全人工髖關節損壞機制之研究：臨床與實驗取得殘屑之比較

Failure Mechahism of Hip Joint Prothesis:Wear Debris Obtained from Tissue-detached Particles in Comparison with Laboratory Assessmnet

邱耀慶(Yao-Ching Chiu)

指導教授 ： 廖峻德

中原大學/工學院/醫學工程研究所/碩士(2001年)

https://doi.org/10.6840/cycu200100253

摘要

全人工髖關節鬆脫所引起的相關骨科問題是影響植入物固定的重要因素。針對關節組件產生磨耗機制及其所引發殘屑對植入物周圍組織反應，本研究探討殘屑在生理代謝系統、以及人工關節周圍骨組織發生再吸收，而導致全人工關節最終失敗的可能影響。藉由交叉式髖臼-球模擬磨耗機，以接近人體步態的條件進行模擬，收集並分析模擬人工關節磨耗所產生的殘屑，並與自置換病人取出鬆脫關節周圍組織進行萃取後之殘屑進行比較，嘗試解釋人工關節固定失敗的發生原因。實驗結果顯示：以去離子水為循環液模擬關節滑液，以小孔徑濾紙約0.7μm進行收集，可得到小型殘屑約10μm；同時，該孔徑濾紙適合使用過濾去組織的殘屑，並防止乾燥後顆粒的聚集（亦約10μm）。模擬殘屑產生的形態與磨損界面的磨耗型式相關。超高分子聚乙烯臼杯之機械性質因承受金屬球頭的不同負載而產生磨損誘發效應，如：使外表層分子堅硬或應變硬化。磨耗初期，分子經斷鍵產生極性，導致殘屑彼此聚集成泡狀形態；交叉形式的磨耗引起對漸進硬化層的剪力作用，導致片狀殘屑的產生。模擬磨耗殘屑的形態與成分隨測試次數而有不同。平均殘屑累積質量約為16.5 mg每百萬測試次，與先前模擬磨耗或臨床統計約每年18 mg的結果相近。對殘屑元素分析結果發現：臨床及模擬磨耗殘屑皆僅含微量金屬元素，推測殘屑應以含聚乙烯物種為主。若發生聚乙烯被磨穿而使金屬球頭與金屬外襯互相磨損，則臨床殘屑明顯含有較高的金屬元素比例。

關鍵字

臨床殘屑 ； 模擬磨耗殘屑 ； 全人工髖關節 ； 超高分子聚乙烯

並列摘要

Loosening of total hip joint prosthesis provokes related orthopedic problems, which greatly influence the failure events from implant fixation. Aimed to study the wearing mechanics of joint components and the wear debris induced peri-prosthetic tissue responses, this work looks into the impact of wear debris generation in human physiological system and of bone resorption leading to eventual failure of hip joint prosthesis. A cross-mode cup-on-ball hip joint simulator is utilized for testing under assigned conditions. Study of laboratory-made wear debris compared with tissues-detached particles tries to interpret the occurrence of fixation failure for hip prosthesis. Experimental result has demonstrated that using de-ionized water as circulation liquid for lubricating, a filter with reduced pore dimensions (~0.7 mm) is capable to obtain small particles such as ~10 mm in size. Similarly, this filter is suitable to sieve tissue-detached particles and to prevent them from agglomeration (~10 mm in size). Morphologies of laboratory-made wear debris are correlated with the wearing modes at the bearing interface. Mechanical properties of UHMW polyethylene acetabular cup against metallic ball head diversify with the degree of applied loads and abrasion-induced effects such as molecular rigidity or strain hardening at the outmost surface. In the early stage, the scission of polymeric chains creates polarizable ends and initiates foam-like agglomerates; then, crossing-mode abrasion provokes shear stress on the gradually hardened layer and leads to the generation of plate-like debris. Morphologies and compositions of laboratory-made wear debris differ with testing cycles (TCs). An average mass release of ~16.5 mg per million TCs is calculated, which corresponds to clinical findings as well as previous simulations (~18 mg per million TCs). Laboratory-made debris and tissue-detached particles do not obviously contain metallic elements. It is thus estimated that wear debris is mainly composed of polyethylene species. In clinical case of wearing concentration on polyethylene cup that causes metal ball head rubbing through it and bearing with metal cup or mesh, the content of metal elements in tissue-detached particles becomes evident.

並列關鍵字

and tissue-detached particles ； laboratory-made wear debris ； ultra-high molecular polyethylene ； Total hip joint prosthesis

參考文獻

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