全膝置换术中股骨假体旋转参照轴的影像学比较研究

目的比较全膝置换术中确定股骨假体旋转对线的参照方法———股骨上髁轴与Whiteside′s线的准确性,旨在为国人的人工膝关节手术技术提供实验依据,以减少术后髌股关节并发症的发生率。方法选择80例正常人(年龄19～42岁,男女各半)的膝关节作为研究对象,应用螺旋CT扫描(层厚0.5mm)获取股骨远端精确的横断面图像,通过测量比较股骨上髁轴、Whiteside′s线与股骨后髁轴之间的关系,运用统计学方法分析其准确性。结果股骨上髁轴与股骨后髁轴的夹角(股骨后髁角)为男性6.7°±1.5°,女性6.4°±1.8°,Whiteside′s线与股骨后髁轴的夹角为男性7.2°±3.1°,女性7.8°±3.2°。性别之间无显著性差异(P>0.05)。结论股骨上髁轴作为股骨假体旋转对线的参照较为恒定可靠,而Whiteside′s线的变异度较大、重复性较差。国人的股骨后髁角比西方人大,术中如以股骨后髁轴外旋3°来放置股骨假体,容易出现假体内旋。     

全膝关节置换术中髌骨处理方法的研究

目的 比较全膝关节置换术(total knee arthroplasty,TKA)中保留髌骨下进行髌骨成形与髌骨置换的术后临床疗效,探讨膝关节置换中合适的髌骨处理方法.方法 回顾性分析2002年1月-2008年12月收治的共198例行TKA治疗的单纯骨关节炎患者,其中62例行髌骨置换术,136例行保留髌骨下髌骨成形术.术中对髌骨进行去除骨赘后进行成形,使之与原髌骨关节面比较相近.术后定期随访进行美国膝关节协会评分(KSS)、Bristol髌骨评分、患者满意度、膝关节活动度及分析术后膝前疼痛发生率,并复查X线片了解内置物情况.结果 共125例获得随访,其中置换组43例,成形组82例,随访时间36～80个月,平均51个月.两组患者术后较术前各项评分明显提高.术后1年随访时两组患者术后膝关节活动度、KSS总评分、髌骨评分、患者满意度差异无统计学意义,而KSS功能评分两组之间差异有统计学意义,成形组优于置换组.而术后膝前疼痛发生率两者有差异但无统计学意义.术后X线片示髌股匹配程度、术后膝前疼痛发生率及髌骨相关并发症发生率两组间差异无统计学意义.结论 髌骨成形术在TKA中髌骨不置换时能够使髌股关节达到良好匹配,术后膝前疼痛发生率低,中短期疗效与髌骨置换相当.     

旋转平台高屈曲型人工全膝关节置换术的临床应用

目的 探讨旋转平台高屈曲型人工全膝关节置换术(total knee replacements,TKR)的特点及临床效果.方法 对61例患者(78膝)行旋转平台高屈曲型(Sigma RP-F)人工TKR,其中17例为双侧膝关节置换.男13例15膝,女48例63膝;年龄45～79岁,平均64.3岁.术前诊断:膝骨关节炎56例,类风湿关节炎5例.采用正中切口髌旁内侧入路,所有膝关节都未进行髌骨置换,但对髌骨进行去神经化和修复术.结果 本组随访3～16个月,平均10.5个月.影像学显示无松动,无髌骨翘起、半脱位或脱位.临床评定采用美国膝关节学会(KSS)评分,术前平均膝评分48分(33～72分),膝功能评分41分(28～63分),术后随访膝评分97分(88～100分),膝功能评分96分(84～99分),膝关节活动度平均为(130.)(110.～150.),未发现假体旋出、不稳定或感染的患者.结论 旋转平台高屈曲人工全膝关节可提供足够的关节接触面积、全程的髌骨轨迹、足够的胫骨关节轴向旋转自由度,使膝关节可安全达到高屈曲的目的,近期随访疗效满意,但是否达到实验室分析的减少磨损、增加假体使用寿命的目的仍需进一步随访.     

