【专题文献】之人工髋关节置换——髋关节翻修术中髋臼失败的重建和翻修

【专题文献】之人工髋关节置换

全髋翻修讲座之一：全髋关节置换疼痛的评估 By: 宋兵乙
全髋翻修讲座之二：髋关节翻修术中内植物的取出 By: 宋兵乙
全髋翻修讲座之三：髋关节翻修术中髋臼失败的重建和翻修 By: 宋兵乙
全髋翻修讲座之四：髋关节翻修术中股骨失败的重建和翻修 By: 宋兵乙
全髋翻修讲座之五：全髋关节置换术后髋关节脱位的处理 By: 飘洋过海
全髋翻修讲座之六：全髋关节置换术假体周围感染的处理 By: shiitake
全髋翻修讲座之七：下肢假体周围骨折的处理 By：宋兵乙

MINI-SYMPOSIUM: REVISION HIP SURGERY
小讲座：髋关节翻修术之三

(iii) Reconstruction/revision of acetabular failure in revision hip replacement

髋关节翻修术中髋臼失败的重建和翻修

Peter W Howard

Abstract
Reconstruction of the acetabulum following acetabular failure in hip arthroplasty presents a wide array of challenges. The extent of bone loss present at revision may require a number of different potential techniques, aiming wherever possible to restore bone stock to that of the primary arthroplasty situation. Gaining primary implant stability is the key to success for all revision methods. Success rates are generally inferior to primary hip arthroplasty, and more so the greater the loss of bone stock.

Keywords acetabular reconstruction; allograft; impaction grafting; revision hip arthroplasty

摘要
髋关节置换术后髋臼失败的髋臼重建，充满挑战。在翻修时广泛的骨缺损，可能需要几种不同的潜在技术，尽可能恢复到初次置换术时的骨量。获得内植物的初始稳定是所有翻修手术成功的关键。成功率普遍低于首次全髋置换术，且骨量缺损越多，成功率越低。

关键词
髋臼重建，同种异体骨移植，打压植骨，髋关节翻修





Keypoints
Bone stock restoration and primary implant stability are the main aims
Investigation reveals the extent of bone present but not its quality
Bone stock loss identified at surgery is generally greater than anticipated pre-operatively
Implants, bone and consent need to be in place to deal with the unexpected
Success rates diminish with greater bone stock loss

关键点
骨量恢复和内植物的初始稳定性是主要目标。
调查显示，（更重要的是）骨质呈现的范围，而不是骨质量。
在术中对骨量缺损的鉴定，通常重要于术前对其的期望。
内固定，骨和其相互关系，需要在位以应付意外。
骨量缺损越多，成功率越低。






Introduction
Revision surgery of the acetabulum covers a wide spectrum of complexity, with a myriad of techniques for dealing with the difficulties that can arise. Careful pre-operative assessment and planning is vital, as is having alternative plans and the inventory to support them if the (not infrequently) unexpected occurs. Many of the techniques and implants are applicable to more than a few of the scenarios; often there is little to choose between them in terms of reported outcomes. The main goals are to provide a stable and lasting fixation, and where possible to improve the bone stock, most commonly with the use of allograft bone. Excellent results have been reported with both cemented and cementless options.1,2

引言
髋臼翻修具有广泛范围的复杂性，对可能出现的困难需要繁多技术。仔细的术前评估和计划是极重要的，如果有意外发生（并不是不常见）有备选方案和支持手术的器械也是极重要的。很多技术和内植物可以用于不同的用途。通常，在依据报道的结果，在这些技术和内植物之间，选择是很少的。主要的目标是提供稳定的和耐用的内固定，尽可能的提高骨量，更常见的是使用同种异体同移植。使用骨水泥型和非骨水泥型假体选择都报道有优良结果。


Pre-operative assessment
The plain radiograph often gives sufficient information in what could be termed straight-forward cases. The standard views are an antero-posterior (AP) view, combined with a horizontal beam lateral (not a turned lateral). Oblique or Judet views are helpful in further assessment, but these are perhaps now being supplanted by the use of computer tomography (CT) with modern software that can remove the artefacts produced by the scatter from the metal implants (Figure 1). It is always worth emphasising that these studies only quantify the bone present; the quality of the bone can be quite different to that which is expected, and this is one of the factors that can dictate a change of plan per-operatively.

