股骨假体旋转对线技术对髌骨轨迹优化的临床研究

目的进行人工全膝关节置换术中股骨假体旋转对线技术对髌骨轨迹作用的随机化、前瞻性的临床研究。方法150例骨关节炎患者接受初次人工全膝关节置换术，其中40例接受双膝同期置换，密封信封抽样随机分组确定股骨假体旋转对线的参照标准，以“布巾钳试验”评价髌骨轨迹，决定是否作外侧支持带松解。结果股骨上髁轴组10个膝需行外侧支持带松解，股骨后髁轴组23个膝需行外侧支持带松解，两组差异有显著性（P〈0．05）。结论股骨假体旋转对线对于髌骨轨迹的优劣有着显著影响，股骨上髁轴作为旋转对线的参照轴可以明显改善髌骨轨迹。     

全膝关节置换术中股骨假体旋转对髌股关节生物力学影响的实验研究

目的探讨全膝置换术中股骨假体的轴向旋转对髌股关节生物力学的影响,为临床指导人工膝关节置换的手术技术提供实验依据,以减少术后髌股关节的并发症。方法取9具正常国人新鲜冷冻尸体的9个膝关节作为研究对象,模拟膝关节自站立位屈膝下蹲的动作,设计制作膝关节实验架,与Instron 8501生物力学测试仪共同搭建实验平台。人工膝关节采用Nexgen LPS全膝系统,手术由同一位有经验的术者实施以控制实验误差,不置换髌骨。比较股骨假体相对于经股骨上髁轴内旋2°、内旋4°、旋转0°(与经股骨上髁轴平行)、外旋2°、外旋4°、平行于Whiteside线等6个不同的轴向旋转位置时的髌股关节的生物力学指标。选择屈膝30°、60°、90°、120°为观察角度,采用日本富士公司生产的压敏片测定髌股接触面积和峰值接触压,最后经扫描和软件处理得到数字化的结果。结果当股骨假体的旋转与经股骨上髁轴平行时,测得的髌股关节峰值接触压结果最优(P< 0．05)。各股骨假体旋转对线组测得的髌股接触面积无显著差异(P>0．05)。但不同标本、不同观察角度下的髌股接触形态不同。结论全膝置换术中股骨假体的轴向旋转对线对于髌股关节的接触压影响较显著,经股骨上髁轴作为股骨假体的旋转对线的参照较为可靠。     

两种不同股骨假体旋转设计对全膝关节置换术后髌骨轨迹的影响

目的探讨传统股骨假体外旋技术和内置外旋的股骨假体设计对全膝关节置换（TKA）术后髌骨轨迹和整体疗效的影响.方法 本前瞻随机对照研究纳入2004年9月至2008年3月间共360例接受TKA的患者,术前随机将患者分为A组（股骨假体外旋放置组,使用PFC Sigma固定平台假体）和B组（内置外旋股骨假体组,使用Genesis Ⅱ固定平台假体）,每组各180例.所有手术均由同一组高年资关节外科医师实施,均未置换髌骨,仅行髌骨表面修整,根据术中髌骨轨迹决定是否需要行外侧支持带松解,术后接受相同的围手术期镇痛和康复训练流程.术后常规随访,使用HSS评分和WOMAC评分评估整体疗效,术后1年及末次随访时拍摄髌骨轴位片评估髌骨位置.结果 纳入研究的360例患者,均完成术后3个月及1年的随访.坚持随访的163例患者（A组74例,B组89例）平均随访时间为5.25年（3.5～7年）,其中2例因术后假体感染而翻修,无假体失败病例.术中外侧支持带松解发生率A组为8.1%（13/160）,B组为6.9%（11/160）,两组间没有统计学差异.术后1年髌骨轴位片两组均未出现髌骨脱位病例.两组间术后膝前疼痛的发生率、术后HSS评分与WOMAC评分无统计学差异.结论 传统股骨假体外旋技术和内置外旋的股骨假体设计均可获得良好的平衡伸直-屈曲间隙,改善髌骨轨迹.鉴于患者股骨外旋变异较大,传统股骨假体外旋技术应综合参照后髁轴和经上髁轴,内置外旋的股骨假体设计也应根据患者个体差异进行调整.     

