Finding and defining the ideal patellar resection plane in total knee arthroplasty

Asymmetric resection of the patella during total knee arthroplasty (TKA) correlates with anterior knee pain, bony impingement and patellar maltracking. Despite this, there is no consensus regarding the desired landmarks; the cut is often done freehand; and there has been no quantitative comparison of proposed resection planes. The objectives of this study were to: determine the intra- and inter-surgeon repeatability of two radiographic resection definitions (medial–divot, MD, and medial–lateral extents, MLE); calculate two additional definitions from the radiographic patellar circumferences (parallel to the anterior surface, ANT, and perpendicular to the anteroposterior tangent points, PERP); compare the clinical resection line to the previous four definitions before and after introducing the MD method clinically; and identify distinguishing features of patellae with better vs. worse resection angles. We hypothesized that the MD method would improve repeatability both radiographically and clinically, that the different radiographic definitions would produce comparable angles, and that we could identify distinguishing features. For the radiographic study, three surgeons drew lines on 40 preoperative X-rays plus 9 interspersed repetitions of 3 of these X-rays. For the clinical study, we compared the patellar resection angle for 20 patients immediately before and after implementing the new method. Given that the clinical goal is to have equal distances from the resection surface to the anterior surface, we compared all results to the ANT definition as the theoretically ideal definition. Confirming the first hypothesis, intra-surgeon repeatability (10 repetitions of 3 X-rays) and inter-surgeon repeatability (3 surgeons×40 X-rays) were both significantly better using the new MD method compared to the MLE method (p<0.001). Contrary to the second hypothesis, clinical use of the MD method did not improve resection symmetry. Contrary to the third hypothesis, the PERP definition was significantly different from the other three definitions. In agreement with the fourth hypothesis, female patellae and more deformed patella had significantly greater asymmetry (p<0.001). Given the inherent variability shown in drawing the ‘patellar horizon’, we encourage researchers to draw the line several times and average the results when comparing tilt or the resection angle to this horizon. Based on the distinguishing characteristics of asymmetrically resurfaced patellae in our series, we recommend that clinicians be particularly careful when resecting laterally deformed patellae and the patellae of female patients.     

全膝关节置换术使用不可吸收线加强缝合内侧关节囊对术后髌骨倾斜的影响

目的:分析比较在初次全膝关节置换术(TKA)中使用不可吸收线加强缝合髌骨内侧关节囊对术后髌骨倾斜的影响。方法:本研究回顾性分析了从2014年12月至2017年9月期间在我院治疗的22例随访资料齐全的初次全膝关节置换的患者资料,根据术中是否使用不可吸收线加强缝合内侧关节囊,将患者分为普通组和加强缝合组,普通组12例,加强缝合组10例。通过患者手术前后的X线片测量髋膝踝角(HKA)、Insall-Salviti指数(ISR)、髌骨倾斜角(PTA),采用美国膝关节协会(KSS)评分评价患者手术前后膝关节功能。比较两组患者手术前以及术后1个月、术后末次随访时HKA、ISR、PTA以及KSS评分等指标。结果:普通组患者KSS评分、ROM、HKA,术后有明显改善(P0.05),其中ROM在术后末次随访时改善更为显著;PTA术后较术前增大(P0.05);ISR手术前后无明显差异(P0.05)。加强缝合组患者KSS评分、ROM,在术后1个月时无明显提升(P0.05),但在术后末次随访时提升明显(P0.05)。PTA术后较术前减小(P0.05)。HKA、ISR手术前后无明显差异(P0.05)。无论在术后1个月还是术后末次随访时,加强缝合组PTA都小于普通组(P0.05)。结论:在使用内侧髌旁入路的TKA中,使用不可吸收线加强缝合内侧关节囊可在一定程度上减小术后髌骨的倾斜,提升髌骨的稳定性,值得临床推广应用。     

