Time-varying stiffness of human elbow joint during cyclic voluntary movement

Summary The objective of this study was to determine the extent to which subjects modulate their elbow joint mechanical properties during ongoing arm movement. Small pseudo-random force disturbances were applied to the wrist with an airjet actuator while subjects executed large (1 rad) elbow joint movements. Using a lumped parameter model of the muscle, tendom and proprioceptive feedback dynamics, a time-varying system identification technique was developed to analyze the phasic changes in the elbow joint's mechanical response. The mechanical properties were found to be time-varying, and well approximated by a quasi-linear second-order model. The stiffness of the arm was found to drop during movement. The arm was always underdamped, with the damping ratio changing during movement. Inertia estimates were constant and consistent with previous measurements. Overall, the moving arm was found to be very compliant, with a peak stiffness value less than the lowest value measured during posture, and a natural frequency of less than 3 Hz. Changing the speed of movement, or the load from gravity, changed the stiffness measured, but not in strict proportion to the change in net muscle torque.     

The relationship between main elbow flexion skin crease and osseous anatomy of the elbow joint

Background  Studies that investigate the relationships between the main elbow flexion crease and the underlying osseous anatomy are lacking. Methods  The relationship between the flexion skin crease and osseous anatomy of the elbow joint was studied. Markers were placed along the main flexion skin crease of both elbows in 50 healthy volunteers. Measurements were expressed in millimeters of perpendicular distance from each skin crease to the osseous structures of the elbow joint including medial and lateral epicondyles, tip of the olecranon, and radial head. Results  The mean perpendicular distances between the elbow crease from osseous structures were found to be as follows: from medial epicondyle, 6.93 mm; from lateral epicondyle, −0.25 mm; from olecranon, 9.97 mm; and from radial head, −21.97 mm. There was no statistical significant difference between the dominant versus non-dominant hand. Conclusions  The association between the main flexion elbow crease and the bony structures observed in this study seems to support that the elbow crease can be a useful surface anatomy landmark and expected to aid in the placement of surgical incisions.     

Modulation of elbow joint stiffness in a vertical plane during cyclic movement at lower or higher frequencies than natural frequency

The purpose of the present study was to determine how joint stiffness during cyclic movement in a vertical plane is modulated at lower or higher frequencies than the natural frequency of the system. Five male subjects were instructed to swing their forearms rhythmically in a vertical plane under various frequency conditions (0.7–2.25 Hz). To estimate the mechanical properties of the elbow joint, external perturbations were applied by an electromagnetic torque motor system to the forearm of each subject during the movement. Joint stiffness showed a significant quadratic trend with a minimum close to the natural frequency of the apparatus–forearm system (1.09±0.08 Hz). The resonant frequency showed the similar tendencies to joint stiffness and was significantly different from movement frequency in the lower frequency range (0.7–0.9 Hz). In addition, the ratio of joint stiffness to the background torque (ST_ratio) was greater in the frequency conditions below the natural frequency than in the frequency conditions above the natural frequency and was relatively constant in the latter. These results suggested that: (1) the modulation of joint stiffness for movement in a vertical plane, by which the resonant frequency of the system is kept close to the movement frequency, may be limited to the movement frequency range above the natural frequency; and (2), in the case of movement in a vertical plane, the mechanism by which joint stiffness is modulated may change according to the relation between natural frequency and movement frequency.Due to an error in the citation line, this revised PDF (published in December 2003) deviates from the printed version, and is the correct and authoritative version of the paper.     

Axial and transverse stiffness measures of cochlear outer hair cells suggest a common mechanical basis

