AAOS：金对金全髋关节置换失败情况及翻修适应症

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 

原始材料:

Session: ARH Posters-Adult Reconstruction Hip Posters Date/Time: Tuesday, Feb 07, 2012, 8:00 AM - 6:00 PM
Poster Hall/ Multimedia/ Scientific Exhibits: Tuesday, Feb 7 - Saturday, Feb 11, 2012, 8:00 AM - 6:00 PM Presentation Number: P101 Posterboard Number: P101 Title: Patterns of Failure in Metal-on-Metal Hip Arthroplasty and Implications for Revision Classification: Adult Reconstruction Hip Keywords: Bearing Surfaces; Total Hip Arthroplasty; Complications; Revision / Acetabular Component; Revision / Femoral Component Author(s): Alexander D. Liddle, MBBS, London, United Kingdom
Keshthra Satchithananda, FRCR, London, United Kingdom
Johann Henckel, BM, London, United Kingdom
Shiraz Sabah, MD, London, United Kingdom
Karuniyan V. Vipulendran, HAVERFORDWEST, United Kingdom
Angus Lewis, FRCS, London, United Kingdom
Justin P. Cobb, MD, London, United Kingdom
John Skinner, FRCS, London, United Kingdom
Alister Hart, FRCS, London, United Kingdom
Abstract: INTRODUCTIONPrevious 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.
METHODSData 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.
RESULTSThirty-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 CONCLUSIONMetal-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.