人工關節用骨水泥調製機轉之影響研究

The Study on the Mechanism of Bone Cements Applying to Arthroplasty

方強如(Chiang-Lu Fang)

指導教授 ： 黎文龍 ； 劉建緯

國立臺北科技大學/機電學院/製造科技研究所/碩士(2011年)

摘要

人工膝關節置換術治療後之患者在植入十年後約有70 %需要再次進行手術，造成病患困擾，且再次進行二次手術對於患者的身心都有極大的創傷；造成二次手術發生的原因與骨水泥相關者包含以下數種情況：（1）骨水泥固化時間過快，以致於醫師在進行手術時工作時間之不足，導致骨水泥無法有效的與骨骼或人工植入物結合。（2）骨水泥混合後產生的高放熱溫度使得骨骼周圍的組織遭到破壞造成骨壞死的現象。（3）骨水泥聚合過程中釋出有害的甲基丙烯酸甲酯（Methyl methacrylate, MMA）單體流入血液造成肺栓塞、心跳異常等副作用。（4）骨水泥抗壓強度太高以致壓迫骨骼導致骨骨折現象發生。綜上所述，因骨水泥導致須實施二次手術的原因，皆與骨水泥之機轉有相當大的關聯。
故本研究針對市面上販售之醫用骨水泥在不加入添加物，將以不同的聚甲基丙烯酸甲酯（polymethylmethacry acid, PMMA）與MMA比值1：1、2：1、3：1並在真空與非真空之環境下以ASTM F451-99a測得其黏團時間、最大放熱溫度、固化時間、抗壓應力、抗拉應力及彈性模數，進而找出最適合之PMMA與MMA之混合比例，以降低患者進行二次手術的機率。
由本研究實驗結果得知真空環境下調和之骨水泥，其黏團時間、最大放熱溫度以及固化時間比非真空環境下的骨水泥更適合在手術上運用；且其PMMA/MMA之比值越大的骨水泥最大放熱溫度越小，可以有效的減少骨壞死的機率。
在抗壓強度與黏團時間方面，PMMA/MMA比值越大其值越小，而骨水泥的彈性模數無論何種比例、環境下攪拌，其值皆不會大於人體骨骼之彈性模數，故不會產生骨骨折（fracture）現象，總合各種指標以真空狀態下PMMA與MMA比值為3：1配方之骨水泥最為佳。

關鍵字

骨水泥 ； 機械性質 ； 人工膝關節置換術

並列摘要

There are about 70 percent of patients who accepted knee arthroplasty operation over 10 years need second surgery. That bothers them and is really a big trauma for the patients’ minds and bodies. The reasons are following: First, the setting time of bone cement is too fast, which leads to not enough time for the doctor who may place the bone cement in inappropriate time during surgery and bone cement is not to connect with bone or implant. Second, mixing bone cement will result in high temperature and destroy the tissues around the bone, which calls the phenomenon “osteonecrosis”. Third, some monomer of methyl methacrylate monomer released from the polymerization process of bone cement, and as them flow into the blood, causing harmful pulmonary embolism, heart abnormalities and other side effects. At last, the higher the compressive strength of bone cement, the probibilty of bone fractures occuring due to oppression to the bones. According to the states above, the necessary of second surgery is strongly relative to the bone cement mechanism.
In this research, one does not add supplements to market bone cement. One sets the different bone cement mixing rates of PMMA to MMA, which are tested for 1:1, 2:1 and 3:1. And with different environment, the peak exothermic, compressive stress, tensile stress, elastic modulus, setting time and dough time are measured by ASTM F451-99a in this study individually. The research then obtains the most proper prescription of reducing the probability of second surgery formation.
According to the experimental results of mixing bone cement in vacuum environment, the setting time, polymerization temperature and dough time are better than which in non-vacuum one for surgical operation. And for the higher PMMA to MMA ratio, the polymerization temperature of bone cement will be smaller, which can effectivly reduces the probibility of osteonecrosis formation.
The experimental results of dough time and compressive strength show that they decrease with the increasing of the PMMA to MMA ratio., And the elastic modulus of bone cement, regardless of using which proportion of PMMA and MMA, or testing in different environment, will not exceed the elastic modulus of a human’s skeleton. Thus, the bone fracture phenomenon will not occur.
In conclusion, the fine bone cement with 3:1 PMMA to MMA ratio and making in a vacuum enviroment is suggested in this research.

並列關鍵字

bone cement ； mechanical property ； knee arthroplasty

參考文獻

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