) underwent reoperation. Conclusion: Small-head metal-on-metal total hip arthroplasty is associated with a high degree of complications at mid-term follow-up period. Considering this, we discourage the use of metal-on-metal total hip arthroplasty regardless of head size.

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