金对金全髋关节置换失败的情况和其翻修适应症

2012-02-23 文章来源：www.aaos.org 点击量：2678 　　我要说

翻译：广东省人民医院骨科，广东省医学科学院　林子洪，郑秋坚

前言

　　因金属碎屑副作用而翻修的金对金全髋关节置换 (metal-on-metal hip replacement, MOM-HR)预后差，脱位率、松动率和再手术率均比较高。MOM-HR的翻修率在逐渐增高，而至今仍无恰当的处理方法。本研究通过分析MOM-HR翻修病例，探讨术前翻修原因确诊检查的作用，目的是能准确做好术前准备和避免并发症。

方法

　　前瞻性收集 MOM-HR翻修病例的资料，全部病例进行术前X光、MRI、CT检查和功能评分，并记录术中情况。随访时进行功能评分和记录并发症。最后根据CT数据、MRI数据、术中情况、肌肉或骨质缺失程度和假瘤或其它常见失败原因，将所有病例分为5组。

结果

　　39髋(36例)翻修病例，中位年龄61岁(25-76岁) ，男女比例为 M:F 7:32。8例因感染或撞击而翻修，7例有明显骨溶解但没有假瘤，7例有假瘤伴随肌肉缺失，2例假瘤较大且边界清楚，但没有局部破坏，15例没有明显假瘤或骨骼肌肉缺失。早期随访时间为20个月(2-44个月) ，其间一例因假瘤复发而再行手术，其他病例在此期间无一脱位或再翻修。

讨论和结论

　　金对金全髋关节置换常见的失败原因均可以在翻修术前的影像检查中予以明确，从而可以更准确地做好术前准备，最终使翻修获得更好的预后。

表1 基于影像学资料和术中情况，有疼痛症状的金对金全髋关节置换的分类系统

	影像学	手术	危害	手术计划
1型特发性疼痛	MRI没发现或有小假瘤液体信号影	无或者轻微软组织反应	误诊	需要除外其它原因：感染、机械等，进一步检查腰大肌，翻修术中取冰冻切片
2型明显骨溶解	平片、CT发现骨溶解，MRI情况如1型	杯松动，无或者轻微软组织反应	骨量丢失且需要广泛重建	可能需要广泛重建，CT和骨盆外科医生辅助较为重要，早手术可以预防骨折
3型明显假瘤	MRI可见大假瘤液体信号影但无肌肉破坏，可侵入骨盆	大面积软组织反应，边界清楚且肌肉完整	若切除不彻底可二次感染	完全切除，可能需要骨盆探查
4型破坏性	MRI可见大假瘤液体或实体信号影，大面积软组织破坏	外展肌可能缺失，大转子区裸露	翻修后不稳	肌肉重建和大臼杯，可能需要骨盆外科医生完全切除假瘤

INTRODUCTION

Previous studies have shown poor results after revision of metal-on-metal hip replacement (MOM-HR) for adverse reactions to metal debris, with high rates of dislocation, loosening and reoperation. The revision burden in MOM-HR is increasing and optimal management remains unclear. We present our revision series, demonstrating the role of pre-operative investigations in classifying such cases, allowing accurate preoperative planning and avoidance of complications.
METHODS

Data were collected prosepectively on revisions of MOM-HR at our institution. Patients underwent preoperative radiographs, MRI, CT, and functional scoring. Intraoperative findings were recorded. Scores and complications were recorded at follow up. Patients were classified into five groups by CT, MRI and intraoperative appearance, depending on the degree of muscle or bone loss and presence of pseudotumour or conventional cause of failure.
RESULTS

Thirty-nine hips (36 patients) were revised. Median age was 61 (25-76), M:F ratio was 7:33. Eight patients were found to have ‘conventional’ causes of failure such as infection or impingement. Seven had predominant osteolysis with no pseudotumour, seven had a destructive pseudotumour with muscle loss, two had a well-demarcated large pseudotumour without local destruction. The majority (15) had no findings of significant pseudotumour, muscle or bone loss. Early results at a mean follow up of 20 postoperative months (range 2-44 months) are favorable with one re-operation for recurrent pseudotumour, no dislocations or re-revisions.
DISCUSSION AND CONCLUSION

Metal-on-metal hips fail in predictable patterns, determinable on preoperative imaging. Classifying such cases using imaging findings allows accurate preoperative planning and may lead to better outcomes after revision.

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