Human Elbow Joint Research Articles

지자기센서를 이용하지 않는 6축 IMU 기반의 3차원 관절각 추정용 순환 신경망

Inertial measurement unit (IMU)-based 3D joint angle estimation have a wide range of important applications, among them, in gait analysis and exoskeleton robot control. Conventionally, the joint angle was determined via the estimation of 3D orientation of each body segment using 9-axis IMUs including 3-axis magnetometers. However, a magnetometer is limited by magnetic disturbance in the vicinity of the sensor, which highly affects the accuracy of the joint angle. Accordingly, this study aims to estimate the joint angle using the 6-axis IMU signals composed of a 3-axis accelerometer and a 3-axis gyroscope without a magnetometer. This paper proposes a recurrent neural network (RNN) model, which indirectly utilizes the joint kinematic constraint and thus estimates joint angles based on 6-axis IMUs without using a magnetometer signal. The performance of the proposed model was validated for a mechanical joint and human elbow joint, under magnetically disturbed environments. Experimental results showed that the proposed RNN approach outperformed the conventional approach based on a Kalman filter (KF), i.e., RNN 3.48° vs. KF 10.01° for the mechanical joint and RNN 7.39° vs. KF 21.27° for the elbow joint.

The role of the joint capsule in the stability of the elbow joint.

Existing studies lack a clear understanding of the interaction of the joint capsule with surrounding tissues and the local mechanical environment. Particularly, a finite element model of human elbow joint incorporating active behavior of muscle was constructed. The simulation was performed during the elbow joint flexion movement under different injury conditions of capsule (anterior capsule, posterior capsule, medial anterior capsule, lateral anterior capsule, medial posterior capsule, and lateral posterior capsule). The stress distribution and transfer of the joint capsule, ulnar cartilage, and ligaments were obtained under different injuries and flexion angles, to explore the influence of capsule injures on the stability of the elbow joint. In medial injury posterior capsule, the peak stress of the ulnar cartilage occurred at 60° flexion and shifted from posteromedial to anteromedial. And the stress was about 1.8 times that of no injury capsule. In several cases of posterior capsule injury, the stress of capsule decreased significantly and the peak stress was 40% of that in no injury joint capsule. In the case of anterior capsular injury, the cartilage stress did not change significantly, and the stress of anterior bundle and annular ligament changed slightly in the late flexion movement. These findings provide some help for doctors to treat elbow injury and understand the interaction of tissues around the joint after trauma.

Biomechanics of the human upper limb for sustainable approach to design smart clothing

The creation of smart clothing with universal design solutions, improved ergonomic properties, high performance and strength parameters is a striking example of the implementation of the concept of “slow” fashion. Determining the optimal choice of topographical arrangement of sensory control elements of flexible printed circuit boards and structural and decorative elements of clothing with intelligent functions is one of the key factors in increasing the overall comfort of the designed products. The results of the study of indicators of physiological and psychological characteristics when changing the angle of flexion of the human elbow joint are necessary for understanding the neurophysiological basis of the issues of subjective assessment of the comfort of clothing.

Three-Dimensional Modeling and Kinematic Analysis of Human Elbow Joint Axis Based on Anatomy and Screw Theory

Ensuring the motion consistency of human and exoskeletons is the key to the research of wearable exoskeleton robots. However, as the complexity of the coupling of sliding and rolling motion in human joint tissue, it is hard to depict the dynamic states of the joint axis. Exploring the changed human joint axis can be significant in the process of studying the bionic joint of the exoskeleton robots. We proposed a method to build the biological joint model based on anatomy and used screw theory to explore the human biological joint axis on it. The humerus and ulna models were only reconstructed by scanning CT images of the elbow joint in any single position. According to anatomy, humerus trochlear and trochlear notch of models were tangent to build a movable elbow joint model. The screw theory was used to study the elbow joint axis based on the kinematic data of samples in the motion simulation of joint model. Comparing the motion between model and human experiment, the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\boldsymbol{R}^{\boldsymbol{2}}}$</tex-math></inline-formula> of the Euler angles were above 0.97, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\boldsymbol{RMSE}$</tex-math></inline-formula> were below 2.85, which showed the model following anatomical principles can reflect the human joints well. And the pattern that depicted joint axis travelled is similar to the shape of the Mobius Strip. This work provides a new method to study human joint axis, and the axis results provide references to the design of exoskeleton joints and bionic robots.