全膝关节置换术治疗晚期类风湿性关节炎的早期临床随访研究

目的:探讨全膝关节置换术(TKA)治疗晚期类风湿性膝关节炎(RA)的早期临床疗效和安全性。方法:回顾性分析2006年~2011年接受TKA治疗的69例(102膝)晚期膝关节RA患者的临床资料,术后及随访时分析患者的影像学资料,末次随访时进行膝关节HSS评分,采用英国矫形外科协会标准评定患者满意度,SF-36健康量表评定患者的生活质量。结果:54例(81膝)患者术后获得2~7年(平均4.3年)随访;6例(7膝)死亡,6例(10膝)失访,3例(4膝)翻修,获得随访患者中1例(1膝)发生下肢深静脉血栓,经介入放置滤网治疗康复后出院,1例(1膝)感染。末次随访时,膝关节活动度(ROM)从术前平均(71.03°±29.51°)提高至(92.26°±10.29°),膝关节HSS评分从术前平均(47.30±10.06)分提高至(75.93±9.17)分;疼痛发生率和疼痛评分均较术前显著降低;冠状面和矢状面畸形率均较术前显著降低;身体健康(PCS)平均(47.98±6.96)分,心理健康(MCS)平均(41.45±5.67)分,均较术前显著增加,差异均有统计学意义(P0.05)。患者的治疗满意率为96.30%,膝关节假体X线片采用膝关节学会的X线评价与计分系统评价未见假体松动。结论:TKA治疗晚期膝关节RA患者2~7年的临床及影像学效果良好,未发现骨溶解、假体松动及严重衬垫磨损等并发症。     

Effects of femoral component placement on the balancing of a total knee at surgery

Misalignment and soft-tissue imbalance in total knee arthroplasty (TKA) can cause discomfort, pain, inadequate motion and instability that may require revision surgery. Balancing can be defined as equal collateral ligament tensions or equal medial and lateral compartmental forces during the flexion range. Our goal was to study the effects on balancing of linear femoral component misplacements (proximal, distal, anterior, posterior); and different component rotations in mechanical alignment compared to kinematic alignment throughout the flexion path. A test rig was constructed such that the position of a standard femoral component could be adjusted to simulate the linear and rotational positions. With the knee in neutral reference values of the collateral tensions were adjusted to give anatomic contact force patterns, measured with an instrumented tibial trial. The deviations in the forces for each femoral component position were then determined. Compartmental forces were significantly influenced by 2 mm linear errors in the femoral component placement. However, the errors were least for a distal error, equivalent to undercutting the distal femur. The largest errors mainly increase the lateral condyle force, occurred for proximal and posterior component errors. There were only small contact force differences between kinematic and mechanical alignment. Based on these results, surgeons should avoid overcutting the distal femur and undercutting the posterior femur. However, the 2–3 degrees varus slope of the joint line as in kinematic alignment did not have much effect on balancing, so mechanical or kinematic alignment were equivalent.     

全膝关节置换术后多模式镇痛中非选择与选择性COX-2抑制剂的对比应用研究

目的：评价全膝关节置换术后病人早期功能锻炼过程中应用选择性环氧化酶-2（COX-2）抑制剂帕瑞昔布钠与非选择性环氧化酶（COX）抑制剂氟比洛芬酯之间的镇痛效果是否存在差异,以及对早期功能锻炼结果的影响。方法：前瞻性、随机、双盲、平行对照研究,根据纳入/排除标准,连续选取2009年6月至2010年3月在我科行单侧人工全膝关节置换术的病人60名。手术均采用腰麻联合硬膜外阻滞麻醉,由同一组手术医师完成,术中假体安装前关节周围软组织注射＂鸡尾酒＂镇痛液（罗哌卡因注射液150mg＋肾上腺素（1：1000）0.5ml,由生理盐水稀释为100ml）。手术结束后进行病人自控静脉镇痛（PCIA）。术后当天患者在护士的指导下进行股四头肌收缩功能锻炼及直腿抬高功能锻炼。术后第一天起行膝关节被动伸屈功能锻炼（CPM）及主动伸屈功能锻炼。术后第3至5天患者停PCIA镇痛后,进行试验干预。帕瑞昔布钠组给予注射用帕瑞昔布钠40mg,静注1/12小时。氟比洛芬酯组给予氟比洛芬酯注射液100mg,静注1/12小时。观察病人术后第3至5天静息状态下和活动锻炼时膝关节最大主动屈曲时的疼痛强度（VAS评分）,手术侧膝关节的主动伸屈活动度及术后1月复查时的手术侧膝关节的主动伸屈活动度,KSS评分,术后第2天与第6天的血红蛋白值。结果：两组病人给药后在静息状态及膝关节最大主动屈曲时,在不同时间点的VAS评分、膝关节主动活动度及术后1月患者膝关节的主动活动度和KSS评分的差异均无统计学意义（P〉0.05）。应用抗凝治疗后,帕瑞昔布钠组患者血红蛋白下降值与氟比洛芬酯组存在差异（P=0.042）。结论：尚不能认为人工全膝关节置换术后多模式镇痛中同时抑制COX-1和COX-2与选择性抑制COX-2之间存在差异。但应用选择性COX-2抑制剂（帕瑞昔布钠）镇痛更安全,因其有利于减少全膝关节置换术后患者抗凝治疗过程中的隐性失血。     