应用旋转平台人工全膝关节置换术的初步报告

目的探讨旋转平台人工全膝关节置换术的临床效果。方法对49例患者行70膝的Sigma旋转平台人工全膝关节置换术，其中21例为双侧膝关节置换。男7例，女42例；年龄38—78岁，平均63岁。术前诊断膝骨关节炎42例，类风湿关节炎7例。采用正中切口髌旁内侧入路、后稳定型假体，所有膝关节都未进行髌骨置换，但对髌骨进行去神经化和修复术。结果本组随访时间6—22个月，平均12．7个月，共70膝。影像学显示均无松动，无髌骨脱位。对膝关节临床评定采用美国膝关节学会评分（KSS评分），术前膝评分49分（35—70分），膝功能评分40分（30—60分），术后最后一次随访膝评分为96分（83—100分）；功能评分为95分（65—100分），没有旋转平台的旋出，没有翻修或者感染的发生。结论旋转平台人工全膝关节置换术在运动学分析和实验室磨损试验的数据上有潜在的优势，尤其是在年轻的活动能力强的患者，近期随访获得了满意的疗效，远期的疗效还需进一步随访。     

全膝关节置换术的隐性失血及影响因素分析

目的 研究全膝关节置换术(total knee arthroplasty,TKA)后隐性失血的特点及影响因素,为临床工作提供参考依据. 方法对75例因膝关节骨性关节炎行初次单侧TKA患者(男21例,女54例;平均年龄68.7岁)进行回顾性分析;应用Gross方程推算隐性失血量.分析性别、术中是否松止血带止血、是否应用自体引流血回输等因素对TKA术后隐性失血量的影响. 结果 本组围术期总失血量(1 551.3±369.6)ml,隐性失血量(792.3±228.6)ml.男性患者的隐性失血量高于女性(P＜0.05);术中松止血带止血能减少隐性失血量(P＜0.05);应用自体引流血回输对隐性失血量无显著影响. 结论取术后红细胞压积(Hct)的最低值(行异体输血的患者选输血后的最低值)作为参数计算隐性失血量更具有代表性.男女患者之间的相对隐性失血量差异无统计学意义;术中松止血带止血可减少隐性失血量,但对围术期总失血量不产生影响.术后自体引流血回输并不影响围术期总失血量和隐性失血量,但可降低异体血输血率.     

全膝关节置换术的并发症

膝关节置换真正进入临床阶段，是在1970年以后。三十多年来，技术不断改进，人工关节的使用寿命逐渐延长，10年寿命可达95.4％～98％，90％超过了15年。但是由于其非生物自然体属性，必然会带来不少并发症，从而使TKR翻修逐年增加。膝关节置换种类很多，目前使用最多的是表面型全膝关节置换术(total condylar prosthesis)，     

全膝关节置换术后的功能康复训练

目的介绍全膝关节置换术后的康复训练方法，总结其效果。方法对140例行全膝关节置换术的患者，进行1年系统的康复训练，按美国特种外科医院（HSS）膝关节功能评分标准，术前膝关节评分（51．25±6．10）分，康复内容包括：肌力、肌耐力、本体感受功能、活动度、理疗、心理治疗。通过功能评分、稳定性、肌力、满意度等几方面，评价其效果。结果术后3个月，膝关节肿胀已消除，术后平均1年患膝股四头肌、胭绳肌、腓肠肌肌力均达到Ⅳ级[徒手肌力评定（MMT）分级]以上，88．33％患者均能恢复正常步态和上下楼梯。患者主观满意程度高，术后12个月膝关节功能评分（87．13±7．43）分，与术前相比，差异有统计学意义（P〈0．01）。结论对于行全膝关节置换术后患者，采用该康复方法切实有效。     

全膝关节置换术后MAVRIC-SL技术减低金属伪影效果的评估

目的:与二维快速自旋回波金属伪影减少序列（2D FSE MARS）相比较,评估多采集变谐波图像融合-选择性激发序列（MAVRIC-SL）在全膝关节假体置换术后的减低金属伪影效果。方法:前瞻性收集2018年12月至2020年12月间在北京清华长庚医院接受全膝关节置换术后78例患者（101侧膝关节）,均于术后2周内接受3....     

