全髋关节置换术后假体周围发生骨折的列线图预测模型构建和评估

目的:构建评估行全髋关节置换术(total hip arthroplasty,THA)患者术后假体周围发生骨折的列线图预测模型。方法:选取2013年4月至2019年2月行THA患者538例为研究对象,男318例,女220例,年龄40~60(50.79±6.37)岁。根据对所有行THA患者跟踪随访3年的结果,将其分为无骨折组506例和骨折组32例。单因素和多因素Logistic回归分析行THA患者术后假体周围发生骨折的影响因素;构建行THA患者术后假体周围发生骨折的列线图预测模型,评估该预测模型的有效性、区分度。结果:骨折组行THA患者中存在骨质疏松状态、有外伤史、有髋关节翻修占比高于无骨折组(P<0.05),骨水泥型假体占比低于无骨折组(P<0.05)。骨质疏松状态[OR=4.177,95%CI(1.815,9.617),P<0.05],外伤史[OR=7.481,95%CI(3.104,18.031),P<0.05],髋关节翻修[OR=11.371,95%CI(3.220,40.153),P<0.05]是影响行THA患者术后假体周围发生骨折的独立危险因素,骨水泥型假体[OR=0.067,95%CI(0.019,0.236),P<0.05]是影响行THA患者术后假体周围发生骨折的独立保护因素。Hosmer-Lemeshow拟合优度检验显示, χ²=7.864,P=0.325。受试者工作特征(receiver operating characteristic curve,ROC)曲线评估行THA患者术后假体周围发生骨折的曲线下面积(area under curve,AUC)为0.892,敏感度为87.5%,特异性为77.7%。结论:本研究构建的行THA患者术后假体周围发生骨折的列线图预测模型区分度较好,有益于临床预测行THA患者假体周围是否发生骨折,为进行个体化预防骨折提供便利。     

唑来膦酸对全髋置换术后假体周围骨密度的影响

目的评价唑来膦酸对骨质疏松患者全髋置换术后假体周围骨密度影响。 方法检索主要数据库从建库至2019年11月10日唑来膦酸对骨质疏松患者全髋置换术后应用并评价假体周围骨密度结局指标的随机对照试验,筛选合格研究进行分析。偏倚风险评价应用Cochrane评价员手册,质量评价应用Jadad评分法。应用Rev Man 5.3软件对假体周围骨密度指标进行Meta分析。 结果符合纳入标准的文献共5篇。Meta分析结果显示,术后3个月假体周围骨密度Gruen 2区均数差(MD)＝0.11,95%可信区间(CI)(0.01,0.21),治疗组与对照组比较,假体周围骨密度Gruen 2区差异有统计学意义(Z ＝2.21,P＝0.03);Gruen 3区MD＝0.11,95%CI (0.01,0.21),治疗组与对照组比较,假体周围骨密度Gruen 3区差异有统计学意义(Z＝2.24,P＝0.03);Gruen 6区MD＝0.12,95%CI(0.04,0.21),治疗组与对照组比较,假体周围骨密度Gruen 6区差异有统计学意义(Z＝2.76,P＝0.006)。术后6个月假体周围骨密度Gruen 1区MD＝0.05,95%CI(0.01,0.09),治疗组与对照组比较,假体周围骨密度Gruen 1区差异有统计学意义(Z＝2.20,P＝0.03);Gruen 2区MD＝0.08,95%CI(0.03,0.14),治疗组与对照组比较,假体周围骨密度Gruen 2区差异有统计学意义(Z＝3.03,P＝0.002);Gruen 3区MD＝0.05,95%CI (0.00,0.10),治疗组与对照组比较,假体周围骨密度Gruen 3区差异有统计学意义(Z＝2.10,P＝0.04);Gruen 4区MD＝0.10,95%CI(0.04,0.15),治疗组与对照组比较,假体周围骨密度Gruen 4区差异有统计学意义(Z＝3.46,P＝0.0005);Gruen 5区MD＝0.08,95% CI(0.03,0.14),治疗组与对照组比较,假体周围骨密度Gruen 5区差异有统计学意义(Z＝2.87,P＝0.004)。术后12个月假体周围骨密度Gruen 1区MD＝0.09,95%CI(0.05,0.14),治疗组与对照组比较,假体周围骨密度Gruen 1区差异有统计学意义(Z＝4.22,P<0.0001);Gruen 2区MD＝0.11,95%CI(0.05,0.16),治疗组与对照组比较,假体周围骨密度Gruen 2区差异有统计学意义(Z＝3.91,P<0.0001);Gruen 3区MD＝0.08,95%CI(0.03,0.13),治疗组与对照组比较,假体周围骨密度Gruen 3区差异有统计学意义(Z＝3.42,P＝0.0006);Gruen 4区MD＝0.15,95%CI(0.09,0.20),治疗组与对照组比较,假体周围骨密度Gruen 4区差异有统计学意义(Z＝5.01,P<0.00001);Gruen 5区MD＝0.10,95%CI(0.05,0.16),治疗组与对照组比较,假体周围骨密度Gruen 5区差异有统计学意义(Z＝3.77,P＝0.0002)。纳入研究均无重大不良反应发生。 结论唑来膦酸能有效延缓全髋置换术后假体周围骨密度的降低,增加假体生物学稳定性,且临床应用安全,但需要更多高质量、多中心严格设计的随机对照试验进一步验证。     