 The function of the hearing organ is based on mechanical processes occurring at the cellular level. The mechanical properties of guinea-pig isolated sensory cells were investigated using two different techniques. The stiffness of the outer hair cells along the longitudinal axis was measured by compressing the cell body using stiffness-calibrated quartz fibres. For cells with a mean length of 69 μm, the mean axial compression stiffness was 1.1±0.8 mN/m (±SD). There was an inverse relation between stiffness and cell length. The stiffness of the cell membrane perpendicular to the longitudinal axis of the sensory cell was measured by indenting the cell membrane with a known force. The mean lateral indentation stiffness was 3.3±1.5 mN/m (±SD) for cells with a mean length of 64 μm. Longer cells were less stiff than short cells. Modelling the hair cell as a shell with bending resistance, finite element calculations demonstrated that the axial compression stiffness correlated well with the lateral indentation stiffness, and that a simple isotropic model is sufficient to explain the experimental observations despite the different stress strain states produced by the two techniques. The results imply that the two different stiffness properties may originate from the same cytoskeletal structures. It is suggested that the mechanical properties of the outer hair cells are designed to influence the sound-induced motion of the reticular lamina. In such a system, stiffness changes of the outer hair cell bodies could actively control the efficiency of the mechanical coupling between the basilar membrane and the important mechanoelectrical transduction sites at the surface of the hearing organ. Received: 12 June 1997/Received after revision: 13 November 1997/Accepted: 19 January 1998     

A topographical study of cartilaginous lesions to the elbow

Summary The macroscopic examination of 40 anatomical preparations of the elbow has enabled us to describe the location of cartilaginous lesions to the humeral, radial and ulnar joint surfaces. A protocol for the macroscopic examination of the lesions was drawn up for the observation of 40 anatomical elbow-joint preparations. The results demonstrated that the cartilage of the lateral compartment (humero-radial) was preferentially affected as compared with that of the medial compartment (humero-ulnar) for which it will be necessary to search for a functional explanation.

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Etude topographique des lésions cartilagineuses du coude

Résumé L'observation macroscopique de 40 préparations anatomiques de coudes a permis de décrire la localisation des lésions cartilagineuses des surfaces articulaires humérales, radiales et ulnaires. Un protocole d'examen macroscopique des lésions a été constitué en vue de l'observation de ces pièces. Les résultats démontrent une atteinte préférentielle des cartilages du compartiment latéral (huméro-radial) par rapport à ceux du compartiment médial (huméro-ulnaire) à laquelle il faut rechercher une explication fonctionnelle.

     

眼科麻醉应用解剖观测

利用100个成人颅骨对与眼部神经阻滞麻醉有关的结构进行了观测。结果表明:球后麻醉时可根据枕额径判断眶深度以决定进针深度;眶下孔上缘至眶下缘距离小于7mm时,眶下管内穿刺深度不应超过10mm;眶下沟有被骨壁覆盖的情况,对麻醉不利,各测量数据可作为麻醉时进针深度的参考。     

Knee stiffness following anterior cruciate ligament reconstruction: The incidence and associated factors of knee stiffness following anterior cruciate ligament reconstruction

We reviewed 100 patients retrospectively following primary ACL reconstruction with quadruple hamstring autografts to evaluate the incidence and factors associated with postoperative stiffness. Stiffness was defined as any loss of motion using the contra-lateral leg as a control. The median delay between injury and operation was 15 months.The incidence of stiffness was 12% at 6 months post-reconstruction. Both incomplete attendance at physiotherapy (p < 0.005) and previous knee surgery (p < 0.005) were the strongest predictors of the stiffness. Anterior knee pain was also associated with the stiffness (p < 0.029). Factors that failed to show a significant association with the stiffness included associated MCL sprain at injury (p = 0.32), post-injury stiffness (p = 1.00) and concomitant menisectomy at reconstruction (p = 0.54). Timing of surgery also did not appear to influence the onset of stiffness (median delays: 29 months for stiff patients; 14 months for non-stiff patients). The rate of stiffness fell to 5% at 12 months postreconstruction, without operative intervention.     