术前评估
在直接了当的病例中，放射学平片经常能提供足够的信息。标准的片子是一个前后位平片，联合的一个水平侧位片（不是翻转的侧位）。斜位或Judet位对于进一步的评估很有用，但是目前可能己被CT所代替，使用现代软件的CT可以移除由分散的金属植入物所产生的伪影（图1）。有必要强调，所有的研究只能对骨量进行定量，骨的质量能和术前估计的完全不同，这也是能主导术前计划改变的影响因素之一。


图1

Classification systems seek to place the varying amounts and directions of bone stock loss into differing categories, to help guide which method is to be used, and for comparing the literature results of differing methods and implants. Most widely used are the AAOS3 and Paprosky4 grading systems, briefly summarised in Tables 1 and 2.

分类系统力图定位不同类别的不同的数量和骨量缺损的指标，以帮助指导哪一种方法可以使用，用于比较不同方法和内植物的文献结果。更常使用的系统是AAOS分类和Paprosky分级系统，简要概述在表1和表2.

表1

表2

In the assessment of bony defects, a key issue is containment.If a defect is well contained by surrounding bone, it is readily amenable to bone grafting. If not, then containment can become a major factor in achieving primary stability. Most defects requiring bone grafting will necessitate the use of allograft bone by virtue of the quantity required; host bone is usually in short supply, with the exception of patients requiring a contra-lateral primary hip or a knee replacement at around the same time. In such instances, the bone can be harvested and frozen for use at the subsequent revision. There are several substitutes for allograft bone that can be used by themselves or to supplement allograft, for example hydroxyapatite granules, coral and bovine bone, each with their advocates.

在骨量缺损的评估中，一个关键的问题是包容。如果缺损被周围骨很好的包容，这将很容易进行植骨。如果不是，包容能变成获得初始稳定的一个主要影响因素。很多需要植骨的缺损，由于需要的数量巨大，将需要使用同种异体骨移植，自体骨通常供应不足，除非是在同一时间需要对侧初次髋或膝置换的病例。在这样的病例中，可以将骨块采集并冷冻起来以用于随后的翻修。有几种替代物可以替代同种异体移植骨，能独自使用或作为同种异体骨的补充，比如说羟基磷灰石颗粒，珊瑚和牛骨，每一种都有其倡导者。

Differing indications for revision will have an influence on choice of method and implant. The commonest indication for revision of the acetabulum is aseptic loosening, with or without bone loss and/or osteolysis; for this the implant choice is widest. For recurrent dislocation with a relatively well positioned and well fixed implant the options narrow; they would include cup augmentation, revision to a much larger bearing size, and revision to a constrained component. When the implant to be revised has been infected, and significant reconstruction with allograft is the chosen option, then a staged revision is often considered to be a safer choice.

不同的翻修指征，对方法和内植物的选择上有影响。最常见的关于髋臼翻修的指征是无菌性松动，伴或不伴有骨量丢失和（或）骨溶解，对于这种情况，内植物的选择是最广泛的。对于相对定位良好的和固定良好的内植物发生的反复脱位，其选择是狭窄的，可能包括臼杯增大，翻修为更大尺寸的股骨头，和翻修到限制性假体。当需要翻修的内植物己经感染，并且需使用同种异体骨植骨进行有效重建是重要的选择方案，一步翻修法经常被认为是一个安全的选择。

Techniques for specific instances
The well fixed or minimally loose cup with good bone stock The first key, where bone stock restoration does not seem to be required, is that implant removal does not compromise that situation. A well fixed cementless cup can be removed with virtually no loss of bone by specific tools for the purpose, such as the ‘‘Explant’’. A well fixed cemented component can be removed with the aid of an ultrasonic tool, or by cutting the plastic into quarters and removing it piecemeal.