微创股骨头置换术与股骨近端防旋髓内钉治疗高龄粉碎性股骨转子间骨折的疗效比较

目的：探讨微创股骨头置换术与股骨近端防旋髓内钉（proximal femoral nail antirotation,PFNA）内固定术治疗高龄粉碎性股骨转子间骨折患者的临床疗效。方法：2020年4月至2020年10月治疗高龄粉碎性股骨转子间骨折患者76例,分别采用微创股骨头置换术（假体组）与PFNA内固定术。假体组35例,女24例,男11例,年龄（86.2±6.1）岁;PFNA组41例,女28例,男13例,年龄（84.6±5.3）岁。观察比较两组手术时间、术中出血量、术后下地活动时间、住院时间及并发症发生情况,术后1、6、12个月行髋关节功能Harris评分。结果：患者均获得随访,时间13~17（14.3±1.4）个月。假体组手术时间长于PFNA组（P<0.05）;PFNA组出血量少于假体组（P<0.05）;术后下地活动时间假体组明显早于PFNA组（P<0.05）;术后1、6个月假体组的Harris评分高于PFNA组（P<0.05）,术后12个月两组Harris评分比较,差异无统计学意义（P>0.05）。假体组并发症少于PFNA组（P<0.05）。结论：高龄粉碎性股骨转子间骨折患者,采用微创股骨头置换术治疗是一种良好选择,有利于术后早期康复,减少并发症,提高生活质量,减轻家属及社会负担。     

带股骨距假体置换与髓内钉治疗高龄股骨转子间骨折的临床疗效对比

目的：分析采用带股骨距假体髋关节置换术与同期行闭合复位防旋股骨近端髓内钉（proximal femoral nail antirotation,PFNA）内固定术治疗高龄患者（≥ 80岁）股骨转子间不稳定型骨折（Evans Ⅲ、Ⅳ型）的临床疗效。方法：回顾分析2016年6月至2018年3月采用假体置换与PFNA治疗的高龄股骨转子间不稳定型骨折患者60例,根据手术方式分为PFNA组与假体组,其中PFNA组男21例,女15例,年龄（84.3±2.9）岁;假体组男10例,女14例,年龄（82.9±2.4）岁。观察比较两组手术时间、术前与术后1 d血红蛋白差值、术后下地活动时间、住院时间及并发症发生情况,术后3、12个月行髋关节功能Harris评分。结果：患者均获得随访,时间12~24（19.3±4.8）个月,假体组1例1年后死于肺癌,随访终止。假体组手术时间长于PFNA组（P<0.05）;术前后血红蛋白差值,假体组与PFNA组无差异（P>0.05）;下地活动时间,假体组早于PFNA组（P<0.05）;并发症出现数量,假体组少于PFNA组（P<0.05）;治疗前假体组与PFNA组Harris评分差异无统计学意义,治疗后两组评分均较治疗前显著升高（P<0.05）,术后3个月随访假体组评分高于髓内钉组（P<0.05）,术后12个月差异无统计学意义（P>0.05）。。结论：对高龄不稳定型股骨转子间骨折,尤其骨质疏松严重者,实施带股骨距假体髋关节置换术治疗是一种良好选择,有利于高龄患者术后功能锻炼和早期下地活动,减少并发症,提高生活质量,减轻家属及社会负担。     