肘前入路钢板内固定联合Kocher入路桡骨头置换治疗肘关节恐怖三联征

目的探讨采用肘关节前方入路微型钢板内固定联合外侧Kocher入路桡骨头置换治疗肘关节恐怖三联征的临床疗效。方法回顾性分析从2015年6月至2017年6月我科收治和采用肘关节前方入路微型钢板内固定联合外侧Kocher入路桡骨头置换治疗肘关节恐怖三联征的8例病例资料。其中男7例,女1例;年龄20～47岁,平均28.3岁;患者均为单侧损伤,右侧损伤5例,左侧3例。尺骨冠状突骨折按Regan-Morrey分型:Ⅰ型1例,Ⅱ型5例,Ⅲ型2例;桡骨头骨折按Mason分型:Ⅲ型5例,Ⅳ型3例。均采用肘关节前方入路微型钢板内固定联合外侧Kocher入路桡骨头置换治疗,记录手术时间、术中出血量,观察切口愈合、骨折愈合情况及术后并发症情况,应用Mayo肘关节功能评分标准(MEPS)评定肘关节功能。结果本组获随访10～23个月,平均15.7个月,所有8例患者切口均一期愈合,骨折均获得临床愈合。未见神经、血管损伤及肘关节骨化性肌炎等并发症。根据患者肘关节的运动功能、稳定性、疼痛和日常活动等情况采用Mayo肘关节功能评分标准(MEPS)评估手术疗效:优3例,良4例,中1例,优良率87.5%。结论采用肘关节前方入路微型钢板内固定联合外侧Kocher入路桡骨头置换治疗肘关节恐怖三联征,具有术中显露充分、固定可靠及手术时间短等优势,临床疗效满意。     

Anatomical basis of lumboscopy

Lumboscopy provides an approach to the retroperitoneum for the majority of upper urinary tract operations. The technique involves a knowledge of specific anatomical landmarks that differ from those in classical open surgery, because of the inferior approach to the renal pedicle with the kidney initially mobilized in a ventral and cranial position. An anatomical study was conducted on five cadavers, using images from surgical operations, in order to describe the vascular elements of the retroperitoneal spaces as they are approached during lumboscopy, as well as to define specific anatomical landmarks. Identification of psoas major is crucial as it is then possible to locate the renal pedicle opposite and the area of the great vessels medially. During dissection of the renal pedicle the renal vein and its branches are the first elements to be approached. On the left side the distal portion of the renal vein can be confused with a reno-hemi-azygo-lumbar trunk, due to the initial ventral mobilization of the kidney stretching it. Because of the inferior view of the renal pedicle the reno-hemi-azygo-lumbar trunk can obscure part of the renal artery and may be confused with the renal vein. On the right side initial identification of the inferior vena cava on the medial aspect of psoas major facilitates identification of the gonadal, renal and suprarenal veins all located in the same plane.     

Perception of difficulties with vision-related activities of daily living among patients undergoing unilateral posterior capsulotomy

OBJECTIVES

To assess the influence of Nd:YAG (neodymium: yttrium-aluminum- garnet) laser unilateral posterior capsulotomy on visual acuity and patients’ perception of difficulties with vision-related activities of daily life.

METHODS

We conducted an interventional survey that included 48 patients between 40 and 80 years of age with uni- or bilateral pseudophakia, posterior capsule opacification, and visual acuity ≤0.30 (logMAR) in one eye who were seen at a Brazilian university hospital. All patients underwent posterior capsulotomy using an Nd:YAG laser. Before and after the intervention, patients were asked to complete a questionnaire that was developed in an exploratory study.

RESULTS

Before posterior capsulotomy, the median visual acuity (logMAR) of the included patients was 0.52 (range 0.30–1.60). After posterior capsulotomy, the median visual acuity of the included patients improved to 0.10 (range 0.0–0.52). According to the subjects’ perceptions, their ability to perform most of their daily life activities improved after the intervention (p<0.05).

CONCLUSIONS

After patients underwent posterior capsulotomy with an Nd:YAG laser, a significant improvement in the visual acuity of the treated eye was observed. Additionally, subjects felt that they experienced less difficulty performing most of their vision-dependent activities of daily living.     

Measurement of muscle and tendon stiffness in man

Human first dorsal interosseous muscle was stimulated tetanically using several levels of percutaneous electrical current which produced forces in the muscle-tendon complex of between 30% and 100% of maximum. During the tetanus the muscle was subjected to a small fast stretch. The ratio of the force response to the displacement of the muscle-tendon complex gave a measure of the stiffness of the total complex. An adaptation of the method of Morgan (1977) allowed the stiffness to be separated into two components the stiffness of the muscle fibres and the stiffness of the tendon. The results showed that at full activation the stiffness of the muscle fibres and the tendon are approximately the same. The normalised stiffness values obtained in the experiments compared well with animal data.     