Immunofluorescence analysis of sensory nerve endings in the periarticular tissue of the human elbow joint.

To investigate the dynamic aspects of elbow stability, we aimed to analyze sensory nerve endings in the ligaments and the capsule of elbow joints. The capsule with its anterior (AJC) and posterior (PJC) parts, the radial collateral ligament (RCL), the annular ligament (AL), and the ulnar collateral ligament with its posterior (PUCL), transverse (TUCL) and anterior parts (AUCL) were dissected from eleven human cadaver elbow joints. Sensory nerve endings were analyzed in two levels per specimen as total cell amount/ cm2 after immunofluorescence staining with low-affinity neurotrophin receptor p75, protein gene product 9.5, S-100 protein and 4',6-Diamidin-2-phenylindol, Carbonic anhydrase II and choline acetyltransferase on an Apotome microscope according to Freeman and Wyke's classification. Free nerve endings were the predominant mechanoreceptor in all seven structures followed by Ruffini, unclassifiable, Golgi-like, and Pacini corpuscles (p ≤ 0.00001, respectively). Free nerve endings were observed significant more often in the AJC than in the RCL (p < 0.00002). A higher density of Ruffini endings than Golgi-like endings was observed in the PJC (p = 0.004). The RCL contained significant more Ruffini endings than Pacini corpuscles (p = 0.004). Carbonic anhydrase II was significantly more frequently positively immunoreactive than choline acetyltransferase in all sensory nerve endings (p < 0.05). Sensory nerve endings were significant more often epifascicular distributed in all structures (p < 0.006, respectively) except for the AJC, which had a pronounced equal distribution (p < 0.00005). The high density of free nerve endings in the joint capsule indicates that it has pronounced nociceptive functions. Joint position sense is mainly detected by the RCL, AUCL, PUCL, and the PJC. Proprioceptive control of the elbow joint is mainly monitored by the joint capsule and the UCL, respectively. However, the extreme range of motion is primarily controlled by the RCL mediated by Golgi-like endings.

Adaptive cooperative control of a soft elbow rehabilitation exoskeleton based on improved joint torque estimation

A current challenge with robot-assisted rehabilitation is to combine the active involvement and voluntary participation of patients into the rehabilitation training process to enhance therapy outcome. This paper presents a soft elbow exoskeleton for the rehabilitation training of disabled patients. An adaptive cooperative control strategy is investigated to promote active participation based on an improved joint torque estimation method and a time-delay sliding mode control scheme. The surface electromyography signals from biceps and triceps are input into a Hill-type musculoskeletal model and a Gaussian radial basis functional network to estimate human elbow joint torque and motion intention. The joint torque estimation experiment, intention-based trajectory following experiment and patient-active free-motion training experiment are carried out by five healthy volunteers and five stroke patients to evaluate the performance of proposed control strategy. The results indicate that the proposed scheme can guarantee the joint torque estimation accuracy and position control accuracy. Moreover, it allow patients to actively dominate the training path based on their motion intention with different training intensity.

Paper 36: Change in Humeral Anchor Position Significantly Affects Isometry in UCL Repair: A 3-Dimensional Computer Modeling Study