软组织平衡对全膝关节置换时膝外翻畸形的矫正作用观察

目前认为,膝关节周围软组织不平衡是影响全膝关节置换术后远期效果的主要因素之一,可使金属假体与聚乙烯内衬之间应力集中,加速内衬磨损,也可由于膝关节不稳定而导致假体松动。因此,保证全膝关节置换术中软组织平衡极为重要。膝外翻畸形患者行人工全膝关节置换术难度较大,争议颇多,我科2006-2010年行膝关节置换矫正外翻畸形23例,术中应用软组织平衡技术,取得了较好疗效,现报告如下。     

膝关节股骨远端截骨导板的旋转对截骨准确性的影响

目的:研究股骨远端截骨定位器械旋转对股骨远端截骨面的影响。方法:术中截骨验证:在外旋位时股骨远端截骨导板相对后倾;内旋位时股骨远端截骨导板相对前倾;股骨截骨导板的外翻角度则随着内外旋角度的增大而减小。据此建立数学模型计算:以髓内杆为旋转轴,标准位时股骨远端截骨导板与髓内杆在冠状面存在有角度A的外翻,而在矢状面上有角度B的前后倾。定义实际外翻角A’为实际的截骨面与髓内杆垂直面在冠状面上的夹角,实际前后倾角度B’为实际的截骨面与髓内杆垂直面之间在矢状面上的夹角,实际股骨远端截骨导板相对标准位的截骨导板旋转角度为C。通过数学模型计算实际外翻角A’和实际前后倾角度B’。结果:通过计算得出tan A’=tan A*cos C,sin B’=sin A/(1+cos2 A/tan2C)1/2(当C为正值时B’取正值,当C为负值时B’取负值)。当A取5°、6°或7°时,在30°股骨截骨导板的旋转偏差范围内,对实际的外翻角度的影响较小,在1°偏差以内。无论内外旋转,实际的外翻角度均小于设定的外翻角A;但对于实际的前后倾影响较大,当A取6°、旋转角度为30°时,前后倾的偏差约3°。结论:膝关节置换术中股骨远端截骨导板的旋转对截骨面的前后倾与外翻有较大的影响。     

Rotation of intramedullary alignment rods affects distal femoral cutting plane in total knee arthroplasty

Purpose

Intramedullary rods are widely used to align the distal femoral cut in total knee arthroplasty. We hypothesised that both coronal (varus/valgus) and sagittal (extension/flexion) cutting plane are affected by rotational changes of intramedullary femoral alignment guides.

Methods

Distal femoral cuts using intramedullary alignment rods were simulated by means of a computer-aided engineering software in 4°, 6°, 8°, 10°, and 12° of valgus in relation to the femoral anatomical axis and 4° extension, neutral, as well as 4°, 8°, and 12° of flexion in relation to the femoral mechanical axis. This reflects the different angles between anatomical and mechanical axis in coronal and sagittal planes. To assess the influence of rotation of the alignment guide on the effective distal femoral cutting plane, all combinations were simulated with the rod gradually aligned from 40° of external to 40° of internal rotation.

Results

Rotational changes of the distal femoral alignment guides affect both the coronal and sagittal cutting planes. When alignment rods are intruded neutrally with regards to sagittal alignment, external rotation causes flexion, while internal rotation causes extension of the sagittal cutting plane. Simultaneously the coronal effect (valgus) decreases resulting in an increased varus of the cutting plane. However, when alignment rods are intruded in extension or flexion partly contradictory effects are observed. Generally the effect increases with the degree of valgus preset, rotation and flexion.

Conclusion

As incorrect rotation of intramedullary alignment guides for distal femoral cuts causes significant cutting errors, exact rotational alignment is crucial. Coronal cutting errors in the distal femoral plane might result in overall leg malalignment, asymmetric extension gaps and subsequent sagittal cutting errors.

     

Changes in patellar alignment after total knee arthroplasty

Although the results of total knee arthroplasty continue to improve, problems related to the patellofemoral joint remain significant. This study examined the factors affecting patellar alignment after total knee arthroplasty and subsequent changes in 56 knees during a postoperative period of 5.3 years. None of the knees examined displayed any clinical complications of the patellofemoral joint; no revision surgeries were necessary, with acceptable patellar alignment on average. The patellar resection angle had a strong influence on patellar alignment. Thinning of the patellar remnant on the medial side can increase postoperative lateral tilt, which leads to a need for lateral retinacular release. Although the changes in patellar alignment were minimal, the tendency that postoperative varus alignment resulted in patellar lateral tilt was observed. As postoperative femorotibial misalignment can lead to patellofemoral problems after total knee arthroplasty, surgeons need to pay scrupulous attention to femorotibial alignment and proper patellar preparation to decrease patellofemoral complications.     

