Pseudotumors in Small-Head Metal-on-Metal Total Hip Arthroplasties at a Minimum Follow-Up of 20 Years

BackgroundMetal-on-metal (MOM) surfaces in total hip arthroplasty (THA) have been used widely. Serum cobalt and chromium levels have been the standard investigation for follow-up examinations, but magnetic resonance imaging (MRI) with metal artifact reducing sequences has shown good results in detecting pseudotumors. The aim of this study is to survey a significant correlation among MRI findings, serum metal levels, and clinical scores in patients with small-head MOM implants and if serum cobalt and chromium levels are sufficient in detecting patients with pseudotumors in the long-term follow-up.MethodsAt a minimum follow-up of 20 years, 26 patients (29 THAs) of the original 98 patients (105 THAs) included in this study between November 1992 and May 1994 were available for follow-up examination. Clinical scores, serum metal ion levels, and MRIs were obtained.ResultsWe found mean serum cobalt levels of 1.87 μg/L (±3.44) and chromium levels of 2.23 μg/L (±2.96) and very good clinical and functional results (mean Harris Hip Score 88.6) in the long-term follow-up. Pseudotumors were detected in MRIs of 21 hips. There were no significant differences between patients with or without pseudotumors regarding serum metal levels and the correlation for clinical outcome scores, demographic data, and cup inclination. The cumulative rate of survival was still at 91.4% at 22.8 years.ConclusionThis study presents the first published data on small-head MOM hips, comparing metal ion levels, pseudotumors, clinical, and radiological results in a follow-up period of more than 20 years and reveals that serum metal levels are not significantly higher in patients with pseudotumors.Level of EvidenceTherapeutic Level III     

Effects of cobalt and chromium ions on glycolytic flux and the stabilization of hypoxia‐inducible factor‐1α in macrophages in vitro

Implant wear and corrosion have been associated with adverse tissue reactions that can lead to implant failure. Wear and corrosion products are therefore of great clinical concern. For example, Co²⁺ and Cr³⁺ originating from CoCrMo‐based implants have been shown to induce a proinflammatory response in macrophages in vitro. Previous studies have also shown that the polarization of macrophages by some proinflammatory stimuli is associated with a hypoxia‐inducible factor‐1α (HIF‐1α)‐dependent metabolic shift from oxidative phosphorylation (OXPHOS) towards glycolysis. However, the potential of Co²⁺ and Cr³⁺ to induce this metabolic shift, which plays a determining role in the proinflammatory response of macrophages, remains largely unexplored. We recently demonstrated that Co²⁺, but not Cr³⁺, increased oxidative stress and decreased OXPHOS in RAW 264.7 murine macrophages. In the present study, we analyzed the effects of Co²⁺ and Cr³⁺ on glycolytic flux and HIF‐1α stabilization in the same experimental model. Cells were exposed to 6 to 24 ppm Co²⁺ or 50 to 250 ppm Cr³⁺. Glycolytic flux was determined by analyzing extracellular flux and lactate production, while HIF‐1α stabilization was analyzed by immunoblotting. Results showed that Co²⁺, and to a lesser extent Cr³⁺, increased glycolytic flux; however, only Co²⁺ acted through HIF‐1α stabilization. Overall, these results, together with our previous results showing that Co²⁺ increases oxidative stress and decreases OXPHOS, suggest that Co²⁺ (but not Cr³⁺) can induce a HIF‐1α‐dependent metabolic shift from OXPHOS towards glycolysis in macrophages. This metabolic shift may play an early and pivotal role in the inflammatory response induced by Co²⁺ in the periprosthetic environment.     

MRI of spinal hardware: comparison of conventional T1-weighted sequence with a new metal artifact reduction sequence

Objective. This study was designed to compare diagnostic quality of MR images of patients with spinal hardware acquired using a conventional T1-weighted spin-echo sequence and a new metal artifact reduction sequence (MARS). Conclusion. The new MARS sequence effectively reduces the degree of tissue-obscuring artifact produced by spinal fixation hardware and subjectively improves image quality compared with the conventional T1-weighted spin-echo sequence. Received: 30 May 2000 Revision requested: 12 September 2000 Revision received: 27 September 2000 Accepted: 27 November 2000     