Objectives:Medial ulnar collateral ligament (UCL) repair utilization is increasing in recent years, bolstered by shorter rehabilitation and satisfactory clinical outcomes. While previous literature has illustrated the importance of tunnel position on restoring graft isometry in UCL reconstruction, there remains a paucity of literature guiding anchor placement in UCL repair. Herein, we describe a 3-dimensional (3D) elbow model to measure and optimize anchor location during UCL repair.Methods:A 3D computer model of a human elbow joint was created using CT and MRI images from a single patient. The humeral and ulnar attachments of the UCL were plotted using three distinct methodologies: 1) geometric cloud mapping; 2) quantitative measurements as described by the anatomical studies by Camp et al1; and 3) Frangiamore et al2. A 3.5mm-diameter clockface was placed on each attachment site which allowed for simulation of 12 distinct, 1.75mm deviations in anchor position. The three elbow models were then ranged through 0-120 degrees of flexion at 10-degree increments, and the 3D distances were measured between the two ligament centroids. The humeral and ulnar anchors were sequentially repositioned around the clockfaces, and ligament lengths were again measured to evaluate changes in isometry. An independent t-test was performed to determine if there was a significant difference in isometry between the humeral or ulnar anchor deviations.Results:Using method 1, the UCL length at 90 degrees of elbow flexion was 26.8mm. This ligament underwent 13.6mm of total excursion for a 46.4% change in length throughout arc of motion. Method 2 produced a 19.3mm ligament that underwent 0.8mm of excursion for a 3.9% length change throughout the arc. Method 3 produced a 24.5mm ligament that underwent 2.3mm of excursion for a 9.4% length change throughout arc. Identifying ligament footprints using the quantitative anatomical measurements as described by Camp et al1 and Frangiamore et al2 produced better ligament isometry through 120 degrees of flexion (ligament length changes of 3.9% and 9.4%, respectively) when compared to using the geometric cloud technique (46.4% length change). Humeral anchor deviations produced a statistically significant increase in ligament excursion when compared to ulnar anchor deviations (p < 0.001).Conclusions:When performing UCL repair, small deviations in humeral anchor position may significantly influence graft and ligament isometry. Anchor position was most isometric while using the quantitative measurements as described in Camp et al1. Particularly when addressing detachments of the humeral footprint, surgeons should be critical of the humeral anchor position in order to restore native anatomy and optimal biomechanics.

Effect of Electroacupuncture at Wushu Acupoints of the Cardiopulmonary Meridian on the Autophagy in Rats with Acute Myocardial Ischemia.

Wushu acupoints are the five acupoints distributed below the human elbow and knee joint. They are all located on the same meridian and divided into five categories: Jing, Ying, Shu, Jing, and He. It has been shown that electroacupuncture (EA) at Shenmen point of heart meridian can improve acute myocardial ischemia (AMI) early. However, it is still unclear if all the Wushu acupoints of the heart meridian can improve AMI. Hence, this study emphasizes Wushu acupoints of heart meridian, compares them with Wushu acupoints of lung meridian, and studies the therapeutic effect of EA at Wushu acupoints on AMI and its possible mechanism. It also discusses the specificity of the heart meridian to heart disease. The AMI model is established by ligation of the left anterior descending coronary artery. The detection methods like the physiological recorder, TTC staining, ELISA, and so forth were used to determine the ECG, myocardial infarct size, serum myocardial enzymes, and myocardial tissue-related protein expression in rats. The heart rate (HR) and ST segment along with creatine kinase (CK), creatine kinase isoenzymes (CK-MB), lactate dehydrogenase (LDH), and myocardial infarctions increased after the induction with AMI. Furthermore, the expressions of PINK1 and Parkin protein also showed an increase. However, EA at Wushu acupoints in the heart meridian can reverse the above changes, whereas EA at the lung meridian exhibits limited effect. It is depicted that the heart meridian has a relatively specific relationship with the heart in a diseased state.

The load transfer effect of monopolar and bipolar radial head prosthesis designs on capitellar cartilage: A comparative biomechanical cadaver study.

The aim of this study was to determine whether bipolar radial head arthroplasty may transfer less load to the capitellum than monopolar radial head arthroplasty and native radial heads. Six human elbow joints were obtained from six fresh frozen cadavers (3 males, 3 females; mean age = 78 years, age range = 66-80). None of the elbow joints had a previous osseous injury, a chondral defect, osteoarthritis, or instability. In group 1, load transfer of the native radial head was measured in each specimen under 100 N of compression force using a custom-made load cell at 0°, 30°, 60°, 90°, and 120° flexion of the elbow in supination, neutral rotation, and pronation, respectively. After excision of the radial heads, the same testing protocol was first applied for monopolar radial head arthroplasty (Group 2) and then for bipolar radial head arthroplasty (Group 3). The mean load transfer on the capitellum was significantly higher in each forearm rotation and all angles of the elbow flexion in the arthroplasty groups than the native radial head group. Mean load transfer values of bipolar prostheses were between the values of native radial heads and monopolar prostheses in all positions. Bipolar prostheses showed similar load transfer characteristics compared to those of the native radial head in supination at 60° flexion; in neutral rotation at 0°, 30°, 60°, and 120° flexion; and in pronation at 90° and 120° flexion. The results of this study have revealed that bipolar radial head arthroplasty transfers similar loading as the native radial head on the capitellum in certain forearm positions and at elbow flexion angles. No significant differences could be found between load transfer values of bipolar head design and monopolar head design except in the pronation at full extension.