止血带对全膝关节置换术中股骨远端旋转定位时髌骨轨迹的影响

目的 探讨止血带对全膝关节置换术中以外科髁上轴线为股骨远端旋转定位线的髌骨轨迹的影响.方法 2002年12月至2008年8月,首选以外科髁上轴线为股骨远端旋转定位标志的初次全膝关节置换349例(526膝),男124例(155膝),女225例(371膝);年龄33～84岁,平均68岁.膝内翻387膝,膝外翻94膝.均使用同一种保留后十字韧带的活动平台假体,由同一位手术医生操作.采用前内侧髌旁入路,以外科髁上轴线为股骨远端旋转定位线,以no thumb test检测髌骨轨迹.对髌骨轨迹不良者,缝合髌骨内上缘支持带并松开止血带.对再次检查髌骨轨迹不良者行外侧支持带松解术.术后3个月患者能够极度屈曲膝关节时摄X线片检查髌骨轨迹.结果 术中no thumb test阳性138膝,其中半脱位12膝(膝外翻),髌骨倾斜126膝(膝外翻74膝).缝合髌骨内上缘支持带并松开止血带后,no thumb test阳性40膝,其中半脱位8膝(膝外翻),髌骨倾斜32膝(膝外翻29膝).髌骨外侧支持带松解率7.6%(40/526),膝外翻松解率39.4%(37/94).结论 在全膝关节置换术中,高压止血带对髌骨轨迹有干扰作用.术中缝合髌骨内上缘支持带并松开止血带,可降低外侧支持带松解率.     

止血带对全膝关节置换术中股骨远端旋转定位时髌骨轨迹的影响

Objective To explore, the influence of tourniquet application on patellar tracking with using the surgical transepieondylar axis as distal femur alignment in total knee arthroplasty (TKA). Methods From December 2002 to August 2008, 349 cases (526 knees) of primary TKA were performed. There were 124 males and 225 females with an average age of 68 years from 33 to 84 years. A total of 387 knees had varus deformity and 94 had valgus deformity. All of prosthesis were rotating platform with posterior cruciate ligament retaining provided by Gemini MK Ⅱ. All patients underwent anterior medial parapatellar approach. The surgical transepieondylar axis had been principally used as the distal femur alignment. Patellar tracking was checked with no thumb test. For maltracking ones, we prefered to use a single retinacular closing stitch at the superior medial arthrotomy and deflate tourniquets. Patellar tracking was checked again. Finally, later-al retinaeular releases (LRR) had been performed to obtain optimizing patellar tracking. Results Intraoper-atively, no thumb test were positive in 138 knees, including patellar subluxation (vaigus deformity) in 12 knees and patellar inclining (74 of valgns deformity and 52 of varus deformity) in 126 knees. After using a single retinacular closing stitch at the superior medial arthrotomy and deflating tourniquets, no thumb test were positive in 40 knees, including patellar subluxation (valgus deformity) in 8 knees and patellar inclining (29 of valgns deformity) in 32 knees. The total rate of LRR was 7.6% (40/526), the rate of LRR in valgus deformity was 39.4% (37/94) and that in yarns deformity and no deformity was 0.7% (3/432). Conclusion There was significant influence of tourniquet application on patellar tracking during the TKA. We were not falsely correcting patellar tracking problems with using a single retinaeular closing stitch at the superior me-dial arthrotomy anti deflating tourniquets intraoperatively and reducing the rate of LRR.     

胫骨假体旋转对线技术对髌股关节生物力学影响的实验研究

[目的]探讨全膝置换术中改变胫骨假体的旋转对线技术对髌股关节生物力学的潜在影响,指导术中进行正确的胫股旋转对线,以减少术后髌股关节并发症的发生。[方法]取9个新鲜冷冻人膝关节做实验,自行设计膝关节实验架,与Instron 8501生物力学测试仪共同搭建实验平台,模拟生理状态下膝关节自站立位屈膝下蹲的动作。人工膝关节采用LPS全膝系统,手术由同一位有经验的术者实施以控制实验误差,比较以胫骨结节内、中1/3交界为标志(胫骨结节对线技术)和以股骨假体位置(ROM对线技术)确定胫骨假体旋转的2种技术所获得的髌股关节的生物力学指标,选择30°、60°、90°、120°为实验的观察角度进行各组实验,应用日本富士公司生产的超低敏感型压敏片、低敏感型压敏片测定髌股关节的接触面积和接触压,最后用FPD-305E、FPD-306E压力测定仪和电脑软件处理后得到数字化结果。[结果]人工膝关节置换术中胫骨结节对线技术组与ROM对线技术组所获得的髌股关节的平均峰值接触压、平均接触面积等指标无统计学差异(P>0.10)。[结论]全膝置换术中股骨假体参照经股骨上髁轴确定旋转方位后,采用胫骨结节对线技术抑或ROM对线技术来确定胫骨假体的旋转对线对髌股关节的生物力学未见显著差异。对于旋转限制性较高的假体,ROM技术能够在正确的胫股旋转对线和良好的髌骨轨迹之间作出平衡。     

