Anatomic and functional reconstruction of the joint in severe bone and ligamentous knee instability with semi-constrained systems of total knee replacement

Background. The study was made to evaluate efficiency of semi-constrained systems of TKR in correction of severe bone and ligamentous instability in knee joint with degenerative disease. Material and methods. Retrospective investigation of the 50 consecutive TKRs performed in 40 patients (40 women) between 1995-2000 was made. There were following prosthesis implanted: GSB - 45 and Endo-Model - 5. 48 knees were evaluated. Patients' mean age was 65,6 years old. Mean time of follow-up was 32,8 months (range: 1-5 years). Functional status was evaluated according to KSS scale and radiographic results were investigated with standard plain x-ray pictures. Anatomic results were investigated by the computed posturography with the use of Metrecom Systems. Results. In study group there were: 26% excellent, 68% good, 4% fair and 2% poor results respectively in Knee Score (KSS). There are no statistical differences between anatomical and radiological results of TKR in the knee joints with severe deformity. A little poorer efficiency of the semi-constrained system of total knee arthroplasty in functional reconstruction of the knee joint was due to poor general-health status of the patients and multi-joint nature of their disease. Conclusions. 1. Results of TKR with semi-constrained systems in short-term follow-up (1-5 years) are very good. 2. Posturographic and radiographic studies show that with semi-constrained system of TKR allows for reconstruction of proper anatomy of the knee joint even in severe deformed cases. 3. Functional results of TKR with semi-constrained systems are good in severely unstable and deformed knee joints.     

Biomechanical assessment of unicompartmental knee arthroplasty, total condylar arthroplasty and tibial osteotom

A prospective biomechanical study of unicompartmental arthroplasty using the Oxford Meniscal Knee, total condylar arthroplasty, and tibial osteotomy is described. The 50 patients all had degenerative osteoarthrosis of the knee associated with a varus or valgus deformity. The decision as to which operation a patient would undergo was made on clinical grounds alone; 20 patients underwent unicompartmental arthroplasty, 10 patients total condylar arthroplasty, and 20 patients tibial osteotomy. Dynamic assessments of functional knee joint biomechanics were performed both before and after the surgery. Cadence, velocity and stride length improved in all three groups. Changes in sagittal plane knee parameters were generally small. In the corona) plane, all groups showed correction of varus or valgus deformity, with corresponding decreases in the adduction/ abduction moment. In the unicompartmental group the postoperative corona) plane angulation was predictable from its preoperative value. Some overcorrection of the varus deformity was observed after tibial osteotomy, and the total condylar arthroplasty group showed a small degree of residual deformity.     

Total knee arthroplasty in patients with severe deformities due to rheumatoid arthritis

In RA patients with a very aggressive disease, pathological changes in the knee occur in 90% of cases in the end-stage period. These changes are often accompanied by severe deformities, such as flexion contracture, valgus deformity, and more rarely varus deformity. In order to provide soft tissue balance, these deformities require additional surgery before implantation of the prosthesis. In this article the authors describe different methods, depending on the nature of the deformities, such as posterior release and lateral soft-tissue release, which should be done in successive stages. The problem of the patella and loss of bone stock for reconstruction is briefly discussed.     

Total knee arthroplasty in patients with severe deformities due to rheumatoid arthritis

In RA patients with a high activity disease, pathological changes in the knee occur in 90% of cases in the end-stage period. These changes are often accompanied by severe deformities, such as flexion contracture, valgus deformity, and more rarely varus deformity. In order to provide soft tissue balance, these deformities require additional surgery before implantation of the prosthesis. In this article the authors describe different methods, depending on the nature of the deformities, such as posterior release and lateral soft-tissue release, which should be done in successive stages. The problem of the patella and loss of bone stock for reconstruction is briefly discussed.     

