Treatment of extensive acetabular bone deficiency in revision hip arthroplasty]

Basing on a retrospective analysis of 87 cases the author presents the results of treatment of massive acetabular bone deficiency in revision hip arthroplasty. Augmentation of bony deficits with corticocancellous bone grafts and implantation of the acetabular cup in a physiological position will increase the chances of achieving a good result. Graft fixation with screws and other such devices (anti-protrusion cages) made of a different material than the prosthesis leads to lytic processes and mechanical failure of the construct. This causes early cup loosening. Chronic steroid use, intake of nitric compounds, and radiotherapy of the pelvis are all factors that influence osteolytic processes of the grafts.     

全髋翻修术中髋臼骨缺损翻修重建

全髋关节置换术后髋臼失败的翻修重.是骨科医生面临的巨大的技术挑战.翻修时面对广泛的髋臼骨缺损,可能需要采用几种不同技术,尽可能使髋臼侧恢复到初次全髋关节置换术时的骨量.获得翻修假体初始稳定是翻修手术成功的关键.该文就全髋翻修术中髋臼骨缺损的分类、术前计划和翻修重建策略作一综述.     

颗粒骨打压植骨结合多孔非骨水泥臼杯在AAOSⅢ型髋臼大面积骨缺损翻修中的应用

背景：颗粒骨打压植骨是修复髋臼骨缺损的重要方法,对大面积髋臼骨缺损采用打压植骨结合非骨水泥臼杯重建仍然存在争议。目的：探讨同种异体颗粒骨打压植骨结合多孔非骨水泥臼杯髋臼重建术修复AAOSⅢ型髋臼大面积骨缺损的方法及近期疗效。方法：随访2005年6月至2010年4月收治的28例（28髋）AA0SⅢ型髋臼大面积骨缺损患者。男18例,女10例,年龄34-74岁,平均53．8岁。髋关节置换术后感染醐翻修9例,骨溶解及髋臼假体松动翻修19例。本组AAOSⅢ型髋臼骨缺损面积大,术中见髋臼骨缺损超过髋臼关节面的50％。全部采用同种异体颗粒骨打压植骨结合多孔非骨水泥臼杯髋臼重建术。术后定期随访,观察臼杯有无松动、植入骨与宿主骨整合情况,髋关节功能评分采用Harris评分。结果：28例均获得随访,术后随访时间为13-70个月,平均43个月。Harris评分由术前32-48分,平均41分,提高至末次随访时86-95分,平均90分。28例髋臼假体均固定牢固无松动征象,植入骨逐渐与宿主骨整合,无感染及坐骨神经损伤。结论：在获得臼杯初始稳定固定的情况下,大面积颗粒骨打压植骨（臼杯与宿主骨接触面积〈50％）结合多孔非骨水泥臼杯髋臼重建术修复AAOSⅢ型髋臼大面积骨缺损近期疗效较好,远期疗效尚待进一步随访。     

Cancellous impaction bone grafting of acetabular defects in complex primary and revision total hip arthroplasty

The reconstruction of major acetabular bone defects during revision, conversion, and primary total hip arthroplasties (THAs) is challenging. We reviewed a consecutive series of 168 THAs (108 revisions, 8 conversions, and 52 primary THAs) performed by 1 surgeon (S.B.G.) between 1997 and 2008 using impaction bone grafting for acetabular reconstruction. Autograft, cancellous allograft croutons, and demineralized bone matrix were used to fill bone defects as needed. The acetabular bone deficiency was classified according to the American Academy of Orthopaedic Surgeons: type I, segmental deficiency with significant rim defect; type II, cavitary defects medially or posteriorly; type III, combined cavitary and segmental deficiency; type IV, pelvic discontinuity; and type V, arthrodesis. According to this method, 56 hips had type I, 31 hips had type II, 48 hips had type III, and 27 hips had type IV deficiencies. Of the 168 patients, 19 subsequently died of causes unrelated to the THA, and 11 were lost to follow-up. All patients had at least 2 years of follow-up. Average Harris Hip Score improved from 45.5±17.9 preoperatively to 81.1±16.5 postoperatively (P<.05) for revision THAs, from 40.0±11.3 preoperatively to 85.0±12.8 postoperatively (P<.05) for conversion THAs, and from 42.3±14.9 preoperatively to 85.0±12.0 postoperatively (P<.05) for primary THAs. All impaction grafted bone (allograft, autograft, or a combination) incorporated radiographically, thus restoring bone stock. Complications included 1 early infection, which was managed successfully with debridement and liner exchange, and 2 late infections that were managed successfully with staged revision. Two revisions required subsequent re-revision for late loosening. Two hip dislocations occurred, 1 of which required surgical treatment to place a constrained liner.     

