胫骨内翻畸形对全膝关节置换术胫骨假体对线影响的临床研究

目的胫骨内翻畸形(tibia vara)是膝关节关节外畸形的一种特殊类型。胫骨内翻畸形会给全膝关节置换术中胫骨假体的正确对线和安装带来困难。本研究的目的在于:a)测量国人内翻膝关节骨关节炎患者的胫骨平台内翻角(tibial varus angle,TVA),分析胫骨内翻畸形在内翻膝关节骨关节炎患者中所占的比例;b)探讨胫骨内翻畸形对全膝关节置换术术后胫骨假体对线和临床功能的影响。方法本研究回顾了我科从2015年8月至2015年12月收治的连续60例女性内翻膝关节骨关节炎的全膝关节置换患者资料,将患者分为正常组和胫骨内翻畸形组两组,术前下肢全长X线片中测量髋膝踝角(hip knee ankle angle,HKA)、TVA,术前所有患者的膝关节功能评分采用美国膝关节协会(knee society score,KSS)评分和西大略湖麦克马斯特大学(Western Ontario McMaster Universities,WOMAC)评分系统,术后下肢全长X线片中测量HKA以及胫骨假体近端内侧角(medial proximal tibial angle,MPTA),采用KSS评分和WOMAC评分系统评价膝关节功能。结果正常组TVA为(0.69±0.44)°,胫骨内翻畸形组TVA为(2.53±0.56)°,两组差异具有统计学意义。60例患者平均TVA为(1.12±0.52)°。正常组中TVA为0°的患者9例,占正常组病例数的20%。胫骨内翻畸形组中TVA大于等于2°的患者14例,占胫骨内翻畸形组的100%,即TVA大于等于2°为胫骨内翻畸形,胫骨内翻组患者占总病例数的23.3%。术后正常组HKA为(178.8±1.5)°,大于术后胫骨内翻畸形组HKA(177±2.0)°。术后正常组HKA异常值(Outlier值)有2例,占正常组病例的4.3%;术后胫骨内翻畸形组HKA Outlier值有3例,占胫骨内翻畸形组病例的21.4%。术后正常组活动度(range of motion,ROM)为(112.0±11.5)°,大于胫骨内翻畸形组ROM(105±8.0)°,两组比较差异有统计学意义。正常组术后WOMAC评分为(15.6±3.2)分,胫骨内翻畸形组WOMAC评分为(16.8±4.0)分。正常组术后KSS功能评分为(92.5±3.5)分,胫骨内翻畸形组术后KSS功能评分为(94.0±2.4)分。结论本研究中有23.3%的女性内翻膝骨关节炎患者合并胫骨内翻畸形(TVA大于等于2°),女性内翻膝关节骨关节炎患者平均TVA为(1.12±0.52)°。术前TVA大于等于2°的患者行全膝关节置换术发生术后对线不良的风险显著增加,手术时须注意胫骨近端正确截骨以及胫骨假体偏外安装,以避免术后对线不良的发生。     

滑移截骨在关节外畸形全膝关节置换中的应用

目的:针对伴有复杂股骨关节外畸形导致的严重膝骨性关节炎、内翻膝患者在进行全膝关节置换手术时施行滑移截骨技术达到内外侧软组织平衡,观察其临床疗效。方法:自2014年6月至2018年1月共收治22例伴有复杂股骨关节外畸形的重度膝骨性关节炎患者,施行全膝关节置换手术。男5例,女17例;年龄48~76(61.3±13.8)岁。均为内翻畸形,由股骨关节外畸形所导致。术前测量髋膝踝角(hip-knee-ankle,HKA)角(158.8±9.7)°,膝关节学会评分系统(Knee Society score,KSS)临床评分(32.6±6.1)分,功能评分(35.8±9.6)分,美国特种外科医院(Hospital for Special Surgical,HSS)评分(39.7±4.6)分。术前膝关节活动度(80.6±10.7)°。在关节置换时均采用机械对线法,先平衡屈曲间隙,冠状面的不平衡均采用内侧股骨髁行冠状面垂直上下滑移截骨,伸直间隙内外侧的差距决定截骨块滑移的距离,直至间隙平衡。以数枚螺钉固定截骨块后按常规安装假体。结果:所有患者伤口Ⅰ期愈合,无伤口并发症发生。22例均获随访,时间18~36(28.2±10.1)个月。拍X线片见截骨块骨折线消失时间2~5(3.5±1.5)个月,无骨不愈合发生;末次随访测量HKA角(178.8±0.7)°,较术前提高;HSS评分(91.3±6.0)分,KSS临床评分(93.7±3.5)分,KSS功能评分(81.2±6.5)分,膝关节活动度(121.7±11.6)°,均较术前改善。结论:针对伴有复杂股骨关节外畸形的严重膝骨性关节炎患者施行滑移截骨,内翻畸形严重者向下滑移股骨内髁,手术相对简单、损伤小,易于达到屈伸间隙内外侧软组织平衡,短期临床疗效满意。     

