生物型和骨水泥型股骨假体全髋关节置换术治疗老年骨质疏松性股骨颈骨折的临床效果对比

目的：对比老年骨质疏松股骨颈骨折使用生物型股骨假体柄与骨水泥型股骨假体柄行全髋关节置换术治疗效果。方法对本组进行老年骨质疏松股骨颈骨折100例（100髋）进行的全髋关节置换术根据手术方式分为A组（股骨假体柄骨水泥型全髋关节置换术,60髋）, B组（股骨假体柄生物型全髋关节置换术,40髋）。对比两组髋关节功能、关节活动度、髋关节影像学特点及术后疼痛情况。结果老年骨质疏松股骨颈骨折行全髋关节置换术,采用生物型股骨假体柄与骨水泥型股骨假体柄的全髋关节置换术临床疗效对比差异显著（ P＜0.05）。结论对于老年骨质疏松股骨颈骨折行全髋关节置换术,应用骨水泥型者股骨假体柄术后近期疗效明显优于生物型,但它有诱发深静脉血栓栓塞和骨水泥危象的风险。     

全髋关节置换术髋臼假体周围骨折的临床特征及其影响因素分析

目的观察全髋关节置换术髋臼假体周围骨折的临床特征,分析初次全髋关节置换术髋臼假体周围骨折的影响因素。方法回顾性分析自2013-01—2018-06完成的584例初次或翻修全髋关节置换术,17例出现髋臼假体周围骨折,初次手术13例,翻修手术4例。比较初次全髋关节置换术假体周围骨折组与未骨折组在性别、年龄、体重指数、手术侧别、疾病类型、手术入路、骨质疏松状态、假体类型、假体覆盖比例及主刀医师手术量方面的差异。结果全髋关节翻修手术中髋臼假体周围骨折发生率高于初次全髋关节置换术,差异有统计学意义(P<0.05)。多因素Logistic回归分析结果显示疾病类型(髋关节发育不良、类风湿性关节炎)、合并骨质疏松、生物型假体、假体覆盖比例>80%、主刀医师手术量≤80台/年是初次全髋关节置换术髋臼假体周围骨折的危险因素。结论全髋关节翻修手术中髋臼假体周围骨折发生率高于初次手术。对于髋关节发育不良、类风湿性关节炎、合并骨质疏松患者,以及选用生物型假体、假体覆盖比例>80%、主刀医师经验不足时,初次全髋关节置换术中需要警惕髋臼假体周围骨折发生。     

偏瘫侧股骨颈骨折应用双动全髋关节假体的疗效分析

目的:探讨双动全髋关节假体在偏瘫侧股骨颈骨折的临床疗效。方法 :回顾性分析2014年3月至2016年12月使用双动全髋关节假体对偏瘫侧股骨颈骨折行初次髋关节置换术并有完整随访资料的18例患者,男5例,女13例;年龄65～70(66.50±1.38)岁;左侧12例,右侧6例;股骨颈骨折GardenⅢ型4例,Ⅳ型14例。偏瘫侧肢体肌力Ⅳ级。均采用髋关节后外侧入路,双动全髋关节假体。通过X线检查评价假体植入位置、假体脱位及假体松动。采用Harris髋关节评分和Merle D'aubigne髋关节评分进行髋关节功能评估。结果:手术时间70～90(81.56±7.48) min。出血量160～200(170.32±12.56) ml。术中均未输血,术后切口均Ⅰ期愈合。随访时间28～60(36.0±3.5)个月。Harris髋关节评分由术前的16.94±0.73提高到末次随访时的96.19±1.27(P0.05)。Merle D'Aubigne评分由术前的3.96±0.06提高到末次随访时的16.81±0.63(P0.05)。术中未发生骨折及神经、血管损伤。术后X线片显示假体位置良好。术后及随访期间无关节脱位、假体内脱位、假体松动、假体周围骨折、大腿前方疼痛、髂骨处自攻螺钉断裂及迟发感染等并发症发生。结论:双动全髋关节假体具有良好的初始稳定性及假体脱位率低的优点,在偏瘫侧股骨颈骨折的全髋关节置换术中临床应用疗效满意。     