髌下深囊形成的解剖学基础

目的通过尸体解剖和活体测量,研究髌下深囊的形成,为滑膜的分化及非遗传性滑液囊形成的预防提供依据。方法对成年人尸体膝关节标本进行解剖,显露髌韧带、关节腔、髌下深囊、髌下脂肪垫等结构。活体及骨标本观察并测量相关的数据。结果尸体测量结果显示,膝关节伸位时,髌下深囊长0.9~1.1 cm,最宽处0.5 cm,高0.3~0.5 cm,髌韧带长度为4.7~4.8 cm;膝关节屈位时（45°）,髌下深囊长0.8~1.0 cm,最宽处0.8 cm,高0.4~0.5 cm。活体测量结果膝关节伸位时,髌骨下缘与胫骨粗隆的距离为4.5~4.8 cm,屈位时（145°）为9.0~9.5 cm。结论髌下深囊的形成是因为髌韧带与胫骨之间长期摩擦诱导的结果。     

单臂铰链式外固定支架治疗不稳定性肘关节骨折脱位

目的 探讨单臂铰链式外固定支架治疗不稳定性肘关节骨折脱位的方法及临床疗效。方法 2005年1月至2006年6月，采用单臂铰链式外固定支架结合有限内固定治疗不稳定性肘关节骨折脱位患者36例，完整随访33例。男25例，女8例；平均年龄34．3岁（17—65岁）；左侧7例，右侧24例，双侧2例。以Mayo评分进行肘关节功能评定。结果 平均随访时间10．6个月（8个月～12个月）。Mayo评分平均85分（64～95分），优24例，良6例，中3例。结论 单臂铰链式外固定支架结合有限内固定治疗不稳定性肘关节骨折脱位，能提高术后肘关节的稳定性，保证早期安全的功能锻炼，预防关节僵硬，减少异位骨化的发生，可使肘关节获得满意的复位和功能。     

A simple method for quantitative assessment of elbow flexion strength

Assessment of elbow flexion strength is an important component of upper limb neurological examination and is necessary for patient screening, planning of surgical interventions and rehabilitation. Medical Research Council (MRC) Scale is the most widely used method for grading muscle strength. The major drawback of MRC grading is that it is observer dependent and imprecise. A quantitative measure of elbow flexion strength is an objective measure that eliminates such bias. Several instruments have been developed for quantifying the elbow flexion power. However, availability, quality and measuring standards vary widely between these instruments most being cumbersome and expensive. We report the design of an instrument that is simple and cost effective for quantifying elbow flexion strength objectively. The validity of elbow flexion strength obtained from normal participants using this in-house instrument supports its clinical use in patients with brachial plexus injury.     

A meta-analysis of tourniquet assisted arthroscopic knee surgery

The purpose was to compare the intra- and post-operative outcomes of tourniquet assisted to non-tourniquet-assisted surgery during arthroscopic knee procedures. A systematic review was undertaken of the electronic databases MEDLINE, CINAHL, AMED and EMBASE, in addition to a review of unpublished material and a hand search of pertinent orthopaedic journals. The evidence-base was critically appraised using the Cochrane Bone, Joint and Muscle Trauma Group quality assessment tool. Study heterogeneity was statistically measured using the Chi² and I² statistical tests. When appropriate, a random-effect meta-analysis was undertaken to pool the results of the primary studies assessing the mean difference of each outcome. Nine studies were identified evaluating seven outcome measures and parameters. Arthroscopic ACL reconstruction knee surgery with a tourniquet experienced less operative visualisation difficulties compared to surgery without a tourniquet. There was no significant difference between tourniquet and non-tourniquet arthroscopic knee surgery for all other outcomes. The evidence-base exhibited a number of methodological limitations. There is limited evidence to suggest that a tourniquet assists in arthroscopic knee surgery. The methodological quality of the present evidence-base remains weak. Further study is required to answer this research question.     