经股内侧肌下微创入路与传统入路行人工全膝关节置换术的前瞻性随机对照研究北大核心CSCD

目的采用前瞻性随机对照研究,比较经股内侧肌下微创入路与传统手术入路行人工全膝关节置换术(total knee arthroplasty,TKA)的疗效。方法将2011年1月—2012年4月收治并符合选择标准的94例(104膝)拟行TKA的骨关节炎患者纳入研究,随机分为传统入路组(46例、52膝)和微创入路组(48例、52膝);其中传统入路组45例(51膝)、微创入路组45例(49膝)获得完整随访,纳入最终分析。两组患者性别、年龄、体质量指数、侧别、骨关节炎分级以及术前髋膝踝角(hip-knee-ankle angle,HKA)、美国特种外科医院评分(HSS)、美国膝关节协会评分(KSS)、疼痛视觉模拟评分(VAS)、膝关节活动度等一般资料比较,差异均无统计学意义(P>0.05)。比较两组手术时间、切口长度、总失血量、术后输血例数、住院时间、术后开始行直腿抬高锻炼时间及切口愈合情况;术后膝关节主动活动时VAS评分以及膝关节活动度,膝关节功能HSS及KSS评分;X线片测量的HKA、股骨解剖轴线与股骨假体关节面夹角(股骨角)、胫骨解剖轴线与胫骨假体关节面夹角(胫骨角)、股骨假体屈曲角、胫骨平台后倾角。结果两组患者均获随访,传统入路组随访时间60.0~72.5个月,平均66.4个月;微创入路组为60.0~71.2个月,平均65.6个月。与传统入路组相比,微创入路组切口明显缩短、手术时间延长、患者开始直腿抬高锻炼时间提前,比较差异有统计学意义(P<0.05)。两组总失血量以及术后输血例数、住院时间比较,差异均无统计学意义(P>0.05)。微创入路组并发症发生率为8.2%(4/49),传统入路组为0,差异无统计学意义(P=0.054)。术后1、3 d,微创入路组VAS评分及膝关节活动度明显优于传统入路组(P<0.05);14 d时两组以上指标比较,差异无统计学意义(P>0.05)。术后1、3、6、12个月以及3、5年,两组HSS评分及KSS评分比较,差异均无统计学意义(P>0.05)。X线片复查提示,随访期间假体无松动表现。末次随访时,两组HKA、股骨角、胫骨角、股骨假体屈曲角以及胫骨平台后倾角测量值及其异常发生率比较,差异均无统计学意义(P>0.05)。结论经股内侧肌下微创入路行TKA有利于膝关节功能早期恢复,但远期疗效与传统手术入路TKA一致;同时因显露范围有限增加了手术并发症发生风险。     

