【专题文献】之人工髋关节置换——下肢假体周围骨折的处理

【专题文献】之人工髋关节置换——下肢假体周围骨折的处理

【专题文献】之人工髋关节置换

宋兵乙

宋兵乙

飘洋过海

MINI-SYMPOSIUM: REVISION HIP SURGERY

小讲座：髋关节翻修术之七

(vii) Management of periprosthetic fractures in the lower limb

(vii) 下肢假体周围骨折的处理

Panos Makrides;Harpal Singh Uppal;Steve Krikler

Abstract

The incidence of periprosthetic fractures is rising significantly as more replacement arthroplasties are performed. They are a potentially devastating complication associated with high morbidity and mortality. Their management is a sub-specialty in itself. This article outlines the principles of the management of periprosthetic fractures of the lower limb.

Keywords bone graft; internal fixation; peri-prosthetic fracture

摘要

当实施了更多的关节置换手术，假体周围骨折的发生正在显著增加。这是潜在的毁灭性的并发症，伴随着很高的发病率和死亡率。其处理本质上是一个亚专业。本文列举了下肢假体周围骨折的处理原则。

关键词：骨移植，内固定，假体周围骨折。

Introduction

An aging population with higher standards of living has led to a steady increase in replacement arthroplasties in developed countries as recorded by the Scandinavian, Australian, UK and Mayo Clinic Registers. The positive outcome of an otherwise successful procedure can be compromised by a periprosthetic fracture (PPF). It is a major problem, associated with high rates of morbidity and mortality.1,2 The prevalence is difficult to ascertain but the consensus is that they are increasing both numerically and in complexity. In 2006 Lindahl et al. reported the cumulative incidence of periprosthetic hip fractures as 0.4%.3 According to the Swedish Hip Registry, PPF is the third commonest reason for revision arthroplasty, after aseptic loosening and dislocation.4 Periprosthetic fractures around a total knee arthroplasty are less common but equally important. They are more common in the distal femur (0.3e2.5%) compared with the proximal tibia (0.39% to 0.5%).

引言：

老年人群，由于更高生活标准，导致发达国家的人工关节置换稳步上升，如同斯堪的那维亚，澳大利亚，英国和梅奥医院登记处（美国）所记录的。一个成功手术的好结果，能被假体周围骨折（PPF）所危害。这是一个大问题，伴随着很高的发病率和死亡率。患病率很难去查明，但并发症在数量和复杂程度上正在增加，这是一致意见的。在2006年，Lindahl等报道了假体周围骨折的累积发病率为0.4%。根据瑞典髋关节登记中心，PPF是翻修的第三常见的原因，排在无菌性松动和脱位之后。在全膝置换的假体周围骨折不常见，但是同样重要。相对于胫骨近端（0.39－0.5%），全膝置换的假体周围骨折更常见于股骨远端（0.3－2.5%）。

Periprosthetic fractures can be divided into those occurring intra-operatively and post-operatively. Intra-operative fractures are usually caused by the insertion of the stem in the femur or the tibia. The incidence varies with different fixation methods. In the femur, uncemented stems carry a higher risk; Berry et al. report a rate of 0.3% in cemented and 5.4% in uncemented. The rates are significantly

【专题文献】之人工髋关节置换——下肢假体周围骨折的处理

higher in revision surgery.

The post-operative incidence of periprosthetic fractures in primary total hip arthroplasties (THA) has been reported by the Mayo clinic registry as 1.1% of total hip replacements done between 1969 and 1999).

体周围骨折可以分为术中和术后。术中骨折通常由插入假体到股骨或胫骨引起。其发病率因不同的内固定方法而不同。在股骨，非骨水泥型假体有更高的风险，Berry等报道其发病率在骨水泥型假体时0.3%，在非骨水泥型假体时为5.4%。在翻修手术时，其发病率显著增高。

