Details of human middle ear morphology based on micro‐CT imaging of phosphotungstic acid stained samples

A multitude of morphological aspects of the human middle ear (ME) were studied qualitatively and/or quantitatively through the postprocessing and interpretation of micro‐CT (micro X‐ray computed tomography) data of six human temporal bones. The samples were scanned after phosphotungstic acid staining to enhance soft‐tissue contrast. The influence of this staining on ME ossicle configuration was shown to be insignificant. Through postprocessing, the image data were converted into surface models, after which the approaches diverged depending on the topics of interest. The studied topics were: the ME ligaments; morphometric and mechanical parameters of the ossicles relating to inertia and the ossicular lever arm ratio; the morphology of the distal incus; the contact surface areas of the tympanic membrane (TM) and of the stapes footplate; and the thickness of the TM, round window of the cochlea, ossicle joint spaces, and stapedial annular ligament. Some of the resulting insights are relevant in ongoing discussions concerning ME morphology and mechanical functions, while other results provide quantitative data to add to existing data. All findings are discussed in the light of other published data and many are relevant for the construction of mechanical finite element simulations of the ME. J. Morphol. 276:1025–1046, 2015. © 2015 Wiley Periodicals, Inc.     

Intracellular Calcium Response of ACL and MCL Ligament Fibroblasts to Fluid-Induced Shear Stress

This study examines the real-time intracellular calcium concentration, [Ca²⁺]_i, response of canine medial collateral ligament (MCL) and anterior cruciate ligament (ACL) fibroblasts subjected to a fluid-induced shear stress of 25 dynes/cm². In experiments using a modified Hanks' Balanced Salt Solution (HBSS) perfusate, both cell types demonstrated a significant increase in peak [Ca²⁺]_i compared to respective no-flow controls, the response of MCL fibroblasts being nearly 2-fold greater than that of ACL fibroblasts. In studies where the cells were bathed in a medium of HBSS supplemented with 2% newborn bovine serum (NBS) and then introduced to flow with the same medium, ACL fibroblasts responded nearly 3-fold greater than MCL fibroblasts. Neomycin (10 mM), thapsigarigin (1 μM) and Ca²⁺-free media supplemented with EGTA (1 mM) were able to inhibit significantly the [Ca²⁺]_i response to flow with HBSS in both fibroblasts. Thapsigargin also blocked the NBS flow response in both cell types, while neomycin and Ca²⁺-free media significantly inhibited the ACL response. Our findings demonstrate that ACL and MCL cells are not the same. These differences may be related to the disparate healing capacity of the ACL and MCL observed clinically.     

A dynamic multibody model of the physiological knee to predict internal loads during movement in gravitational field

Obtaining tibio-femoral (TF) contact forces, ligament deformations and loads during daily life motor tasks would be useful to better understand the aetiopathogenesis of knee joint diseases or the effects of ligament reconstruction and knee arthroplasty. However, methods to obtain this information are either too simplified or too computationally demanding to be used for clinical application. A multibody dynamic model of the lower limb reproducing knee joint contact surfaces and ligaments was developed on the basis of magnetic resonance imaging. Several clinically relevant conditions were simulated, including resistance to hyperextension, varus–valgus stability, anterior–posterior drawer, loaded squat movement. Quadriceps force, ligament deformations and loads, and TF contact forces were computed. During anterior drawer test the anterior cruciate ligament (ACL) was maximally loaded when the knee was extended (392 N) while the posterior cruciate ligament (PCL) was much more stressed during posterior drawer when the knee was flexed (319 N). The simulated loaded squat revealed that the anterior fibres of ACL become inactive after 60° of flexion in conjunction with PCL anterior bundle activation, while most components of the collateral ligaments exhibit limited length changes. Maximum quadriceps and TF forces achieved 3.2 and 4.2 body weight, respectively. The possibility to easily manage model parameters and the low computational cost of each simulation represent key points of the present project. The obtained results are consistent with in vivo measurements, suggesting that the model can be used to simulate complex and clinically relevant exercises.     