金属对金属新假体临床使用体会

目的:探讨金属对金属大头(ASRTMXL)全髋关节置换术的早期疗效和临床体会,以及该技术的安全性和有效性。方法:2007年1月至2008年3月,采用金属对金属大头全髋关节置换术治疗37例(39髋)髋关节疾患,男24例,女13例;年龄43～75岁,平均58.5岁。其中股骨头坏死14例、骨性关节炎2例、新鲜股骨颈骨折18例、先天性髋关节发育不良3例。结合手术前后患者髋关节功能检查、Harris评分及X线分析,对金属大头全髋的临床应用特点进行分析。结果:术后患者伤口均Ⅰ期临床愈合,无早期并发症发生。37例(39髋)均获随访,随访时间12～19个月,平均16.5个月。术后X线片显示关节假体位置良好,肢体长度及股骨偏心距基本恢复正常。髋关节活动度得到大幅改善,前屈由(20.1±8.2)°增加到(85.7±9.8)°(t=32.86,P0.01),外展由(10.2±4.4)°增加到(41.5±9.1)°(t=19.34,P0.01),内收由(16.3±8.8)°增加到(40.3±10.4)°(t=11.00,P0.01),外旋由(12.3±5.2)°增加到(42.0±7.7)°(t=19.96,P0.01),内旋由(3.4±1.1)°增加到(23.0±9.8)°(t=12.41,P0.01)。Harris髋关节评分从术前(39.3±5.6)分提高到最后随访的(91.4±10.3)分(t=27.75,P0.01)。结论:金属对金属大头全髋假体设计具有臼杯变形小、磨损率低、活动范围大、脱位发生率低等特点。其为治疗术后活动量要求较高的髋关节疾病如股骨头缺血性坏死、骨关节炎、股骨颈骨折、髋发育不良患者提供了一种新的有价值的手术方式。     

Large Diameter Metal on Metal Articulations. Comparison of Total Hip Arthroplasty and Hip Resurfacing Arthroplasty

The use of large diameter metal bearing total hip arthroplasty (THA) and hip resurfacing arthroplasty (HRA) increased in popularity in the last decade. More recent literature has highlighted the effect of head size in patient outcomes. Data was obtained from the Australian Orthopaedic Association National Joint Replacement Registry (AOA-NJRR) to evaluate the Birmingham (MoM) bearing surface when used with THA and HRA. There is no difference in the overall rate of revision between the THA and HRA but head size has a significant effect on revision rate. The data show that small diameter metal bearings in HRA (below 50 mm) have a higher rate of revision than large diameter metal bearings in HRA (equal to and above 50 mm) (P < .001). Conversely the large diameter metal bearings in THA have a higher rate of revision than the small diameter metal bearings in THA (P = .027). The revision rate for large diameter HRA compared to small diameter THA is not significantly different P = .670. We recommend caution when choosing either a large diameter (≥ 50 mm) metal on metal THA or small diameter (< 50 mm) HRA.     

4种不同冠边缘形式的钴铬合金烤瓷冠强度的研究

目的 研究4种不同冠边缘形式的钴铬合金金属烤瓷冠的强度. 方法 按照4种不同的冠边缘形式制作4组钴铬合金烤瓷冠,其中第1组金属基底冠止于肩台唇侧边缘,第2组止于肩台唇侧中部,第3组止于肩台与轴壁交角,第4组止于肩台与轴壁交角冠方1 mm处.将粘固后的4组样本保存于37℃的人工唾液中24 h后,在Instron1342万能材料测试机上以1 mm/min的速度对样本施加平行于样本长轴的压力,直至样本边缘颈部崩瓷,记录并得出每个样本崩瓷时所承受的载荷力值. 结果 第2组样本崩瓷时所受平均载荷力值最大(P＜0.05);第4组样本崩瓷时所受平均载荷力值最小(P＜0.05);第1组与第3组的载荷力值间比较,差别无统计学意义(P＞0.05). 结论 金属基底冠止于肩台唇侧中部的金属烤瓷冠崩瓷时的所受载荷力值最大;金属基底冠唇侧止于肩台与轴壁交角冠方l mm处且颈部应用肩台瓷的金属烤瓷冠所受载荷力值最小.但4种不同冠边缘形式的钴铬合金烤瓷冠都能满足正常的咬合功能需要.     

银离子、铜离子和锌离子对常见念珠菌的抗菌性能比较

目的 探讨银离子(Ag⁺)、铜离子(Cu²⁺)、锌离子(Zn²⁺)对5种常见念珠菌(白色念珠菌、热带念珠菌、近平滑念珠菌、克柔念珠菌和光滑念珠菌)的抗菌作用。方法 使用去离子水分别将硝酸银、氯化铜和氯化锌配制为0.1 mol·L^-1的水溶液。取保存的白色念珠菌标准菌株ATCC-60193、近平滑念珠菌、光滑念珠菌、热带念珠菌、克柔念珠菌,加入溶菌肉汤培养液,使用比浊仪调配菌液浊度为0.5麦氏单位,然后使用无菌去离子水将菌液稀释至10⁶ CFU·L^-1。取配制好的0.1 mol·L^-1的硝酸银、氯化铜和氯化锌溶液,分别倍比稀释为6个浓度(10^-2、10^-3、10^-4、10^-5、10^-6、10^-7 mol·L^-1),分别取各浓度的金属离子溶液100μL与预制好的5种念珠菌悬液100μL进...     