Minimally Invasive Arthroscopic Treatment of Patients with Medial Epicondylitis

Background. There is not enough research on the topic of arthroscopic treatment of medial epicondylitis. Topographic studies are needed to justify surgical approaches with minimal trauma to the medial collateral ligament and ulnar nerve. The aim of the study was to optimize the arthroscopic treatment of medial epicondylitis and evaluate its clinical effectiveness based on the results of the topographic and anatomical study. Materials and Methods. The material for the topographic and anatomical study was 12 «fresh» anatomical preparations of the human elbow joint, of which 6 were taken from female cadavers, and 6 — from men. The features of the structure and topography of the elbow medial collateral ligament were studied, and the safety and effectiveness of arthroscopic approaches to the elbow for the flexor carpi radialis release were determined. A prospective cohort comparative study was performed, which included 70 patients. Two comparative groups were formed. In the group I (35 patients) surgical treatment was carried out by the open method. The group II included 35 patients who underwent minimally invasive surgical treatment using arthroscopic technique. The results were evaluated by Mayo Elbow Perfomance Score (MEPS) and VAS before surgery and 1, 6, and 9 weeks after. Results. Functional results in 9 weeks: group I — 81.77 (95% CI 81.13; 82.41); group II — 92.66 (95% CI 91.61–93.70) points. The average score for VAS in the same period: group I — 34.30 (31.89–36.68) points; group II — 1.5 (0.46–2.45) points. Conclusion. The safe zone is located above the midline of the humeroulnaris joint by 2 (1.0–3.2) mm. The risk of the medial ulnar collateral ligament anterior bundle injury is minimal in this area. Treatment of patients with the medial epicondylitis according to the developed arthroscopic technique can significantly improve the patients functional state and quality of life.

Study of movements estimation method by EMG using a human elbow joint movement model acquired by FES

Study of movements estimation method by EMG using a human elbow joint movement model acquired by FES

A wearable fiber-optic sensor for monitoring human elbow and wrist joint motion

This article describes a wearable sensor for monitoring the motion of human elbow and wrist joints. The sensor converts the joint motion angle into a displacement, which is monitored using a fiber-optic sensor based on reflective light intensity modulation. A mathematical model is established, and the potential influencing factors of the sensor are investigated. Two prototypes for elbow and wrist joint angle monitoring are fabricated and validated. The experimental results indicate that the proposed sensor has a measurement range of 0–60° (0–120°), with a resolution of 0.338° (3.6°) for monitoring the wrist joint palm flexion (elbow joint flexion). The proposed sensor has the potential to be used for rehabilitation purposes and monitoring of joint angles while performing reaching tasks, which are the most common upper-limb gestures.

Development of single-shaft joint mechanism imitating a cartilage cushioning

There is a labor shortage due to population decline, and robots are expected to work in human working spaces to address this problem. You need to protect your robot from disturbances that are difficult to predict from multiple directions. Therefore, we simply imitated the connector structure, including the cartilage of the human elbow joint, and incorporated it into the robot’s joints. What we considered was a single axis joint spring element. In this study, the effectiveness of spring elements was predicted using the computer-aided engineering (CAE) function of CAD software. Next, to verify the validity of the prediction results, we conducted a spin test on the motor shaft of the developed uniaxial joint and a destructive test on the frame. These two experimental results show that a single axis joint with a spring element can protect the motor shaft and frame under certain conditions.

