Does a tensioning device pinned to the tibia improve knee anterior–posterior load‐displacement compared to manual tensioning of the graft following anterior cruciate ligament reconstruction? A cadaveric study of two tibial fixation devices

Devices that are pinned to the tibia to tension an anterior cruciate ligament (ACL) graft produce joint reaction loads that in turn can affect the maintenance of graft initial tension after tibial fixation and hence knee anterior-posterior (AP) load-displacement. However, the effect of these devices on AP load-displacement is unknown. Our objectives were to determine whether tensioning by device versus tensioning by hand causes differences in AP load-displacement and intraarticular graft tension for two commonly used tibial fixation devices: a bioresorbable interference screw and a WasherLoc. AP load-displacement and intraarticular graft tension were measured in 20 cadaveric knees using a custom arthrometer. An initial tension of 110 N was applied to a double-looped tendon graft with the knee at extension using a tensioning device pinned to the tibia and a simulated method of tensioning by hand. After inserting the tibial fixation device, the 134 N anterior limit (i.e., anterior position of the tibia with respect to the femur with a 134 N anterior force applied to the tibia) and 0 N posterior limit (i.e., AP position of the tibia relative to the femur with a 0 N force applied to the tibia) were measured with the knee in 25 degrees flexion. Intraarticular graft tension was measured at extension. These limits and intraarticular graft tension were also measured after cyclically loading the knee 300 times. Compared to a simulated method of tensioning by hand, tensioning with a device pinned to the tibia did not decrease the 134 N anterior limit and did not cause posterior tibial translation. However, intraarticular graft tension was maintained better with a tensioning device pinned to the tibia for the Washerloc, but not the interference screw. For two commonly used tibial fixation devices, a tensioning device pinned to the tibia does not improve AP load-displacement at 25 degrees flexion over tensioning by hand when the graft is tensioned at full extension, but does improve the maintenance of intraarticular graft tension for the Washerloc.     

Transfer of lumbosacral load to iliac bones and legs Part 1: Biomechanics of self-bracing of the sacroiliac joints and its significance for treatment and exercise

This study deals primarily with the stability of the base of the spine. The sacroiliac joints are vulnerable to shear loading on account of their predominantly flat surfaces. This raises the question of what mechanisms are brought into action to prevent dislocation of the sacroiliac joints when they are loaded by the weight of the upper part of the body and by trunk muscle forces. First a model is introduced to compare load transfer in joints with spherical and with flat joint surfaces. Next we consider a biomechanical model for the equilibrium of the sacrum under load, describing a self-bracing effect that protects the sacroiliac joints against shear according to ‘the sacroiliac joint compression theory’, which has been demonstrated in vitro. The model shows joint stability by the application of bending moments and the configuration of the pelvic arch. The model includes a large number of muscles (e.g. the gluteus maximus and piriformis muscles), ligaments (e.g. the sacrotuberous, sacrospinal, and dorsal and interosseous sacroiliac ligaments) as well as the coarse texture and the ridges and grooves of the joint surfaces.     

月骨周围进行性不稳定的腕运动力学研究

目的探索腕月骨周围进行性不稳定的运动力学变化。方法对１４具新鲜冷冻尸体腕关节，用计算机辅助测量了正常腕和各阶段月骨周围不稳定时腕动力肌腱在腕屈伸、尺桡偏时滑动幅度，根据肌腱滑动幅度和关节运动范围计算动力肌腱力臂。结果月骨周围进行性不稳定时屈腕肌腱力臂明显增大，屈指肌腱力臂减小；桡侧腕动力肌腱力臂以增大为主，尺侧肌腱力臂以减小为主。桡侧腕屈肌腱在腕屈伸或尺桡偏时均显著增大。结论腕运动力学变化对月骨周围不稳定的形成、运动力学变化、腕部塌陷起重要起动作用。     