锁定钢板治疗全髋关节置换术后Vancourer B1型假体周围骨折

目的探讨锁定钢板治疗全髋关节置换术后Vancourer B1型假体周围骨折的临床疗效。方法对8例全髋关节置换术后Vancourer B1型假体周围骨折给予切开复位锁定钢板内固定术。结果随访3个月~6年,术后复查X线片,骨折均骨性愈合,愈合时间3~6个月,患肢髋关节功能恢复良好,患肢功能恢复正常。结论应用锁定钢板治疗全髋关节置换术后Vancourer B1型假体周围骨折具有创伤小、手术时间短、术后恢复快等优点,值得临床应用。     

髋关节置换术中假体周围骨折12例报告

目的 分析髋关节置换术中并发假体周围骨折的原因及防治措施.方法 自1999年5月～2010年9月,笔者施行人工髋关节置换术385例,共12例发生术中假体周围骨折,其中全髋关节置换术7例,髋关节翻修术4例,股骨头置换1例.全部病例术中均同期内固定.结果 11例获得随访,平均随访时间17.3个月(9～28个月),骨折均骨性...     

全髋关节置换术后翻修的原因分析

目的分析全髋关节置换术后行翻修手术的具体原因,并与以往文献报道的结果进行比较。方法回顾性分析自2014-01—2019-06完成的93例全髋关节翻修术,翻修术前均为初次单侧全髋关节置换术。将患者分为早期组(假体使用时间5年)和晚期组(假体使用时间≥5年),统计行翻修手术的原因,并对数据进行描述性分析。结果 45例(48.4%)全髋关节翻修原因为假体无菌性松动,19例(20.4%)为假体周围感染,15例(16.1%)为假体周围骨折,8例(8.6%)为聚乙烯内衬磨损,4例(4.3%)为髋关节反复脱位,髋关节疼痛、骨水泥游离体各1例。93例假体使用时间为(7.72±6.39)年,早期组38例,假体使用时间为(1.50±1.50)年;晚期组55例,假体使用时间为(12.02±5.09)年。早期组中13例假体周围感染,10例假体无菌性松动,9例假体周围骨折,4例髋关节反复脱位,1例聚乙烯内衬磨损,1例骨水泥游离。晚期组中35例假体无菌性松动,7例聚乙烯内衬磨损,6例假体周围感染,6例假体周围骨折,1例髋关节疼痛。结论假体无菌性松动是全髋关节置换术后最常见的翻修原因,随后依次为假体周围感染、假体周围骨折、聚乙烯内衬磨损、髋关节脱位等,这与国内外许多学者的研究一致。     

髋关节置换术后股骨假体周围骨折的治疗

目的探讨人工髋关节置换术后股骨假体周围骨折的有效处理方法。方法对7例人工髋关节置换术后股骨假体周围骨折进行手术,包括人工全髋关节翻修术、人工全髋关节翻修术加锁定钢板固定术、环抱器固定术以及锁定钢板固定术等几种手术方法。结果 7例病例均得到随访,随访时间6个月~4年,骨折愈合时间为2~6个月,平均3.5个月。手术前髋关节H arris平均分值为84分,术后髋关节为78分,无骨折不愈合、松动、假体感染及深静脉栓塞形成。结论髋关节置换术后股骨假体周围骨折的处理,应根据骨折类型、骨骼的质量及患者的经济情况等选择不同的治疗方法。     

人工髋关节置换术中术后股骨假体周围骨折的治疗体会

目的探讨人工髋关节置换术中术后股骨假体周围骨折的处理方式及原则。方法笔者自2010-01—2014-09对8例人工髋关节置换术中术后股骨假体周围骨折采用锁定钢板固定术、人工半髋或全髋关节翻修术、人工髋关节翻修加锁定钢板固定术和环抱器固定术等治疗。结果术后随访7~24个月,平均19个月。骨折愈合时间为8~16个月,平均11个月。术前Harris评分平均85(83~89)分,术后平均81(80~85)分。髋关节功能良好,无切口感染、假体松动下沉、骨折不愈合等并发症发生。结论髋关节置换术中术后股骨假体周围骨折的处理原则是重建髋关节的稳定性,改善患者生活质量,充分考虑患者预期寿命、经济条件、假体类型、骨折类型及骨量情况选择相应的处理方式。     

