Metallic debris from metal-on-metal total hip arthroplasty regulates periprosthetic tissues

The era of metal-on-metal(MoM) total hip arthroplasty has left the orthopaedic community with valuable insights and lessons on periprosthetic tissue reactions to metallic debris. Various terms have been used to describe the tissue reactions. Sometimes the nomenclature can be confusing. We present a review of the concepts introduced by Willert and Semlitsch in 1977,along with further developments made in the understanding of periprosthetic tissue reactions to metallic debris. We propose that periprosthetic tissue reactions be thought of as(1) gross(metallosis, necrosis, cyst formation and pseudotumour);(2) histological(macrophage-dominated, lymphocyte-dominated or mixed);and(3) molecular(expression of inflammatory mediators and cytokines such as interleukin-6 and tumor necrosis factor-alpha). Taper corrosion and modularity are discussed, along with future research directions to elucidate the antigen-presenting pathways and materi-al-specific biomarkers which may allow early detection and intervention in a patient with adverse periprosthetic tissue reactions to metal wear debris.

Management of failed metal-on-metal total hip arthroplasty

The theoretical advantages of metal-on-metal(MOM)bearing couples in total hip arthroplasty(THA) have been recently balanced by concerns regarding adverse local and systemic effects. Higher than anticipated early revision rates have been reported by several joint registries. Failed MOM hips present with a spectrum of symptoms and findings and traditional methods of failure must be considered in addition to the failure modes that appear to be unique to the MOM bearing couple. Metal hypersensitivity and soft tissue immune reactions remain incompletely understood and require careful ongoing study. The tools available to evaluate MOM THAs and the indications for revision surgery remain to be defined. Outcomes following revision of MOM hips appear to depend on appropriate evaluation, early identification, and appropriate surgical management.

Mid-Term Review of ADEPT Metal-On-Metal Hip Prosthesis. Functional, Radiological and Metal Ion Analysis

Background: There is much interest regarding metal-on-metal implants in medical and general media. Much of this has been regarding failure of specific implant systems and metal ion toxicity. We present our early mid-term experience of the ADEPT metal-on-metal system which has both modular and non-modular hip options. Methods: Functional assessment, blood metal ion quantification, and radiographic analysis were performed for the modular and non-modular ADEPT variants. Fifty implants were implanted with a mean follow up time of 28 months. Unpaired t-tests were used to compare modular and resurfacing groups, standardised hip scores were used to compare function to conventional total hip arthroplasty. Results: Metal ion levels were significantly higher in modular prostheses compared to resurfacing implants, but not at “harmful” levels (as determined by a previous metal-on-metal implant recall). Functional outcomes were excellent and revision rates were lower than expected. Conclusions: At our institution we have good outcomes with the ADEPT hip prosthesis. Though patient selection and implant position are crucial, poor performance of metal-on-metal hip replacements is implant specific.

Control study of short-term curative effect of minimally invasive total hip arthroplasty using metal-on-metal large-diameter femoral head for the elderly patients with femoral neck fractures

Objective To discuss the postoperative curative effects of two surgical techniques of minimally invasive total hip arthroplasty (THA) using metal-on-metal largediameter and conventional diameter femoral head for the elderly patients

一锅法合成噁唑啉金属配合物研究进展

一锅法合成金属配合物是近年来金属有机化学研究的一个热点之一。在对国内外噁唑啉金属配合物的合成及应用进行大量文献调研基础上,综述了本课题组近年来用腈类与手性氨基醇作用,在不同物质的量的金属盐如氯化锌、乙酸铜和氯化钴等金属氯化物或金属乙酸盐作用下,一锅法一步合成系列噁唑啉金属配合物及应用研究进展。同时,对该方法在其他噁唑啉金属配合物合成及应用领域提出展望。