Proteoglycan fragments in knee joint fluid after exercise

The concentration of cartilage proteoglycan fragments in knee joint fluid was measured before and after one event of physical exercise in 33 healthy athletes. Nine athletes ran on a treadmill for 60 min, 16 ran on road for 80 min and 8 played one soccer game (90 min). Before exercise, the levels of proteoglycan fragments in the athlete joint fluid were lower than in a previously analyzed reference group. After exercise, the concentration of proteoglycan fragments increased in all of the 7 athletes that could be directly compared before and after exercise. This increased concentration of proteoglycan fragments in the joint fluid could be an effect of mechanical loading of the cartilage in combination with a possible high turn-over rate of the cartilage matrix in the athletes.     

基于贝叶斯多变量联合模型的体检人群脑卒中发病风险因素的纵向研究

背景 脑卒中是目前影响人类健康的主要公共卫生问题之一;健康体检纵向数据累积了大量的健康信息,由于缺失数据多、样本量小等诸多问题,导致其利用率低、重要信息未能得到充分挖掘,进而对常见慢性病的有效防控等工作带来一定困难。目的 基于贝叶斯多变量联合模型,探讨体检人群脑卒中发病风险因素,为慢性病风险因素分析提供新的方法。方法 本研究使用空军军医大学西京医院健康医学中心2008—2015年的体检资料。随访情况：以首次发生脑卒中为结局事件,发生结局事件立即停止随访;若未发生,到2015年体检信息收集完成后结束随访;体检间隔时间为1年。依据随访过程中是否发生脑卒中分为脑卒中组和非脑卒中组。纵向观察变量包括总胆固醇（TC）、三酰甘油（TG）、低密度脂蛋白胆固醇（LDL-C）、高密度脂蛋白胆固醇（HDL-C）、体质指数（BMI）和收缩压（SBP）。采用多因素Cox回归模型分析基线情况对脑卒中结局事件的影响;采用贝叶斯多变量联合模型,分析随访过程中TC、TG、LDL-C、HDL-C、BMI和SBP的纵向变化轨迹对脑卒中发病的影响。结果 本研究共纳入234例研究对象,1 581条纵向随访记录,平均随访时间为...     

等速离心训练对肩关节内外旋肌的肌力平衡及神经肌肉控制能力的影响

背景 肩关节内外旋肌肌力失衡会增加肩部运动损伤的风险,研究等速离心训练(IET)能否提高肌力平衡并改善神经肌肉控制能力具有重要的损伤预防意义。目的 探讨IET对健康青年人肩关节内外旋肌的肌力平衡及神经肌肉控制能力的影响。方法 2020年12月至2021年11月在复旦大学附属中山医院招募32例健康青年志愿者为研究对象,随机将其分为试验组(n=16)和对照组(n=16)。试验组接受4周IET,对照组接受4周连续被动运动训练(2次/周)。采用Biodex System 4 Pro多关节等速肌力测试与训练系统(美国Biodex公司)对两组研究对象的优势侧肩关节内、外旋肌群进行训练干预,分别在60(°)/s、120(°)/s速度下进行,干预前1周、干预结束后1周对两组肩关节内外旋肌的功能性比率(FR)、加速时间(AT)和达峰力矩时间(TPT)进行评估并比较。结果 试验组全部完成了4周的训练干预和评估,对照组2例中途退出。最终共30例研究对象数据纳入统计学分析。在60(°)/s和120(°)/s速度下,试验组干预后FR高于对照组(P<0.001),试验组干预后FR高于干预前(配对t检验：t<...     

Comparison of the biomechanical effect of posterior condylar offset and kinematics between posterior cruciate-retaining and posterior-stabilized total knee arthroplasty

Background

The effect of the changes in the femoral posterior condylar offset (PCO) on anterior–posterior (AP) translation and internal–external (IE) rotation in cruciate-retaining (CR) and posterior-stabilized (PS) total knee arthroplasty (TKA) remains unknown. The purpose of this study was to compare the kinematics in CR and PS TKA with respect to the difference in prosthetic design and PCO change through a computational simulation.