髋关节置换术中及术后股骨干骨折使用捆绑带固定的临床研究

目的 探讨人工全髋关节置换术中及术后股骨干骨折使用捆绑带固定的治疗方法及临床疗效.方法 回顾性分析1999年8月至2007年9月由同一术者连续进行的人工全髋关节置换术(包括翻修手术)2186例,发生术中及术后股骨干骨折22例,其中术中骨折12例,术后外伤骨折10例.男性10例,女性12例,初次置换术9例,翻修术13例.Vancouver骨折分型为B1型骨折15例,B2型骨折7例,并且均为斜形骨折.处理方法为切开骨折复位,根据骨折长度和范围采用2～5根钛制捆绑带环形捆扎,其中13例选用2根,7例选用3根,1例选用4根,1例选用5根.同时根据术中原假体稳定性决定是否更换,其中15例B1型骨折和1例B2型骨折患者术中未予更换股骨柄假体,另外6例B2型骨折患者因股骨假体松动给予更换同类型的加长柄假体.结果 所有患者术后平均18周(12～ 20周)时X线片显示骨折愈合.术后随访4～11年(平均6.5年),髋关节Harris评分80～ 95分(平均90分),髋关节活动度105°～135°(平均120°).股骨假体固定良好,无下沉,无明显透亮线及松动迹象.结论 全髋关节置换术中及术后发生股骨干斜形骨折时可采用捆绑带固定,如果股骨柄假体稳定及分型为B1型骨折时不更换原假体,如果假体柄不稳定分型为B2型时直接更换同类型的加长柄假体,可获得骨折处的坚强固定和股骨柄假体良好的初始稳定性,中长期随访临床效果满意.     

全髋关节置换术治疗髋臼骨折继发创伤性髋关节炎和股骨头坏死中远期疗效观察

目的 :评价全髋关节置换术治疗髋臼骨折后继发创伤性髋关节炎或股骨头坏死的中远期疗效。方法 :2000年1月至2005年12月,对33例髋臼骨折继发创伤性髋关节炎和(或)股骨头坏死患者实施全髋关节置换术。其中男21例,女12例;年龄27~69岁,平均52岁。23例骨折曾行切开复位内固定术,前侧入路5例,后侧入路12例,混合入路6例;10例行保守治疗。髋关节置换术均采用后外侧入路,术前髋臼骨折均已愈合,术中完全去除内固定5例,去除部分内固定3例,植骨20例。6例术中使用骨水泥假体,27例使用生物型假体。观察术中情况和术后并发症,比较术前Harris髋关节评分和术后10年评分,以假体松动、骨溶解或翻修为终点的生存分析显示假体10年生存率。结果:所有患者获随访,术后10年死亡1例,随访时间平均12年(10~15年),术后10年时Harris髋关节评分较术前升高。1例假体早期无菌性松动行翻修术,2例骨溶解形成合并假体无菌性松动并行翻修术治疗,单纯骨溶解无假体松动1例,术后深静脉血栓4例,假体脱位2例,切口感染和假体周围感染各1例。假体10年生存率为84.8%(28/133)。结论:全髋关节置换术治疗髋臼骨折后继发创伤性髋关节炎或股骨头坏死能明显改善患者的髋关节的功能,并有较高的假体生存率,具有良好的中远期疗效,是一种有效的治疗手段。     

髋关节置换术中股骨假体周围骨折危险因素的分析

目的分析髋关节置换术中股骨假体周围骨折的发生情况和危险因素。方法选择本组自2002年1月至2008年12月所有行初次和翻修髋关节置换术患者共3021髋(初次置换术2718髋,翻修术294髋),分析术中股骨假体周围骨折的发生情况,并用Logistic回归分析骨折发生的相关因素,包括性别、年龄、术前诊断、假体类型、固定方式。用2检验进行初次置换和翻修术中发生骨折的差异性检验。结果总的术中股骨假体周围骨折发生率为5.7%(173/3021),其中初次置换发生率为4.0%(110/2718),翻修术发生率为21.4%(63/294)。初次置换应用骨水泥股骨假体术中骨折发生率为1.9%(8/429),非骨水泥股骨假体术中骨折发生率为4.5%(102/2289),初次置换术中骨折82.7%(91/110)发生于干骺端;翻修术应用骨水泥股骨假体术中骨折发生率为18.8%(21/112),非骨水泥股骨假体术中骨折发生率为23.1%(42/182),翻修术术中骨折62%(39/63)发生于骨干部。Logistic回归分析显示:初次髋关节置换术中骨折的危险因素包括性别、术前诊断、固定方式、假体类型;翻修术性别、年龄、假体固定方式不是引起术中骨折的危险因素。应用2检验,翻修术中股骨假体骨折的风险与初次置换相比差异有统计学意义(P0.000),OR值为6.5,95%CI(4.6,9.1)。结论初次髋关节置换术中股骨假体周围骨折的发生率为4.0%,主要发生于干骺端(83.6%),女性、髋关节发育不良、髋部骨折、高位脱位、非骨水泥固定是术中骨折的危险因素;髋关节翻修术中股骨假体周围骨折的发生率(21.4%),远高于初次髋关节置换术,主要发生于骨干部(61.9%),骨折的发生与否可能主要取决于翻修时的骨质情况,性别、年龄、假体固定方式并不是主要的影响因素。     

