2000 Fiscal Year Final Research Report Summary
Electrochemical evaluation of the damage to the bearing suface of a metal head joint prosthesis
| Project/Area Number |
11671454
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Orthopaedic surgery
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| Research Institution | KITASATO UNIVERSITY |
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Principal Investigator |
YAMADA Tomohisa Kitasato-Univ.School of Medicine, Res.Assoc., 医学部, 助手 (00230467)
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| Co-Investigator(Kenkyū-buntansha) |
MORITA Masafumi Kitasato Univ.School of Allied Health Science Associate Professor, 医療衛生学部, 助教授 (20112667)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Implant / Arthroplasty / Wear / corrosion / Passivation / Titanium alloy / Cobalt alloy / Biotribology |
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| Research Abstract |
Implant metals are obtained a good corrosion resistance due to the passive film in the body. While, the film is damaged mechanically with sliding and the metal ions are released into the fluid. Then the wear toxicity is appeared in the body. According to clarify the relationship between the corrosion resistance and the toxicity of metal ion release, a simple pin on disk friction test were carried out using three types of metals, SUS3 16L S.Steel, Co-28Cr-6Mo, and Ti-6Al-4V alloys in PBS(-) to estimate the range of loads that can be applied to the bearing surface of a joint prosthesis.
The main results are follows ; (1) When two metals of the same type were rubbed against each other, the passivation film was almost completely destroyed immediately after the onset of friction, even when a very low normal load was applied. (2) In the metal to UHMWPE friction test, the passivation film was severety damaged immediately after the onset of friction. However, the passivation film was recovered until the polarization potential reached a certain level, which was specific to each metal. (3) The allowable load on the bearing head of hip arthroplasty was calculated, assuming that the degree of damage to the passivation film was 20 or 40%. When a metalacetabulum socket was used, damage to the passivation film on the head was severe, regardless of the type of metal used for both the acetabulum socket and the head. When a UHMWPE acetabulum socket was used, the allowable load ranged from 8.16×10^2N to 1.31×10^5 N for SUS3 16L S.Steel, from 7.83×10^3N to 1.31×10^5N for Co-28Cr-6Mo alloy, and from 43N to 6.08×10^2N for Ti-6Al-4V alloy.
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