由梅奥医院登记处报道的在初次全髋置换时术后假体周围骨折发生率，自1969－1999年完成的全髋置换术，其PPF发生率为1.1%。

Aetiology

According to the Swedish Hip registry, trauma accounts for 75% of all PPFs.5 The majority are low velocity falls from a standing or sitting position. There are numerous possible risk factors for periprosthetic fractures; while patients with long standing THA are probably at higher risk of developing periprosthetic fracture but there are many possible confounders for this variable including the increased age of this patient group, other co-morbidities, poor bone stock and osteoporosis. Tsiridis6 suggests that female gender is associated with increased risk of PPF which is supported by various studies, and is probably related to the increased prevalence of osteoporosis in females. Beals and Tower reported that 38% of PPF in their study were associated with previous osteoporotic vertebral or metaphyseal fractures. However, the most common cause of PPF in older implants is osteolysis.7,8 The terms osteolysis and aseptic loosening are often used interchangeably and are essentially in reference to a common pathway. Osteolysis is believed be caused by the host s response to particulate wear debris associated with cement failure and subsequent loosening of the prosthesis. The choice of implant, cementation technique (or un-cemented) and operative technique are therefore directly related to the processes which are most likely to be important risk factors for late periprosthetic fracture.

病因 根据瑞典髋关节登记中心，创伤占所有假体周围骨折的75%。主要是从站位或坐位时低速跌倒。对于假体周围骨折有很多可能的风险因素，当病人长时站立时，全髋关节可能有较高的风险发生假体周围骨折，但对此变量有很多干扰因素，包括该组病例的年龄增加，其他基础疾病，骨量较差和骨质疏松。Tsiridis发现女性病人和增高的PPF风险有关，这被很多研究所证实，并且可能和女性的骨质疏松患并率增加有关。Beals和Tower在他们的研究中报道38%的PPF和之前的骨质疏松性椎体或干骺端骨折有关。然而，在较老的假体，PPF最常见的病因为骨溶解。骨溶解和无菌性松动，这两个名词常常互相替换，本质是参考一个共同路径。骨溶解相信是由于宿主对骨水泥失败相关的磨损微粒的反应和随之的假体松动而引起的。假体选择，骨水泥技术（或非骨水泥技术）和手术技术，因此和此过程直接相关，这可能是后期假体周围骨折的最重要的风险因素。

The original diagnosis is relevant to the risk of periprosthetic fracture; rheumatoid arthritis has been shown to be a risk factor for PPF by both the Finnish and Swedish Registries.9 Fractures of the proximal femur treated by arthroplasty are at higher risk for sustaining periprosthetic fracture; osteoporotic fractures of the neck of femur are regarded as pathological fractures and the ongoing pathological process is likely to be responsible for the increased incidence of PPF which increases with age, and from the index operation.10,11 Lindahl, based on the Swedish Registry, shows that initially PPF is the third commonest reason for revision, but from four years onwards, it is the second commonest reason.12

原始诊断和假体周围骨折的风险有关。类风湿性关节炎在荷兰和瑞典的登记中心都显示出是一个PPF的风险因素。股骨近端骨折，使用关节置换治疗的，有更高的PPF风险。股骨颈的骨质疏松性骨折被看成是病理性骨折，其进展的病理学过程，可能是PPF发病率增加的原因，而PPF的发病率随病人年龄而增加。依据瑞典登记中心，Lindahl发现首次PPF是翻修术的第三位常见原因，但是在之前四年，PPF是第二位常见原因。

Classification of periprosthetic fractures around the hip

While classification is essential to aid communication and for research, it is of most use to assist management. Numerous classification systems have been devised. Most, like Parrish (Table 1), classify the fracture according to its location. While simple and straightforward it does not help in deciding the correct treatment.

髋周假体周围骨折的分类

为了交流和研究，分类是必须的，它对于促进治疗帮助最大。己发明许多不同的分类系统，像Parrish系统（表1）一样，大多数系统依据骨折位置进行分类。由于简单和直接，此种方式并不能在决定正确的治疗方案上起到帮助。

【专题文献】之人工髋关节置换——下肢假体周围骨折的处理

表

1

Coventry classification (Modified from Ninan et al.13)

Ninan et al. produced the Coventry classification for PPF.13 We find this is comprehensive, easy to apply and also helpful in decision making for what is difficult and challenging problem. They divided periprosthetic fractures into two types; Type 1 hips include the happy hips , did not have problems pre-injury, and whose X-Ray shows that the stem is generally well-fixed with no evidence of loosening, or bone loss. In these cases treatment should focus on treating the fracture without interfering with the prosthesis.

In Type 2, or unhappy hips the fixation is compromised and the implant has to be revised as part of the treatment of the fracture.

Vancouver classification

The Vancouver Classification can be used similarly, but is far more complex. Types A, B1 and C can be managed in the same way as the type 1(happy hips), whereas types B2 and B3 can be thought of as type 2 (unhappy) hips, which require revision (Table 2).