全髋关节置换术127°小颈干角和135°大颈干角假体的比较

目的：探讨127°小颈干角和135°大颈干角假体行全髋关节置换术（total hip arthroplasty,THA）的疗效。方法：2014年1月至2016年6月行THA患者84例,男44例,女40例;年龄45~72（53.4±8.1）岁,股骨头坏死68例（左侧32例,右侧36例）,其他原因导致严重髋关节骨性关节炎16例,病程9~36（24.0±5.5）个月。分别采用小颈干角（127°）和大颈干角（135°）假体,每组42例,术后两组患者进行髋关节Harris评分,疼痛视觉模拟评分（visual analogue scale,VAS）评分,双下肢长度测量,不同颈干角生物力学评估,比较术后并发症发生情况以及患者术后24个月生活质量。结果：两组患者各有2例患者失访,其余患者均获得随访,随访时间30~36（33.0±1.6）个月。术前及术后1、6、12、24个月进行Harris评分及双下肢长度测量,两组患者髋关节Harris评分及双下肢长度差与术前比较均得到明显改善（P<0.05）,而组间差异无统计学意义（P>0.05）。两组术后1、6、12、24个月VAS评分均低于术前（P<0.05）;两组VAS评分术前差异无统计学意义（P>0.05）,但术后大颈干角组VAS评分明显低于小颈干角组（P<0.05）。两组术后并发症（包括假体松动、脱位）的发生率差异无统计学意义（P>0.05）。两组患者术后24个月生活质量较术前生活质量明显提高（P<0.05）,且组间比较发现135°大颈干角组生活质量较127°小颈干角组生活质量更高（P<0.05）。。结论：大、小颈干角假体的THA均能较好地恢复患者髋关节的功能,但是大颈干角更能降低术后疼痛程度,进而提高患者术后的生活质量。     

短柄股骨假体全髋关节置换术后股骨近端骨改建及有限元分析

目的通过观察股骨假体周围骨密度改变情况来分析短柄股骨假体全髋关节置换术后股骨近端骨改建情况。方法纳入自2011-06—2016-06完成的71例全髋关节置换术,35例(37髋)采用短柄股骨假体(短柄组),36例(37髋)采用常规股骨假体(常规组)。比较两组术后1年疼痛VAS评分、髋关节功能Harris评分、股骨假体周围骨密度。采用有限元法分析两种股骨假体置入后的应力遮挡情况。结果 71例均获得随访,随访时间13～15(13.2±0.8)个月。短柄组与常规组术后1年疼痛VAS评分、髋关节功能Harris评分差异无统计学意义(P0.05)。与术后1周比较,术后1年短柄组股骨假体周围Gruen 1区和5区骨密度无明显变化,Gruen 4区骨密度降低,而Gruen 2、3、6、7区骨密度增加;常规组术后1年股骨假体周围Gruen 1、2、3、5、6、7区骨密度降低,而Gruen 4区骨密度升高。术后1年短柄组股骨假体周围所有Gruen分区骨密度均高于常规组,差异有统计学意义(P0.05)。有限元分析结果显示常规组股骨近端内侧与外侧均出现应力遮挡,而短柄组仅在股骨近端外侧出现应力遮挡。结论短柄股骨假体具有良好的力学传导特性,全髋关节置换术中使用短柄股骨假体可促进股骨近端骨改建并减少应力遮挡。     

椎体后凸成形术后的不同治疗对骨质疏松性骨折疗效的影响

目的:探讨椎体后凸成形术后的不同治疗方案对骨质疏松性骨折患者疼痛和功能的影响。方法:将2010年3月至2012年3月收治的138例(165椎)胸腰椎椎体骨质疏松性骨折患者随机分为3组(对照组、治疗组和综合组),每组46例, 均采用PKP治疗。对照组术后采用钙剂配合骨化三醇治疗;治疗组在对照组方案基础上, 加用鲑鱼降钙素肌注治疗;综合组在治疗组方案基础上, 督促患者渐进性腰背肌功能锻炼。分别在术前, 术后3 d、2周, 1、6、12个月进行疼痛视觉模拟评分(VAS)、Oswestry功能障碍指数(ODI评分)及BMD检测。结果:所有患者手术顺利, 其中对照组38例(45椎)、治疗组36例(44椎)、综合组40例(49椎)获得完整随访, 各组患者的随访率比较差异无统计意义(P>0.05).与术前相比较, 各组术后不同时期的VAS和ODI评分均明显降低(P<0.01);与对照组比较, 治疗组和综合组在术后3 d 、2周、1个月的VAS评分均降低(P<0.05),而各组间ODI评分比较差异无统计学意义 (P>0.05);术后6、12个月, 对照组与治疗组的VAS、ODI评分比较差异无统计学意义(P>0.05),而综合组的VAS评分与对照组和治疗组比较明显降低(P<0.05),且综合组的ODI评分呈持续下降(P<0.01);术后12个月, 各组患者的BMD与术前比较均有所升高(P<0.01),其中综合组的BMD明显高于对照组和治疗组(P<0.05).结论:PKP是治疗胸腰椎椎体骨质疏松性骨折的有效方法, 术后系统使用降钙素联合钙剂、活性维生素D有助于提高PKP术后的短期疗效, 而坚持腰背肌功能锻炼能提高PKP的长期疗效, 改善患者的生活质量。     