优势区图的计算机绘制系统

介绍了新开发的优势图计算机绘制系统，提出了绘制优势区图的一种新算法——主元素活度项法，说明了绘制含一种金属的三元系及含两种金属的四元系的优势区图绘制的算法原理，解决了四元系中双金属化合物的归属问题．算法简易，效率高，符合热力学原理．系统采用Ｃ＋＋语言，基于Ｗｉｎｄｏｗｓ３．Ｘ／Ｗｉｎ９５平台编制了优势图绘制系统的应用程序．该系统具有使用简单，维护方便，界面友好，输入少量的信息即可得到完整的优势区图．

Pseudotumor recurrence in a post-revision total hip arthroplasty with stem neck modularity: A case report

BACKGROUND This unique presentation of hip swelling is only the seventh reported case of pseudotumor recurrence in a non-metal-on-metal total hip arthroplasty(THA)construct.The constellation of patient symptoms and laboratory findings contradict the expected elevated serum metal ion levels associated with the formation of pseudotumor.The presentation,lab trends,and imaging findings contribute to the growing base of knowledge surrounding the effects of corrosion in arthroplasty constructs with stem-neck modularity.CASE SUMMARY A 74-year-old man status post primary THA presented with left hip swelling and elevated serum metal ions five years after implantation of a modular stem-neck prosthesis.The swelling was diagnosed as pseudotumor based on laboratory trends and imaging findings and was treated with revision arthroplasty that completely resolved the initial hip swelling.The patient presented with recurrent hip swelling and recurrent pseudotumor findings on imaging in the same hip four months later.Non-operative management with ultrasound-guided hip aspiration resulted in symptom relief and resolution of the recurrent swelling.After one year of follow-up,the patient had no further recurrences of hip swelling.CONCLUSION This case of post-revision pseudotumor recurrence elucidates attributable patient,surgical,and implant factors with a discussion of diagnostics,management,and prognosis for patients with pseudotumor in non-metal-on-metal arthroplasty constructs.

Review on squeaking hips

Squeaking is a well-recognized complication for hardon-hard bearings.The nature of squeaking is not yet completely understood however it is considered a multifactorial phenomenon.Patient,implant,and surgical factors play a role in squeaking.It is believed that mechanisms damaging the fluid film lubrication in which these bearings function optimally have a critical role.Such mechanisms include edge loading,stripe wear,impingement,third body particles and ceramic fracture.The resonance of metallic parts can produce noise in the human audible range hence the implant metallurgic composition and design may play a role.Implant positioning can facilitate impingement and edge loading enhancing the occurrence of squeaking.The recent introduction of large heads(> 36 mm) 4th generation ceramic-on-ceramic bearing may accentuate the conditions facilitating noise formation; however the current literature is insufficient.Clinically,squeaking may manifest in extreme hip positions or during normal gait cycle however it is rarely associated with pain.Evaluations of patients with squeaking include clinical and radiographic assessments.Computer tomography is recommended as it can better reveal ceramic breakage and implant malposition.The treatments for most squeaking patients include reassurance and activity modification.However for some,noise can be a problem,requiring further surgical intervention.In the occurrence of ceramic fracture,implant failure,extreme components malposition,instability and impingement,surgery should be advised.This review will aim to discuss the current literature regarding squeaking.

Tigecycline sclerotherapy for recurrent pseudotumor in aseptic lymphocyte-dominant vasculitis-associated lesion after metal-onmetal total hip arthroplasty:A case report

BACKGROUND Metal-on-metal(MoM)total hip arthroplasty(THA)has been associated with adverse reactions to metal debris,presenting clinically as pseudotumors.CASE SUMMARY This case report presents a female aged 73 year-old with MoM THA-related pseudotumor.After arthrotomy and bursectomy surgeries,histologic examinations of surgical specimens revealed a specific lymphocyte-dominant immunologic response,now known as aseptic lymphocyte-dominant vasculitisassociated lesion(ALVAL).Due to soft tissue persisting effusion after arthrotomy and bursectomy,revision surgery was then performed with ceramic-onpolyethylene THA.However,revision did not resolve the patient’s symptoms.Here we describe our application of tigecycline sclerotherapy to treat recurrent pseudotumor after revision THA and no recurrence after 24-mo follow-up.CONCLUSION Tigecycline sclerotherapy is safe and effective in the management of recurrent pseudotumor after revision non-MoM THA in ALVAL cases.