考文垂分类（Ninan等改进）

Ninan等发明了用于PPF的考文垂分类，我们发现该分类很广泛，容易应用，也对那些困难和有挑战性问题的治疗选择有帮助。他们将假体周围骨折分为两类，1型的髋包括：“幸福的髋”，伤前没有问题，和那些X线片显示假体干总体固定良好没有松动的表现，或骨丢失。在这些案例的治疗中，应该集中于治疗骨折，不干扰假体。

在2型，或称之不“令人烦恼的髋”，假体固定受到危害，作为治疗骨折的一部分，假体必须进行翻修。

温哥华分类

温哥华分类使用简单，但是远为复杂。A型，B1和C型能使用相同的路径治疗，如同考文垂分类1型，而B2型和B3型能看成为考文垂分类2型，需要进行翻修。（表2）

表2

Vancouver classification

【专题文献】之人工髋关节置换——下肢假体周围骨折的处理

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Clinical assessment [/img]

Revision arthroplasty and the management of periprosthetic fractures is a sub-specialty in its own right. It is important that the management of these patients is at least discussed with and ideally managed by surgeons who have experience in the field.

Assessment of a periprosthetic fracture should be standardised. The patient should be investigated biochemically and haematologically to assess their fitness for surgery.

Radiologically, it is of paramount importance to obtain good quality radiographs which should be assessed carefully, comparing them with previous X-Rays. CT scanning may be useful, provided there is adequate suppression of artefact from the implant.

临床评估

关节翻修术和假体周围骨折的处理，都有各自的亚专业。处理这些病人时，由那些在此领域有经验的外科医生处理或至少和他们讨论，这是

【专题文献】之人工髋关节置换——下肢假体周围骨折的处理

重要的。

假体周围骨折的评估应该是标准化的。应该调查病人的生化和血液学检查，以评估他们适合手术。 在放射学检查方面，获得高质量的放射学图片是极重要的，对放射学资料应仔细评估，同之前的资料进行比较。CT扫描可能很有用，假如有足够的内植物伪影抵制。

Management

If the patient is unfit for surgical treatment, closed reduction can be attempted; but the associated prolonged bed rest can lead to serious complications. Malunion is a major concern in this group as it can be detrimental to function, and can make future revision, if that becomes possible, extremely challenging.

The surgical management of periprosthetic fractures depends on the site of the fracture, the bone quality and the stability of the components. When the stem is stable, fixation of the fracture should be performed, either open or closed. Special consideration should be given to transverse fractures at the tip of the stem. These are very difficult to treat conventionally and many surgeons advocate stem revision despite the prosthesis itself being stable.

处理

如果病人不适合手术治疗，应尝试闭合复位。但是与之相同的延长的卧床休息能导致严重的并发症。在此种方式下，畸形愈合是个主要问题，它能影响功能，并在未来可能可以进行的翻修时带来极度挑战。

外科处理假体周围骨折依赖于骨折部位、骨质量和假体稳定性。当假体干是稳定的，应该固定骨折，不管是开放或闭合方式。应对假体尾部的横形骨折给予特别注意，按照常规治疗此种骨折非常困难，尽管假体本身是稳定的，但很多外科医生倡导假体干翻修。

Historically Ogden in 1972 used a long plate designed to accommodate pre-existing intramedullary devices. It had slots to accommodate wires and bands. However, biomechanical analysis showed that these resulted in high tensile stress at the fracture site and stress shielding at the proximal lateral cortex, leading to fractures below the plate and component loosening. The Partridge system, introduced in 1982, consisted of a nylon plate and straps which were introduced around the fracture. Over time it proved to be unsuccessful, with poor results, especially in more distal fractures, largely due to band loosening. Another popular device was the Mennen Plate, a paraskeletal clamp-on plate device, but reports of its use were controversial. It gave semi-rigid stability and was first introduced for non weight-bearing bones, but Lam et al. advocated its suitability and use for femoral periprosthetic fractures. 14 The general consensus is that they give sub-optimal results were technically difficult to apply, and the surgical approach and exposure were not soft tissue friendly.