经股内侧肌下微创入路与传统入路行人工全膝关节置换术的前瞻性随机对照研究

目的采用前瞻性随机对照研究,比较经股内侧肌下微创入路与传统手术入路行人工全膝关节置换术(total knee arthroplasty,TKA)的疗效。方法将2011年1月—2012年4月收治并符合选择标准的94例(104膝)拟行TKA的骨关节炎患者纳入研究,随机分为传统入路组(46例、52膝)和微创入路组(48例、52膝);其中传统入路组45例(51膝)、微创入路组45例(49膝)获得完整随访,纳入最终分析。两组患者性别、年龄、体质量指数、侧别、骨关节炎分级以及术前髋膝踝角(hip-knee-ankle angle,HKA)、美国特种外科医院评分(HSS)、美国膝关节协会评分(KSS)、疼痛视觉模拟评分(VAS)、膝关节活动度等一般资料比较,差异均无统计学意义(P0.05)。比较两组手术时间、切口长度、总失血量、术后输血例数、住院时间、术后开始行直腿抬高锻炼时间及切口愈合情况;术后膝关节主动活动时VAS评分以及膝关节活动度,膝关节功能HSS及KSS评分;X线片测量的HKA、股骨解剖轴线与股骨假体关节面夹角(股骨角)、胫骨解剖轴线与胫骨假体关节面夹角(胫骨角)、股骨假体屈曲角、胫骨平台后倾角。结果两组患者均获随访,传统入路组随访时间60.0~72.5个月,平均66.4个月;微创入路组为60.0~71.2个月,平均65.6个月。与传统入路组相比,微创入路组切口明显缩短、手术时间延长、患者开始直腿抬高锻炼时间提前,比较差异有统计学意义(P0.05)。两组总失血量以及术后输血例数、住院时间比较,差异均无统计学意义(P0.05)。微创入路组并发症发生率为8.2%(4/49),传统入路组为0,差异无统计学意义(P=0.054)。术后1、3 d,微创入路组VAS评分及膝关节活动度明显优于传统入路组(P0.05);14 d时两组以上指标比较,差异无统计学意义(P0.05)。术后1、3、6、12个月以及3、5年,两组HSS评分及KSS评分比较,差异均无统计学意义(P0.05)。X线片复查提示,随访期间假体无松动表现。末次随访时,两组HKA、股骨角、胫骨角、股骨假体屈曲角以及胫骨平台后倾角测量值及其异常发生率比较,差异均无统计学意义(P0.05)。结论经股内侧肌下微创入路行TKA有利于膝关节功能早期恢复,但远期疗效与传统手术入路TKA一致;同时因显露范围有限增加了手术并发症发生风险。     

Innex假体5年治疗结果:临床疗效及存活率分析

[目的]对使用Innex假体行全膝关节置换术(TKA)的患者行术后中期的影像学及临床随访,研究Innex 假体的临床疗效及存活率.[方法]对2003年9月～2005年12月使用后交叉韧带牺牲型Innex(Zimmer,Warsaw,Indiana)假体行TKA的88例(98膝)患者行平均5年的随访,回顾分析获得随访的74例(82膝)临床疗效及X线表现,通过问诊、查体、HSS评分进行临床评估,膝关节前后位、侧位X线片以及髌骨轴位X线片进行影像学评估,观察假体位置、关节线高度改变、胫骨平台后倾角、髌骨位置,有无假体松动、骨溶解.假体的存活率采用Kaplan -Meier分析,以任何原因所致的翻修为终点.[结果]患者术前的膝关节活动度平均91°(450～130°),随访时膝关节活动度平均108°(90°～132°);术前HSS评分为49分(18～86分),随访时提高到90分(54～98分).影像学评估显示假体位置良好,外翻角为5.6°,90.2%改变在3°内,关节线高度的改变为4.2mm(-15～14 mm),胫骨平台后倾角平均5.4°.所有的髌骨未出现错位、倾斜、半脱位.截至随访时,无1例因松动、骨溶解或其他原因翻修.[结论]Innex假体中期疗效良好,但仅可认为这是假体整个使用年限中的初步判断,长期效果仍需进一步随访.     

60岁以下患者全膝置换术生物性一体化钽金属胫骨假体平均10年随访结果

正对于60岁以下患者,全膝置换术采用生物性胫骨假体可能有一定优势。作者分析了79例(96膝)膝关节置换术患者资料,所有患者年龄60岁,均采用一体化钽金属后稳定性胫骨假体。60例(76%)获得完整随访,其中6例接受了翻修;7例死亡,12例失访。平均随访10年(8～12年)。影像学未见进展性透亮线,KSS评分平均为68分,6例翻修都不是因为胫骨假体失效。因此作者认     