全髋关节翻修术中髋臼骨缺损的处理方法

目的探讨全髋关节翻修术中对于髋臼骨缺损重建的方法及其术后疗效。方法回顾性分析自2007-03—2011-12的75例（76髋）全髋关节翻修术,髋臼骨缺损根据Paprosky分型：Ⅰ型9髋,ⅡA型21髋,ⅡB型18髋,ⅡC型11髋,ⅢA型10髋,ⅢB型7髋。髋臼骨缺损采用不同方式修复,术后定期随访。采用髋关节功能Harris评分评估髋关节功能,根据X线片判断假体是否松动、植骨是否融合。结果 75例（76髋）均获得平均36（16~73）个月随访。术后12个月不同类型骨缺损患者髋关节功能Harris评分较术前明显提高,差异有统计学意义（P〈0.05）。术后症状和关节功能明显改善,未出现髋臼骨折、感染、下肢深静脉血栓形成、坐骨神经损伤等严重并发症。X线片可见移植骨与宿主骨质交界处有连续性骨小梁通过,假体未见松动迹象。结论髋臼假体无菌性松动及骨溶解是需要进行全髋关节翻修的主要原因,而髋臼骨缺损Paprosky分型法对髋臼翻修重建方法有指导意义,正确选择假体类型及合理选择植骨方式是全髋关节翻修术后取得满意疗效的保证。     

Management of acetabular bone loss in revision total hip arthroplasty

Most acetabular revisions can be managed with a hemispherical component with screw fixation. Areas of segmental bone loss that preclude acetabular component stability may be managed with structural allograft or second-generation porous metal augments. Acetabular cages have a limited application but can be a useful tool in the management of massive bone loss and pelvic discontinuity.     

人工全髋关节翻修术中髋臼骨缺损的分类和重建

人工全髋关节置换术作为一项逐渐成熟的技术,已经被越来越多的骨科医师所熟知和开展,但随之也使髋关节翻修术患者增多。翻修的原因主要包括假体的无菌性松动、不稳、周围骨折、内衬磨损等,而髋臼骨缺损和髋臼假体的选择一直困扰着广大医师。本文总结了人工全髋关节翻修术中髋臼骨缺损的分类和重建,比较各种分类法的优缺点,在此基础上有多种植骨方式及髋臼假体的选择来重建髋臼,阐述了植骨的材料来源、植骨方式、复杂髋臼骨缺损的重建以及假体固定方式的选择,为临床医生处理各种髋臼骨缺损提供依据,以期更精准地指导临床个体化治疗。     

Bank bone grafts in revision hip arthroplasty for acetabular protrusion

In 23 revision hip arthroplasties in which acetabular protrusion was encountered, homologous bone grafting was used to reconstruct or reinforce the medial wall of the acetabulum. Loosening of the acetabular component was the cause of the protrusion in all the cases. Postoperative follow-up showed a solid bone socket around the acetabular cup in all the cases and no signs of loosening at 3-years' follow-up.     

Bank bone grafts in revision hip arthroplasty for acetabular protrusion

In 23 revision hip arthroplasties in which acetabular protrusion was encountered, homologous bone grafting was used to reconstruct or reinforce the medial wall of the acetabulum. Loosening of the acetabular component was the cause of the protrusion in all the cases. Postoperative follow-up showed a solid bone socket around the acetabular cup in all the cases and no signs of loosening at 3-years' follow-up.     

