BACKGROUND Multiple cases of dissociation of the head from the neck termed as gross trunnion failure (GTF) in total hip replacement have been described. Very little quantitative data is available for patient and implant factors associated and predisposing to this complication. STUDY PURPOSE To systematically review and analyze all studies which have gross trunnion failure in case of metal on polyethylene (MoP) total hip replacement. METHODS PubMed database was searched. We also performed a secondary search by pearling bibliography of all full text articles obtained. Predefined inclusion and exclusion criteria were used for abstract screening by two independent observers. A total 46 cases met our inclusion criteria. These were included in the final analysis and data was pooled. RESULTS Till date, 46 cases of GTF in MoP THR have been reported. The mean age at time of revision was 70.13 years (range 50 to 89 years). The mean time to revision surgery was 8.24 years (range 4.7 to 14 years). 91.4% cases were male. BMI was ≥ 25 in 38/41 cases and ≥ 30 in 21/41 cases. Pain (95.5%) and difficulty or inability to walk (97.7%) were the most common symptoms. A total of 19/44 cases described varying sounds like click, clunk, and pop before dislocation. Accolade TMZF/TMZF plus was the most common stem used in 34/46 cases. The stem neck angle was 127 degrees in 97% cases (32/33 cases). A positive neck offset of 4 mm or more was used in 91.1% cases (40/44 cases). The head size ≥ 36 mm in approximately 90% cases. The head material was cobalt chromium in all 45 cases, where data was available. Among the intra-operative findings, the most common findings were metallosis (41/44), black or brow coloured synovial fluid (21/44), pseudotumour (19/44), synovial hypertrophy (18/44), damage to the abductor musculature (17/44), proximal femoral osteolysis (5/44 cases), and heterotrophic ossification (2/44 cases). Histopathological analysis was available in 11 cases and was suggestive of fibrous tissue with chronic cellular infiltrate in all cases. The serum cobalt and chromium concentrations were raised above normal in 86.4% (19/22) and 21.7% cases (5/23) respectively. CONCLUSIONS Gross trunnion failure may not be as uncommon as was previously thought. A number potential associations and predisposing factors of this complication have been highlighted in this review. But due to small sample size and weak level of evidence, further studies are needed in this field.

中文翻译：

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聚乙烯全髋关节置换术中金属的总耳轴衰竭-文献综述。

背景技术已经描述了在全髋关节置换中称为大耳轴衰竭（GTF）的头部与颈部分离的多种情况。很少的定量数据可用于与这种并发症相关并易于引起并发症的患者和植入物因素。研究目的系统地回顾和分析所有在金属对聚乙烯（MoP）全髋关节置换术中发生总耳轴衰竭的研究。方法检索PubMed数据库。我们还对所有获得的全文文章进行了书目检索，以进行二级搜索。预定义的包含和排除标准由两名独立观察员用于抽象筛选。共有46例符合我们的纳入标准。这些都包含在最终分析中，并汇总了数据。结果截至目前，已报道MoP THR中有46例GTF病例。修订时的平均年龄为70.13岁（范围为50至89岁）。翻修手术的平均时间为8.24年（4.7至14年）。男性为91.4％。BMI在38/41例中≥25，在21/41例中≥30。最常见的症状是疼痛（95.5％）和行走困难或无法行走（97.7％）。总共19/44个案例描述了脱位前的各种声音，例如咔嗒声，喀unk声和pop啪声。Accolade TMZF / TMZF plus是34/46例中最常用的茎。97％的病例（32/33例）的茎颈角为127度。91.1％的病例（40/44例）使用4 mm或更大的阳性颈部偏移。在大约90％的情况下，头部尺寸≥36 mm。在所有有数据的情况下，头部材料均为钴铬合金，共45例。在术中发现中，最常见的发现是金属病（41/44），黑色或额头滑液（21/44），假瘤（19/44），滑膜肥大（18/44），外展肌的损伤（17/44），股骨近端骨溶解（5/44例）和异养性骨化（2/44例）。11例可进行组织病理学分析，提示所有病例均伴有慢性细胞浸润的纤维组织。血清钴和铬的浓度分别高于正常水平的86.4％（19/22）和21.7％的病例（5/23）。结论耳轴总失败可能并不像以前想象的那样罕见。这篇综述强调了这一并发症的许多潜在关联和诱发因素。但是由于样本量小且证据水平低，该领域需要进一步研究。滑膜肥大（18/44），外展肌的损伤（17/44），股骨近端骨溶解（5/44例）和异养骨化（2/44例）。11例可进行组织病理学分析，提示所有病例均伴有慢性细胞浸润的纤维组织。血清钴和铬的浓度分别高于正常水平的86.4％（19/22）和21.7％的病例（5/23）。结论耳轴总失败可能并不像以前想象的那样罕见。这篇综述强调了这一并发症的许多潜在关联和诱发因素。但是由于样本量小且证据水平低，该领域需要进一步研究。滑膜肥大（18/44），外展肌的损伤（17/44），股骨近端骨溶解（5/44例）和异养骨化（2/44例）。11例可进行组织病理学分析，提示所有病例均伴有慢性细胞浸润的纤维组织。血清钴和铬的浓度分别高于正常水平的86.4％（19/22）和21.7％的病例（5/23）。结论耳轴总失败可能并不像以前想象的那样罕见。这篇综述强调了这一并发症的许多潜在关联和诱发因素。但是由于样本量小且证据水平低，该领域需要进一步研究。11例可进行组织病理学分析，提示所有病例均伴有慢性细胞浸润的纤维组织。血清钴和铬的浓度分别升高了86.4％（19/22）和21.7％（5/23）。结论耳轴总失败可能并不像以前想象的那样罕见。这篇综述强调了这一并发症的许多潜在关联和诱发因素。但是由于样本量小且证据水平低，该领域需要进一步研究。11例可进行组织病理学分析，提示所有病例均伴有慢性细胞浸润的纤维组织。血清钴和铬的浓度分别高于正常水平的86.4％（19/22）和21.7％的病例（5/23）。结论耳轴总失败可能并不像以前想象的那样罕见。这篇综述强调了这一并发症的许多潜在关联和诱发因素。但是由于样本量小且证据水平低，该领域需要进一步研究。结论耳轴总失败可能并不像以前想象的那样罕见。这篇综述强调了这一并发症的许多潜在关联和诱发因素。但是由于样本量小且证据水平低，该领域需要进一步研究。结论耳轴总失败可能并不像以前想象的那样罕见。这篇综述强调了这一并发症的许多潜在关联和诱发因素。但是由于样本量小且证据水平低，该领域需要进一步研究。