颈椎间管壁骨质增生的观察及其意义

在甘肃地区出土的成人颈椎骨骼标本390套(2730块)上,观测了钩椎关节、椎间关节、横突孔和椎体后缘的骨质增生,出现率高达22.5%。增生骨唇占据椎间管、横突孔和椎管的情况分轻、中、重三度.     

Computed tomographic study of the posterior condylar angle in arthritic knees: its use in the rotational positioning of the femoral implant of total knee prostheses

The epicondylar axis is a reliable reference to check the rotation of the femoral implant in total knee prostheses (TKPs). However, during the operation it seems easier to use the posterior condylar axis as a landmark. The angle between these two axes is called the posterior condylar angle (PCA). The aim of this study was to measure the PCA in arthritic knees to assess the reliability of the posterior condylar axis as a reference for the control of the rotation of the femoral implant and to look for correlation with other radiological measurements. This prospective study consisted of 103 arthritic knees (81 varus, 22 valgus) before a TKP had been done in 103 patients (75 women, 28 men). The assessment of the PCA was made by computed tomographic scanning (CT). The HKA, HKS and HKT angles were measured on the pangonogram. The posterior condylar axis was internally rotated with respect to the epicondylar axis. The average value for all the patients was 2.65° degrees with a range from 0° to 7°. The PCA was significantly increased in the valgus knees. There was no correlation between the angles on the pangonogram and the posterior condylar axis. While the preoperative assessment of the PCA by CT scanning is reliable, the results obtained indicate the marked variability in its value. If one wishes to use the posterior condylar axis as a guide for rotation, it is therefore necessary to assess the PCA for each patient using adjustable jigs according to the value obtained. No measurement on standard radiographs allowed an extrapolation of the value of the PCA, and CT scanning seems to be the preferable radiological examination.

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Electronic Supplementary Material The french version of this article is available in the form of electronic supplementary material and can be obtained by using the Springer Link server located at

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Etude tomodensitométrique de l'angle condylien postérieur dans les genoux arthrosiques. Intérêt dans le positionnement en rotation de l'implant fémoral dans les prothèses totales de genou

Résumé L'axe épicondylien est une référence fiable pour le contrôle de la rotation de l'implant fémoral dans les prothèses totales de genou (PTG). Mais, lors de l'intervention, il semble plus facile d'utiliser l'axe condylien postérieur comme repère. L'angle entre ses deux axes est appelé angle condylien postérieur (ACP). Le but de cette étude était de mesurer l'ACP dans les genoux arthrosiques, d'évaluer la fiabilité de l'axe condylien postérieur comme référence pour le réglage de la rotation de l'implant fémoral, de rechercher une corrélation avec d'autres mesures radiologiques. Une étude prospective comportant 103 genoux arthrosiques (81 varus et 22 valgus), avant PTG a été effectuée, chez 103 patients (75 femmes et 28 hommes). L'évaluation de l'ACP a été faite par examen tomodensitométrique (TDM). Les angles HKA, HKS et HKT ont été mesurés sur le pangonogramme. L'axe condylien postérieur était en rotation interne par rapport à l'axe épicondylien. La valeur moyenne pour tous les patients était de 2.65°, avec des valeurs de 0 à 7°. La valeur de l'angle CP augmentait avec une différence significative dans le groupe des genu valgum. Il n'y avait pas de corrélation entre les angles du pangonogramme et l'ACP. Si l'évaluation pré-opératoire de l'ACP par TDM est fiable, les résultats obtenus mettent en évidence une variabilité importante de sa valeur. Il faut donc, si l'on veut utiliser l'axe condylien postérieur comme repère de rotation, évaluer pour chaque patient l'ACP, et utiliser un ancillaire réglable reportant la valeur obtenue. Aucune mesure sur des radiographies standard ne permettant d'extrapoler la valeur de l'ACP, la TDM semble l'examen radiologique de choix.