A Novel Cable-Driven 7-DOF Anthropomorphic Manipulator

Safety design of robot arm is important for human-robot interaction. In this article, an anthropomorphic seven-DOF cable-driven manipulator, including a three-DOF shoulder joint module, a one-DOF elbow joint module, and a three-DOF wrist joint module, is proposed for human-robot interaction. These three joint modules are connected serially and the motion transmission is realized by rope. The joint stiffness and workspace of joint module are numerically analyzed and compared to that of the human arm joint. A protype of manipulator is machined and used to evaluate the joint stiffness and workspace of the joint module through experiments. The mass of the designed manipulator is approximately 4.8 kg, which is similar to that of a human arm. The stiffness of elbow joint is 185.25 N·m/rad in positive direction and 133.75 N·m/rad in negative direction, which is smaller than that of the human elbow joint. The stiffness of wrist joint is 48.25 N·m/rad. The stiffness of shoulder joint under two configurations is 138 and 124 N·m/rad. The workspace matching index (WMI) is used to evaluate the workspace of joint module by comparing to that of the human arm joint. The WMI of the developed shoulder joint is approximately 40% of the human shoulder joint due to the structure constraint. While the workspaces of the developed elbow joint and wrist joint are the same with that of human joint.

A New Progress in Random Hydrodynamic Lubrication for Movable Non-Rotational Curvilinear Biosurfaces with Phospholipid Bilayers

This paper aims to highlight the result of a new progression of mathematical estimation methods of stochastic bio-hydrodynamic lubrication parameters for arbitrary, curvilinear, non-rotational, co-operating, living biological surfaces coated with phospholipid bi-layers. Movable, non-rotational, co-operating surfaces occur in various biological friction nods like the collar bone, the blade bone, the jump joint, and the wrist joint. Specifically, the author presents a synthetic and comprehensive estimation of stochastic bio-hydrodynamic lubrication parameters for co-operating, rotational cartilage bio-surfaces with phospholipid bi-layers occurring in human spherical hip joints and cylindrical elbow joints. The method of research discussed in this paper focuses on a review of stochastic analytical considerations performed by the author. This research is based on the measurements of the gap height between two movable, non-rotational bio-surfaces. The gap is restricted between two co-operating biological surfaces. After several experiments, it could be inferred that there are symmetric as well as asymmetric random increments and decrements in the gap height. Such changes are applicable to the hydrodynamic pressure, load-carrying capacity, friction forces, and wear of the co-operating biological surfaces in human friction nods and contacts. The prime purpose of this paper is to demonstrate the influence of variations in the expected values and standard deviation of the gap height on the hydrodynamic lubrication parameters that occur during the friction process. It can thus be concluded that the apparent dynamic viscosity of biological lubricant varies in the ultra-thin gap height direction, depending on the susceptibility of the superficial layer of the lubricated bio-surface. The results presented in this paper are obtained considering the 3D variations in the dynamic viscosity of the biological fluid, particularly the random variations crosswise the film thickness in non-Newtonian biological fluid properties.

A safe human–robot interactive control structure with human arm movement detection for an upper-limb wearable robot used during lifting tasks

Manual lifting tasks involve repetitive raising, holding and stacking movements with heavy objects. These arm movements are notable risk factors for muscle pain, fatigue, and musculoskeletal disorders in workers. An upper-limb wearable robot, as a 6-DOF dual-arm exoskeleton, which was designed to augment workers’ strength and minimize muscular activation in the arm during repetitive lifting tasks. To adjust the robot joint trajectory, the user needs to apply an interactive torque to operate the robot during lifting tasks when a standard virtual mechanical impedance control structure is used. To reduce overshooting of the interactive torque on the user’s joint, a three-tier hierarchical control structure was developed for the robot in this study. At the highest level, a human arm movement detection module is used to detect the user’s arm motion according to the surface electromyography signals. Then, a Hammerstein adaptive virtual mechanical impedance controller is used at the middle level to reduce overshooting and yield an acceptable value of torque for the user’s elbow joint in actual lifting tasks. At the lowest level, the actuator controller on each joint of the robot controls the robot to complete lifting tasks. Several experiments were conducted, and the results showed that the interactive torque on the user’s elbow was limited and the muscular activations of erector spinae and biceps brachii muscles were effectively decreased. The proposed scheme prevents potential harm to the user due to excessive interactive torque on the human elbow joint, such as related muscle fatigue and joint injuries.