地佐辛超前镇痛对全膝关节置换术患者围术期细胞因子的影响

目的：探讨地佐辛超前镇痛对全膝关节置换术患者围术期白介素-6（IL-6）、白介素-8（m-8）和肿瘤坏死因子-α（TNF-α）浓度的影响。方法：40例择期行单侧全膝关节置换术患者,随机分为超前镇痛组（实验组）和术后镇痛组（对照组）,每组20例。均采用蛛网膜下腔麻醉,患者静脉自控镇痛（PCIA）：地佐辛0．8mg／kg,生理盐水稀释至100mL。负荷剂量：5mL,持续剂量：2mL／h,追加剂量：0．5mL／次,锁定时间：15min。实验组于入室后10分钟麻醉操作前开始静脉负荷量和背景量,对照组于术毕开始PCIA镇痛,方法同实验组,记录患者术后6、8、12、24小时的疼痛视觉模拟评分（VAS评分）以及术后48小时内患者恶心呕吐的发生情况,于入室后10分钟麻醉操作前（T1）、手术开始后10分钟（T2）、术毕2h（T3）、4h（T4）、8h05）、24h（T6）时间点抽取静脉血样,测定细胞因子IL-6、IL-8、TNF-α水平。结果：术后6h、8h、12h时间点VAS评分实验组较对照组明显降低（P〈0．05）,24hVAS评分变化不大,无统计学差异（P〉0．05）。术后48小时内,实验组发生恶心呕吐1例,对照组2例。与本组T1比较,血浆IL-6、IL．8浓度实验组在各时点变化不大,无统计学差异（P〉0．05）,对照组浓度升高（P〈0．05）。组间比较,相同时点血浆IL-6、IL-8浓度实验组均低于对照组（P〈0．05）。两组血浆TNF-α浓度比较差异无统计学意义（P〉0．05）。结论：全膝关节置换术术前预先给予地佐辛可产生良好的超前镇痛效果,减少患者围术期细胞因子的产生。     

新辅助化疗联合人工膝关节置换治疗膝关节附近骨肉瘤

目的:评价新辅助化疗联合人工膝关节置换治疗膝关节附近骨肉瘤的临床疗效。方法:38例膝关节附近骨肉瘤采用新辅助化疗和人工膝关节置换,所有病例均进行肿瘤细胞坏死率、5年内肿瘤局部复发率、5年生存率和膝关节功能评估。结果:38例患者新辅助化疗后肿瘤细胞坏死率平均95.8%;随访6-9年,38例患者中5年内肿瘤局部复发12例(31.6%),5年后生存31例(81.6%),膝关节功能优良率92.1%。结论:新辅助化疗联合人工膝关节置换治疗膝关节附近骨肉瘤可有效提高骨肉瘤5年生存率,保存患肢功能,是骨肉瘤保肢治疗的一种较好的方法。     

人工全髋关节置换术中Delta陶瓷的界面选择

目的:Delta陶瓷较Forte陶瓷在材料复合方面进步明显,并采用了36 mm大直径球头的设计,其组成的界面具有耐磨性好,关节活动度大,稳定性佳,不易脱位等优点,适合年轻及活动量大的患者,但其价格较其他界面更为高昂.观察采用Delta陶瓷-陶瓷界面与Delta陶瓷-高交联聚乙烯界面假体行全髋关节置换术的患者术后效果的差异.方法:选取2009年10月-2012年10月在我院选择Delta陶瓷-高交联聚乙烯界面行全髋关节置换术的35例患者(A组),以同期在我院选择Delta陶瓷-陶瓷界面26例行全髋关节置换术的患者(B组)作为对照.通过随访影像学复查,以及术后Harris功能评分进行临床效果的评价.结果:所有患者均得到随访,随访时间6个月到2年.所有患者在影像学方面,未发现松动下沉,脱位以及碎裂等现象.假体周围未见骨溶解所致透亮线形成以及异位骨化.两组患者行人工全髋关节置换术后Harris评分较术前均有显著提高,但两组之间无显著差异.结论:Delta陶瓷作为最新一代的生物陶瓷,其优异性能毋庸置疑.采用Delta陶瓷-陶瓷界面及Delta陶瓷-高交联聚乙烯界面在短期内未见明显差异,其中长期效果仍有待进一步随访观察.     