全膝关节置换治疗膝关节外翻畸形

背景：膝关节外翻畸形临床相对较少,人工膝关节置换的治疗效果不如膝关节内翻畸形。对于置换入路、软组织松解方法步骤及假体选择目前均无统一看法。目的：总结病例资料,观察全膝关节置换治疗膝关节外翻畸形的临床效果。方法：回顾性分析甘肃省中医院关节骨一科同一组医师在2010年1月至2012年12月采用全膝关节置换治疗膝关节外翻畸形患者37例（42膝）的临床资料,其中男11例,13个膝关节;女26例,29个膝关节。年龄56-78岁,平均63．7岁。对比分析患者置换前后膝关节活动范围、股胫角及美国特种外科医院膝关节评分的差异,评估全膝关节置换治疗膝关节外翻畸形的临床效果。结果与结论：置换后随访6-36个月。患者膝关节活动范围由置换前平均68．5°提高到置换后末次随访时平均108．5°,置换前股胫角平均16．82°。减少到置换后末次随访时平均5．62°,置换前美国特种外科医院膝关节评分平均39分提高到置换后末次随访时88分,末次随访时与置换前比较差异有显著性意义（P〈0．05）。提示全膝关节置换治疗膝关节外翻畸形疗效肯定,是改善畸形的有效手段。     

半限制性假体治疗重度畸形膝关节病的疗效分析

目的观察使用半限制性假体全膝关节置换术治疗膝关节骨关节病重度畸形的近期疗效。方法对23例(28膝)重度畸形的膝关节退行性骨关节病患者使用半限制性假体行全膝关节置换术。术前拍负重位下肢全长X线片,测量膝关节内翻、外翻角度。本组病例外翻膝外翻角均>15°,内翻膝内翻角均>20°,同时伴有程度不同的屈曲及旋转畸形。行全膝关节置换术,术中使用半限制性假体,使用金属垫块修复骨缺损。所有病例均进行跟踪随访与资料积累分析。结果术中关节畸形可有效修复,承载假体可靠;术后X线片显示假体位置及下肢力线恢复良好。术前HSS评分平均33.9分,术后随访6月~3年,平均随访2.3年,HSS评分平均87.6分。23例(28膝)中15例(18膝)为优,6例(8膝)为良,2例(2膝)尚可;其优良率92.9%。结论半限制性假体对严重畸形造成的骨缺损及软组织疲劳亏损导致的松弛能够进行满意的弥补。其设计及操作流程的科学性、可控性及合理性减少该类患者发生早期关节不稳定、下肢力线偏移、假体松动的几率。后期疗效有待于进一步观察随访。     

佩带膝外翻支具膝骨关节炎患者膝关节的生物力学变化

背景：佩带膝关节外翻矫形器已被证明是一种可以有效减轻内侧间室膝骨关节炎患者疼痛的方法,但是佩带矫形器后的膝关节所产生的运动学以及动力学变化至今尚不明确。目的：观察内侧间室膝骨关节炎患者佩带膝关节矫形器前后的膝关节运动学以及动力学参数变化,便于为将来设计新型膝关节矫形器提供依据。方法：纳入20例内侧间室膝骨关节炎患者,分别通过三维步态分析系统和测力板对其在佩带膝外翻矫形器及不佩带膝外翻矫形器两种情况步行中的运动学及动力学参数进行采集,并进行对比。结果与结论：相比未佩带膝关节外翻支具,佩带膝关节外翻支具后患者在步行过程中膝关节内收力矩明显减小,与此同时膝关节内翻角度明显减小,外翻角度明显增加（P均〈0.05）,膝关节在步行过程中的最大屈曲角度以及时间空间参数差异无显著性意义。提示膝关节外翻矫形器可有效地通过增加内侧间室膝骨关节炎患者膝关节在步行过程中的外翻角度减小内翻角度从而降低膝内侧间室所承受的压力,与此同时纠正膝关节非正常对线。     

Mechanical alignment changes during flexion in total knee arthroplasty without affecting clinical outcomes