人工全膝关节置换术治疗终末期膝关节病变合并膝外翻畸形的手术技巧及临床疗效评价

目的探讨对终末期膝关节病变合并膝外翻畸形患者行经髌旁内侧入路人工全膝关节置换(total kneearthroplasty,TKA)时膝外翻畸形矫正方法及临床疗效。方法 1998年11月-2010年10月,收治64例72膝合并膝外翻畸形的终末期膝关节病变患者。男18例,女46例;年龄23～82岁,平均62.5岁。骨关节炎44例49膝,类风湿性关节炎17例20膝,血友病性关节炎2例2膝,创伤性关节炎1例1膝。双膝8例,单膝56例。膝关节屈伸活动度为(82.2±28.7)°,X线片测量股胫角为(18.0±5.8)°。膝关节学会评分系统(KSS)临床评分为(31.2±10.1)分,功能评分(37.3±9.0)分。根据Krackow膝外翻分型标准:Ⅰ型65膝,Ⅱ型7膝。手术经髌旁内侧入路,采用常规方法行股骨及胫骨截骨,Ranawat技术进行软组织松解。6例7膝采用保留后交叉韧带型假体,54例60膝采用后稳定型假体,4例5膝采用髁限制型假体。结果术后患者切口均Ⅰ期愈合。1例血友病性关节炎合并严重膝外翻畸形(股胫角41°)、屈曲挛缩20°的患者术后出现腓总神经麻痹,经保守治疗1年后神经功能恢复。1例术后2年发生深部感染,行二期翻修术后治愈。患者术后均获随访,随访时间1～13年,平均4.9年。末次随访时X线片示股胫角为(7.0±2.5)°,与术前比较差异有统计学意义(t=15.502,P=0.000)。KSS临床评分为(83.0±6.6)分,功能评分(85.1±10.5)分,膝关节屈伸活动度为(106.1±17.0)°,与术前比较差异均有统计学意义(P0.05)。5例遗留12～15°膝外翻畸形,但患膝关节功能良好。结论通过恰当的术中截骨和软组织平衡,采用经髌旁内侧入路TKA治疗合并膝外翻畸形的终末期膝关节病变可有效改善膝外翻畸形和恢复关节功能,临床疗效满意。     

不同程度膝内翻患者初次全膝关节置换术后下肢力线分布与近期临床疗效的关系

目的:探讨不同程度膝内翻畸形患者行初次全膝关节置换术后下肢力线分布与近期临床疗效之间的关系。方法:自2016年12月至2018年3月行初次全膝关节置换术治疗的膝骨性关节炎患者87例(101膝),男21例(25膝),女66例(76膝);年龄51～85(67.6±7.0)岁。根据患者全膝关节置换术后下肢髋膝踝角(hip knee ankle angle,HKA)不同分为4组:中立位组(A组),-3°≤HKA≤3°,50膝;轻度内翻组(B组),3°HKA6°,20膝;严重内翻组(C组),HKA≥6°,20膝;外翻组(D组),HKA-3°,11膝。比较4组患者术前性别、年龄、体质量指数、手术侧别、术前及术后膝关节活动度,美国特种外科医院膝关节评分(Hospital for Special Surgery Knee Score,HSS),美国膝关节协会评分(Knee Social Score,KSS),并分别比较术后股骨、胫骨假体力线分布与近期临床疗效的关系。结果:所有病例获得随访,时间(18.4±4.0)个月。4组患者术后末次随访膝关节活动度、HSS、KSS评分均较术前提高(P0.001)。4组患者术后末次随访HSS、KSS评分组间比较差异具有统计学意义(P0.05);A组评分优于C、D两组(P0.05),B组评分优于C、D两组(P0.05),A、B两组间以及C、D两组间比较差异无统计学意义(P0.05);4组患者术后膝关节活动度组间比较差异无统计学意义。股骨假体力线在±3°以内组评分优于3°以外组(P0.05),胫骨假体力线在±3°以内组评分较3°以外组差异无统计学意义(P0.05)。结论:膝内翻型骨关节炎患者初次全膝关节置换术后近期临床疗效与下肢力线分布有关,力线轻度内翻位分布可获得与中立位相似的近期临床疗效,股骨假体力线分布与初次膝关节置换术后近期临床疗效有关。     

全膝关节翻修术中应用金属垫片修复非包容性骨缺损的中期随访

目的探讨在全膝关节翻修术中采用金属垫片修复股骨及胫骨侧非包容性骨缺损的临床效果。方法对1992~2001年间227例全膝关节翻修术中使用金属垫片修复AORI-Ⅱ型非包容性骨缺损而获得随访的62例患者进行回顾性分析,男28例,女34例;年龄42~87岁,平均67.8岁;假体松动翻修30例,感染后假体二期植入19例,假体周围骨溶解3例,假体位置、下肢力线不佳或关节不稳定10例。采用金属垫片来修复骨缺损及恢复关节线水平,并使用髓内假体柄来增加翻修假体的稳定性。结果术后随访13~132个月,平均60.8个月。根据膝关节协会评分,膝评分从术前平均25分(15~60分)增加到随访时的平均76分(30~95分);功能评分从术前的40分(15~65分)增加到随访时的62分(25~90分);膝关节活动度从术前的78°(30°~100°)增加到随访时的87°(40°~130°)。2例感染后二期假体植入的病例由于感染复发而失败。11例股骨后侧、4例胫骨内侧可见金属垫片下骨水泥与骨界面有透亮带,但均未呈进行性发展。结论采用金属垫片修复全膝关节翻修术中非包容性骨缺损,尤其适用于老年患者,既可以方便手术操作,获得即刻稳定性,又可以提高翻修成功率。     