历史上，Ogden在1972年使用一块具有适应之前存在的髓内装置的设计的长钢板。它具有沟槽可以应用钢丝或捆绑带。然而，生物力学分析特别是更远端骨折，很大程度上归咎于捆绑带松动。另一个流行的器械是Mennen钢板，一种环报器钳夹钢板，但使其此种钢板的报道结果手术入路和暴露对软组织损伤较大，结果并不是很理想。 显示这导致骨折部位高度应力集中和近端外侧皮质的应力遮挡，导致钢板下方骨折和假体松动。久而久之，己证明此方法不成功，结果较差，是有争议。它有半坚硬稳定性，最初用于非负重骨折，但Lam等倡导此器械适用并使用于假体周围骨折。意见一致的是，此器械技术较困难，

Current concepts for the treatment of any fracture should follow AO principles. If the prosthesis is satisfactory both clinically and radiologically the focus should be on treating the fracture on its own merits. Thus if the fracture is distal to the tip of the femoral stem, the use of conventional DCP, DCS or LCP plates should be considered (Figure 1). The LCP plate is a newer development in plate osteosynthesis which has revolutionised the principles of internal fixation, providing better purchase in low quality bones, and gives excellent angular stability. Chakravarthy et al. confirmed this.15 The angular stability provided by the locking screws abolishes the need to compress the plate on to the bone, thus avoiding compression and strangulation of the periosteal blood supply.

治疗任何骨折的当前理念应该遵从AO原则。如果假体在临床和放射学方面都满意，则应关注于治疗骨折本身。因此如果骨折在股骨假体干尾部的远端，应当考虑使用传统DCP，DCS或LCP钢板（图1）。在钢板接骨术中，LCP钢板是一种较新的进展，它具有***性的内固定原则，对于较低的骨质量提供了更好的稳定性，并有优秀的角度稳定性。Chakravarthy等证实了这种优点。由锁定螺钉带来的角度稳定性，不需要钢板与骨的摩擦，因此避免了骨膜血供的压迫。

图1

【专题文献】之人工髋关节置换——下肢假体周围骨折的处理

A further development of locking plate osteosynthesis is the concept of Less Invasive Stabilization System (LISS system). This is a pre-shaped plate applied to the extra-medullary surface using locking screws. It combines a locking device conferring good angular stability with a minimally invasive approach to the fracture. The plate can be inserted antegrade or retrograde (Figure 2). This minimal approach results in less periosteal stripping and less disruption to the soft tissues, leading to more favourable biology for bone healing and union. Kobbe et al. reported good mid-term functional results of the use of the LISS system in the treatment of periprosthetic fracture.3 The LISS is most commonly used for more distal diaphyseal fractures and it widely used for supracondylar fractures above a knee arthroplasty as will be discussed later.

关于锁定钢板骨接合术的更进一步的进展是LISS系统（微创钢板稳定系统）。这是一种术前依据髓外骨表面塑形的钢板，使用锁定螺钉。对于骨折它结合了锁定装置的角度固定稳定性和最小的创伤入路（图2

）。这个最小入路导致更小的骨膜剥离和对软组织的更小干扰，对于骨折愈合有更好的生物学优势。Kobbe等报道使用LISS系统治疗假体周围骨折有好的中期功能结果。LISS系统对于更远端骨干骨折是最常用的方法，它广泛用于随后要讨论的膝关节置换术后的股骨髁上骨折。

图2

Combining screw fixation with cerclage wires with a locking system remains controversial. The combination is said to give better fixation of the plate and hence give a more stable construct, but critics suggest that the good hold provided by the locking system renders the use of cerclage wires unnecessary and they also regard them as dangerous as they can act as stress risers.

For conventional plate fixation onto bone the consensus is that screws, cerclage wires or bands have proven to be inefficient when used on their own. A combination has been shown to give good results. Tsiridis et al. showed good results using the Dall-Miles plate, essentially a

【专题文献】之人工髋关节置换——下肢假体周围骨折的处理

development of the Ogden plate, which uses a combination of cable and screw fixation proximally and conventional screw fixation distally.

螺钉固定联合环扎术并联合锁定系统仍然是争议的。联合使用可以有更好的钢板固定效果，因此有更稳定的结构，但是反对者声称由锁定装置带来的好的把持力，使环扎术的使用不是那么必须，且反对者认为他们是危险的，因为可以导致应力升高。

通常的，钢板固定到骨上，意见一致的是螺钉，环扎术或捆绑带在独立应用时被证明是无效的。联合应用显示出好结果。Tsiridis等显示在使用Dall-Miles钢板，本质上是Ogden钢板的进化物，并且联合使用环扎带和螺钉固定近端，传统螺钉固定远端，有一个好结果。

Special attention should be given to the proximal screw fixation. In this case the use of uni-cortical screws is recommended around the stem of the implant and bi-cortical screws below this level. The more proximal the periprosthetic fracture the more challenging the fixation is. The prosthesis and the cement mantle restrict the options for screw and plate placement and insertion of the screws can fracture the cement or act as stress risers, altering the biomechanical properties of the cement and leading to instability and interference with the prosthesis/bone interface with consequent loosening and long term osteolysis.