Kinematic analysis and simulation of human upper limb rehabilitation training mechanism

A rehabilitation training mechanism of human upper limb is proposed, it consists of the 3-RRS parallel mechanism and the crank-rocker mechanism. First, their degrees of freedom are analyzed. Then, their kinematics are analyzed by analytical method. Finally, the 3-RRS parallel mechanism and the crank-rocker mechanism are simulated with the software UG and SolidWorks respectively, the results of simulation show that the movement path of the handle on the moving platform of the 3-RRS parallel mechanism coincides with the trajectory of the human arm, it can be used for the rehabilitation training of the human shoulder joint. For the crank-rocker mechanism, the center angles of movement path of the rocker and the handle on the connecting-rod are within the range of motion angles of human elbow joint and wrist joint, it can be used for the rehabilitation training of the elbow and wrist joints. They will all produce soft impulses at the beginning and end points, and the soft impulses will increase as the rotating speed of the driving links increases, so their driving links must rotate at a lower speed.

A Human Joint Torque Estimation Method for Elbow Exoskeleton Control

Exoskeleton for motion assistance has obtained more and more attention due to its advantages in rehabilitation and assistance for daily life. This research designed an estimation method of human joint torque by the kinetic human–machine interaction between the operator’s elbow joint torque and the output of exoskeleton. The human elbow joint torque estimation was obtained by back propagation (BP) neural network with physiological and physical input elements including shoulder posture, elbow joint-related muscles activation, elbow joint position, and angular velocity. An elbow-powered exoskeleton was developed to verify the validity of the human elbow joint torque estimation. The average correlation coefficients of estimated and measured three shoulder joint angles are 97.9%, 96.2%, and 98.1%, which show that estimated joint angles are consistent with the measured joint angle. The average root-mean-square error between estimated elbow joint torque and measured values is about 0.143[Formula: see text]N[Formula: see text]m. The experiment results proved that the proposed strategy had good performance in human joint torque estimation.

SEMG-MMG State-Space Model for the Continuous Estimation of Multijoint Angle

Continuous joint angle estimation plays an important role in motion intention recognition and rehabilitation training. In this study, a surface electromyography- (sEMG-) mechanomyography (MMG) state-space model is proposed to estimate continuous multijoint movements from sEMG and MMG signals accurately. The model combines forward dynamics with a Hill-based muscle model that estimates joint torque only in a nonfeedback form, making the extended model capable of predicting the multijoint motion directly. The sEMG and MMG features, including the Wilson amplitude and permutation entropy, are then extracted to construct a measurement equation to reduce system error and external disturbances. Using the proposed model, a closed-loop prediction-correction approach, unscented particle filtering, is used to estimate the joint angle from sEMG and MMG signals. Comprehensive experiments are conducted on the human elbow and shoulder joint, and remarkable improvements are demonstrated compared with conventional methods.

Sensory innervation of the human elbow joint and surgical considerations.

Based on the currently available literature, total denervation of the elbow joint is considered impossible. However, consensus with respect to the anatomic location of sensory branches is lacking. The aim of this literature review was to establish consensus with respect to the anatomic features of the articular branches innervating the elbow joint, as well as the distribution of sensory receptors about its capsule. Four electronic databases were queried, between January 1945 and June 2019. Twenty-one original articles providing a detailed description of the distribution of sensory receptors about the elbow joint capsule (5) and its articular branches (16) were reviewed. The posterior capsule was found to be primarily innervated by the ulnar and radial nerves via combined articular branches and sensory branches of the medial antebrachial cutaneous nerve. The anterior capsule was found to be primarily innervated by a plexus of articular ramifications from muscular branches of mixed nerves (ulnar, musculocutaneous, radial, and median nerves). A higher density of nociceptors and mechano-receptors was identified within the posterior and anterior capsules, respectively. Thorough denervation, via the technique proposed herein, is likely to be sufficient in eliminating pain from degenerative conditions of the elbow joint.