Epidemiology: hip and knee

This article reviews the epidemiologic features of periprosthetic fractures around total hip arthroplasty and total knee arthroplasty according to the site of fracture occurrence. The frequency and cause of intraoperative and postoperative periprosthetic fractures vary by anatomic site. For each anatomic site, unique risk factors, some demographic and some technical, appear to be related to risk of fracture. For several anatomic sites, excellent articles that collate large numbers of series are available to the reader to provide aggregate information concerning the epidemiology of these fractures.     

髋关节置换术后股骨假体周围骨折手术治疗的疗效分析

目的 :分析比较人工髋关节置换术(hip arthroplasty,HA)后股骨假体周围骨折(periprosthetic femur fracture,PFF)不同分型手术治疗的临床疗效。方法:回顾性分析自2010年9月至2016年9月因人工髋关节置换术后假体周围骨折入院的手术患者47例(共47髋),其中男13例,女34例;依据Vancouver分型,AG型2例,B1型17例,B2型19例,B3型7例,C型2例;年龄56～94(71.5±8.3)岁。入院后采用营养风险筛查(NRS2002)评估患者营养状况,18例(38%)患者存在营养不良风险(NRS3分),患者入院后依据不同分型予相应手术治疗,记录术中出血量,应用Harris评分评价患髋关节功能,入院及术后进行视觉模拟评分(visual analogue scale,VAS)评分。结果:47例患者均顺利完成手术,随访19～62(34±11)个月,术前及术后1年随访时的Harris评分分别为(41.8±12.1)分、(89.0±2.6)分,两组间比较差异有统计学意义(t=29.7,P0.01);术前及术后1年随访时的VAS评分分别为(8.0±0.6)分、(0.5±0.6)分,两组间比较差异有统计学意义(t=80.7,P0.01);B1型营养不良风险患者及无营养不良风险患者术中出血量分别为(730±68) ml、(688±127) ml,两者比较差异有统计学意义(t=4.6,P0.05); B2型营养不良风险患者及无营养不良风险患者术中出血量分别为(916±118) ml、(884±88) ml,两者比较差异有统计学意义(t=8.7,P0.05)。末次随访时所有患者骨折均愈合,下肢力线良好,随访期间未发生内固定松动、移位、断裂及假体松动、脱位等情况。结论:治疗髋关节假体周围骨折患者应依据患者的一般情况、影像学资料、术中校正分型等制定符合患者的个体化治疗方案,对于术前有营养不良风险的患者,在术前进行营养学的干预或能减少术中出血。     

Prevalence of Postoperative Periprosthetic Femur Fractures Between Two Different Femoral Component Designs Used in Direct Anterior Total Hip Arthroplasty

BackgroundPeriprosthetic femur fractures are a well-documented complication following direct anterior uncemented total hip arthroplasty. The purpose of this study is to compare the prevalence of postoperative periprosthetic femur fractures between 2 different femoral component designs used in direct anterior total hip arthroplasty.MethodsBeginning in February 2015, a single fellowship-trained adult reconstruction surgeon performed 361 consecutive direct anterior total hip replacements using a flat, single-taper, wedged femoral implant. In June 2016, that same surgeon, using the exact same surgical technique and postoperative weight-bearing protocol, began using a dual-taper, hydroxyapatite-coated implant for 789 consecutive hips. The patients were carefully monitored for 3 months after surgery to identify the frequency of periprosthetic femur fractures. A Fisher’s exact test was used to determine if the prevalence of periprosthetic femur fractures differed between the 2 implant designs.ResultsFive of 361 (1.4%) patients sustained proximal femur fractures at an average of 19.6 days postoperatively in the first group, all demonstrating a Vancouver type B2 periprosthetic fracture and requiring femoral revision. No patients (0/789, 0%) in the second cohort sustained a postoperative, periprosthetic fracture (P = .006).ConclusionIn this comparison of 2 consecutive cohorts, the dual-taper, hydroxyapatite-coated implant had a statistically significant lower postoperative periprosthetic fracture rate than a flat, single-taper, wedged design.     