右美托咪定联合罗哌卡因连续股神经阻滞对全膝关节置换术后患者镇痛效果、炎性因子和神经递质的影响

摘要 目的：探讨右美托咪定联合罗哌卡因连续股神经阻滞对全膝关节置换术（TKA）后患者镇痛效果、炎性因子和神经递质的影响。方法：选取2017年2月~2019年12月期间我院收治的行TKA的患者98例,采用随机数字表法分为对照组和研究组,各49例。对照组给予罗哌卡因连续股神经阻滞,研究组在对照组的基础上联合右美托咪定,比较两组患者镇痛效果、炎性因子、神经递质和不良反应。结果：两组术后1h、6h、12h、24h、48h静息及运动状态的视觉疼痛模拟评分法（VAS）评分均呈先升高后降低趋势（P<0.05）;研究组术后1h、6h、12h、24h、48h静息及运动状态的VAS评分均低于对照组（P<0.05）。两组术前、术后24h、术后48h白介素-1β（IL-1β）、白介素-6（IL-6）、肿瘤坏死因子-α（TNF-α）呈先升高后下降趋势,但研究组术后24h、术后48hIL-1β、IL-6、TNF-α低于对照组（P<0.05）。两组术前、术后24h、术后48h P 物质、β-内啡肽及孤啡肽呈先升高后下降趋势,但研究组术后24h、术后48h P 物质、β-内啡肽及孤啡肽低于对照组（P<0.05）。两组不良反应发生率对比未见统计学差异（P>0.05）。结论：行TKA患者采用罗哌卡因联合右美托咪定连续股神经阻滞,术后镇痛效果确切,可减少炎性因子和神经递质水平,且不增加不良反应发生率,安全性佳。     

等长伸膝动作的运动单元放电特征分析

本研究基于表面肌电分解技术,分析伸膝动作中不同发力状态下大腿肌肉运动单元的解码准确性,并对比神经特征和肌电特征在肌肉激活程度估计中的效果. 12名大学生分别以2种发力速度和4种发力等级完成伸膝动作的等长收缩.实验同步采集受试者股内侧肌和股外侧肌处的高密度表面肌电信号和伸膝动作收缩力.基于卷积核补偿算法解码肌电信号得到运动单元动作电位,提取神经特征用于收缩力的互相关分析.结果发现,对于股内侧肌,2种任务及4种收缩力等级下平均解码得到(7±4)个运动单元,股外侧肌平均解码得到(9±5)个运动单元.它们的平均脉冲信噪比(pulse-to-noise ratio,PNR)为30.1 d B,对应解码准确率大于90%.股内侧肌的两种神经特征与力之间的平均相关性分别为(0.79±0.08)和(0.80±0.08),股外侧肌的两种神经特征与力之间的平均相关性分别为(0.85±0.05)和(0.85±0.06).综上可见,基于肌电分解技术可以准确识别不同发力状态下大腿肌肉的运动单元放电活动,并且运动单元放电频率与伸膝动作力高度相关,研究结果可用于运动康复、运动训练及人机接口等领域.     

Knee joint biomechanics in closed-kinetic-chain exercises

Effective management of knee joint disorders demands appropriate rehabilitation programs to restore function while strengthening muscles. Excessive stresses in cartilage/menisci and forces in ligaments should be avoided to not exacerbate joint condition after an injury or reconstruction. Using a validated 3D nonlinear finite element model, detailed biomechanics of the entire joint in closed-kinetic-chain squat exercises are investigated at different flexion angles, weights in hands, femur-tibia orientations and coactivity in hamstrings. Predictions are in agreement with results of earlier studies. Estimation of small forces in cruciate ligaments advocates the use of squat exercises at all joint angles and external loads. In contrast, large contact stresses, especially at the patellofemoral joint, that approach cartilage failure threshold in compression suggest avoiding squatting at greater flexion angles, joint moments and weights in hands. Current results are helpful in comprehensive evaluation and design of effective exercise therapies and trainings with minimal risk to various components.     