BackgroundPrimary aim of this study is to investigate if Hip-Knee-Ankle angle, measured in the coronal plane, changes with knee flexion after total knee arthroplasty. The secondary aim is to assess the relationship between Hip-Knee-Ankle during knee flexion and clinical outcome at mid-term follow up.Methods334 computer assisted total knee arthroplasties were retrospectively evaluated. A total of 233 patients were available for assessment of clinical outcomes at last follow up (mean 35 months). Hip-Knee-Ankle angle at different degrees of knee flexion and components' alignment were recorded intraoperatively.FindingsPatients were stratified based on the preoperative alignment: 202 varus knees, 99 neutral knees, and 33 valgus knees. In the varus knee group, 146 patients (89%) maintained a neutral overall limb alignment when flexed to 20°, 118 (72%) remained neutrally aligned at 45° and 92 (54%) at 90°. In valgus knee group, 26 (90%) remained neutrally aligned at 20°, 22 (75%) at 45° and 16 (55%) at 90°. In neutrally-aligned knee group, 88 (96%) remained neutrally aligned at 20°, 73 (79%) at 45° and 61 (66%) at 90°. Femoral component external rotation was correlated with varus alignment in flexion. Good outcomes were reported in 181 (78%) cases, fair results in 28 (12%) cases, poor results in 24 (10%) of cases. Poor results were not correlated to Hip-Knee-Ankle angle at different knee flexion angles.InterpretationThis study demonstrates that intraoperative Hip-Knee-Ankle angle changes as the knee moves into deeper flexion. However, neutral Hip-Knee-Ankle through the range of motion does not correlate with superior outcomes.     

髌旁外侧人路进行外翻膝人工全膝关节置换术的探讨

目的 探讨应用外侧入路进行外翻膝全膝关节置换术的疗效.方法 2008年12月至2011年3月,对10例(12膝)外翻膝畸形患者施行了全膝关节置换术.女3例,男3例,平均年龄71.4岁(61~77岁).所有患者均采用膝关节外侧人路,将外侧支持带进行冠状面"Z"字成形,分步骤按照拉花技术进行髂胫束止点、后外侧关节囊、外侧副韧带等松解以获得屈、伸间隙的软组织平衡,假体就位后错位缝合外侧支持带的浅、深层.术后3、6、12个月及之后每年门诊随访,应用HSS评分对膝关节功能进行评价.结果 所有病例均应用后稳定型假体(G2,施乐辉公司,美国),全部患者的外翻畸形均获得矫正,下肢力线由术前平均外翻18.4°(15°~24°)恢复至平均外翻6.8°(4°~9°).所有病例获得随访,平均12.4个月(3~24个月).至最后随访时,HSS评分由术前的平均42.4分(35~58分)恢复到平均86.4分(76~95分).结论 膝关节外侧入路能很好地显露外翻膝的外侧挛缩结构,有利于对挛缩结构进行准确的松解,外侧支持带的"z"字成型方法有效地解决了髌骨的松解和假体软组织覆盖的矛盾,是中、重度外翻膝进行膝关节置换的良好入路.     

Associations between gait and clinical parameters in patients with severe knee osteoarthritis: A multiple correspondence analysis

Background

Given the complexity of the gait of patients with knee osteoarthritis, a multiple correspondence analysis may be helpful to optimise the extraction of relevant gait and clinical information. Therefore, the aims of this study are to identify the main associations with clinical and gait biomechanical parameters and to evaluate whether there are more specific knee osteoarthritis groups with different gait profiles.

Methods

Ninety patients with severe knee osteoarthritis and twenty-six healthy individuals participated in this study. Pain and function were assessed with the WOMAC Index; knee joint deformity was assessed by the hip-knee-ankle angle on full-limb radiography; and full body gait analysis was performed with a motion analysis system and force plates.

Findings

Using multiple correspondence analysis, two categories of gait parameters that best explain the gait variance of patients with knee osteoarthritis were highlighted. The forward displacement category is composed of the parameters speed, stride length, hip flexion and knee flexion. The frontal category is composed of the parameters thorax obliquity and knee adductor moments. Moreover, based on these parameters, four distinct gait profiles were identified: two gait profiles were associated with knee varus deformities, increased thorax obliquity and different forward displacements, while two gait profiles were associated with valgus deformities and different forward displacements.

Interpretation

These gait parameters can be used to simplify the characterisation of the gait of the knee osteoarthritis population. Patients in varus profiles increase thorax obliquity on the stance limb and may reduce forward displacement. Patients in valgus profiles, however, only reduce forward displacement.     