粉球电阻的理论分析

在粉体金属中,基于理想粉球单轴向压缩变形模型,推导出单个变形粉球的电阻公式,分析了公式自身存在条件和有意义物理的适用范围:即变形端面的半径必须大于零,小于粉球半径;用Mathematica软件绘制了不同参数变化时电阻变化趋势的三维图形,显示其变化规律为:R随变形端面的半径的增加而下降,初始时下降很快,随后降幅趋于平缓;随着粉球半径增大,R先迅速上升,后开始下降,当粉球半径达到一定值后,电阻R接近一水平线.

双金属金属有机骨架材料的制备及性能研究进展

金属有机骨架材料(MOFs)具有拓扑结构的多样性和丰富的比表面积,使其在催化和吸附领域具有潜在的应用价值。双金属MOFs具有两种金属中心,较之单金属MOFs具有更加多元的催化活性位点和吸附位点,因此吸附选择性、选择催化性以及结构稳定性等均得到了提升。本文就如何制备性能优异的双金属MOFs材料,以及这种材料的结构特点、性能提升和应用前景展开了概述。

金属酞菁化合物多晶体的“金属—半导”性转变

本文研究了掺碘酞菁镍多晶体、掺碘酞菁铜多晶体及它们两者混合物的粉末压片的电导率随温度变化的关系,发现有“金属—半导”性转变存在。并探讨了这种转变出现的原因及机理。研究表明这种转变不是导电金属酞菁化合物的结构在某一温度下发生了突变,而是由非均相结构的存在所致。根据非均相模型推导出来的电导率公式对实验结果进行拟合后所得的曲线与实验点相符很好。

智能手机前壳设计方案研究

针对智能手机前壳的设计方案要求,介绍了纯塑胶前壳、塑胶+金属嵌件前壳、一体式金属中框的结构、材质、制作、表面处理的选择方法。

Blood metal concentrations and cardiac structure and function in total joint arthroplasty patients

BACKGROUND There is concern regarding potential long-term cardiotoxicity with systemic distribution of metals in total joint arthroplasty(TJA)patients.AIM To determine the association of commonly used implant metals with echocardiographic measures in TJA patients.METHODS The study comprised 110 TJA patients who had a recent history of high chromium,cobalt or titanium concentrations.Patients underwent two-dimensional,three-dimensional,Doppler and speckle-strain transthoracic echocardiography and a blood draw to measure metal concentrations.Age and sex-adjusted linear and logistic regression models were used to examine the association of metal concentrations(exposure)with echocardiographic measures(outcome).RESULTS Higher cobalt concentrations were associated with increased left ventricular end-diastolic volume(estimate 5.09;95%CI:0.02-10.17)as well as left atrial and right ventricular dilation,particularly in men but no changes in cardiac function.Higher titanium concentrations were associated with a reduction in left ventricle global longitudinal strain(estimate 0.38;95%CI:0.70 to 0.06)and cardiac index(estimate 0.08;95%CI,-0.15 to-0.01).CONCLUSION Elevated cobalt and titanium concentrations may be associated with structural and functional cardiac changes in some patients.Longitudinal studies are warranted to better understand the systemic effects of metals in TJA patients.

A One-dimensional Linear Polymeric Au(Ⅰ) Compound With Strong Au-Au Interaction: Preparation and Structure of [AuS_2CNEt_2]_(4n)

Dialkyldithiocarbamate （R2NCS-2） acting as either bridging or terminal ligand plays an important role in modern coordination chemistry. The molecules of the univalent coinage metals （Cu, Ag, and Au） with dialkyldithiocarbamate ligands form a class of compounds in which the sterical restriction influences strongly the crystal structures, and several types of polymerizates were found. However, only a few structures in linear form