唑来膦酸对绝经后骨质疏松症患者假体周围骨密度的影响

目的研究唑来膦酸对绝经后骨质疏松症患者假体周围骨密度的影响。方法选取2015年11月至2016年4月符合入组标准的32例绝经后骨质疏松症患者,随机分成对照组(16例,年龄74.4岁±5.7岁)和治疗组(16例,年龄73.3岁±6.6岁),进行为期一年的随访研究。于术后1周、3个月、6个月、12个月通过双能X线扫描(DEXA)测定假体周围骨密度值,于术前、术后3个月、6个月、12个月通过血清学检查测定相关骨代谢标志物的水平。结果两组患者术后3个月、6个月、12个月与术后1周(基线)相比,Gruen1-7区骨密度均呈不同程度下降。术后6个月对照组在Gruen1、4、6、7区及术后12个月在Gruen1、2、4、6、7区的骨密度丢失明显高于治疗组。术后3个月、6个月、12个月对照组的骨吸收标志物(β-CTX)水平明显高于治疗组,两组的骨形成标志物(TP1NP)水平仅在术后12个月具有统计学意义(对照组高于治疗组),两组的25(OH)D水平在术后3个月、6个月、12个月均无统计学意义。结论绝经后骨质疏松症妇女行全髋关节置换术后使用5 mg唑来膦酸能有效预防假体周围的骨密度丢失及改善骨的重建。     

唑来膦酸对骨质疏松患者全髋关节置换术后假体周围骨密度的影响

目的：探讨注射用唑来膦酸5 mg对骨质疏松患者全髋关节置换术后假体周围骨密度的影响。方法选取2012年3月至2013年2月期间因骨质疏松性髋部骨折行全髋关节置换术的患者31例,所有患者初次诊断均为原发性骨质疏松症合并髋部骨折,入院前未曾行任何抗骨质疏松治疗,根据随机数字表分为两组：治疗组（16例,平均年龄73.8岁）,全髋关节置换术后5～7 d给予唑来膦酸5 mg,静脉滴注30 min,同时口服钙尔奇600 mg/d及阿尔法D30.25 ug/d;对照组（15例,平均年龄74.1岁）,术后仅给予口服钙尔奇600 mg/d及阿尔法D30.25 ug/d。分别于术后1周、3个月、6个月、12个月使用双能X线骨密度仪（ DEXA）测定两组患者假体周围各感兴趣区的骨密度值。结果两组患者术后3个月、6个月、12个月与术后1周（基线）股骨近端假体周围骨密度除Gruen1区外,2～7区骨密度均呈不同程度下降。治疗组与对照组骨密度变化值相比,术后3个月Gruen 4区（0.84％vs -3.34％, t＝3.5805）、7区（-3.61％vs -16.7, t＝4.0455）组间差异有统计学意义（P＜0.05）;术后6个月Gruen 1区（9.96％vs 1.17％, t＝2.1293）、4区（1.21 vs -2.96, t＝2.0892）、6区（-0.56 vs -6.16, t＝2.9500）、7区（-5.71 vs -22.8, t＝4.3959）组间差异有统计学意义（ P＜0.05）;术后12个月Gruen 1区（13.83 vs 1.39, t＝2.1795）、4区（0.81 vs -3.68, t＝2.1805）、6区（0.14 vs -6.04, t＝0.0247）、7区（-8.39 vs -25.4, t ＝3.8959）组间差异有统计学意义（ P＜0.05）。术后使用唑来膦酸3个月即表现出明显抑制骨量丢失的作用,并且于6个月、12个月时唑来膦酸对Gruen 1、4、6、7区骨量有持续的正向影响;Gruen 7个区中对1、7区的影响最大,治疗组1区骨密度增幅是对照组的9.95倍,7区骨密度减幅是对照组的1/3。结论唑来膦酸注射液5 mg能有效减少股骨假体周围骨密度的丢失,潜在的增加假体生物学稳定性,减少假体无菌性松动的概率,延长假体使用寿命。     