下肢全长负重位X线检查在膝关节炎内外翻畸形中的临床价值

目的:探讨膝关节炎患者下肢全长负重位X线片对膝内、外翻畸形诊断的临床价值。方法:选取32例临床诊断为膝关节炎51膝分别拍摄下肢全长负重X线片,测量下肢力线和机械轴偏距(mechanical axis offset distance,MAD),解剖学股胫骨角(anatomical femor-tibial angle,aFTA),股骨远端力学外侧角(mechanical lateral distal femoral angle,mLDFA),胫骨近端力学内侧角(mechanical medial proximal tibial angle,mMPTA),对图像数据进行分析,对膝关节炎进行X线K/L分级,通过SPSS 17.0统计对下肢力线各参数与关节炎的相关性进行分析。结果:①膝关节下肢全长负重位X线片显示,关节有不同程度骨质增生,关节间隙变窄。②51膝骨关节炎中确诊膝内翻畸形38膝(74.51.%)和膝外翻畸形8膝(10.42%),5膝均无内外翻畸形。③膝关节炎X线K/L分级显示,0级:5膝(9.8%),I级:12膝(23.5%),II级:22膝(43.1%);III级:9膝(17.6%);IV级:3膝(59%)。④膝内翻组中股骨内翻7膝(18.42%),胫骨内翻18膝(47.36%),股骨、胫骨均内翻13膝(34.21%);膝外翻组中股骨外翻6膝,股骨、胫骨均外翻2膝。⑤在膝内翻组中,aFTA与骨关节炎X线K/L分级呈正相关(B值=0.132,t=2.648,P=0.012,P<0.05)。结论:下肢全长负重X线显示下肢结构清晰、完整,通过测量下肢力线参数评估,可全面诊断膝关节炎的内翻畸形或外翻畸形,膝内翻中以胫骨内翻显著,膝外翻中则以股骨外翻显著。因此,膝关节骨性关节炎的下肢全长负重X线检查具有较高的临床价值。     

Matched comparison of kinematics in knees with mild and severe varus deformity using fixed- and mobile-bearing total knee arthroplasty

Background

We examined knee kinematics in three 16-knee cohorts with the same implant design to clarify the influence of bearing mobility and preoperative deformity on the kinematics of posterior-stabilized knee arthroplasty. Compared to knees with mild deformity and a fixed-bearing implant, we hypothesized that a matched group of knees with mobile-bearing prostheses would show greater tibial axial rotation. We hypothesized that knees with the same fixed-bearing implant, but severe preoperative deformity, would have less axial rotation.

Methods

A total of 58 knees in 48 patients were involved in this study from a consecutive single-surgeon total knee arthroplasty series. Sixteen knees received mobile-bearing prostheses, and a best-matched cohort of knees with fixed-bearing implants was selected. The 16 fixed-bearing knees with most severe preoperative deformity were selected as a third group. All knees were examined at least 1.5 years after surgery. Flexion, femoral external rotation, anteroposterior translation of both femoral condyles during squatting and deep knee flexion activities were evaluated using model-image registration techniques.

Findings

We found some statistically significant, but small differences among the three groups in dynamic and static knee kinematics. In squatting, total femoral rotation for knees with fixed- and mobile-bearing implants, and knees with fixed-bearing implants after severe preoperative varus deformity, was not significantly different. [7° (SD3°), 9° (SD3°), 8° (SD3°), respectively, P = 0.08].

Interpretation

Similar kinematic results for knees with different tibial bearing surfaces and preoperative deformities indicate a robust treatment with this posterior stabilized implant. However, knees did not exhibit normal femoral rotations or functional flexion ranges.     