用于特殊案例的技术
伴良好的骨量的固定良好的或松动最小的髋臼杯，第一关键点是，在那些不是必须恢复骨量的病例，内植物的取出不应该影响到骨量。固定良好非骨水泥型髋臼杯能使用为此的特制工具在几乎没有骨量丢失的情况下取出，如“取出器”。固定良好的骨水泥型假体能使用超声工具的帮助下取出，或将塑形物切割成四分之一块并一点点的取出。


Once the cup is removed and the quality and quantity of the bone assessed as not requiring restoration, the choice of implant and method of fixation is essentially the same as for a primary hip replacement. It is, however, often the case that there is more compromise to the bone stock than initially anticipated, and it is therefore vital that the tools for restoration are to hand, including allograft bone, and that the patient has been both appropriately informed and consented in advance.

一旦髋臼杯被取出，评估出骨的质量和数量不需要恢复，内植物的选择和固定的方法实质上同初次全髋置换是相同的。然而，通常的情况是对于骨量的更多危害超过了一开始的预期，因此用于恢复骨量的工具在手边，包括同种异骨体，和对病人预先的告知和知情同意许可，这是极重要的。

The well fixed cementless cup with osteolysis
The situation of a well fixed cup with polyethylene wear and osteolysis of the pelvis is usually associated with cementless metal backed components. Depending on the extent of the problem, there are a number of options. Curettage of the lytic area and allograft bone grafting is a viable option (Figure 2), followed by replacement with a new polyethylene liner, with replacement of the femoral head (if modular), as this is likely to be scratched. A similar technique is to graft the lesion and then cement a polyethylene socket into the shell. This is suited to a well fixed reasonably large shell, where osteolysis is recognised as a frequent problem for that particular implant. Alternatively, the cup can be removed and one may proceed as in next section. This is preferable if the cup is well fixed but fixation is only in a few contact areas.

伴有骨溶解的固定良好的非骨水泥型髋臼杯
固定良好的髋臼杯，伴聚乙烯颗粒和骨盆的骨溶解，这种状态通常和非骨水泥型金属支持组件有关。依赖于这问题的广泛性，有几种选择。刮除骨溶解区域，进行同种异体骨移植是一种可行选择(图2），之后进行一个新的聚乙烯衬垫置换，并置换股骨头（如果是组装模式的），因为股骨头很可能有划痕。一相似技术是移植损伤处，然而将聚乙烯髋臼窝用骨水泥固定在髋臼壳内。这适合于固定良好的适当的大髋臼壳，而骨溶解对于此种特殊的内植物确认为是一个经常的问题。可选择的，髋臼杯能被取出，可以进行下一步骤。如果髋臼杯固定良好但是固定只在很少的接触区域，这是很好的。


图2

The contained defect with an intact rim
This is the ideal situation for allograft bone grafting, either with a cemented or cementless component. Morcellised allograft with a cemented component has been widely reported.2 The limits to the technique are not well defined; there is some suggestion that greater graft thickness, perhaps over 2 cm, may be associated with a higher failure rate.5 A minor lack of containment is acceptable so long as the vast majority of the graft is well contained and the cup well supported－as in Figure 3. Techniques of graft preparation vary; a mixture of sizes and shapes has some biomechanical advantage for impaction, and this can be produced readily by a combination of chips from a bone mill and morcellising 1 cm slices of allograft femoral head with a bone nibbler. Washing the graft is recommended.

有完整边缘的被包容缺损
对于骨水泥型或非骨水泥型假体而言，这是同种异体骨移植的理想状态。Morcellised同种异体骨移植，伴骨水泥型假体，被广泛报道。技术的局限性仍没有很好定义，有些人建议，可能是超过2cm的最大的移植厚度，可能和更高的失败率有关。只要绝大多数移植物包容良好和髋臼杯支持良好，小的包容缺损是能接受的，如图3。移植物的准备是不同的，不同大小和外形的混合物用于打压植骨有一些生物力学的优势，通过小骨片混合，这可以很容易产生，小骨片的混合来自骨搅拌机和morcellising的使用碎骨钳将同种异体股骨头打成1cm的骨片。


图3

The long term reported success rates of cementless acetabular fixation are comparable.4 With larger contained defects, when a rim fix (cementless) can be obtained the depth of the graft becomes less important. Remodelling often accompanies incorporation (Figure 4).