Incidence,Classification, and Risk Factors for Intraoperative Periprosthetic Femoral Fractures in Patients Undergoing Total Hip Arthroplasty With a Single Stem: A Retrospective Study

BackgroundThe collum femoris preserving (CFP) stem was a specially designed femoral neck preserving component. The incidence, classification, and risk factors for intraoperative periprosthetic femoral fractures with this special stem remain unclear.MethodsThis was a retrospective study. We analyzed the clinical and radiological data of all patients who underwent primary hip arthroplasty with a CFP stem in our hospital between January 2006 and November 2018. Demographic characteristics and radiological features were obtained from the medical records and the Picture Archiving and Communication System, respectively. The incidence, Vancouver classification, and risk factors for intraoperative periprosthetic femoral fractures were identified.ResultsA total of 1633 hips were included. The incidence rate of periprosthetic femoral fractures in patients undergoing total hip arthroplasty with a CFP stem was 3.2%. According to the Vancouver classification, there were 24 patients (45.3%) with Vancouver type A fractures, 27 patients (50.9%) with Vancouver type B fractures, and 2 patients (3.8%) with Vancouver type C fractures. Five independent risk (protective) factors were found, including surgical history (odds ratio [OR] = 3.275, 95% confidence interval [CI] = 1.192-8.997), neck-shaft angle (OR = 1.104, 95% CI = 1.058-1.152), neck length preserved (OR = 0.913, 95% CI = 0.850-0.980), canal flare index (OR = 0.636, 95% CI = 0.413-0.980), and bone mineral density (OR = 0.083, 95% CI = 0.016-0.417).ConclusionThe detailed characteristics of intraoperative periprosthetic femoral fractures in patients who received a CFP stem were identified in this study. Cracks of the femoral neck and fractures on the front side of the proximal femur were more common in patients with CFP stems. As a kind of a femoral neck preserving stem, the anatomical features (eg, neck-shaft angle, preserving length) of the remaining femoral neck might influence the incidence and characteristics of intraoperative periprosthetic femoral fractures in patients with CFP stems.     

全髋关节置换术后股骨假体周围Vancouver B型骨折治疗的随访研究

目的 探讨全髋关节置换术后股骨假体周围Vancouver B型骨折治疗方法的选择,总结同种异体皮质骨板移植重建股骨假体周围骨折的临床效果.方法 22例全髋关节置换术后股骨假体周围骨折患者,男7例,女15例;年龄平均65岁(53～75岁).Vancouver分类B1型5例,B2型4例,B3型13例.B1型骨折采用异体皮质骨板移植加钢丝环扎治疗;B2型骨折选择加长股骨柄翻修;B3型骨折选择骨水泥柄翻修,加同种异体皮质骨板移植和钢丝环扎同定.所有患者均获得随访,随访时间平均67个月(37～95个月).采用Harris髋关节功能评分、X线片、外周血T淋巴细胞亚群、抗体免疫复合物检测 和核素骨显像对治疗结果进行评价.结果 22例患者骨折全部愈合,21例患者能自由行走,1例需要助 行器帮助.末次随访Harris评分平均89分(79～93分).患者未发生免疫排斥反应;术后3个月,骨折愈合,术后12个月,移植骨板与宿主骨骨性愈合,股骨皮质厚度增加3～5mm;核素骨显像骨板移植区放射性核素分布较对侧浓集.3例患者移植骨板出现部分吸收现象.术后2年.骨板与宿主骨融合,移植骨板吸收停止.结论 针对股骨假体周围骨折不同类型分别采取不同方法治疗能够取得较好疗效,同种异体皮质骨板移植在维持骨折稳定性、促进骨折愈合、增加局部骨量和改善骨强度方面有较好疗效.     