全膝关节置换术中髌骨面修整与髌骨置换的比较研究

目的比较全膝关节置换术髌骨面修整和髌骨置换的临床结果。方法2002年1月至12月对60例（60膝）行初次全膝关节置换术的骨性关节炎患者进行前瞻性、随机化研究。所有患者接受相同的后交叉韧带替代型全膝关节假体（PFC）,患者随机行髌骨面修整（髌骨面修整组）或髌骨置换（髌骨置换组）。58例患者平均随访54个月（40～60个月）,对其进行临床评价,包括膝关节协会评分（KSS）、膝关节活动度（ROM）、患者满意度和X线检查。结果两组患者KSS总评分（P=0．12）、KSS疼痛评分（P=0．90）、患者满意度（P=0．22）无明显差异;两组术后膝前痛的发生率均为10％亦无明显差异。两组ROM（P=0．028）和KSS功能评分（P=0．0098）差异有统计学意义。结论全膝关节置换术不论是髌骨面修整还是髌骨置换均能明显减轻疼痛和改善功能。术后膝前痛可能与假体设计和手术技术有关,并非与是否置换髌骨有关。     

全膝关节置换术中放开止血带并缝合内上缘支持带对髌骨轨迹的影响

目的 探讨在初次全膝关节置换术(TKA)中放开止血带且缝合内上缘支持带对髌骨轨迹的影响.方法 选择2006年3月至2008年2月初次行TKA的83例患者136侧膝关节.使用前内侧髌旁人路,检测髌骨轨迹.对于不良的髌骨轨迹,术中松开止血带且仅用一针缝合髌骨内上缘支持带.再次检查髌骨轨迹.最后,对残留不良髌骨轨迹的患者行外侧支持带松解术,以求获得满意的髌骨轨迹.采用no-thumb试验作为检测髌骨轨迹的标准.结果 在初次行TKA的83例患者136侧膝关节中,在未松开止血带前,髌骨轨迹不良率为64.7%(88/136).放开止血带且缝合髌骨内上缘支持带后,髌骨外侧支持带松解率为26.5%(36/136),差异有统计学意义(X2=38.55,P＜0.01).其中,膝外翻畸形患者的松解率为58.6%(17/29),膝内翻和无明显畸形患者的松解率为17.8%(19/107).结论 高压止血带对行前内侧髌旁人路TKA的患者髌骨轨迹的干扰作用非常明显.术中松开止血带且缝合髌骨内上缘支持带明显降低了外侧支持带的松解率,从而降低了其可能带来的并发症.     

全膝关节置换术中髌骨置换与否对早期疗效及膝前痛的影响

 目的 探讨全膝关节置换术中髌骨置换与否对早期疗效及膝前痛发生率的影响。方法 2010年6月至2011年6月拟行全膝关节置换术患者100例,随机分为两组：髌骨置换组43例50膝,髌骨未置换组57例66膝。比较术后6个月、12个月两组患者的西安大略和麦克马斯特大学(West Ontario and McMaster Universities,WOMAC)骨关节炎指数、美国膝关节外科协会(Knee Surgery Society,KSS)膝评分和功能评分、膝前痛视觉模拟评分(visual analogue scale,VAS)。结果 髌骨置换组与髌骨未置换组患者术后膝前痛VAS评分均较术前明显降低,两组间VAS评分及膝前痛发生率的差异无统计学意义。WOMAC骨关节炎指数6个月分别为28.8±11.2和18.6±7.2、术后12个月分别为20.7±6.2和16.0±5.5,KSS膝评分6个月分别为(87.0±8.3)分和(90.9±7.2)分、术后12个月分别为(84.2±10.6)分和(88.8±9.2)分,KSS功能评分术后6个月分别为(86.6±21.6)分和(84.9±16.5)分、术后12个月分别为(85.2±16.4)分和(91.0±10.0)分,组间差异均无统计学意义。髌骨轴位X线片示髌骨与股骨假体滑车吻合度良好,无不稳及脱位表现。术后1年内无翻修、髌骨表面再置换病例。结论 全膝关节置换术对改善因骨关节炎或类风湿关节炎导致的膝关节疼痛、功能受限有效;髌骨置换与否对术后短期疗效及膝前痛发生率没有影响。     