Evaluation of knee functional calibration with and without the effect of soft tissue artefact

Functional calibration methods were devised to improve repeatability and accuracy of the knee flexion–extension axis, which is used to define the medio-lateral axis of the femur coordinate system in gait analysis. Repeatability of functional calibration methods has been studied extensively in healthy individuals, but not accuracy in the absence of a benchmark knee axis. We captured bi-plane fluoroscopy data of the knee joint in 17 subjects with unilateral total knee arthroplasty during treadmill walking. The prosthesis provided a benchmark knee axis to evaluate the functional calibration methods. Stereo-photogrammetry data of thigh and shank marker clusters were captured simultaneously to investigate the effect of soft tissue artefact (STA). Three methods were tested, the Axis Transformation Technique (ATT) finds the best single fixed axis of rotation, 2DofKnee finds the axis that minimises knee varus–valgus and trajAJC finds the axis perpendicular to the trajectory, in the transverse plane of the femur, of a point located on the longitudinal axis of the tibia. Using fluoroscopy data, functional axes formed an angle of less than 2° in the transverse plane with the benchmark axis. True internal–external range of movement was correlated with decreased accuracy for ATT, while varus–valgus range of movement was correlated with decreased accuracy for 2DofKnee and trajAJC. STA had negative impact on accuracy and variability. Using stereo-photogrammetry data, the accuracy of 2DofKnee was 1.7°(SD: 5.1°), smaller than ATT 2.9°(SD: 5.1°) but not to trajAJC 1.7°(SD: 5.2°). Our results confirm that of previous studies, which utilised the femur condylar axis as reference.     

全膝关节置换术后多模式镇痛中非选择与选择性COX-2抑制剂 的对比应用研究

目的:评价全膝关节置换术后病人早期功能锻炼过程中应用选择性环氧化酶-2(COX-2)抑制剂帕瑞昔布钠与非选择性环氧化酶(COX)抑制剂氟比洛芬酯之间的镇痛效果是否存在差异,以及对早期功能锻炼结果的影响。方法:前瞻性、随机、双盲、平行对照研究,根据纳入/排除标准,连续选取2009年6月至2010年3月在我科行单侧人工全膝关节置换术的病人60名。手术均采用腰麻联合硬膜外阻滞麻醉,由同一组手术医师完成,术中假体安装前关节周围软组织注射"鸡尾酒"镇痛液(罗哌卡因注射液150mg+肾上腺素(1:1000)0.5ml,由生理盐水稀释为100ml)。手术结束后进行病人自控静脉镇痛(PCIA)。术后当天患者在护士的指导下进行股四头肌收缩功能锻炼及直腿抬高功能锻炼。术后第一天起行膝关节被动伸屈功能锻炼(CPM)及主动伸屈功能锻炼。术后第3至5天患者停PCIA镇痛后,进行试验干预。帕瑞昔布钠组给予注射用帕瑞昔布钠40mg,静注1/12小时。氟比洛芬酯组给予氟比洛芬酯注射液100mg,静注1/12小时。观察病人术后第3至5天静息状态下和活动锻炼时膝关节最大主动屈曲时的疼痛强度(VAS评分),手术侧膝关节的主动伸屈活动度及术后1月复查时的手术侧膝关节的主动伸屈活动度,KSS评分,术后第2天与第6天的血红蛋白值。结果:两组病人给药后在静息状态及膝关节最大主动屈曲时,在不同时间点的VAS评分、膝关节主动活动度及术后1月患者膝关节的主动活动度和KSS评分的差异均无统计学意义(P>0.05)。应用抗凝治疗后,帕瑞昔布钠组患者血红蛋白下降值与氟比洛芬酯组存在差异(P=0.042)。结论:尚不能认为人工全膝关节置换术后多模式镇痛中同时抑制COX-1和COX-2与选择性抑制COX-2之间存在差异。但应用选择性COX-2抑制剂(帕瑞昔布钠)镇痛更安全,因其有利于减少全膝关节置换术后患者抗凝治疗过程中的隐性失血。     