金属垫块结合Jumbo臼杯在人工髋关节翻修髋臼骨缺损重建中的应用研究

目的：探讨金属垫块结合Jumbo臼杯在人工髋关节翻修髋臼骨缺损重建中的应用效果及影像学变化。方法：回顾性分析2019年9月至2021年10月行人工髋关节翻修髋臼骨缺损重建术的83例患者临床资料,按手术方式不同分两组,42例采用金属垫块结合Jumbo臼杯方式进行翻修为A组,男26例,女16例,年龄44~72(60.57±4.62)岁;41例采用金属垫块联合骨水泥型臼杯进行翻修为B组,男22例,女19例,年龄42~71(58.74±4.25)岁。比较两组手术相关指标,术前及术后1、12个月Harris髋关节功能评分和疼痛视觉模拟评分(visual anagolue scale,VAS);根据X线片评估两组患者术前及术后12个月髋关节旋转中心高度、髋臼外展角、股骨偏心距以及影像学标准合格率,并比较两组并发症发生率。结果：两组手术时间、术中出血量以及术后引流量比较差异无统计学意义(P＞0.05)。两组均获得随访,时间12~36(25.36±3.59)个月。两组术后1个月Harris疼痛、功能、畸形评分及总分均高于术前(P＜0.05),两组术后12个月Harris疼痛、功能、畸形、关节活动度评分及总分均高于术前和术后1个月(P＜0.05),且术后12个月A组Harris各项评分及总分高于B组(P＜0.05)。两组术后1、12个月VAS均依次降低(P＜0.05),但两组各时间点VAS比较差异无统计学意义(P＞0.05)。两组术后12个月股骨偏心距均升高(P＜0.05),且A组高于B组(P＜0.05);两组术后12个月旋转中心高度及髋臼外展角均降低(P＜0.05),且A组旋转中心高度低于B组(P＜0.05),但两组髋臼外展角比较差异无统计学意义(P＞0.05)。A组的影像学合格率高于B组(P＜0.05);两组并发症发生率比较差异无统计学意义(P＞0.05)。结论：金属垫块结合Jumbo臼杯治疗髋臼骨缺损可改善髋关节功能,恢复髋关节旋转中心、股骨偏心距以及髋臼外展角,临床效果明显。     

Restoration of proximal periprosthetic bone loss by denosumab in cementless total hip arthroplasty

Summary

Denosumab contributed to the restoration of proximal periprosthetic bone loss around the femoral stem that were measured using a DEXA, especially in zone 7, at 1 year after cementless THA in elderly osteoporotic patients.

Introduction

Although bone quality is an important issue in elderly osteoporotic patients who underwent total hip arthroplasty (THA) with a cementless stem, periprosthetic bone mineral density (BMD) in the proximal femur has been reported to be decreased by 15–40% postoperatively. Some authors have examined the use of several types of bisphosphonates to prevent decreases in BMD in the proximal femur after cementless THA; however, few reports have demonstrated success in restoring BMD in the proximal medial femoral bone, such as zone 7.

Methods

We conducted prospective study comparing patients who underwent cementless THA administered with denosumab (10 patients) and without denosumab (10 patients). BMD around the femoral stem were measured using a DEXA immediately after surgery, and at 6 months and at 1 year after surgery. No difference was found between the two groups referred to the patient’s demographic data.

Results

We found that denosumab displayed definitive effects in increasing the % change in periprosthetic BMD at zone 7 by an average of 7.3% in patients with cementless THA, compared to control group who were given only vitamin D.

Conclusion

Denosumab is one of a number of anti-osteoporotic agents to have a definitive effect on the restoration of proximal periprosthetic bone loss, especially in zone 7, after cementless THA. Denosumab contributed to the restoration of decreased periprosthetic BMD to normal levels. As the decrease in BMD in the proximal femur after THA is considered to be apparent at 6–12 months after surgery, it is believed that prevention of the deterioration of bone quality is important in the proximal femur immediately after cementless THA for elderly female patients with osteoporosis.