The femoral sulcus in total knee arthroplasty

The position of the femoral sulcus relative to the midline of the distal femoral resection in total knee arthroplasty (TKA) was studied to determine if centralized placement of the femoral component on the distal femur was justified in terms of aligning the prosthetic sulcus with the native femoral sulcus. The location of the femoral sulcus was studied in 112 consecutive patients undergoing TKA. The mean sulcus position was 0.7 mm lateral to the midline of the distal femoral resection (SD 1.4, 95% CI, 0.5–1.0 mm). However, the variation in sulcus positions ranged from 4 mm medial to 4 mm lateral to the midline. The mean sulcus position in valgus knees was 1.0 mm lateral to the midline (SD 1.8), and that in varus knees was 0.7 mm lateral to the midline (SD 1.2) (P = 0.501). It appears prudent to centre the femoral component on the native sulcus rather than the midline of the distal femoral resection, so as to ensure accurate alignment of the prosthetic sulcus with the native sulcus and to encourage normal patella tracking.     

The accuracy of the extramedullary and intramedullary femoral alignment system in total knee arthroplasty for varus osteoarthritic knee

Purpose

The intramedullary (IM) femoral alignment system does not alway guarantee accuracy of the component position in the total knee arthroplasty (TKA). In some cases, the extramedullary (EM) femoral alignment system in total knee arthroplasty (TKA) is a useful alternative surgical option to adjust femoral component alignment. In the EM technique, accuracy of the femoral head center location is mandatory. The purpose of this prospective randomized study was to compare the alignment after TKA using two different femoral alignment systems.

Methods

From January 2009 to December 2009, 91 patients (106 knees) with osteoarthritis underwent TKA. The IM femoral alignment system was used in 50 TKAs, and the EM system was used in 56 TKAs. We measured the coronal, sagittal alignment of the femoral component, and overall alignment from full-length standing. Anteroposterior radiographs were taken 1 year after surgery.

Results

The overall limb alignment was 0.2° ± 1.9° varus in the EM group and 1.1° ± 1.9° valgus in the IM group (p = 0.001). The coronal alignment of the femoral component was 90.0° ± 1.1° in the EM group and 90.3° ± 1.2° in the IM group, not statistically different (n.s.). The sagittal alignment of the femoral component was 2.3° ± 1.7° in the EM group and 2.5° ± 1.0° in the IM group (n.s.). Clinically acceptable overall limb alignment was achieved in 91.1 % of EM group and 84.0 % of IM group (n.s.).

Conclusion

The present study suggests that by applying our EM technique that uses a newly designed mechanical axis marker system, the alignment of the femoral component and overall limb alignment is reliable and at least as accurate as the standard IM technique.

Level of evidence

I.     

Fixed versus mobile weight-bearing prosthesis in total knee arthroplasty

Purpose

This study was designed to compare clinical, radiological, and general health results of two prostheses (mobile vs. fixed weight-bearing devices) that are used in total knee arthroplasty with a 5-year follow-up.

Methods

This randomized controlled study was conducted from 2004 to 2010 in the Department of Orthopedic Surgery at two university hospitals in Isfahan, Iran. Three hundred patients with expected primary total knee arthroplasty (TKA) without severe deformity (a fixed varus or valgus deformity greater than 20°) received fixed weight-bearing (n = 150) or mobile weight-bearing (n = 150) devices. Clinical, radiological, and quality of life outcomes were compared between the two groups at six-month intervals for the first year, after which the comparisons were made annually for the next 4 years.

Results

Both groups had similar baseline characteristics. Although there was significant improvement in both groups, there was no significant difference between the groups with regard to the means of the Knee Society Scores, which were 92 (SD: 12.1) for the fixed weight-bearing device and 93 (SD: 14.2) for the mobile weight-bearing device (n.s.) at the final follow-up point. Radiographs showed that there was no significant difference in prosthetic alignment and no evidence of loosening. After TKA, the SF-36 score increased in both groups, but there was no statistical difference between the groups in quality of life at the final follow-up (62 (12.2) vs. 64 (14.3), n.s.). There was no revision after 5 years.