全膝关节置换术治疗类风湿性关节炎的临床效果分析

目的:探讨全膝关节置换术对类风湿性关节炎的临床疗效。方法:回顾性分析2012年10月至2014年1月在我院接受全膝关节置换术的80例风湿性关节炎患者的临床资料。采用HSS评分标准对膝关节疼痛情况进行评价,根据膝关节活动度(ROM)评价膝关节置换术的临床效果,观察患者术后并发症的发生情况,采用SF-36健康量表评估患者术后的生活质量。结果:患者术后膝关节疼痛评分低于术前(P0.05);患者术后膝关节活动度高于术前,且膝关节伸直和最大屈曲状态均优于术前(P0.05);术后膝关节冠状面和矢状面的畸形率均低于术前,差异具有统计学意义(P0.05);患者术后生存质量明显高于术前,差异具有统计学意义(P0.01)。术后发生感染2例,下肢深静脉血栓3例,膝前区疼痛2例,经对症治疗均获得缓解。结论:全膝关节置换术治疗类风湿性关节炎具有显著的临床效果,值得推广应用。     

Towards a patient-specific estimation of intra-operative femoral fracture risk

Abstract

Total Hip Arthroplasty requires pre-surgical evaluation between un-cemented and cemented prostheses. A Patient with intra-operative periprosthetic fracture and another with a successful outcome were recruited, and their finite element models were constructed by processing CT data, assuming elastic-plastic behavior of the bone as function of the local density. To resemble the insertion of the prosthesis into the femur, a fictitious thermal dilatation is applied to the broach volume. Strain-based fracture risk factor is estimated, depicting results in terms of the total mechanical strain expressed using a simple “traffic lights” color code to provide immediate, concise, and intelligible pre-operative information to surgeons.     

七氟烷复合麻醉对老年骨科患者术后早期认知功能的影响

摘要 目的：探讨七氟烷复合麻醉对老年骨科患者术后早期认知功能的影响。方法：选择2017年12月~2019年6月在西安医学院第二附属医院（本院）骨科诊治单侧老年全膝关节置换手术患者112例,随机数字表法分为七氟烷组与对照组,各56例。对照组给予常规静脉注射全身麻醉,在此基础上七氟烷组给予七氟烷吸入麻醉,记录与调查两组术后早期认知功能。结果：经过对比,两组手术时间、术中出血量对比差异无统计学意义(P>0.05),而七氟烷组的术后苏醒时间(7.10±0.22)min、拔管时间(8.65±0.46)min等都显著短于对照组(14.09±1.09)min、(18.76±1.44)min,两组对比有统计学意义(P<0.05)。所有患者在T1、T2、T3与T4时间点的心率和血氧饱和度均表现正常,对比均无统计学意义(P>0.05)。七氟烷组术后1 d、术后14 d的血清白介素(Interleukin,IL)-6、肿瘤坏死因子(Tumor necrosis factor,TNF)-α值显著低于对照组,对比有统计学意义(P<0.05),且两组术后14 d的血清IL-6与TNF-α值均显著低于术后1 d (P<0.05)。术后1个月七氟烷组的认知功能障碍发生率为1.8 %（1/56）,显著低于对照组的12.5 %（7/56）,两组间对比有统计学意义(x²=4.846,P=0.028)。结论：七氟烷复合麻醉在老年骨科患者中的应用能促进患者康复,安全性比较好,能抑制炎症因子的释放,从而减少术后早期认知功能障碍的发生。     

大剂量氨甲环酸对全膝关节置换患者术后纤溶活性与炎症因子的影响

目的:探讨大剂量氨甲环酸对全膝关节置换患者术后纤溶活性与炎症因子的影响。方法:回顾性分析在我院行初次全膝关节置换术的180例患者,按照给药方式分为对照组、常规组、大剂量组,每组各60例。对照组患者直接给予生理盐水,常规组给予10 mg/kg氨甲环酸,大剂量组给予15 mg/kg氨甲环酸。比较三组术后总失血量、隐形失血量、术前与术后3天三组凝血功能(纤维蛋白原、凝血酶原时间、活化部分凝血活酶时间)、纤溶活性[纤维蛋白(原)降解产物(FDP)、D-二聚体]以及炎性因子[C-反应蛋白(CRP)、白介素-6(IL-6)]水平变化及术后2周血栓事件的发生情况。结果:大剂量组与常规组的总失血量与隐形失血量均明显低于对照组,大剂量组总失血量与隐形失血量均低于常规组(P0.05);三组患者纤维蛋白原、凝血酶原时间以及活化部分凝血活酶时间相比差异均无统计学意义(P0.05);术后3天,大剂量组和常规组FDP与D-二聚体、CRP、IL-6水平均显著低于对照组,且与常规组相比,大剂量组水平较低(P0.05);术后2周,三组肌间静脉血栓发生率比较均无显著差异(P0.05)。结论:在全膝关节置换术后使用氨甲环酸可进一步减少术后隐形失血量,且不会增加血栓事件的风险,且随着药物剂量的增加,其止血效果越强,同时具有更为显著的抗纤溶作用与抗炎效果。     