     

Denosumab Prevents Early Periprosthetic Bone Loss After Uncemented Total Hip Arthroplasty: Results from a Randomized Placebo-Controlled Clinical Trial

Implant loosening is the most common indication for revision surgery after total hip arthroplasty (THA). Although bone resorption around the implants plays a pivotal role in the pathophysiology of loosening, it is unknown whether potent early inhibition of osteoclasts could mitigate this process and thus reduce the need for revision surgery. We performed a randomized, double-blind, placebo-controlled phase 2 trial in 64 patients aged 35 to 65 years with unilateral osteoarthritis of the hip. They underwent surgery with an uncemented THA and were randomized to either two subcutaneous doses of denosumab (n = 32) or placebo (n = 32) given 1 to 3 days and 6 months after surgery. Patients were followed for 24 months. Primary outcome was periprosthetic bone mineral density (BMD) of the hip at 12 months as measured by dual-energy X-ray absorptiometry (DXA). In addition, [¹⁸F] sodium fluoride positron emission tomography/CT (F-PET) was performed in half of the patients for analysis of periprosthetic standardized uptake value (SUV). Analyses were made according to intention-to-treat principles. The trial was registered at ClinicalTrials.gov 2011-001481-18, NCT01630941. Denosumab potently inhibited early periprosthetic bone loss. After 12 months, BMD in the denosumab group was 32% (95% confidence interval [CI] 22–44) higher in Gruen zone 7 and 11% (95% CI 8–15) higher in zones 1 to 7. After 24 months, the difference in BMD between groups had decreased to 15% (95% CI 4–27) in zone 7 and 4% (95% CI 0–8) in zones 1 to 7. In both groups, SUV increased after surgery, but the increase was less pronounced in the denosumab group. Biochemical markers of bone metabolism decreased in the denosumab group in the first 12 months, but a rebound effect with marker concentrations above baseline was observed after 24 months. Denosumab potently prevents early periprosthetic bone loss after uncemented THA; however, the effect diminishes after discontinuation of treatment. Further research is needed to determine whether this bone loss will prove to be of clinical importance and, if so, whether the positive effect observed in this study could be preserved by either prolonged treatment with denosumab or additional antiresorptive treatment. © 2019 American Society for Bone and Mineral Research. © 2019 American Society for Bone and Mineral Research.     

Changes in Bone Mineral Density of the Acetabulum and Proximal Femur After Total Hip Resurfacing Arthroplasty

Our aim was to investigate the changes in bone mineral density (BMD) of acetabulum and proximal femur after total hip resurfacing arthroplasty. A comparative study was carried out on 51 hips in 48 patients. Group A consisted of 25 patients (26 hips) who had undergone total hip resurfacing and group B consisted of 23 patients (25 hips) who had had large-diameter metal-on-metal total hip arthroplasty (THA). BMDs around the acetabulum and proximal femur were measured using dual-energy x-ray absorptiometry (DEXA) at 2 weeks, 6 months, 1 year and annually thereafter during the 3 years after surgery. At final follow-up, the acetabular net mean BMD decreased by 11% in group A and 10% in group B with no differences between two groups (P = .35). For the femoral side, in Gruen zone 1, the mean BMD increased by 4% in group A, whereas it decreased by 11% in group B (P = .029). In Gruen zone 7, the mean BMD increased by 8% at the final follow-up in group A, whereas it decreased by 13% in group B (P = .02). In both groups the mean BMD increased by 3% in Gruen zones 3, 4, 5, and 6. Stress-related bone loss of the acetabulum was comparable for MOM THA and resurfacing devices, but proximal femoral bone density increased in the resurfacing group and decreased in the THA group.     

Periprosthetic bone remodelling of two types of uncemented femoral implant with proximal hydroxyapatite coating: a 3-year follow-up study addressing the influence of prosthesis design and preoperative bone density on periprosthetic bone loss