膝内外翻畸形时髋臼负重顶区的生物力学变化

背景：膝内、外翻畸形改变了膝关节的形态,除影响膝关节的功能外,还可能改变相邻关节髋关节的生物力学行为,也就是髋臼与股骨头之间的力学传导. 目的：评价不同程度膝内、外翻畸形对髋臼负重顶区的生物力学影响. 方法：取成年男性鲜尸体下肢标本3个,剔除附着的肌肉组织,保留骨膜、韧带及关节囊,通过胫骨高位截骨模拟不同程度的膝内外翻畸形.标本分为中立位组、膝内翻10°组、膝内翻20°组、膝外翻10°组和膝外翻20°组.实验中骨盆的位置选择单足站立中立位.标本通过生物力学试验机加载至50 kg,采用压敏片技术测量髋臼顶负重区的负重面积、平均应力及峰值应力. 结果与结论：髋臼顶区中立位时股胫关节面负重面积为（6.33±0.12） cm2,平均应力（3.62±0.33） MPa,峰值应力为（4.58±0.20） MPa.当膝内、外翻达10°时,髋臼顶区负重面积减少,平均应力及峰值应力有明显的增加,但差异无显著性意义（P〉0.05）;当膝内、外翻达20°时髋臼负重面积显著减少,平均应力峰值及应力显著增加,差异有非常显著性意义（P 〈0.01）.结果提示：随膝内、外翻畸形程度的不同,髋臼负重顶区的负重面积、峰值应力及平均应力也发生变化,当膝内、外翻达20°时,负重面积显著减少,平均应力峰值及应力显著增加,这可能是膝内外翻畸形造成髋骨关节炎的病因之一.因此临床上应重视对膝骨关节炎内、外翻畸形患者的早期干预.     

限制性衬垫在老年患者初次膝关节置换中的应用

背景：内外翻限制性衬垫严格遵循“以最低的限制性获得可靠的稳定性”的原则,在提高假体的稳定性的同时又不增加限制级别。 目的：回顾性分析限制性衬垫在老年初次膝关节置换中内外翻不稳定的应用经验,总结限制性衬垫使用的适应证及临床效果。 方法：2010年3月至2012年3月间收治合并膝内外翻畸形的70例初次膝关节置换老年病例,其中内翻56例（平均15±176;-30±176;）;外翻14例（平均10±176;-20±176;）。70例中在完成标准截骨和软组织平衡操作后出现一侧〈6 mm内外翻不稳定的23例（25膝）使用了限制性衬垫,其中内翻不稳18膝,外翻不稳7膝。23例均使用施乐辉公司普通骨水泥型膝关节假体,均未使用假体延长柄,11膝术中使用了骨水泥或自体骨植骨填补骨缺损。 结果与结论：平均随访2年（18-42个月）,所有病例膝关节疼痛消失,关节稳定,下肢力线纠正,KSS评分从置换前平均39.4分,提高到置换后的平均88.5分。所有患者均无需膝关节支具保护,膝关节最大屈曲度平均110±176;（96±176;-130±176;）,SF-36问卷满意度98%,无感染及脱位等并发症。结果提示在膝关节置换时完成截骨和软组织平衡后出现〈6 mm内外翻不稳定时使用限制性衬垫,在老年初次膝关节置换中可以保留骨量,简化手术操作,近期临床效果良好。     

个体化设计一期关节置换治疗膝骨关节炎合并同侧股骨关节外畸形

背景：全膝关节置换治疗膝关节骨性关节炎合并关节外畸形目前仍面临挑战,为获得良好的力线及恢复恰当的软组织平衡,需制定个体化的置换方案。目的：观察个体化设计一期关节置换治疗膝骨关节炎合并同侧股骨关节外畸形安全及可行性。方法：纳入膝骨关节炎合并同侧股骨关节外畸形患者8例,根据置换前计划,5例患者进行关节内代偿截骨治疗,3例患者行关节外矫正截骨,记录肢体多平面畸形和软组织条件。主要评估指标包括 HSS评分,WOMAC评分和力线偏差。结果与结论：平均随访29个月,患者HSS评分从置换前32.5分提高至置换后87.5分,WOMAC从置换前的37.1分提高到置换后88.8分（P〈0.05）。力线偏差（无论是内翻或外翻）由置换前的17.1°变到置换后1.4°（P 〈0.05）。所有患者关节外矫正截骨的病理3个月内截骨端愈合,无置换后感染,假体松动或静脉血栓栓塞事件发生,仅1例患者残留5°膝过伸。结果证实,依据个体化的置换前计划,一期全膝关节置换治疗膝关节骨性关节炎合并同侧股骨关节外畸形安全有效。     

Collateral ligament strains during knee joint laxity evaluation before and after TKA

