人工髋关节磨损分析和临床失效诊断推理

Wear analysis and diagnostic reasoning on clinical failure of artificial hip joints

目的研究人工髋关节磨损机理及磨损寿命界定准则,分析非正常磨损的具体原因和磨损失效的临床表现形式,建立失效事件的分析推理路线。方法通过弹性流体动力润滑分析和有限元分析确定人工髋关节中的摩擦磨损过程及导致早期非正常磨损的产生因素;通过建立磨损寿命界定准则确定人工髋关节的使用寿命;通过磨损—骨溶解形态学矩阵对磨损失效临床表现形式进行归纳分类;通过临床调研建立失效事件推理逻辑。结果计算得出球头—髋臼间的最小滑膜厚度和接触应力,以及相关参数的影响,作为磨损分析的理论依据;提出人工髋关节以几何形态变化导致的机械学失效和以骨溶解导致的生物学失效两种磨损寿命界定准则;得出磨损失效9种临床表现形式;提出磨损失效事件分析推理路线图。结论人工髋关节运动副中主要发生边界摩擦和混合摩擦,以及粘着、犁沟和三体磨损等磨损过程;髋臼与球头的表面质量、配合间隙及圆度对早期非正常磨损具有重要的影响;金属—UHMWPE配副人工髋关节正常机械学磨损寿命可以达到40年,但生物学磨损寿命最多为15～20年,后者是制约今天假体使用寿命的根源;磨损失效临床表现形式的多样性是机械磨损与骨溶解过程综合的形态学效果;在失效事件分析中推理路线图可提供一定的帮助。

Objective To investigate the wear mechanism of artificial hip joints and the criteria for wear life definition,analyze the causes of abnormal wear and the clinical manifestations of wear failure,establish the reasoning route of failure incidents.Methods The wear process and early factors on abnormal wear in artificial hip joints were studied through elastohydrodynamic lubrication computation and finite element analysis;the service life of artificial hip joints was determined through establishing criteria for wear life definition;the clinical manifestations of wear failure were introduced and classified through wear-osteolysis morphological matrix;the reasoning logic of failure incidents was established through clinical investigation.Results The minimal synovium thickness and contact stress between the femoral head and the acetabular cup were calculated,and the effect of relevant parameters was studied as theoretical references for wear analysis;the criteria on wear life definition of artificial hip joints were proposed,namely the mechanistic failure due to geometric change in artificial hip joints and the biological failure due to osteolysis;nine kinds of clinical manifestation for wear failure were found;the reasoning route for failure incidents was presented.Conclusions Primary wear process in artificial hip joints includes boundary and mixed friction,adhesive,ploughing and third-body wear;surface quality,fit clearance between the acetabular cup and the femoral head,and roundness have great impact on early abnormal wear;normal mechanistic life of metal-UHMWPE artificial hip joint can reach 40 years,but its maximum biological life is no more than 10-15 years,which is the constraint of prosthesis life today;the diversity of clinical manifestations for wear failure is the morphological results of mechanical wear and osteolysis,which is helpful for the reasoning route of failure incidents.