The development,calibration and validation of a numerical total knee replacement kinematics simulator considering laxity and unconstrained flexion motions

Kinematics testing is essential during the development of total knee replacement (TKR) designs. Although computational analysis cannot replace physical testing, it offers repeatability and consistency at a much lower cost and shorter time, making it an excellent complement to experiments. Previous numerical models have been limited by several factors: the validity of the models is usually only considered for a single TKR design, friction models are typically overly simplified and the determination of simulation parameters is often inadequate, or tedious and expensive. The objective of this study is to develop, calibrate and validate a TKR kinematics simulation considering multiple TKR geometries, an accurate friction model and simulation parameters determined using a systematic optimisation method. The calibrated model was able to predict TKR kinematics for different TKR geometries, and is ideal for screening new implant designs, reducing the number of experiments required at the design stage.     

主动运动训练和被动运动训练对人工全膝关节置换患者的随机对照研究

摘要 目的：对比主动运动训练和被动运动训练在人工全膝关节置换（TKA）患者中的应用效果。方法：选择2017年4月~2021年8月期间我院骨科收治的TKA患者65例,根据随机数字表法将患者分为主动组（主动运动训练）和被动组（被动运动训练）,各为33例和32例。对比两组生活自理能力、平衡能力、疼痛情况、膝关节功能情况、膝关节活动度和生活质量。结果：两组术后1周、术后2周Barthel指数（BI）、Berg平衡量表（BBS）、美国膝关节外科学会评分标准（KSS）评分均较术前升高,视觉疼痛模拟法（VAS）评分均较术前下降（P<0.05）。主动组BI、BBS、KSS评分高于被动组,VAS评分低于被动组（P<0.05）。两组术前、术后3 d、术后7 d被动关节活动度（PROM）、主动关节活动度（AROM）均下降后升高（P<0.05）,主动组术后3 d AROM、PROM高于被动组（P<0.05）。两组术后3个月生理职能、生理机能、一般健康、躯体疼痛、社会功能、精力、精神健康、情感职能各维度评分均升高,且主动组高于被动组（P<0.05）。结论：与被动运动训练相比,主动运动训练应用于TKA患者,可减轻患者疼痛,改善膝关节活动度及功能,改善患者生活自理能力,提高其生活质量的效果均更显著。     

Photobiomodulation therapy in knee osteoarthritis reduces oxidative stress and inflammatory cytokines in rats

Knee osteoarthritis (OA) is a chronic disease that causes pain and gradual degeneration of the articular cartilage. In this study, MIA‐induced OA knee model was used in rats to test the effects of the photobiomodulation therapy (PBM). We analyzed the inflammatory process (pain and cytokine levels), and its influence on the oxidative stress and antioxidant capacity. Knee OA was induced by monosodium iodoacetate (MIA) intra‐articular injection (1.5 mg/50 μL) and the rats were treated with eight sessions of PBM 3 days/week (904 nm, 6 or 18 J/cm²). For each animal, mechanical and cold hyperalgesia and spontaneous pain were evaluated; biological analyses were performed in blood serum, intra‐articular lavage, knee structures, spinal cord and brainstem. Cytokine assays were performed in knee, spinal cord and brainstem samples. The effects of the 18 J/cm² dose of PBM were promising in reducing pain and neutrophil activity in knee samples, together with reducing oxidative stress damage in blood serum and spinal cord samples. PBM improved the antioxidant capacity in blood serum and brainstem, and decreased the knee pro‐inflammatory cytokine levels. Our study demonstrated that PBM decreased oxidative damage, inflammation and pain. Therefore, this therapy could be an important tool in the treatment of knee OA.     

Technical note: out-of-plane angular correction based on a trigonometric function for use in two-dimensional kinematic studies

In two-dimensional (2D) kinematic studies, limb positions in three-dimensional (3D) space observed in lateral view are projected onto a 2D film plane. Elbow and knee-joint angles that are less than 20 degrees out-of-plane of lateral-view cameras generally exhibit very little measurable difference from their 3D counterparts (Plagenhoef 1979 Environment, Behavior, and Morphology; New York: Gustav Fisher, p. 95-118). However, when limb segment angles are more than 20 degrees out-of-plane, as is often the case in locomotor studies of arboreal primates, elbow and knee angles can appear significantly more extended than they actually are. For this reason, a methodology is described that corrects 2D out-of-plane angular estimates using a series of trigonometric transformations.