嵌压植骨技术在人工全髋关节翻修术中的应用

目的 探讨使用嵌压植骨技术进行全髋关节翻修术的临床效果。方法1998年12月至2003年9月,采用嵌压植骨技术对48例患者72侧髋关节进行了翻修,平均随访时间25个月,采用Harris评分及X线片观察进行临床疗效评定,并统计并发症的发生率。结果Harris评分从术前平均44．6分提高到术后87．4分,术后优良率为达90．3％;无假体松动及下沉;股骨骨折发生率为4．2％;关节脱位率为1．4％,感染率为1．4％。结论嵌压植骨技术是一种有效重建髋关节置换术后松动所致严重骨缺损的方法。采用冻干异体骨植骨及解剖柄股骨假体同样可以获得满意的临床效果。     

Threaded acetabular components for primary and revision total hip arthroplasty

A clinical and radiographic review of 48 total hip arthroplasty patients with threaded acetabular components was undertaken at 24-44 months of follow-up study. Twenty-five patients had primary hip arthroplasties and 23 had revision procedures. Clinical scores revealed good to excellent results in 60% of primary and 30% of revision procedures. Radiographic analysis revealed stable acetabular components in 88% of primary and 61% of revision procedures. Potentially loose acetabular components were noted in 8% of primary and 4.3% of revision procedures and loose acetabular components in 4% of primary and 34.7% of revision procedures. The rate of acetabular component loosening was considered unacceptably high in revision cases and an area of concern in primary cases. Discretionary use of these components is advised.     

骨移植在髋关节翻修术修复股骨侧缺损中的应用

目的探讨采用颗粒骨及结构骨植骨技术进行人工髋关节股骨侧假体翻修术的临床效果。方法2001年6月至2005年10月，采用颗粒骨或／和结构骨植骨技术对16例人工髋关节股骨侧假体进行了翻修，平均随访时间39个月，采用Harris评分及X线片观察进行临床疗效评定。结果Harris评分从术前平均41．7分提高到术后82．6分，术后优良率为达87．5％；9例患者无假体松动及下沉；余7例出现不同程度的股骨假体下沉，下沉的高度低于0．5～1cm；所有患者未出现假体松动的症状，无需再次翻修术。结论进行有效骨缺损修复，成功地重建股骨近端的骨结构是人工髋关节股骨侧骨假体翻修的关键。     

Reliability of acetabular bone defect classification systems in revision total hip arthroplasty

Three classifications for assessment of acetabular bone loss were evaluated for their reliability. The 3 systems assessed were the system described by Gross, the system described by Paprosky, and the classification of the American Academy of Orthopaedic Surgeons. In this study, we assessed their reliability based on the preoperative radiographs alone. Intraobserver agreement was measured by evaluating the classifications by the 3 innovators, 3 reconstructive orthopaedic surgeons, and 3 residents. Interobserver agreement was assessed among the reconstructive surgeons and the residents. The unweighted kappa statistic was used to establish levels of agreement. The innovators had better intraobserver agreement than the other 2 groups. Their agreement was only in the moderate range, however. For the noninnovators, intraobserver and interobserver agreement generally was poor for all 3 classifications assessed. Our results indicate that these classifications do not provide statistically reliable information for preoperative assessment of acetabular bone stock loss.     

Ganz reinforcement ring for reconstruction of acetabular defects in revision total hip arthroplasty

BACKGROUND: In revision total hip arthroplasty, bone loss due to loosening and migration of the acetabular component makes fixation of a new implant difficult. The purpose of this study was to evaluate the clinical and radiographic outcomes of the use of the Ganz reinforcement ring with nonstructural allograft in the reconstruction of acetabular defects. METHODS: Sixty-one acetabular revisions performed with use of the Ganz reinforcement ring and nonstructural allograft, between 1989 and 1992, in fifty-seven patients with aseptic loosening met our selection criteria. Eleven hips in eleven patients were lost to follow-up, leaving fifty hips available for evaluation five years or more following surgery. According to the American Academy of Orthopaedic Surgeons classification, twenty-four acetabular defects were Type II, twenty-four were Type III, and two were Type IV. Clinical and radiographic evaluations were carried out at a mean of six and nine years after surgery. Twelve more patients were lost to follow-up before the most recent evaluation. RESULTS: The mean Merle d'Aubigné composite score increased significantly compared with the preoperative score (p < 0.001). There were seven failures: six cases of aseptic loosening and one case of septic arthritis. Graft incorporation and bone remodeling occurred in all hips but three in which the ring fixation had been inadequate at the time of surgery. The Kaplan-Meier survivorship rate, with use of revision or loosening of the component as the criterion of failure, was 81% at ten years. Inadequate fixation of the implant at the time of surgery was the only multivariate predictor of failure (p = 0.003). CONCLUSIONS: Patients treated with acetabular revision with a Ganz reinforcement ring had reconstitution of periacetabular bone stock as well as good clinical and radiographic results, provided that the ring had been fixed adequately at the time of surgery. This procedure may not be the preferred approach for reconstructing segmental defects of the medial wall or pelvic discontinuity.     