非骨水泥型髋臼固定的成功率的长期报道被相互比较。对于较大的包容性缺损，当能得到非骨水泥型的边缘固定，移植物的深度变得不那么重要。重塑通常伴随着结合。（图4）

图4

Uncontained defects (excluding pelvic discontinuity)
There are several well established techniques for managing uncontained defects. These are less common procedures and generally regarded as a special field in themselves. As in the other sections, the aim is to gain primary stability and restore bone stock; these two aims are better achieved by some methods than others. Solutions in cemented arthroplasty include the use of mesh screwed onto the pelvis to contain morcellised graft, the use of block/bulk and morcellised allograft combined, the use of a variety of shapes and sizes of supporting rings with graft and a cemented cup, and pegged/stemmed prostheses. Filling a large defect with cement can be considered when only a short term solution is required (eg short life expectancy), but this does not improve bone stock and stability can be short lived.

无包容的缺损（骨盆不连续的除外）
治疗无包容的缺损有好几种确定好的技术。这是不太常见的操作，本身通常被看作为一个特殊领域。正如在其他章节，其目的是为了得到初始稳定性和恢复骨量。这两个目标都通过比其他方式更好的一些方法而得到了。骨水泥型关节置换的解决包括使用螺钉固定钛网到骨盆上，以保持morcellised骨移植，使用阻断或使其扩大和morcellised同种异体骨联合，使用复合移植骨和骨水泥型髋臼杯的多种形状和大小的支持环，固定的或有干的假体。应考虑使用骨水泥填充大的缺损，当只要求解决短期问题时（如预期寿命较短），这并不能改善骨量，但稳定性在短期内有保证的。


An uncontained lateral/postero-lateral deficiency is one of the commoner scenarios (Figure 5), where the bone stock has been eroded by the loosening prosthesis. Containment is achieved in this example with a portion of an allograft femoral head (distal femur is another option), shaped and fixed to the pelvis with screws. The resultant construct is then reamed. Morcellised allograft is then impacted, thereby sealing any small gaps, and a cup cemented in. Longer term concerns with this method are that revascularisation of the graft might result in collapse and loosening,7 but many grafts gain bony union without this happening (Figure 6).

无包容的外侧/后外侧缺损是较常见的情况之一，在这里骨量被松动的假体所侵蚀（图五）。在这个例子中，使用同种异体的股骨头的一部分（股骨远端是另一种选择）以达到包容，修剪形状，使用螺钉固定到骨盆。然后对些复合结构进行扩髓。然后以Morcellised同种异体骨进行打压植骨，因此封闭了任何小的间隙，再使用骨水泥髋臼杯植入。此种方法的长期担心是移植骨的再血管化可能导致松动和崩塌，但很多移植物得到骨性愈合但并没有发生此现像。（图6）

图5

图6

Supporting rings or roof re-enforcement rings,6 almost all available in titanium, can often achieve a reasonable press fit, which is then supplemented with screws. The bone stock is then augmented with morcellised graft prior to cup cementation; in general, their use is for larger uncontained defects. Similar support can be given by titanium mesh screwed onto the pelvis to augment the stability of impacted graft with cementation.

支持环或穹顶反复加强环，几乎所有可用的钛，经常能得到一个适当的压配，并辅以螺钉。在髋臼杯植入前，使用morcellised骨移植进行骨量加强。通常，他们的使用是为了更大的非包容性的缺损。相似的支持可以从螺钉固定到骨盆的钛网得到，以加强骨水泥粘固的打压植骨的稳定性。

Cementless fixation with large uncontained defects has a number of different options. An oversized (or ‘‘jumbo’’) cup can give a reasonable press fit to limited host bone after careful reaming, with cavities then filled with morcellised graft and with screws passed through the cup to enhance early stability. Any exposed/uncovered component can then have bone onlaid.Favourable results have been reported although the technique is limited by the ability to get stable primary fixation, with often less bone available in smaller patients.8

伴有大的无包容缺损的非骨水泥固定有几种不同的选择。一个超大的（或庞然大物）髋臼杯能在小心的扩髓后得到适合的压配以限制宿主骨，腔隙使用morcellised同种异体骨填充，使用螺钉通过髋臼杯以加强早期稳定性。任何暴露的或无遮盖的组件能使骨外露。有利的结果已经公布，尽管该技术在得到初始稳定的固定方面有限制，常常在年轻一点的病人中可用的骨更少。