Conclusions

In terms of clinical, radiological or general health outcomes for people who underwent TKA, the results of this study showed no clear advantage of mobile weight-bearing over the fixed weight-bearing prosthesis at the five-year follow-up.

Level of evidence

I.     

Hindfoot alignment at one year after total knee arthroplasty

Purpose

It has previously been found that valgus hindfoot alignment (HFA) improves 3 weeks following total knee arthroplasty (TKA) for varus knee osteoarthritis (OA). In the present study, HFA was evaluated prior to TKA, as well as 3 weeks and 1 year following TKA. Using these multiple evaluations, the chronological effects of TKA on HFA were investigated.

Methods

The study included 71 patients (73 legs) who underwent TKA for varus knee OA. Radiograph examinations of the entire limb and hindfoot were performed in the standing position prior to TKA, as well as 3 weeks and 1 year following TKA. The varus–valgus angle was used as an indicator of HFA in the coronal plane. Patients were divided into two groups according to the preoperative varus–valgus angle: a hindfoot varus group (varus–valgus angle <76°) and a hindfoot valgus group (varus–valgus angle ≥76°). The changes in the varus–valgus angle were evaluated and compared in both groups.

Results

In the hindfoot valgus group, the mean ± standard deviation varus–valgus angle significantly declined from 80.5 ± 3.1° prior to TKA to 78.6 ± 3.7° 3 weeks following TKA and 77.1 ± 2.7° 1 year following TKA. However, in the hindfoot varus group, the mean varus–valgus angle prior to TKA (72.7 ± 2.6°) did not differ significantly from the mean varus–valgus angles 3 weeks (72.3 ± 3.3°) or 1 year (73.5 ± 3.0°) following TKA.

Conclusions

HFA improved chronologically in legs with hindfoot valgus as a result of the alignment compensation ability of the hindfoot following TKA. However, no improvement was noted in legs with hindfoot varus because the alignment compensation ability of the hindfoot had been lost. The patients with hindfoot varus should be attended for ankle pain in the outpatient clinic after TKA.

Level of evidence

III.

     

Kinematic alignment is a possible alternative to mechanical alignment in total knee arthroplasty

Purpose

A systematic review was conducted to answer the following questions: (1) Does kinematically aligned (KA) total knee arthroplasty (TKA) achieve clinical outcomes comparable to those of mechanically aligned (MA) TKA? (2) How do the limb, knee, and component alignments differ between KA and MA TKA? (3) How is joint line orientation angle (JLOA) changed from the native knee in KA TKA compared to that in MA TKA?

Methods

Nine full-text articles in English that reported the clinical and radiological outcomes of KA TKA were included. Five studies had a control group of patients who underwent MA TKA. Data on patient demographics, clinical scores, and radiological results were extracted. There were two level I, one level II, three level III, and three level IV studies. Six of the nine studies used patient-specific instrumentation, one study used computer navigation, and two studies used manual instrumentation.

Results

The clinical outcomes of KA TKA were comparable or superior to those of MA TKA with a minimum 2-year follow-up. Limb and knee alignment in KA TKA was similar to those in MA TKA, and component alignment showed slightly more varus in the tibial component and slightly more valgus in the femoral component. The JLOA in KA TKA was relatively parallel to the floor compared to that in the native knee and not oblique (medial side up and lateral side down) compared to that in MA TKA. The implant survivorship and complication rate of the KA TKA were similar to those of the MA TKA.

Conclusion

Similar or better clinical outcomes were produced by using a KA TKA at early-term follow-up and the component alignment differed from that of MA TKA. KA TKA seemed to restore function without catastrophic failure regardless of the alignment category up to midterm follow-up. The JLOA in KA TKA was relatively parallel to the floor similar to the native knee compared to that in MA TKA. The present review of nine published studies suggests that relatively new kinematic alignment is an acceptable and alternative alignment to mechanical alignment, which is better understood. Further validation of these findings requires more randomized clinical trials with longer follow-up.

Level of evidence

Level II.