Four-dimensional model of the lower extremity after total hip arthroplasty

We have developed a four-dimensional (4D) model of the lower extremities after total hip arthroplasty in patients. The model can aid in preventing complications such as dislocation and wearing of the sliding surface. The skeletal structure and implant alignment were obtained from CT data. We applied registration method using CAD data to estimate accurate implant alignment from scattered CT data. The reconstructed three-dimensional (3D) skeletal model was combined with motion capture data that were acquired by an optical tracking system. We displayed the patient's skeletal movement and analyzed several parameters that relate to complications. The patient's skeletal model was superimposed onto video footage that was taken by a synchronized and calibrated digital video camera. For validation of the measurement error in this system, we used open MRI to evaluate the relative movement between skin markers and bones. This system visually represents not only the 3D anatomical structure, but also 4D dynamic functions that include the time sequential transitions of components and their positions. The open MRI results indicated that the average error in hip angle was within 5° for each static posture. This system enables clinicians to analyze patient's motions on the basis of individual differences. We found that our system was an effective tool in providing precise guidance of daily postoperative motions that was individualized for each patient. This system will be applicable for surgical planning, assessment of postoperative activities, and the development of new surgical techniques, materials, and prosthetic designs.     

Development of a statistical shape-function model of the implanted knee for real-time prediction of joint mechanics

Outcomes of total knee arthroplasty (TKA) are dependent on surgical technique, patient variability, and implant design. Non-optimal design or alignment choices may result in undesirable contact mechanics and joint kinematics, including poor joint alignment, instability, and reduced range of motion. Implant design and surgical alignment are modifiable factors with potential to improve patient outcomes, and there is a need for robust implant designs that can accommodate patient variability. Our objective was to develop a statistical shape-function model (SFM) of a posterior stabilized implanted knee to instantaneously predict joint mechanics in an efficient manner. Finite element methods were combined with Latin hypercube sampling and regression analyses to produce modeling equations relating nine implant design and six surgical alignment parameters to tibiofemoral (TF) joint mechanics outcomes during a deep knee bend. A SFM was developed and TF contact mechanics, kinematics, and soft tissue loads were instantaneously predicted from the model. Average normalized root-mean-square error predictions were between 2.79% and 9.42%, depending on the number of parameters included in the model. The statistical shape-function model generated instantaneous joint mechanics predictions using a maximum of 130 training simulations, making it ideally suited for integration into a patient-specific design and alignment optimization pipeline. Such a tool may be used to optimize kinematic function to achieve more natural motion or minimize implant wear, and may aid the engineering and clinical communities in improving patient satisfaction and surgical outcomes.     

The effect of patient positioning on the precision of model-based radiostereometric analysis

A repeatable method for in vivo and in vitro measurement of polyethylene wear in total knee replacement (TKA) is needed. This research examines the model-based radiostereometric analysis’ (MBRSA) in vitro precision under different patient-radiograph orientations and flexion angles of the knee using a TKA phantom. Anterior–posterior and medial–lateral imaging orientations showed the highest precision; better than 0.036 mm (3-dimensional translation) and 0.089° (3-dimensional rotation). Flexion of the knee did not affect MBRSA precision. Medial–lateral imaging is advantageous as it allows for flexion of the knee joint during an RSA examination, thus providing greater information for wear measurement.     