测量股骨髁旋转力线的比较研究

目的 探讨测量股骨后髁角(PCA)、髁扭转角(CTA)及前后轴线的垂线与后髁轴线的夹角(PAPA)的可重复性,为人工全膝关节置换术(TKA)股骨髁外旋截骨提供恒定可靠的参考角度. 方法选择80例正常成人膝关节的CT资料,由第一、第二观察者分别测量PCA、CTA和PAPA各3次,比较不同观察者测量以上角度均数的差异是否具有统计学意义. 结果对不同观察者分别测量所得的PCA均数进行比较,差异无统计学意义(P>0.05);对不同观察者分别测量所得的CTA及PAPA均数进行比较,差异具有统计学差异(P<0.05). 结论PCA作为TKA股骨髁外旋截骨的参考角度,其测量恒定可靠,可重复性强.     

Femoral Anterior Tangent Line of the Osteoarthritic Knee for Determining Rotational Alignment of the Femoral Component in Total Knee Arthroplasty

Several reference axes have been used to establish femoral rotational alignment during total knee arthroplasty. The current study examined the configuration of the anterior surface of the femur immediately proximal to the trochlea as an alternative rotational landmark. An analysis of computed tomographic images of 150 knees with osteoarthritis indicated that the configuration of the surface is mostly flat or slightly depressed, and the line tangential to the surface (femoral anterior tangent line; FAT line) was consistently determined to be 12.2° ± 3.6° internally rotated to the transepicondylar axis. This value was relatively constant and as reliable as the femoral anteroposterior axis for determining rotational alignment. In addition, the FAT line was not affected by the degree of the varus-valgus deformity of the osteoarthritic knees.     

Intraoperative Measurements of Femoral Anterior Tangent (FAT) Line for Determining the Rotational Alignment of Femoral Component of Total Knee Arthroplasty

Previously, we reported using CT images that the anterior surface of the femur immediately proximal to the trochlea and its tangent line (femoral anterior tangent line; FAT line) could be used as a good index of the femoral rotation. In this study, we developed a jig that allowed us to measure the FAT line during surgery, and we examine the relation between preoperative and intraoperative measurement values. The results indicated that the average intraoperative measurement value of the ‘surgical’ FAT line was 9.8° ± 3.2° internally rotated using surgical transepicondylar axis reference. This value significantly correlated to preoperative FAT line/clinical transepicondylar axis angle. These findings demonstrated that FAT line is a useful index for appropriate rotational alignment of femoral component, both before and during TKA.     

Patient Variation Limits Use of Fixed References for Femoral Rotation Component Alignment in Total Knee Arthroplasty

Background

Optimal rotational alignment of the femoral component is a common goal during total knee arthroplasty. The posterior condylar axis (PCA) is thought to be the most reproducible reference in surgery, while the transepicondylar axis (TEA) seems to better approximate the native kinematic flexion axis. This study sought to determine if rules based on patient gender or coronal alignment could allow reliable reproduction of the TEA from the PCA.

股骨侧弓畸形对全膝关节置换术预后的影响

目的 探讨冠状位股骨侧弓畸形的存在对全膝关节置换术（total knee arthroplasty,TKA）疗效的影响。方法 回顾性分析西安交通大学附属红会医院膝关节外科2015年1月至2017年12月接受TKA手术病人142例,其中男28例,女114例;年龄为（67.3±6.7）岁（52~82岁）。根据标准负重正位X线片测量病人股骨侧弓角（femoral bowing angle,FBA）。将FBA＜177°定义为股骨侧弓畸形,根据是否存在股骨侧弓畸形将病人分别纳入股骨侧弓畸形组和直股骨组。使用美国膝关节协会评分（Knee Society score,KSS）及西安大略和麦克马斯特大学（Western Ontario and McMaster University,WOMAC）骨关节炎指数评估病人功能状态。结果 142例病人平均随访49.4个月（43~55个月）。股骨侧弓畸形组59例,直股骨组83例,且股骨侧弓畸形组女性病人比例明显高于直股骨组,差异有统计学意义（P＜0.05）。所有病人在末次随访时的KSS评分、WOMAC评分及分量表均较术前得到明显的改善（P＜0.05）。进一步分析发现,末次随访时直股骨组与股骨侧弓畸形组病人的KSS膝总分［（78.1±6.2）分 vs. （75.1±7.8）分］、疼痛评分［（48.2±2.4）分 vs. （47.0±4.0）分］、WOMAC B部分（僵硬部分）得分［（0.4±0.7）分 vs. （0.7±1.1）分］相比,差异均有统计学意义（P＜0.05）。结论 股骨侧弓畸形多发生于女性;存在股骨侧弓畸形的骨关节炎病人行TKA术后近中期临床效果不及直股骨病人。     