Background

Passive knee stability is provided by the soft tissue envelope. There is consensus among orthopedic surgeons that good outcome in Total Knee Arthroplasty requires equal tension in the medial/lateral compartment of the knee joint, as well as equal tension in the flexion/extension gap. The purpose of this study was to quantify the ligament laxity in the normal non-arthritic knee before and after Posterior-Stabilized Total Knee Arthroplasty. We hypothesized that the Medial/Lateral Collateral Ligament shows minimal changes in length when measured directly by extensometers in the native human knee during varus/valgus laxity testing. We also hypothesized that due to differences in material properties and surface geometry, native laxity is difficult to reconstruct using a Posterior-Stabilized Total Knee.

Methods

Six specimens were used to perform this in vitro cadaver test using extensometers to provide numerical values for laxity and varus–valgus tilting in the frontal plane.

Findings

This study enabled a precise measurement of varus–valgus laxity as compared with the clinical assessment. The strains in both ligaments in the replaced knee were different from those in the native knee. Both ligaments were stretched in extension, in flexion the Medial Collateral Ligament tends to relax and the Lateral Collateral Ligament remains tight.

Interpretation

As material properties and surface geometry of the replaced knee add stiffness to the joint, we recommend to avoid overstuffing the joint, when using this type of Posterior-Stabilized Total Knee Arthroplasty, in order to obtain varus/valgus laxity close to the native joint.     

Limb length discrepancy after total knee arthroplasty: A systematic review and meta-analysis

BACKGROUNDLimb length discrepancy (LLD) after total knee arthroplasty (TKA) has been considered as one of the reasons for the unsatisfactory outcome. However, there is no consensus about the extent of LLD that can be considered as clinically relevant.AIMTo evaluate the incidence of radiographic LLD and its impact on functional outcome following TKA.METHODSAll randomized-controlled trial and observational studies on LLD in TKA, published till 22^nd June 2020, were systematically searched and reviewed. The primary outcome was “limb lengthening or LLD after TKA”. The secondary outcomes included “assessment of LLD in varus/valgus deformity” and “impact of LLD on the functional outcome”. RESULTSOf 45 retrieved studies, qualitative and quantitative assessment of data was performed from eight studies and six studies, respectively. Five studies (n = 1551) reported the average limb lengthening of 5.98 mm. The LLD after TKA was ranging from 0.4 ± 10 mm to 15.3 ± 2.88 mm. The incidence of postoperative radiographic LLD was reported in 44% to 83.3% of patients. There was no difference in the preoperative and postoperative LLD (MD -1.23; 95%CI: -3.72, 1.27; P = 0.34). Pooled data of two studies (n = 219) revealed significant limb lengthening in valgus deformity than varus (MD -2.69; 95%CI: -5.11, 0.27; P = 0.03). The pooled data of three studies (n = 611) showed significantly worse functional outcome in patients with LLD of ≥ 10 mm compared to < 10 mm (standard MD 0.58; 95%CI: 0.06, 1.10; P = 0.03). CONCLUSIONLimb lengthening after TKA is common, and it is significantly more in valgus than varus deformity. Significant LLD (≥ 10 mm) is associated with suboptimal functional outcome.     

