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.     

A combined passive and active musculoskeletal model study to estimate L4-L5 load sharing

A number of geometrically-detailed passive finite element (FE) models of the lumbar spine have been developed and validated under in vitro loading conditions. These models are devoid of muscles and thus cannot be directly used to simulate in vivo loading conditions acting on the lumbar joint structures or spinal implants. Gravity loads and muscle forces estimated by a trunk musculoskeletal (MS) model under twelve static activities were applied to a passive FE model of the L4-L5 segment to estimate load sharing among the joint structures (disc, ligaments, and facets) under simulated in vivo loading conditions. An equivalent follower (FL), that generates IDP equal to that generated by muscle forces, was computed in each task. Results indicated that under in vivo loading conditions, the passive FE model predicted intradiscal pressures (IDPs) that closely matched those measured under the simulated tasks (R² = 0.98 and root-mean-squared-error, RMSE = 0.18 MPa). The calculated equivalent FL compared well with the resultant force of all muscle forces and gravity loads acting on the L4-L5 segment (R² = 0.99 and RMSE = 58 N). Therefore, as an alternative approach to represent in vivo loading conditions in passive FE model studies, this FL can be estimated by available in-house or commercial MS models. In clinical applications and design of implants, commonly considered in vitro loading conditions on the passive FE models do not adequately represent the in vivo loading conditions under muscle exertions. Therefore, more realistic in vivo loading conditions should instead be used.     

Metal ion release barrier function and biotribological evaluation of a zirconium nitride multilayer coated knee implant under highly demanding activities wear simulation

Total knee arthroplasty is a well established treatment for degenerative joint disease, which is also performed as a treatment in younger and middle-aged patients who have a significant physical activity and high life expectancy. However, complications may occur due to biological responses to wear particles, as well as local and systemic hypersensitivity reactions triggered by metal ions and particles such as cobalt, chromium and molybdenum. The purpose of the study was to perform a highly demanding activities (HDA) knee wear simulation in order to compare the wear characteristics and metal ion release barrier function of a zirconium nitride (ZrN) coated knee implant, designed for patients with suspected metal ion hypersensitivity, against an uncoated knee implant made out of CoCrMo. The load profiles were applied for 5 million HDA cycles, which represent 15–30 years of in vivo service depending on the activity level of the patient. Results showed a significant wear rate reduction for the coated group (1.01 ± 0.29 mg/million cycles) in comparison with the uncoated group (2.89 ± 1.04 mg/million cycles). The zirconium nitride coating showed no sign of scratches nor delamination during the wear simulation, whereas the uncoated femurs showed characteristic wear scratches in the articulation areas. Furthermore, the metal ion release from the coated implants was reduced up to three orders of magnitude in comparison with the uncoated implants. These results demonstrate the efficiency of zirconium nitride coated knee implants to reduce wear as well as to substantially reduce metal ion release in the knee joint.     

Intra-articular implantation of autologous bone marrow–derived mesenchymal stromal cells to treat knee osteoarthritis: a randomized,triple-blind,placebo-controlled phase 1/2 clinical trial

Background

The intra-articular implantation of mesenchymal stromal cells (MSCs) as a treatment for knee osteoarthritis (OA) is an emerging new therapy. In this study, patients with knee OA received intra-articular implantations of autologous bone marrow–derived MSCs. We sought to assess the safety and efficacy of this implantation.

滑膜炎颗粒联合玻璃酸钠治疗创伤性膝关节滑膜炎的疗效及对患者血清炎症因子水平的影响

目的:探讨滑膜炎颗粒联合玻璃酸钠治疗创伤性膝关节滑膜炎的疗效及对患者血清炎症因子水平的影响。方法:选取2015年2月～2017年12月期间我院收治的创伤性膝关节滑膜炎患者216例为研究对象。根据随机数字表法将患者分为对照组(n=108)与研究组(n=108)。对照组患者给予玻璃酸钠治疗,研究组则在此基础上联合滑膜炎颗粒进行治疗,两组均治疗5周。比较两组治疗5周后(治疗后)的临床疗效及治疗前后血清白介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、白介素-1β(IL-1β)水平,采用视觉模拟量表(VAS)评价患者治疗前后膝关节疼痛程度,美国特种外科医院量表(HSS)评价患者治疗前后膝关节功能,同时观察两组治疗期间不良反应发生情况。结果:研究组患者总有效率为92.59%(100/108),高于对照组患者的78.70%(85/108)(P0.05)。两组患者治疗后IL-6、TNF-α以及IL-1β水平均较治疗前降低,且研究组低于对照组(P0.05)。两组患者治疗后VAS评分较治疗前降低,且研究组低于对照组,HSS评分较治疗前升高,且研究组高于对照组(P0.05)。两组患者不良反应发生率对比差异无统计学意义(P0.05)。结论:滑膜炎颗粒联合玻璃酸钠治疗创伤性膝关节滑膜炎安全有效,可显著改善患者血清炎症因子水平以及膝关节功能,并减轻患者疼痛程度,具有一定的临床应用价值。     

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。     

氨甲环酸联合利伐沙班对单侧全膝关节置换术后患者出血量、凝血功能以及膝关节功能的影响

目的:探讨氨甲环酸联合利伐沙班对单侧全膝关节置换术后患者出血量、凝血功能及膝关节功能的影响。方法:选取2015年1月-2016年1月在解放军425医院骨科初次行单侧全膝关节置换术的患者66例为研究对象,按照随机数字表法分为治疗组与对照组,每组各33例。治疗组患者在止血带释放前向关节腔内注射氨甲环酸,对照组患者则给予氯化钠注射液进行静脉滴注,在术后6-12h内两组患者均口服利伐沙班。记录并对比两组患者总失血量、隐性出血量、输血率、输血量,对比两组患者手术前后凝血功能指标、膝关节功能评分、膝关节活动度、疼痛视觉模拟评分(VAS),并观察两组患者并发症发生情况。结果:与对照组对比,治疗组患者的总失血量、隐性出血量、输血量及输血率均明显降低(P0.05);治疗组与对照组患者术前与术后3 d的活化部分凝血酶时间(APTT)、凝血酶原时间(PT)、纤维蛋白原(FG)水平比较均无显著差异(P0.05);术前两组患者的美国膝关节协会评分(AKSS)及膝关节活动度比较无显著差异(P0.05),术后7 d,治疗组与对照组患者的AKSS评分及膝关节活动度均较术前升高(P0.05),且治疗组患者的AKSS评分及膝关节活动度高于同时期对照组(P0.05);术前两组VAS评分比较无显著差异(P0.05),术后1 d,两组患者的VAS评分比较及与同组术前比较均无显著差异(P0.05),术后7 d,两组患者的VAS评分明显较术前及术后1 d降低(P0.05),但两组之间比较无显著差异(P0.05)。两组患者并发症总发生率对比无显著差异(P0.05)。结论:氨甲环酸联合利伐沙班可有效降低行单侧全膝关节置换术患者的出血量,加快关节功能的恢复,且不影响患者的凝血功能,值得临床推广。     

A Simple Method for Measuring the Changeable Mechanical Action of Unloader Knee Braces for Osteoarthritis

Purpose

Today's orthotics should be designed to apply the external orthosis moment to the knee joint solely during the stance phase instead of the entire gait cycle. The aim of this study was to validate the reliability of a simple device for measuring forces at the leg–orthosis interface and describe the behavior of an innovating dynamic unloader knee brace built to interrupt its mechanical action during large knee flexion (swing phase of gait).

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。