Periprosthetic bone loss is a major cause of concern in patients undergoing total hip arthroplasty (THA). Further studies are required to identify the factors determining the pattern of bone remodelling following THA and obtain improvements in the design and durability of prostheses. In this study, we monitored periprosthetic bone loss around two different types of hydroxyapatite coated femoral implant over a 3-year period to evaluate their design and investigate the relationship with the preoperative bone mineral density (BMD) at the spine, hip and forearm. Sixty patients (35 F, 25 M, mean age 63 years, range 46–75 years) undergoing THA were randomised to either the Anatomic Benoist Girard (ABG) or Mallory-Head (MH) femoral stem. Preoperative dual-energy X-ray absorptiometry (DXA) scans were acquired of the posteroanterior (PA) and lateral lumbar spine, the contralateral hip and the non-dominant forearm. Postoperative DXA scans were performed to measure periprosthetic BMD at 10 days (treated as baseline), 6 weeks, and 3, 6, 12, 24 and 36 months after THA using a standard Gruen zone analysis. Results were expressed as the percentage change from baseline and the data examined for the differences in bone loss between the different Gruen zones, between the ABG and MH stems, and the relationship with preoperative BMD. A total of 50 patients (24 ABG, 26 MH) completed the study. Three months after THA there was a statistically significant BMD decrease in every Gruen zone that varied between 5.6% and 13.8% for the ABG prosthesis and between 3.8% and 8.7% for the MH prosthesis. Subsequently, in most zones BMD reached a plateau or showed a small recovery. However, BMD continued to fall in Gruen zones 1 and 7 in ABG patients and Gruen zone 1 in MH patients. Bone loss was less in every Gruen zone in MH patients compared with ABG with the largest difference (10%, P=0.018) in Gruen zone 7. Highly significant relationships were found between periprosthetic bone loss and preoperative BMD measured at the PA spine (P<0.001), total hip (P=0.004) and total distal radius (P<0.001). This study showed differences between two different designs of hydroxyapatite-coated implant that confirmed that prosthesis design influences periprosthetic bone loss. The study also showed that patients bone density measured at the spine, hip or forearm at the time of operation was a major factor influencing bone loss around the femoral stem.     

Bone Preservation in Total Hip Arthroplasty

BackgroundPreserving bone stock in younger and more active patients after total hip arthroplasty (THA) is important for future revision. Newer prosthesis designs, including short femoral stems and isoelastic acetabular cups, are likely to preserve more bone stock. However, long-term follow-up studies on bone remodeling after short-stem THA with an isoelastic monoblock acetabular cup are few. Therefore, we evaluated bone preservation after THA using these prostheses at a 5-year follow-up.MethodsThis prospective observational study is a 5-year follow-up of our previously reported 2-year observational study on the same cohort of patients. We included 45 patients with primary osteoarthritis treated with a calcar-guided femoral short-stem prosthesis and a monoblock press-fit acetabular cup. We evaluated bone mineral density (BMD) around the prostheses using dual-energy X-ray absorptiometry and reported functional outcomes preoperatively and at 3, 12, 24, and 60 months postoperatively. All complications were recorded.ResultsAt the final follow-up, the BMD was comparable with that at 24 months in Gruen zones 3, 4, 5, 6, and 7, whereas it significantly differed in Gruen zones 1 (P < .0001) and 2 (P < .004). On the acetabular side, the BMD leveled off similarly in all DeLee and Charnley zones between 24 and 60 months (P > .05). Moreover, all measured clinical outcomes significantly improved (P < .001). One perioperative dislocation was reported.ConclusionPatients undergoing THA with a calcar-guided femoral short-stem prosthesis and a monoblock acetabular cup can expect preservation of bone stock over a longer follow-up with excellent clinical outcomes and few complications.     

Changes in bone mineral density (BMD) around the cemented Exeter stem: A prospective study in 18 women with 5 years follow‐up

Background and purpose?THA changes the pattern of strain distribution in the proximal femur. We quantified the changes in BMD for 5 years after insertion of the cemented Exeter stem in women.

Methods?18 women aged 55–79 years, undergoing unilateral THA with the cemented Exeter stem, were included in the study. The BMD was measured in 7 femoral regions of interest according to Gruen, and the contralateral hip and spine using dual‐energy X‐ray absorptiometry postoperatively, at 18 and at 60 months of follow‐up. Results were tested using Wilcoxon matched‐pairs signed‐rank test.

Results?During the first 18 months, a significant decrease in BMD was seen in zones 2, 3, 6, and 7. No significant changes were seen in zones 4 and 5, in the contralateral hip, or at the spine. In zone 1, there was a small but significant rise in BMD. From 18 to 60 months, we observed a statistically significant rise in BMD in all zones except 4 and 7. Despite this, the total periprosthetic BMD decreased during the follow‐up relative to the immediate postoperative situation. There was no significant reduction in BMD in the contralateral hip. In the spine, we observed a significant rise in BMD.

Interpretation?18 months after THA, BMD had decreased in Gruen zones 2, 3, 6, and 7. The bone loss was similar to that seen after other implants and appears to be related to the changes in stress pattern within the proximal femur. At 5 years, BMD had increased again in these zones. It remained lower than baseline, however.     