纤维桩联合复合树脂修复穿髓型楔状缺损的临床疗效

目的：研究纤维桩联合光固化复合树脂修复前磨牙穿髓型楔状缺损的临床效果。方法：选择126例患者126颗穿髓型楔状缺损前磨牙,行完善的根管治疗后分别用玻璃纤维桩联合光固化复合树脂充填法、金属桩核烤瓷冠修复法和光固化复合树脂直接充填法进行修复。随访1年,评价临床效果。采用SPSS18.0统计学软件进行数据处理。结果：纤维桩组成功率与金属桩冠组比差异无统计学意义（P＞0.05）,与复合树脂组比差异有统计学意义（P＜0.05）。纤维桩组患者满意度高于其他2组。结论：纤维桩联合光固化复合树脂修复前磨牙穿髓型楔状缺损是一种较好的方法,优于传统的金属桩核烤瓷冠修复法,值得临床推广。 [关键词] 纤维桩;楔状缺损;金属桩冠;光固化复合树脂     

金属螺钉与聚氨酯橡胶慢性脊髓损伤大鼠模型的分析比较

目的:比较金属螺钉与聚氨酯橡胶压迫的慢性脊髓损伤（CSCI）大鼠模型的优劣,探索适合CSCI研究的大鼠模型。方法: 108只雄性Sprague-Dawley大鼠完全随机分组为假手术组（n=36）、金 属螺钉组（n=36）和聚氨酯橡胶组（n=36）,记录造模术前及术后2.5 h、7 d、14 d、21 d、28 d各组下肢行为学运动功能评分（BBB评分）和体感诱发电位（SEP）,取C5段脊髓组织行苏木精-伊红染色 法（HE）和原位末端标记法（TUNEL）染色。结果:BBB评分:金属螺钉组与聚氨酯橡胶组较假手术组均明显降低（金属螺钉组比假手术组,t=9.671,P<0.000 1;聚氨酯橡胶组比假手术组,t=4.997, P=0.002 5）,且金属螺钉组评分低于聚氨酯橡胶组（t=2.705,P=0.035 3）,金属螺钉组持续下降,聚氨酯橡胶组则于术后21 d降至最低后开始上升。SEP:金属螺钉组与聚氨酯橡胶组较假手术组均出 现潜伏期延长（金属螺钉组比假手术组,t=18.02,P<0.000 1;聚氨酯橡胶组比假手术组,t=10.82,P<0.000 1）和波幅下降（金属螺钉组比假手术组,t=145.5,P<0.0001;聚氨酯橡胶组比假手术组, t=3.97,P= 0.007 4）,且金属螺钉组潜伏期延长时间长于聚氨酯橡胶组,金属螺钉组波幅降低幅度先大于聚氨酯橡胶组,后较之略低。HE染色:金属螺钉组与聚氨酯橡胶组均出现脊髓损伤的病理表现 ,且金属螺钉组从腹侧到背侧渐进性加重,聚氨酯橡胶组则表现为一致性。TUNEL染色:金属螺钉组与聚氨酯橡胶组较假手术组TUNEL阳性细胞数明显增多（金属螺钉组比假手术组,t=4.722,P=0.003 2 ;聚氨酯橡胶组比假手术组,t=8.263,P=0.000 2）,且主要集中于脊髓灰质前角。金属螺钉组在术后第7天阳性细胞数达到最高,之后明显减少,聚氨酯橡胶组在术后逐渐增加至术后21 d达到最高。结 论:两种模型均有效地模拟了CSCI,金属螺钉CSCI模型适合损伤程度逐渐加重的CSCI研究,聚氨酯橡胶CSCI模型则适合压迫程度稳定的CSCI研究。     

稀土三元/TMAF体系催化二氧化碳与环氧丙烷交替共聚及机理研究

在稀土三元催化体系（三氯乙酸钇-二乙基锌-甘油）中加入相转移剂四甲基氟化铵（TMAF）,并用于催化二氧化碳和环氧丙烷交替共聚。采用核磁共振（¹H-NMR）、凝胶渗透色谱（GPC）、差示扫描量热（DSC）、热重分析（TG）和原位傅里叶转换红外光谱（in situ FT-IR）等对聚合过程和产物结构性能进行表征分析。采用基于密度泛函理论（DFT）的分子模拟方法对聚合起始步骤链增长机理进行探究。研究结果表明：稀土三元/TMAF催化体系可以在不改变聚合特征和共聚物结构性能的情况下,得到高达4 740.6 g/mol（1 mol Zn催化得到聚合物的质量）的催化活性,且将催化剂诱导期从100 min缩短至20 min。机理研究表明：环氧丙烷的插入步骤为反应的速控步骤,且该步骤所需克服的吉布斯自由能能垒随模型催化剂活性锌中心的自然成键轨道电荷的增加而降低,环状链增长机理中二氧化碳的插入并“返咬”成环所需克服的吉布斯自由能能垒很高,进一步证实了二氧化碳和环氧丙烷共聚反应更倾向于遵循链状链增长聚合机理形成聚碳酸亚丙酯。