Periprosthetic fractures of the humerus

Periprosthetic humeral fractures present a treatment challenge for the orthopedic surgeon. The overall incidence of fracture is between 0.5% and 3%, with the majority of fractures occurring intraoperatively and involving the humeral diaphysis. Excess torque produced during surgery is usually responsible for intraoperative fractures. Improper canal preparation or prosthetic placement may also increase the chance of sustaining a fracture. Postoperative fractures are most commonly caused by minor trauma, such as a fall. Poor bone quality, female sex, advanced age, and history of rheumatoid arthritis are the risk factors most commonly associated with periprosthetic fractures. All 4 systems used to describe periprosthetic humeral shaft fractures classify fracture patterns according to the anatomic relation of the fracture to the prosthetic stem. Treatment decisions should be made with respect to obtaining fracture stability, initiating early gleno-humeral motion, and restoring shoulder function. Intraoperative fractures and any postoperative fracture resulting in prosthetic instability should be treated with a long-stem prosthesis extending at least 2 to 3 cortical diameters past the fracture site with consideration for rigid plate fixation. Short oblique or transverse postoperative fractures should be managed with early stable fixation. There has been some support for conservative treatment of long oblique or spiral postoperative fractures. Postoperative diaphyseal fractures distal to the stem generally are well maintained with standard fracture management.     

Total hip arthroplasty for acute femoral neck fractures using a cementless tapered femoral stem

The purpose of this study was to evaluate the osseointegration potential and implant-related complications of cementless total hip arthroplasty with a titanium alloy collarless, tapered, wedge-shaped femoral stem with a proximal circumferential plasma-spray coating in patients with acute hip fractures. The cohort consists of 85 patients with a mean age of 78.1 years. The mean duration of follow-up was 3.8 years. Total hip arthroplasty conferred significant improvement in function for all patients. All femoral components were stable with evidence of bone ingrowth (84 hips) or fibrous fixation (1 hip). Mild thigh pain was present in 3 patients. The complications included dislocation (3 cases), intraoperative femoral fracture (2 cases), and periprosthetic femoral fracture in the postoperative period (1 case). There was one reoperation for revision of the femoral component in the patient with a periprosthetic fracture. There were 25 (29%) deaths. Cementless total hip arthroplasty using a tapered proximally coated femoral stem is a viable option for the treatment of a displaced hip fracture and preexistent arthritis.     

Total Hip Arthroplasty in Patients With Osteopetrosis

BackgroundOsteopetrosis is an inherited bone disease associated with high risk of osteoarthritis and fracture non-union, which can lead to total hip arthroplasty (THA). Bone quality and morphology are altered in these patients, and there are limited data on results of THA in these patients. The goals of this study were to describe implant survivorship, clinical outcomes, radiographic results, and complications in patients with osteopetrosis undergoing primary THA.MethodsWe identified 7 patients (9 hips) with osteopetrosis who underwent primary THA between 1970 and 2017 utilizing our total joint registry. The mean age at index THA was 48 years and included two males and five females. The mean follow-up was 8 years.ResultsThe 10-year survivorship free from any revision or implant removal was 89%, with 1 revision and 1 resection arthroplasty secondary to periprosthetic femoral fractures. The 10-year survivorship free from any reoperation was 42%, with 4 additional reoperations (2 ORIFs for periprosthetic femoral fractures, 1 sciatic nerve palsy lysis of adhesions, 1 hematoma evacuation). Harris hip scores significantly increased at 5 years (P = .04). Five hips had an intraoperative acetabular fracture, and 1 had an intraoperative femur fracture. All postoperative femoral fractures occurred in patients with intramedullary diameter less than 5 mm at a level 10 cm distal to the lesser trochanter.ConclusionPrimary THA in patients with osteopetrosis is associated with good 10-year implant survivorship (89%), but a very high reoperation (58%) and periprosthetic femoral fracture rate (44%). Femoral fractures appear associated with smaller intramedullary diameters.     

Association of Osteonecrosis and Failure of Hip Resurfacing Arthroplasty

Osteonecrosis (ON) has been reported in femoral remnants removed after failure of hip resurfacing arthroplasty. Experimental and clinical studies have further described thermal effects of the cementation technique, damage of extraosseous blood vessels, and intraoperative hypoxemia as possible causative factors. We analyzed histologically a series of 123 retrieved specimens with a preoperative diagnosis other than ON to investigate the incidence and extent of advanced ON. ON was found in 88% of cases and associated with 60% (51 of a total of 85) of periprosthetic fractures. The fracture incidence correlated with the extent of ON. Collapse of necrotic tissue in three (2%) cases resulted in disconnection of the bone stock-femoral component. We observed smaller regions of superficial ON in the majority of the remaining femoral remnants with periprosthetic fractures and in hips that failed for reasons other than fracture.