应特别注意近端螺钉固定，在此案例下，使用单皮质螺钉推荐用于假体干部，而双皮质螺钉用于假体之下。假体周围骨折更靠近端，内固定越有挑战性。假体和骨水泥封套限制了螺钉选择和钢板位置，插入螺钉能导致骨水泥骨折或使应力升高，改变了骨水泥的生物力学属性，导致假体骨界面的不稳定和干扰，随后出现松动和长期的骨溶解。

In type 2, the unhappy fractures, where the prosthesis is affected or there is evidence of loosening, revision of the prosthesis should be undertaken. When revising a femoral stem in the presence of a periprosthetic fracture, most authors advocate the use of long stems. A long stem can give good results when bone loss is proximal to the isthmus. Larson at al state that cortical perforations and femoral fractures should be bypassed by at least 2 femoral diameters.16 Both cemented and uncemented implants can be used (Figures 3 and 4). The latter depend on good fixation in the femoral diaphysis for initial stability.17 A short stem can be used but it is generally accepted that the fracture should be bypassed distally by at least 5e10 cm. Overall, uncemented porous implants have given the best results.18

在2型，令人烦恼的骨折，假体受影响或有松动的证据，应该进行假体的翻修。当在假体周围骨折的情况下对股骨假体进行翻修，很多作者倡导使用长假体。当骨丢失位于近端到峡部这一区域，一个长的假体干能带来好结果。Larson等表明，假体长度应该通过皮质穿孔和股骨骨折处至少两个股骨直径。骨水泥型假体和非骨水泥型假体都可以使用（图3和图4）。后者依赖于股骨干部良好的固定，以得到初始稳定性。短的假体干可以使用，但是它通常只在假体可以超过骨折端5

－10cm时才可接受。总体而言，非骨水泥多孔假体有最好的效果。

图3

图4

【专题文献】之人工髋关节置换——下肢假体周围骨折的处理

Revision of a prosthesis is challenging and more so in the presence of a periprosthetic fracture. The removal of the old prosthesis and cement requires great care as it can lead to further bone loss, development of a new fracture or extension of the existing one. The surgeon is usually left with significant bone loss and poor remaining bone stock. There are various techniques to overcome these problems, such as the use of cortical onlay grafts. These are usually hemi-cylindrical diaphyseal or cortical fibular allografts, which are fixed to the host bone by circumferential wires. The aim is to provide structural support to the femur by replacing uncontained non-circumferential femoral defects, reducing stress risers and speeding up the healing process.

假体的翻修是挑战性的，特别是在假体周围骨折的情况下。取出旧的假体和骨水泥，需要极大的小心仔细，因为这能导致进一步骨丢失，进展成一个新的骨折或使原先骨折的范围扩大。外科医生通常会留下显著的骨丢失和较差残余骨量。有不同的技术来应付这些问题，如使用外置皮质骨移植。通常使用半环形骨干或腓骨干皮质骨同种异体骨移植，可以使用环形钢丝将此固定到宿主骨。目的是，通过置换非包容的非环形的股骨缺损，减少应力升高和加速愈合进程，提供股骨以结构支撑。

Another technique is impaction grafting, which is usually reserved for severe osteolysis. Firstly, the proximal femur is re-constituted forming a cortical scaffold or containment created using wires, plates or meshes or a combination. Then bone graft is impacted into this tube. Once completed, the reconstructed bony tube can accommodate the femoral component. This technique can also be applied to acetabular defects when compressed graft is used to fill the defect followed by insertion of either a cemented or cementless acetabular component.19

另一种技术是打压植骨，这通常应用于严重骨溶解。首先，股骨近端重新组合后形成皮质支架，或使用钢丝，钢板或钛网或联合使用而得到的包容。然后移植骨被打压进该管道。一旦完成，重建的骨管能适应于股骨假体。该技术也能用于髋臼缺损，使用打压的移植物去填充插入骨水泥型或非骨水泥型假体后形成的缺损。

If a patient is not fit for such a major procedure, there are a few more options available. If the patient is of average functional demand, or if definitive surgery may be possible in the future, in a happy hip external fixation can be considered. If the patient has low functional demand and a loose prosthesis, then a Girdlestone procedure can be considered.