机器人辅助与传统截骨行全膝关节置换术的早期临床疗效对比

目的 对比国产和华瑞博（HURWA）机器人导航辅助全膝关节置换术（robotic-assisted total knee arthroplasty,RATKA）与传统全膝关节置换术（TKA）治疗膝关节骨性关节炎（KOA）的早期临床疗效。方法 回顾性分析我科2021年3月至2022年1月收治的46例行TKA治疗终末期KOA的病人。其中RATKA组23例,男10例,女13例,年龄为（67.54±12.32）岁;传统TKA组23例,男8例,女15例,年龄为（70.34±9.74）岁。记录围手术期的髋-膝-踝角（HKA）偏移、股骨机械轴远端外侧角（mLDFA）、胫骨机械轴近端内侧角（mMPTA）、膝关节线汇聚角（JLCA）,作为评估力线对位及假体放置的影像学指标。采用术前与术后1天血红蛋白（HB）差值、术中出血量、术后引流量评估出血情况。随访并记录手术时间、膝前正中切口长度、术前及术后3个月膝关节活动度,术前、术后1个月、术后1年的美国膝关节协会评分（KSS）及疼痛视觉模拟量表（VAS）评分,以评估短期临床疗效。结果 手术均顺利完成,术后均未出现严重并发症。两组病人力线及假体对位指标均较术前明显改善,且在正常范围,RATKA组HKA偏移及术后JLCA优于传统TKA组,差异有统计学意义（P＜0.05）,但两组术后mLDFA、mMPTA比较,差异无统计学意义（P＞0.05）。RATKA组术中出血量及术后引流量略小于传统TKA组,但差异无统计学意义（P＞0.05）;RATKA组的手术时间、膝前正中切口长度均长于传统TKA组,术后1天与术前的HB差值低于传统TKA组,差异有统计学意义（P＜0.05）。两组病人术后3个月活动度、术后1个月及1年的KSS评分和VAS评分均较术前有明显改善,且RATKA组和传统TKA组术后3个月的活动度比较,差异有统计学意义（P＜0.05）,但两组KSS评分、VAS评分比较,差异无统计学意义（P＞0.05）。结论 国产HURWA机器人辅助行TKA相较传统TKA具有对线及假体放置更精准、出血少、关节活动度恢复更佳的优势,传统TKA在手术时间及切口长度方面优于RATKA。RATKA短期疗效值得肯定,远期预后有待进一步论证。     

MAKO机器人辅助与传统手工全膝关节置换术后下肢力线的对比研究

目的 比较MAKO机器人辅助与传统手工全膝关节置换术（TKA）术后下肢力线的准确性。方法 对2021年5月至2021年12月在解放军总医院第四医学中心骨科医学部关节外科行TKA治疗的74例（78膝）病人的临床资料进行回顾性分析,其中采用MAKO机器人辅助下TKA的37例（41膝）纳入机器人组,同期使用相同膝关节假体行传统手工手术的37例（37膝）纳入传统手工组。分别记录两组病人术中计划与术后实际测量的胫骨近端内侧角（MPTA）、股骨远端外侧角（LDFA）和下肢力线髋-膝-踝（hip-knee-ankle,HKA）角,并进行组内及组间分析比较。结果 两组病人均顺利完成手术,术后无手术相关并发症。机器人组的手术时间长于传统手工组［（110.67±80.56） min vs. （80.56±4.64） min］,差异有统计学意义（t=12.726,P＜0.001）。机器人组术后测量的MPTA、LDFA与术中末次计划的比较,差异均有统计学意义（P＜0.05）;但其计划和实际的HKA比较,差异无统计学意义（P＞0.05）。传统手工组术后测量的MPTA、HKA与术中末次计划的比较,差异均有统计学意义（P＜0.05）;但其计划和实际的LDFA比较,差异无统计学意义（P＞0.05）。通过计算两组病人计划与实际测量的差值,并进行比较,组间差异均有统计学意义（P＜0.05）。结论 MAKO机器人辅助下行TKA术后下肢力线及假体位置平均误差在1°以内,机器人辅助技术有助于精准安放假体,并实现计划力线。     