Structural acetabular allograft in revision total hip arthroplasty

Structural allografts are a surgical option only in cases of severe bone loss. Structural allografting techniques have been developed to fill large bony defects and can be used to provide structural support and reconstitute bone stock. Superior dome allografts are utilized when 50% or more of host bone is available for contact with the ingrowth cup. In revision surgery where the allograft supports more than 50% of the reconstruction, complications are more common. Although good results are reported, implant failure and graft resorption are more commonly seen. The addition of a reconstruction ring to the reconstruction unloads some of the stress applied to the allograft. In these cases, superior results have been reported.     

Cementless acetabular reconstruction in revision total hip arthroplasty

Reconstruction of the failed acetabular component in total hip arthroplasty (THA) can be challenging. Although there are multiple reconstructive options available, a cementless acetabular component inserted with screws has been shown to have good intermediate-term results and is the reconstructive method of choice for the majority of acetabular revisions. We reviewed the results of 138 consecutive acetabular revisions done with a hemispheric, cementless acetabular component that is sintered with Ti fiber metal mesh and was inserted with line-to-line reaming and multiple screws for fixation. At a mean of 15 years, 19 acetabular components had been revised (13.8%); seven were revised for recurrent instability, six were revised for deep periprosthetic infection, five well-fixed cups were removed at the time of femoral revision, and one cup was fixed by fibrous tissue only at the time of femoral revision and was removed. One acetabular component was radiographically loose. Survivorship of the component was 81% at 15 years when revision for any reason was considered as an end point and 96% when revision for loosening or radiographic evidence of loosening was considered as a second end point. Cementless acetabular revision provides durable results at 15 years with a low rate of failure for loosening.     

GIR classivication of acetabular and femoral bone loss in revision hip arthroplasty surgery

Acetabular and femoral bone loss, the common feature of prosthetic failure, represents the most serious problem during revision surgery. The study of bone loss extent starts with pre-operative X-ray analysis, but the definitive evaluation is performed intra-operatively. The Italian Society for Revision Arthroplasty (GIR) has proposed a classification that correlates the various grades of bone loss with surgical strategies for reconstruction. The GIR classification does not distinguish bone loss into types. Instead, it recognizes different grades and emphasizes the possible evolution not only in time, but even during the surgical procedure. In this classification, we recognize four different grades of acetabular and femoral bone loss; for each of them we suggest different surgical strategies and resources.     

Supportive strut grafts for diaphyseal bone defects in revision hip arthroplasty

Large femoral cortical strut allografts were used to provide structural support of the femur in 20 patients in whom uncemented, extensively porous-coated, press-fit revision femoral stems were applied. The mean followup was 4.7 years. Radiographic analysis of the patients who had revision surgery revealed that in all 20 patients, the cortical femoral strut allografts showed incorporation. Small areas of graft resorption were observed in only two patients. Seventeen of the uncemented femoral revision stems radiographically showed bone ingrowth. Three of the revision femoral stems were interpreted as being fixed only by fibrous ingrowth after early subsidence after surgery. There were no reoperations. Before surgery, all patients were unable to walk and had severe pain. At followup, all patients were ambulatory and had considerable improvement in pain relief and in their ability to walk. The mean Harris hip score after surgery was 75 (range, 57.5-92). Complications consisted of one peroneal nerve palsy, which resolved; one deep venous thrombosis; one gastrointestinal ulcer; and one case of pneumonia. Supportive cortical strut allografts represent an alternative to the use of circumferential bulk allografts and total femoral replacements in patients with large combined proximal and diaphyseal bone defects.