Finally, if the defect is very extensive, using a mega-prosthesis, such as are used after tumour resection, can be considered. The femur is osteotomised just below the level of abnormal bone stock and the prosthesis is fixed to the distal diaphysis. The abductor mechanism is then attached to the mega-prosthesis. Satisfactory results with an average Harris hip score of 71 have been reported by Klein et al. 20

In PPFs around the hip most attention is focussed on the femoral component as periprosthetic fractures around the acetabulum are extremely rare, but they are potentially life threatening. Acetabular fractures most frequently occur intraoperatively, but they are also associated with loosening or severe osteolysis around the acetabular component. Obviously loose sockets should be revised.

如果病人不适合这样的大型操作，那么可得的选择很少。如果病人的功能要求是平均水平，或如果在未来最终手术可能会施行，对于一个稳

【专题文献】之人工髋关节置换——下肢假体周围骨折的处理

定的假体周围骨折，应该考虑外固定。如果病人或能要求较低且假体松动，这时可以考虑Girdlestone手术。 最后，如果缺损非常广泛，应当考虑使用一个大型假体，如在肿瘤切除后使用的那种。股骨于不正常的骨量之下切除，假体固定到远端骨干。外展机制附着于大型假体上。Klein等报道了平均Harris髋评分71分的满意结果。

在髋周的假体周围骨折中，更多的注意力集中于股骨假体，因为髋臼周围的假体周围骨折非常少，但他们可能危急生命。髋臼骨折更常见于术中，但同时，和髋臼假体周围的松动和严重骨溶解有关。明显松动的髋臼窝应当翻修。

Classification of periprosthetic fractures around the knee

Various classifications have been proposed for periprosthetic fractures around the knee. Backstein21 et al. described a system based on the position of the fracture, the bone stock and if the prosthesis was loose (Table 3).

The Rorabeck-Lewis classification is a good guide for management, again based on the condition of the prosthesis22 (Table 4).

膝关节周围PPF的分类

有不同的分类系统用于膝周围假体周围骨折的分类。Backstien等描述了基于骨折位置、骨量和假体是否松动的分类。（表3）

Rorabeck-Lewis分类对于治疗是较好的指导，另一方面基于假体状况（表4）。

表3

表4

Management

If, which is quite rare, the fracture is undisplaced and the prosthesis is stable, non-surgical treatment is appropriate using a brace to restrict joint movement and protected weight-bearing. In most cases surgical treatment is necessary. Fractures more than 15 cm away from the femoral implant should not be considered as periprosthetic and should be managed conventionally. The commonest and most widely

【专题文献】之人工髋关节置换——下肢假体周围骨折的处理

advocated method to manage them is by using a retrograde intramedullary nail. The two pre-requisites are a large enough distal fragment to allow fixation of the distal locking screws, and a femoral component that allows access to the medullary canal. Hence, closed box devices are absolute contraindications.

If the fracture is too distal, or there is a closed box implant, locking plates are advocated and have been shown to do well (Figure 5).

处理

如果骨折没有移位且假体是稳定的（这是极少见的），非手术治疗是适当的，使用支具限制关节活动，保护负重。在更多的病例中，必须手术治疗。骨折超过股骨假体15cm应该不考虑为假体周围骨折，应使用传统办法处理。更常见和更广泛的推介方案是处理如此骨折使用倒打髓内钉。两要素是一个足够大的远端骨块以允许远端锁定钉的固定，和一个允许髓内钉通路的股骨假体。因此，假体底部是封闭的，是绝对禁忌症。

如果骨折太近远端，或有一个闭合的假体底部，推荐使用锁定钢板，并且显示出易于处理。（图

5）

图5

Patellar fractures are the second commonest periprosthetic fracture of the knee, with a reported incidence of patello-femoral complications (fracture, loosening, radiolucency) from 0.15%e 12%. Most occur with no evidence of injury within the first two years after surgery.23 Specific risk factors that apply to patellar fracture/component loosening include excessive bone resection or lateral release during the index procedure with resulting maltracking. Patellar resurfacing during the index procedure has a clear correlation.