旋转铰链膝假体在全膝关节置换翻修术后的临床效果

目的探讨使用旋转铰链膝假体进行全膝关节置换(TKA)术后翻修的临床效果。方法回顾性分析2008年10月至2013年5月,广东省人民医院骨科行人工TKA术后翻修且进行随访的重度膝关节畸形患者,其中采用旋转铰链型膝关节假体为10例(10膝)。收治的10例(10膝)TKA术后因假体松动或膝关节感染而需行全膝关节翻修的患者,采用一期翻修或一期清创加自制含抗生素骨水泥植入,可旋转绞链膝假体二期翻修方法治疗。术后进行随访并采用膝关节协会评分(HSS)及膝关节活动度评估膝关节功能。结果全部病例获得2~57个月随访,平均随访时间29个月。10例膝关节全部治愈,无下肢深静脉血栓及肺部感染等并发症。患者膝关节协会评分由术前37分增加至85分,膝关节活动度由术前65°增加至93°。结论在本研究中使用旋转铰链膝假体进行TKA术后翻修,效果确切,患者膝关节功能恢复满意。     

增加胫骨平台后倾角度、后交叉韧带部分松解对全膝关节置换术后膝关节运动影响的实验研究

目的通过增加胫骨平台后倾角度或后交叉韧带（PCL）部分松解对全膝关节置换术（TKA）中屈曲间隙过紧进行处理,分析这两种方法对TKA术后膝关节运动学的影响。方法测量6例新鲜尸体膝关节标本在完整状态下、正常TKA、屈曲间隙过紧、增加胫骨平台后倾角以及PCL部分松解TKA术后膝关节屈曲0°、30°、60°、90°、120°时的前后松弛度、内外翻松弛度、旋转松弛度及最大屈曲度。结果屈曲过紧TKA与正常TKA相比,在屈曲30°、60°、90°和120°时前后松弛度、内外翻松弛度及旋转松弛度均显著较小（P〈0．05）。与屈曲过紧TKA相比,增加胫骨后倾角后,在屈曲30°、60°、90°和120°时前后松弛度、内外翻松弛度和旋转松弛度均明显增大（P〈0．05）。PCL部分松解与屈曲过紧TKA相比,在屈曲30°、60°、90°和120°时前后松弛度明显增加（P〈0．05）;旋转松弛度在屈曲30°、60°、90°时明显增加（P〈0．05）。与PCL部分松解相比,增加胫骨后倾角的内外翻松弛度在屈曲30°、60°、90°时明显较大（P〈0．05）;旋转松弛度在屈曲0°、30°、60°和90°时明显较大（P〈0．05）。屈曲过紧TKA的最大屈曲度（120．4°）与正常TKA（130．3°）及增加胫骨后倾角（131．1°）相比明显较小（P〈0．05）。增加后倾角与PCL部分松解（124．0°）相比,最大屈曲度较大,但差异无统计学意义（P=0．0816）。结论屈曲间隙过紧TKA术后膝关节的前后松弛度、内外翻松弛度、旋转松弛度和最大屈曲度均减小;增加胫骨平台后倾角后,前后松弛度、内外翻松弛度、旋转松弛度和最大屈曲度均明显增大;PCL部分松解仅能明显增大前后松弛度。因此对于TKA术中屈曲紧张的膝关节,增加胫骨平台后倾角比PCL部分松解能更好地改善膝关节的运动学。     