肘关节“恐怖三联征”的治疗――附10例报告

目的探讨肘关节"恐怖三联征"的治疗方法和疗效。方法 10例患者手术治疗9例,其中1例行人工桡骨头置换,并修复肘关节前关节囊及肘内、外侧副韧带;8例内固定,术后予长臂石膏或铰链式支架外固定制动2～3周,早期开始屈伸康复训练。闭合复位保守治疗1例。结果 10例患者均获随访,随访时间3～40月,平均22.5个月。手术组切口均一期愈合。术后8～12周骨折达临床愈合,平均9.2周。肘关节平均屈伸范围为110°±28°,前臂平均旋转活动范围为109°±25°,1例有创伤性关节炎。按照肘关节HHS评分标准评定标准进行评价:优5例、良2例、可1例、差2例(含保守治疗1例),总优良率为70%。结论对于肘关节"恐怖三联征",应积极手术治疗,重建或恢复骨的结构,坚强内固定,修复关节周围支持结构,早期功能锻炼,能有效恢复关节功能,减少骨折并发症。     

Time of day effects on isometric and isokinetic torque developed during elbow flexion in humans

 The aim of this study was, firstly, to confirm or refute the existence of circadian rhythms during several velocities of concentric action of the elbow flexor muscles and, secondly, to compare the characteristics of these circadian rhythms with those obtained during isometric actions. Eight volunteer subjects participated in this study. The circadian rhythms were obtained from six test sessions (TS) carried out at different times of day over 6 days with only one TS a day. During each TS, oral temperature and the torque of the muscle action were measured. The subjects made, on an isokinetic ergometer, two maximal isokinetic concentric elbow flexions at five angular velocities (60, 120, 180, 240 and 300° · s⁻¹) and at an angle of 60°. Torque-angular velocity relationships, which characterised the functioning of the muscle during concentric and isometric actions, were established for the different times of day. The values of the torque recorded at each of the angular velocities presented a clear circadian rhythm. After normalisation of the torque values, no significant differences were observed among the computed characteristics of the circadian rhythms obtained at different angular velocities. Since the circadian rhythms during isometric and concentric torque were the same, the characteristics of the circadian rhythms of the musculo-skeletal system can be studied using either type of muscle action. The results indicated that torque and temperature varied concomitantly during the day. Thus, the recording of body temperature allows one to estimate the times of occurrence of maximal and minimal values in the circadian rhythm of muscle torque. Accepted: 10 October 2000     

关节镜下TightRope绊钢板治疗肩锁关节脱位

目的回顾分析关节镜下TightRope袢钢板技术治疗RockwoodⅢ型及以上肩锁关节脱位的初步临床疗效。方法对11例RockwoodⅢ型及以上肩锁关节脱位患者,采用关节镜下TightRope袢钢板技术进行治疗,参照Karlsson评价标准进行疗效评定。结果 11例均获得随访,据疗效评价标准:优9例,良2例。结论关节镜下TightRope袢钢板技术治疗RockwoodⅢ型及以上肩锁关节脱位,取得良好效果,是治疗该型损伤较为理想的方法。     

膝关节滑膜皱襞综合征的临床诊断和关节镜疗效分析

目的探讨膝关节滑膜皱襞综合征的临床诊断标准和关节镜治疗疗效。方法分析我院自2010年至2016年收住的24例27膝关节内滑膜皱襞综合征患者,用关节镜探查关节腔并行滑膜皱襞清理。按Lysholm评分标准评价手术治疗前后膝关节功能,用配对t检验分析随访结果,评价关节镜治疗效果。结果按Lysholm评分标准评定:术前评分56.296±6.445,术后评分78.481±6.262,t=12.995,P0.001,具有统计学意义。结论膝关节内滑膜皱襞综合征的诊断需依靠临床症状及体征,膝关节MRI平扫可有效提高诊断率,关节镜诊断为金指标,关节镜手术创伤小恢复快,关节清理术治疗效果显著。     

肘关节侧副韧带的解剖结构研究及临床意义

目的分析肘关节侧副韧带的解剖学特点及临床意义,为侧韧带损伤治疗提供解剖学依据。方法对40例正常人左右肘关节标本共80例进行解剖学研究,而且对鹤壁市人民医院30例内侧副韧带损伤患者的治疗效果进行总结。结果内侧副韧带分为前束、后束、斜束,且解剖特点各异。本文肘关节内侧副韧带分为：A型28例,B型37例,C型15例。肘关节外侧副韧带分为：Ⅰ型27例,Ⅱ型16例,Ⅲ型19例,Ⅳ型18例。经过对30名患者手术治疗一年后随访,24例疗效评级为优,占80%,6例为良,占20%。结论对肘关节侧副韧带进行解剖学研究,可以为肘关节副韧带损伤临床治疗提供资料参考。