连续股神经阻滞联合帕瑞昔布对全膝置换患者术后镇痛效果观察

目的:探讨连续股神经阻滞(CFNB)联合帕瑞昔布对全膝关节置换术(TKA)患者术后镇痛效果。方法:选择2015年1月至2016年12月间我院行择期单侧TKA治疗的患者100例,按照随机数字表法分为对照组和研究组,每组各50例。两组患者术后分别接受CFNB和CFNB联合帕瑞昔布镇痛,镇痛时间2 d。观察两组患者术后6 h、12 h、24 h、48 h静息状态和运动状态视觉模拟疼痛评分(VAS)以及术后不良反应发生率。并于术前1 d、术后1 d、2 d、3 d应用美国特种外科医院膝关节评分表(HSS)评定两组患者膝关节功能。结果:术后6 h、12 h、24 h、48 h研究组患者静息状态VAS评分和运动状态VAS评分显著低于对照组患者(P0.05)。两组恶心/呕吐、呼吸抑制、导管相关问题、尿潴留发生率比较无统计学差异(P0.05)。两组患者术前1d HSS评分比较无统计学差异(P0.05),术后1 d、术后2 d、术后3 d两组患者HSS评分均较术前1 d显著升高,且研究组患者HSS评分显著高于对照组(P0.05)。结论:CFNB联合帕瑞昔布具有镇痛效果好、安全可靠的优点,应用TKA术后镇痛有利于患者早期进行膝关节功能锻炼,值得临床推广。     

连续股神经阻滞与静脉自控镇痛对全膝关节置换术后患者凝血功能的影响

目的:比较连续股神经阻滞(CFNB)与静脉自控镇痛(PCIA)在全膝关节置换术中的应用效果及对患者凝血功能的影响。方法:选取2014年1月至2015年12月间我院行单侧全膝关节置换术的患者80例,按照随机数字表法分为CFNB组和PCIA组,每组各40例,两组患者分别接受CFNB和PCIA治疗。观察两组患者术后6 h、12 h、24 h、48 h视觉模拟疼痛评分(VAS),两组患者分别于麻醉前(T1)、术毕(T2)、术后1 d(T3)、术后2 d(T4)进行血栓弹力图检查,观察两组凝血功能变化。并于术后随访1年,比较两组患者膝关节功能。结果:术后6 h、12 h、24 h、48 h CFNB组患者VAS评分显著低于PCIA组患者(P0.05)。T2、T3、T4时点CFNB组患者凝血反应时间(R)、血凝块形成时间(K)较T1升高,血凝块聚合形成速率(α角)、血凝块最大振幅(MA)较T1降低,PCIA组患者R、K较T1降低,α角、MA较T1升高,T2、T3、T4时点CFNB组患者R、K高于PCIA组患者,α角、MA低于PCIA组患者,差异均有统计学意义(P0.05)。两组患者术后均完成1年的随访,两组患者KSS评分、膝关节最大屈曲度、膝关节最大伸直度比较无统计学差异(P0.05)。结论:CFNB对于全膝关节置换术术后患者镇痛效果优于PCIA,有利于改善患者凝血功能,不影响术后患者膝关节功能的恢复。     

Effects of anterior offsetting of humeral head component in posteriorly unstable total shoulder arthroplasty: Finite element modeling of cadaver specimens

A novel technique of “anterior offsetting” of the humeral head component to address posterior instability in total shoulder arthroplasty has been proposed, and its biomechanical benefits have been previously demonstrated experimentally. The present study sought to characterize the changes in joint mechanics associated with anterior offsetting with various amounts of glenoid retroversion using cadaver specimen-specific 3-dimensional finite element models. Specimen-specific computational finite element models were developed through importing digitized locations of six musculotendinous units of the rotator cuff and deltoid muscles based off three cadaveric shoulder specimens implanted with total shoulder arthroplasty in either anatomic or anterior humeral head offset. Additional glenoid retroversion angles (0°, 10°, 20°, and 30°) other than each specimen׳s actual retroversion were modeled. Contact area, contact force, peak pressure, center of pressure, and humeral head displacement were calculated at each offset and retroversion for statistical analysis. Anterior offsetting was associated with significant anterior shift of center of pressure and humeral head displacement upon muscle loading (p<0.05). Although statistically insignificant, anterior offsetting was associated with increased contact area and decreased peak pressure (p > 0.05). All study variables showed significant differences when compared between the 4 different glenoid retroversion angles (p < 0.05) except for total force (p < 0.05). The study finding suggests that the anterior offsetting technique may contribute to joint stability in posteriorly unstable shoulder arthroplasty and may reduce eccentric loading on glenoid components although the long term clinical results are yet to be investigated in future.