Varus Gonarthrosis Predisposes to Varus Malalignment in TKA

Postoperative alignment is a predictor for long-term survival of total knee arthroplasty (TKA). The purpose of this study was to evaluate whether or not preoperative deformities predispose to intraoperative malposition of TKA components. A retrospective radiographic analysis of 53 primary TKA cases was performed. Preoperative AP hip to ankle and lateral knee radiographs were compared with postoperative views to evaluate component positioning. The following angles were measured: the hip–knee–ankle (HKA) angle expressing the mechanical axis of the leg, the mechanical lateral distal femur angle (mLDFA), the medial proximal tibia angle (MPTA), the posterior distal femur angle (PDFA), and the posterior proximal tibia angle (PPTA). Postoperative measurement of the HKA revealed 34.0% of the cases had a deviation of >±3° from neutral alignment. Sixteen knees (30.2%) were in varus and, with one exception, all presented with severe varus gonarthrosis prior to surgery with a mean tibiofemoral angle of 12.4° compared with 1.0° of valgus in the optimally aligned group. Patients (93.3%) with preoperative valgus malalignment showed optimal postoperative HKA. Odds ratios for malalignment of TKA for varus knees in comparison with valgus knees were 7.1 for HKA, 2.4 for MPTA, 4.9 for PDFA, and 1.7 for PPTA. The overall number of outliers in the presented data corresponds well with reports from other authors using different implants and guide systems. The presented data indicate that patients with preoperative varus alignment have a higher risk of postoperative implant malposition than patients with valgus alignment. The data supports that preoperative varus deformity predisposes to varus malposition of TKA. The risk for intraoperative malposition is significantly lower in valgus knees.     

Tibial component failure mechanisms in total knee arthroplasty

The purpose of this study was to examine the failure mechanisms and factors associated with failure of a nonmodular metal backed cemented tibial component. Out of 3152 total knee replacements done for osteoarthritis, 41 tibial components had been revised (1.3%). Four distinct failure mechanisms were identified: 20 knees were revised for medial bone collapse, 13 for ligamentous imbalance, 6 for progressive radiolucencies, and 2 for pain. Factors associated with medial bone collapse were varus tibial component alignment more than 3.0 degrees , Body Mass Index higher than 33.7, and overall postoperative varus limb alignment. Ligamentous imbalance was more prevalent in knees with preoperative valgus deformity. There were no knees revised for tibial component polyethylene wear or osteolysis. We conclude that the dominant failure mechanisms for this component design are related to preoperative deformity, technical factors of component alignment, overall limb alignment, and ligamentous imbalance.     

Different Deformity Origins and Morphological Features in Subtypes of Valgus Knees: A Radiological Classification System

ObjectiveTo analyze the deformity origins and distribution among valgus knees to individualize their morphological features.MethodsRadiographic images of 105 valgus knees were analyzed. Long‐film radiographs and computed tomography were collected for every knee. A malalignment test was performed on standing long‐film radiographs. The hip‐knee‐ankle angle (HKA), the anatomical lateral distal femoral angle (aLDFA), and the anatomical medial proximal tibial angle (aMPTA) were measured on long‐film radiographs. The distal condylar angle and posterior condylar angle on distal femur were further measured on computed tomography scans. The tibial bone varus angle was measured on long‐film radiographs as well. All the valgus knees were sorted into different subtypes according to the origins of bony deformity, and the prevalence of each subtype was reported. Finally, to examine the inter‐observer reproducibility of this classification system, two observers measured the deformities and did the classification for all the 105 knees independently and then the intraclass correlation coefficient (ICC) was calculated.ResultsAmong the 105 knees, 48 knees (45.7%) had apparent deformity from the tibial plateau, and 62 knees (59.0%) had apparent deformity from the supracondylar region of the femur. Eighteen knees (17.1%) had distal condylar angle >7°, among which 11 knees had posterior condylar angle >3° simultaneously. Valgus knees had five subtypes of bone deformity origins—the supracondylar part of the femur, the distal aspect of the lateral femoral condyle, both distal and posterior aspects of the lateral femoral condyle, the tibial plateau, or the metaphyseal segment of the tibia. A valgus knee could be labeled as only one subtype, or a combination of two or more subtypes. Labeling 105 knees with origin of the most severe deformity, the prevalence of each subtype was 40.0%, 5.7%, 9.5%, 28.6%, and 16.2%, respectively. The intra‐observer and inter‐observer ICC of this classification system was 0.992 and 0.976, respectively.ConclusionsValgus knees can be classified into different subtypes according to deformity origins. This radiological classification system has satisfactory reproducibility. It helps surgeons better individualize morphological features of valgus knees.     