Rotational Alignment of the Femoral Component Using Trochlear Navigation During Total Knee Arthroplasty: A Dual-Center Study of 145 Cases

Rotational alignment of the femoral component during TKA is critical. Here we propose a technique using navigation of the femoral trochlea to determine the rotation of the femoral component. The rotation is considered “ideal” when the component position leads to the arthroplasty trochlea being perfectly superimposed over the native trochlea. Thus the arthroplasty trochlea will be aligned on the trochlear groove axis, which itself is perpendicular to the transepicondylar axis. This was a prospective, non-randomized, dual-center study involving 145 knees. In all knees, the rotation of the femoral component was determined intraoperatively by trochlear navigation. The alpha angle obtained with this method was compared to the one calculated on a preoperative or postoperative CT scan. There was excellent agreement between the results obtained with the CT scan method and the ones obtained with trochlear navigation.     

Infection and Instability Increasing the Risk of Patella Baja and Pseudo-Patella Baja after Revision Total Knee Arthroplasty

BackgroundPatella baja with patellar tendon shortening due to traumatic or ischemic injury is a widely known complication after primary total knee arthroplasty (TKA). Pseudo-patella baja may arise from the elevation of the joint line after excessive distal femoral resection. The maintenance of original patellar height is important in revision TKA because postoperative patella baja and pseudo-patella baja can cause inferior biomechanical and clinical results. We investigated the incidence and risk factors of patella baja and pseudo-patella baja after revision TKA.MethodsWe retrospectively reviewed data for 180 revision TKAs. Patella baja was defined as a truly low-lying patella with an Insall-Salvati ratio (ISR) of < 0.8 and a Blackburne-Peel ratio (BPR) of < 0.54. Pseudo-patella baja was defined as a relatively low-lying patella compared to the joint line within the normal range of ISR and with a BPR of < 0.54. Clinically, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and range of motion (ROM) were evaluated. Risk factors increasing the incidence of patella baja and pseudo-patella baja after revision TKA were evaluated using multiple regression analysis.ResultsBefore revision TKA, 169 knees did not exhibit patella baja or pseudo-patella baja, while 9 knees showed patella baja and 2 knees exhibited pseudo-patella baja. At 2 years after revision TKAs, 25 knees (13.9%) showed patella baja and 23 knees (12.8%) exhibited pseudo-patella baja. Despite no differences in the postoperative WOMAC score between groups with and without patella baja and pseudo-patella baja, the postoperative ROM was significantly smaller in the group with patella baja (113.3°) or pseudo patella baja (110.5°) than in the normal group (122.0°). Infection as the cause of revision TKA increased the risk of patella baja (odds ratio, 10.958; p < 0.001), and instability increased the risk of pseudo-patella baja (odds ratio, 11.480; p < 0.001).ConclusionsInfection and instability resulted in increases in the incidence of patella baja and pseudo-patella baja after revision TKA. Information about the risk factors of patella baja and pseudo-patella baja will help TKA surgeons plan the height of the patella after revision TKA and improve clinical outcomes.     

Extrinsic Factors as Component Positions to Bone and Intrinsic Factors Affecting Postoperative Rotational Limb Alignment in Total Knee Arthroplasty

Background

This study aimed to identify the factors affecting postoperative rotational limb alignment of the tibia relative to the femur. We hypothesized that not only component positions but also several intrinsic factors were associated with postoperative rotational limb alignment.

Femoral Component Rotation in Total Knee Arthroplasty: An MRI-Based Evaluation of our Options

Proper femoral component rotation is crucial in successful total knee arthroplasty. Rotation using anatomic landmarks has traditionally referenced the transepicondylar axis (TEA), Whiteside’s Line (WSL), or posterior condylar axis (PCA). TEA is thought to best approximate the flexion-axis of the knee, however WSL or PCA are common surrogates in the operating room. This study evaluated 560 knees using MRI-based planning software to assess the relationship of WSL and PCA to the TEA and determine if the relationships were influenced by pre-operative coronal deformity. Results showed the WSL–TEA relationship has more variability than PCA–TEA and that the PCA is more internally rotated in females and valgus knees. Axis options and historical assumptions about axis relationships may need to be reassessed as imaging technology advances.