Management of patellar periprosthetic fractures is determinedby fracture displacement, the degree of component loosening and whether the extensor mechanism is intact. Type III fractures are the commonest according to Ortiguera and Berry.24Management varies according to the type, but the majority (70%) are managed nonoperatively. Other options include revision arthroplasty (if the implant is loose), internal fixation, or patellectomy (partial or total). Internal fixation is associated with poor union rates, increased infection and a post-operative extension lag of 10 degrees.25,26

髌骨骨折是第二常见的膝部假体周围骨折，报道髌股并发症（骨折，松动，可透射线）的发生率自0.15%－12%。大多数在没有外伤的情况在初次手术操作中，髌骨重新表面化有一个明显的相关性。

髌骨假体周围骨折的处理，由骨折移位、假体松动的程度和是否伸肌机制完整所决定。根据Ortiguera和Berry，III型骨折是最常见的。根据骨折类型有不同的处理方式，但是大多数（70%）是非手术治疗。其他选择包括假体翻修（如果内植物松动），内固定和髌骨切除（部分或全部）。内固定和较差的愈合率，增高的感染和术后10度伸展延迟有关。 下发生于最初的术后两年。与髌骨骨折/假体松动有关的特殊风险因素，包括在最初的手术操作中过度的骨切除或外侧松解，导致髌股轨迹病。

【专题文献】之人工髋关节置换——下肢假体周围骨折的处理

Tibial periprosthetic fractures are far less common. If the component is stable, the fracture can be treated using a buttress plate; peri-articular plates have also been advocated for complex metaphyseal fractures in the presence of a stable component. These plates are anatomically pre-contoured, so require minimal intra-operative bending. The use of locking screws may give a more stable fixation.

If the prosthesis is loose and there is radiological evidence of osteolysis is a difficult problem. Removal of the prosthesis and cement and poor bone stock, can result in significant bony deficiency. This can be made up relatively easily by using a combination of thicker polyethylene implants and metal augments. Small defects can also be filled using cement (poly-methylmethacrylate) but as this has no biological properties, it may prevent fracture healing. In cases of severe bone loss, a custom made mega-prosthesis may have to be considered as this allows reconstruction of fractures with significant bone defects. The disadvantages however are the cost and the lack of intra-operative flexibility.

胫骨的假体周围骨折不常见。如果假体是稳定的，骨折可以使用一块碟形钢板治疗。在假体稳定时，关节周围钢板也被推荐用于复杂的干骺端骨折。这些钢板是术前解剖型塑形的，这样术中可以最小的弯曲。使用锁定螺钉可能得到更稳定的内固定。

如果假体松动，有放射学表现的骨溶解，这将是一个困难的问题。取出假体和骨水泥，和较差的骨量，能导致显著的骨缺损。这可以相对容易的通过联合使用加厚的聚乙烯假体和金属加强而解决。小的缺损可以使用骨水泥填充，但是骨水泥没有生物学属性，因此它可能影响骨折愈合。在严重骨丢失的病例，可能必须考虑定制的大型假体，该假体可以在显著骨缺损的情况下完成骨折重建。然而，该方法的缺点是费用较高，且缺乏术中灵活性。

In all cases where there is loss of bone with comminution and poor bone stock, bone grafting is extremely helpful. Autologous graft is best due to its osteoconductive and osteoinductive properties, but in the majority of patients sufficient volume is not available, limiting its usefulness. Another option is the use of a structural allograft/implant composite; Engh et al. reported good results using structural allograft in cases of severe tibial bone loss.27

Problems have also been reported with periprosthetic fractures after unicompartmental knee replacement, presenting with significant loosening of the components and tibial bone loss. They should be managed by conversion to a total knee replacement with allograft to cover the tibial bone defect which has been shown to have good results.28

所需足够数目的骨块是得不到的，因此限制了它的使用。另一个选择是使用结构性同种异体骨/内植物复合物。Engh等报道对于严重胫骨骨丢失的病例，使用结构性同种异体骨移植，有好的效果。

膝关节单髁置换术后假体周围骨折的问题也有报道，表现出显著的假体松动和胫骨骨丢失。通过转换到全膝置换术，并使用同种异体骨移植以覆盖胫骨缺损，通过这种方式处理，己经显示出有较好结果。 在所有的病例中，当骨丢失伴有较差的骨量，骨移植格化有用。自体骨移植是最好的，因为它的骨传导和骨诱导属性，但是对于大多数病例，

REFERENCES

略（请见原文）

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