Cyclic therapy with etidronate has a therapeutic effect against local osteoporosis after cementless total hip arthroplasty

Proximal bone resorption around the femoral stem is one of the major complications of cementless total hip arthroplasty (THA). The potential complications resulting from proximal bone resorption include femoral fracture and late stem loosening. The purpose of this study was to evaluate the effects of cyclic therapy with etidronate on periprosthetic bone mineral density (BMD) after cementless THA. Fifty-two patients who had undergone cementless THA were randomized for this study. Group A consisted of 30 hips in 29 patients without osteoactive drugs. Group B consisted of 23 hips in 23 patients with cyclic therapy with etidronate (i.e., 400 mg/day of oral etidronate for 2 weeks followed by 12 weeks of 500 mg/day of calcium lactate and repeated every 14 weeks), one of whom was excluded from the study because of side effects attributed to the drug. Periprosthetic BMD in seven regions of interest based on the zones of Gruen et al. (Clin. Orthop. 141 (1979), 17-27) was measured with dual energy X-ray absorptiometry (DXA) at 3 weeks, 6 months, and 12 months postoperatively. The postoperative decreases of BMD in group B were significantly lower than those in group A in zones 1 and 7 (P < 0.05 and P < 0.05, respectively) at 6 months and in zones 1, 2, 6, and 7 (P < 0.05, P < 0.05, P < 0.05, and P < 0.001, respectively) at 12 months. The BMD change appeared to be stabilized at 6 months in all zones in group B, while in group A there was a progressive decrease of average BMD (6.1%) in zone 7 between 6 months and 12 months. These findings suggested that cyclic therapy with etidronate may help to reduce the resorptive changes in the proximal part of the femur after cementless THA. Further follow-up study with larger populations will be required to define the potential efficacy of intermittent cyclic etidronate therapy on postoperative bone loss.     

Periprosthetic bone loss after insertion of an uncemented,customized femoral stem and an uncemented anatomical stem

Background and purpose Customized femoral stems are designed to have a perfect fit and fill in the femur in order to achieve physiological load transfer and minimize stress shielding. Dual-energy X-ray absorptiometry (DXA) is regarded as an accurate method for detection of small alterations in bone mineral density (BMD) around hip prostheses. We present medium-term DXA results from a randomized study comparing a customized and an anatomical femoral stem.

Methods 100 hips were randomized to receive either the anatomical ABG-I stem or the Unique customized femoral stem, both uncemented. DXA measurements were conducted postoperatively and after 3, 6, 12, 24, 36, and 60 months, and BMD was computed for each of the 7 Gruen zones in the proximal femur.

Results Results from 87 patients were available for analysis. 78 completed the 5-year follow-up: 35 patients in the ABG group and 43 patients in the Unique group. In both groups, we found the greatest degree of bone loss in the proximal Gruen zones. In zone 1, there was 15% reduction in BMD in the ABG-I group and 14% reduction in the Unique group. In zone 7, the reduction was 28% in the ABG-I group and 27% in the Unique group. The only statistically significant difference between the groups was found in Gruen zone 4, which is distal to the tip of the stem, with 1.6% reduction in BMD in the ABG-I group and 9.7% reduction in the Unique group (p = 0.003).

Interpretation 5-year DXA results showed that because of stress-shielding, proximal bone loss could not be avoided—either for the anatomical ABG-I stem or for the customized Unique stem.     

Dual X-ray absorptiometry for the evaluation of bone density from the proximal femur after total hip arthroplasty: Analysis protocols and reproducibility

Summary Dual X-ray absorptiometry (DXA) instruments are now able to evaluate bone mineral density (BMD) of bone surrounding metal implants. The assessment of BMD around prosthetic components could provide additional information for the follow-up of total hip arthroplasty (THA). In this study, we evaluated the potential application of DXA in the field of THA. BMD was measured in the proximal femur of both THA and THA-free sides in 14 postmenopausal women 6–18 months after THA. The explored segment was divided into seven zones as proposed by Gruen et al. [18]. The precision error of BMD measurements ranged from 1.8 to 6.8% on the THA side and from 1.1 to 2% to the THA-free side. The reduction of BMD of the THA versus the THA-free side was significant in all seven zones (P < 0.01, t-test for paired data). These results showed significant differences in BMD around femoral components of THA with respect to contralateral healthy side, and demonstrate the sensitivity of DXA for detecting these changes.