Bilobed (or dual diameter) cups were introduced to fill the acetabulum and a lateral defect with implant. Variable results have been reported. The shortcoming of the technique is that bone stock is not restored, and more bone might have to be removed to get the implant to fit. There are a variety of stemmed and pegged implants (Figure 7) reported for gaining stability where there is insufficient host bone to gain a press fit. They are technically demanding, but good results have been reported.9

引入双叶或双直径的髋臼杯，使用该内植物以填充髋臼和外侧缺损。报道有不同的结果。该技术的缺点是，骨量并没有恢复，更多的骨可能需要移开以使内固定物压配。既往报道有很多不同的带干的和带钉的内植物（图7），用在不足的宿主骨用以得到压配，进而得到稳定性。这是技术活，但是良好的结果己经公布。

图7

Trabecular metal implants are a relatively recent advance, and are showing great promise. Essentially, a very porous titanium surface enhances very rapid bony ingrowth as well as providing good grip for primary stability. The implants are available as augments and press fit sockets, but come with not inconsiderable expense. Short term reported results have to date been excellent, offering good versatility.

是相对最新的进展是带小梁的金属内植物，显示出很大的希望。本质上，非常疏松的钛质表面，提高了非常快的骨长入速度，同时，提供了良好的抓吸力以得到早期稳定。该内植物具有增强和压配窝，但是价钱并不是特别贵。短期报道结果目前是优秀的，提供了较好的通用性。

Pelvic discontinuity
Perhaps the most challenging situation of all is where there is a complete pelvic discontinuity, or transverse pelvic fracture, involving usually the acetabular floor and the adjacent anterior and posterior columns. The accompanying loss of bone stock can be variable, and whilst often obviously discontinuous by the alteration of the inner pelvic contour, the finding of a discontinuity at revision surgery is occasionally unexpected. Stability of the fracture must be obtained, usually by internal fixation either through a cage with multiple screws, by combined plate/screw fixation, or via the screw-holes of a cementless cup. The Burch-Schneider cage (Figure 8) has been widely used and reported. It is versatile for its wide choice of screw placement, although there are concerns in the longer term over loosening of these large stiff implants.

骨盆中断
可能最挑战性的状态是完全的骨盆中断，或者经骨盆骨折，包括常见的髋臼底和前后柱连接处。伴随的骨量丢失能多种多样，同时常常由于骨盆内的外形变化出现的明显中断，故在翻修手术时发现骨盆中断只是偶而意外。骨折必须得到稳定性，通常通过多根螺钉的笼子联合钢板螺钉内固定，或通过非骨水泥型髋臼杯的螺钉洞进行内固定。Burch-Schneider笼子（图8）己有广泛使用和报道。它具有广泛的螺钉位置选择，具有多用途性，尽管在长期内对这些大型僵硬植入物松动仍存在顾虑。


图8

Trabecular metal implants are starting to be used in this situation, with some encouraging results reported. Where bone loss is massive, there is a place for the use of massive (whole) acetabular allografts,10 but this is in the surgical repertoire of very few surgeons, with an excision arthroplasty the remaining option for the hip that is otherwise un- reconstructable.

带小梁的金属内植物开始应用于这种状况，并且有一些令人鼓舞的己报道结果。骨丢失巨大的地方，可以使用大块髋臼同种异体移植，但这是极少数外科医生的手术剧目，另外对此状况进行一个关节切除术是剩余选项，但这是另外的不可重建的。

Conclusion
There is a wide variety of techniques and options available for acetabular reconstruction; each with differing merits and some with definite drawbacks. Where possible, the principle of ‘‘building for the future’’ holds sound; gaining primary stability and replacing lost bone stock with bone optimises implant longevity and potentially improves options should subsequent revision ever be needed.

总结
有很多种技术和选择可用于髋臼重建，每一种有不同的优点和一些明显的缺陷。无论如何，“确保将来”这一原则是合理的。获得初始稳定，在骨缺损处植骨，以优化内植物的寿命，并改善了后继翻修的治疗选择，因后继翻修应该是永远需要的。


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