翻译：中南大学湘雅二院　黄添隆

　　前言：目前金对金全髋关节置换术失败病例翻修手术越来越多。金属假体诱发的生物学反应多种多样，炎性假瘤、非感染性淋巴细胞血管炎相关损伤、局部组织不良反应均有相关报道。本研究针对金对金失败病例，分析患者的血清钴、铬离子水平，局部组织病理学反应以及回收假体的界面摩擦学，并假设宿主病理生物学反应与血清学和摩擦学结果相关。
　　方法：本医学中心16名因金对金THA失败或有相关症状行翻修手术的患者，按标准规程测量患者血清钴、铬离子水平，术中取相关病理组织送指定病理研究室，回收假体送指定摩擦学实验室。按病理学研究结果将患者分为两组，一组(10/16 患者)为巨噬细胞侵润或组织坏死为主，另一组(6/16 患者)为淋巴细胞侵润或纤维化改变为主。
　　结果：第一组患者平均血清钴离子为128.7（60.8-198.9），平均血清铬离子水平为41.2(15.6-62.1)，第二组患者血清钴离子为5.1，血清铬离子水平为2.2，与第一组相比血清离子水平下降具有统计学差异。翻修术中发现金属离子炎性反应在第一组患者中常见而第二组患者中少见。摩擦学检查发现所有回收假体均存在髋臼假体边缘高负荷介导的极带磨损，两组间无明显差异。
　　结论：临床失败的金对金THA假体虽然磨损方式相似，但生物学表现多种多样。然而研究发现局部组织病理学上坏死程度与假体周围组织的金属离子炎性反应以及血清金属离子增高相关。本研究结果表明血清金属离子升高可能与进行性组织损伤相关，因此我们建议对于金对金THA患者应常规检测血清金属离子水平，一旦金属离子明显增高则应给予早期翻修手术。

 

 

Introduction
Revision of failed metal on metal (MOM) total hip arthroplasty (THA) is increasingly prevalent. Various biologic responses to MOM implants, including pseudotumors, aseptic lymphocytic vasculitis-associated lesions (ALVAL), and now more generically, adverse local tissue response (ALTR) have been described. In a series of revised MOM implants we investigated serum cobalt and chromium levels, the pathologic tissue examinations and a tribologic analysis of the retrieved implants. We hypothesized that the host biologic response (pathology) could be correlated with the serologic and tribologic findings.
Methods
Sixteen patients underwent revision of failed or symptomatic MOM THA at an academic medical center. Serum cobalt and chromium levels were measured per a standard protocol. Retrieved tissue and implants from sixteen subjects were sent for a detailed pathologic exam as well as a tribologic analysis of the implants, performed at a dedicated tribology lab. Pathologic findings were classified in two main categories: Group 1 (10/16 patients) was macrophage/necrosis dominant while Group 2 (6/16) patients was fibrous/lymphocyte dominant.
Results
Group 1 had a mean Cobalt level of 128.7 (range 60.8-198.9) and mean Chromium level of 41.2 (range 15.6-62.1) and Group 2 had significantly lower mean serum Cobalt and Chromium levels (Co 5.1 vs Cr 2.2, p<0.01). Metallosis was documented as a common intraoperative finding in Group 1 but not Group 2. On tribologic examination the dominant finding on all retrievals was polar stripe wear corresponding to edge loading at the rim of the cup, and did not differ between the two pathologic groups.
Conclusion
Variability in the biologic response to MOM THA implants can be seen despite similar tribologic wear patterns. However, intraoperative findings of metallosis and high serum metal ion levels were correlated with pathologic findings of necrosis. Our findings would suggest that high serum metal ion levels may be associated with advanced tissue damage, and we would recommend that ion levels should be routinely monitored in MOM THA patients and consideration given for early revision in patients with markedly elevated levels.