骨性关节炎患者人工膝关节假体旋转定位标志研究

目的探讨对合并内、外翻畸形的膝关节骨性关节炎行人工全膝关节置换术，以股骨内外上髁外科轴（surgical epicondylar axis，SEA）作为股骨假体旋转参考轴，以胫骨结节内1／3作为胫骨假体旋转定位的骨性标志，判断股骨假体和胫骨假体的旋转对线情况。方法2004年7月～2005年1月，对32例（62膝）拟行人工全膝关节置换术的膝关节骨性关节炎患者（病例组），男2例，女30例；年龄58～80岁，平均68．9岁；内翻畸形55膝，胫股角平均内翻-8．23°；外翻畸形7膝，胫股角平均外翻＋15．48°。于术前行伸膝旋转中立位CT扫描，测量膝关节股骨后髁角（posterior condylar angle，PCA），并以10个正常膝关节作为对照组，测量SEA中点C与髌腱内1／3连线（BC）和经SEA中点C的垂线（AC）之间的夹角，即α角。结果病例组80％以上膝关节CT图像显示股骨内上髁陷凹；PCA中位数为＋2．36°（0～＋7．5°）；对照组膝关节α角为＋6．45±3．68°（0～＋11．8°）；病例组内翻畸形患者膝关节α角为＋10．85±10．47°（0～＋28．1°），与对照组比较差异有统计学意义（P〈0．05），病例组外翻畸形患者膝关节α角为＋11．6±7．3°（-6．5～＋26．8°），与对照组比较差异有统计学意义（P〈0．05）。结论以胫骨结节内1／3作为胫骨假体旋转参考轴线，胫骨假体相对于股骨假体处于轻度外旋位；合并内、外翻畸形患者的胫骨假体外旋角度明显增大，容易使股骨假体和胫骨假体间出现旋转对线不良。     

Factors Correlated with the Reducibility of Varus Deformity in Knee Osteoarthritis: An Analysis Using Navigation Guided TKA

Background

We hypothesized that a number of clinical and radiologic parameters could influence the reducibility of varus deformity in total knee arthroplasty. The aim of this study was to identify the factors correlated with reducibility of varus deformity and predict more accurately the amount of medial soft tissue release required in varus deformity total knee arthroplasty.

Methods

One hundred forty-three knees with preoperative varus alignment and medial osteoarthritis were included in this retrospective study. The total knee arthroplasties were performed using a navigation system (OrthoPilot) by single surgeon. To assess varus deformity, the authors measured preoperative mechanical axis angles and valgus stress angles. Mechanical tibial angles, mechanical femoral angles, femoral osteophyte sizes, and tibial osteophyte sizes were measured. The Ahlbäck grading scale was applied for radiologic parameters, and clinical parameters (age, body mass index, sex, duration of pain, and preoperative range of motion) were documented. Correlations between these factors and preoperative valgus stress angle were analyzed.

Results

A negative correlation was found between preoperative mechanical axis angle and preoperative valgus stress angle (p < 0.01, r = -0.38), and a positive correlation was found between the preoperative mechanical tibial angle and preoperative valgus stress angle (p = 0.01, r = 0.19).

Conclusions

The present study shows that preoperative varus deformity and proximal tibial vara (measured by preoperative mechanical axis angle and mechanical tibial angle, respectively) are correlated with reducibility of varus deformity (measured by preoperative valgus stress angle), and clinical parameters (age, range of motion, duration of pain and body mass index) and other radiologic parameters (osteophyte size, severity of osteoarthritis and angulation of distal femoral joint surface) were not significantly correlated with reducibility of varus deformity.     

Postoperative limb alignment and its determinants after minimally invasive Oxford medial unicompartmental knee arthroplasty

One hundred twenty-two consecutive minimally invasive Oxford phase 3 medial unicompartmental knee arthroplasties in 109 patients were evaluated for postoperative limb alignment and the influence of factors such as preoperative limb alignment, age, body mass index, sex, insert thickness, and surgeon's experience. The mean mechanical preoperative hip-knee-ankle (HKA) angle of 172.2° ± 3.1° improved to 177.1° ± 2.9° postoperatively. In 75% of the limbs, the HKA angle was restored to within an acceptable alignment of 177° ± 3°, 14% of the limbs were in excessive varus (<174°), and 11% were in valgus (>180°). Only preoperative HKA angle was predictive of postoperative HKA angle. Although most of the limbs had acceptable limb alignment after unicompartmental knee arthroplasty, limbs with more severe preoperative varus deformity had a tendency to remain in excessive varus, and limbs with lesser preoperative varus deformity had a greater tendency to go into valgus postoperatively.     

Risk factors of post-operative malalignment in fixed-bearing medial unicompartmental knee arthroplasty

Purpose

The purpose of this study was to identify risk factors of post-operative malalignment in medial unicompartmental knee arthroplasty (UKA) using multivariate logistic regression.