三维骨建模系统在人工全膝关节置换旋转对位中的作

背景:前期人工全膝关节置换试验证实,采用以三维骨建模为基础的计算机辅助系统可以进行精确地假体三维定位及下肢力线重建,减少髌股关节并发症,取得韧带平衡,获得良好的临床效果.目的:拟进行人工全膝关节置换时假体旋转对位的量化分析,验证三维骨建模的计算机辅助手术系统对量化操作的精确性和有效性.设计、时间及地点:回顾性病例分析,于2002-11/2003-06在法国亨利蒙多医院矫形与创伤外科完成.对象:纳入保守治疗无效的三间隔骨性关节炎患者21例(21膝),其中14例膝内翻,7例膝外翻;患者均为初次置换,所用假体为后稳定型人工表面全膝关节(Hermes(R),Ceraver,法国).方法:采用三维骨建模Ceravision系统对21例患者(21膝)进行人工全膝关节置换.计算机系统提供假体预设方案,安置好截骨定位导向装置后进行截骨,注意保持良好的伸屈膝关节间隙和韧带平衡及关节稳定,额面上控制应力下膝内外翻在±3°以内,下肢力线(180±3)°以内,适当地假体旋转对位后行假体固定.主要观察指标:根据相关的临床体检、影像学和导航系统资料,对术中假体旋转对位测量值、置换后3个月膝关节活动度、膝关节松弛度和髌骨稳定性进行观察分析.结果:在保证下肢力线与膝关节额面松弛度于正常范围内,术中股骨假体旋转对位内旋1°～外旋5°,胫骨假体旋转对位内旋0°～外旋5°.其中14例膝内翻患者,股骨假体旋转对位内旋1°～外旋5°,胫骨假体旋转对位内旋2°～外旋5°;7例膝外翻患者,股骨假体旋转对位内旋1°～外旋4°,胫骨假体旋转对位内旋0°～外旋 4°.置换后3个月时,膝关节最大屈膝度为105°～130°,平均115°,无膝痛、髌骨失稳和脱位等并发症,膝关节额面松弛度无异常.结论:应用以三维骨建模为基础的人工全膝关节置换计算机辅助手术系统,可针对患者个体精确三维截骨和假体旋转对位,获得良好的膝关节屈伸位下关节等距间隙,保证良好的膝关节韧带张力与平衡稳定, 避免髌-股并发症,可在手术中常规使用.     

High tibial osteotomy: a retrospective review of 72 cases

Past experience has shown that the results of high tibial osteotomy are difficult to predict. The purpose of this review was to correlate preoperative findings with postoperative results to define more precisely the indications and contraindications and to improve results. Between 1970 and 1983, 72 high tibial osteotomies for osteoarthritis were done at Duke University Medical Center by one surgeon using a consistent surgical technique. Fourteen complications were identified in 72 knees. The only one causing a persistent problem was a fracture of the tibial plateau. Forty-five knees in 38 patients were available for follow-up at an average of six years (range 1.5 to 15.0 years). Results in 15 knees (33%) were classified as "good" (pain free), in 20 knees (44%) as "fair" (improved), and in ten knees (22%) as "poor" (unchanged or worse). Three patients with fair results subsequently had total knee arthroplasty at least nine years after the osteotomy, and two of those with poor results received total knee replacement within two years of the tibial osteotomy. Measurements obtained from standing roentgenograms revealed an average of 3 degrees of preoperative varus and 8 degrees of postoperative valgus, for an average correction of 11 degrees. There was no statistically significant correlation between preoperative measurements of joint space or alignment and postoperative result. This review indicates that preoperative standing films of the knee alone are not a reliable indication for patient selection.     

Varus alignment after total knee arthroplasty results in greater axial rotation during deep knee bend activity

BackgroundsThe correlation between in vivo knee kinematics and alignment has not been fully elucidated. Recently, similar or better clinical outcomes have been reported by restoration of mild varus alignment after total knee arthroplasty for preoperative varus knees. The aim of this study was to evaluate the effect of postoperative alignment on knee kinematics during a deep knee bend activity.MethodsIn vivo knee kinematics of 36 knees (25 patients) implanted with tri-condylar total knee arthroplasty were analyzed with a three dimensional model fitting approach using fluoroscopy. Under fluoroscopic surveillance, individual video frames were digitized at 30° increments from full extension to maximum flexion. Postoperative coronal and sagittal alignments were assessed using radiographs, and rotational alignment was assessed with computed tomography. Pearson correlation coefficients were calculated to determine the correlations between the alignment data and kinematic factors.FindingsCorrelation analysis showed that coronal alignment was significantly correlated with knee kinematics. The varus alignment of the limb and tibial component led to a greater axial rotation from full extension to maximum flexion and more rotated position in the mid to deep flexion range. Neither the rotational alignment of the femoral nor tibial components showed significant correlation with axial rotation from full extension to maximum flexion.InterpretationVarus alignment resulted in greater axial rotation, which could represent near-normal knee kinematics. The current study can be a kinematic rationale reporting similar or better clinical and functional outcomes for the total knee arthroplasty with residual varus alignment.