Methods

We retrospectively enrolled 92 patients who had 127 medial UKAs. According to post-operative limb mechanical axis (hip-knee-ankle [HKA] angle), 127 enrolled knees were sorted into acceptable alignment with HKA angle within the conventional?±?3 degree range from a neutral alignment (n?=?73) and outlier with HKA angle outside?±?3 degree range (n?=?54) groups. Multivariate logistic regression was used to analyse risk factors including age, gender, body mass index, thickness of polyethylene tibial insert, pre-operative HKA angle, distal femoral varus angle (DFVA), femoral bowing angle (FBA), tibial bone varus angle (TBVA), mechanical distal femoral and proximal tibial angles, varus and valgus stress angles, size of femoral and tibial osteophytes, and femoral and tibial component alignment angles.

Results

Pre-operative DFVA, TBVA and valgus stress angle were identified as significant risk factors. As DFVA increased by one degree, malalignment was about 45 times probable (adjusted OR 44.871, 95 % CI 2.608–771.904). Shift of TBVA and valgus stress angle to a more varus direction were also significant risk factors (adjusted OR 13.001, 95 % CI 1.754–96.376 and adjusted OR 2.669, 95 % CI 1.054–6.760).

Conclusions

Attention should be given to the possibility of post-operative malalignment during medial UKA in patients with a greater varus angle in pre-operative DFVA, TBVA and valgus stress angle, especially with a greater varus DFVA, which was the strongest predictor for malalignment.

     

Results of total knee arthroplasty with medial epicondylar osteotomy to correct varus deformity.

The clinical results of using medial epicondylar osteotomies to correct varus deformities in total knee arthroplasties were investigated. Unlike the traditional method of subperiosteal stripping of tibial ligaments, this alternative does not damage ligaments. Between 1991 and 1996, the senior author performed medial epicondylar osteotomies in 80 patients (93 knees) with primary total knee arthroplasty; of these, 60 patients (70 knees) were available for 2- to 4-year followup. At followup, no patients reported knee instability. Mean varus and valgus stability measured 14.2 points (Knee Society scale, 0-15 points). The Knee Society clinical score was 93 points, compared with a preoperative score of 42 points. The mean range of motion at followup was 111 degrees, compared with a preoperative mean of 101 degrees. The postoperative tibiofemoral angle on full limb radiographs taken with the patient weightbearing averaged 7 degrees valgus, compared with an average 6 degrees varus preoperative angle. Ninety-five percent of the patients were satisfied and reported less pain and improved knee function. Bone union occurred in 54% of the knees and fibrous union occurred in 46%. Focal tenderness, restricted motion, or other symptoms were not associated with fibrous union. The results show that epicondylar osteotomy for varus knee deformity provides excellent patient satisfaction, knee stability, motion, and deformity correction.     

Analysis of medial flexion gap after medial release for varus deformity by navigation-guided TKA

The goal of this study was to analyze medial flexion gaps after medial release for varus deformity by navigation-guided total knee arthroplasty (TKA). In each patient, a preoperative standing anteroposterior (AP) radiograph of the lower extremity and an AP valgus stress radiograph of the knee were used to measure preoperative mechanical axis angle and valgus stress angle, respectively. The correlation between preoperative varus deformities and medial flexion gap increases as measured by navigation was examined. Patients were assigned to 2 groups: group A (25 knees), in which the difference between the lateral flexion gap (LFG) and the medial flexion gap (MFG) (LFG-MFG) was ≤ 1 mm; and group B (73 knees), with an LFG-MFG of >1 mm.Mean preoperative mechanical axis angles in groups A and B were 13.21° ± 5.01° varus (range, 3.7°-23.6°) and 10.05° ± 3.70° varus (range, 1.9° - 23.7°), respectively. Mean preoperative valgus stress angles in groups A and B were 1.72° ± 0.89° valgus (range, 0.1° - 4.0°) and 4.84° ± 2.61° valgus (range, 0.1° - 11.7°), respectively. A significant difference was observed between the groups in terms of mechanical axis angle (P = .002) and valgus stress angle (P<.001). Furthermore, valgus stress angle was found to be more strongly correlated with medial flexion gap increase than mechanical axis angle. The cutoff values of mechanical axis angle and valgus stress angle in group A were 13.4° and 2.45°, respectively.This study shows that preoperative valgus stress angle measurements can be used to predict the extent of medial release for varus deformity.