A microprocessor-controlled prosthetic knee and its gait symmetry assessment / 中国康复理论与实践

ObjectiveTo present a method for evaluating the gait symmetry of microprocessor-controlled prosthetic knee (MPK). MethodsA kind of proto-MPK, AiKneeOne, and a wearable gait collect system, were made. The phases of the first double-limb support, the single-limb support, the second double-limb support, and the swing were used to calculate symmetry index (SI), ratio Ⅰ (RI) and ratio II (RII). Five heathy persons walked on the treadmill wearing AiKneeOne at speeds of 0.5, 0.7, 1.1 m/s, and the indice were collected with the wearable gait collect system. ResultsUnder different velocities, The absolute value of SI and RII were very little and the RI were close to one at the phases of the first double-limb support and the second double-limb support, but they were not very satisfactory in the phases of the single-limb support and the swing. ConclusionThe developed MPK AiKneeOne is potential to reconstruct the gait of amputees, and the gait symmetry indice can be used to evaluate the wearing performance of MPK.

Gait Simulation and Analysis of Lower Limb Musculoskeletal Model before and after Total Knee Arthroplasty / 医用生物力学

Objective To compare and analyze the lower limb muscle activity and knee joint force during the stance periods of gait cycle in patients with osteoarthritis before and after total knee arthroplasty (TKA). Methods Based on the OpenSim platform, lower extremity musculoskeletal models of one healthy subject and three patients with osteoarthritis before and after TKA were established. A three-dimensional （3D） motion capture system and a force platform were used to collect the lower limb kinematic data and the ground reaction force during walking, which were used as input parameters to simulate the lower limb muscle activation and knee joint forces. Results The results from the musculoskeletal model were consistent with the results by inverse dynamics based on the 3D motion capture system. The patient's rectus femoris was activated in the loading response and mid stance phases, which was different from that of healthy subject. The activation timing and amplitude of the quadriceps muscle in 3 patients were significantly different before and after TKA. The peak joint forces of 3 patients before TKA were 2.95, 3.15 and 3.43 times of body weight (BW) with the constant load of more than 2 times of BW during stand phase. The peak joint force after TKA were 2.09, 2.48 and 3.96 times of BW respectively. The joint force was not improved and the knee function did not reach the normal level six months after TKA. Conclusions The results of the established musculoskeletal model have certain reliability, and this model can provide a biomechanical auxiliary method for TKA surgery in the future.

Effect of meniscus injury on the biomechanical properties of knee joint under gait cycle / 中国组织工程研究

BACKGROUND: The biomechanical characteristics of knee meniscus have been studied extensively at home and abroad, but most of them focus on the knee flexion motion. The finite element analysis of biomechanics of knee joint meniscus under the complete gait cycle is not yet perfect. OBJECTIVE: To understand the mechanism of biomechanical changes after meniscus injury in the complete gait cycle by comparing the lateral meniscus tear model with the healthy meniscus model. METHODS: Based on the CT scan data of healthy adult knee joints, a finite element model of healthy knee joint including tibia, meniscus and articular cartilage was established. The lateral meniscus tear of knee joint was constructed based on the healthy model. The biomechanical mechanism of lateral meniscus tear in the knee during complete gait cycle was explored and compared with the healthy knee model. RESULTS AND CONCLUSION: (1) The instantaneous stress variation of the tibia cartilage during the complete gait cycle was consistent in both models. The tibial cartilage stress at each instant in the meniscus tear model was higher than that of the healthy meniscus model. The maximum stress values of tibia cartilage in the meniscus tear model and the healthy meniscus model was 30 and 20.5 MPa. (2) The instantaneous stress variation of the meniscus during the complete gait cycle was consistent in both models. The meniscus stress at each instant in the meniscus tear model was higher than that of the healthy meniscus model. The maximum stress values of meniscus in the meniscus tear model and the healthy meniscus model was 69.8 and 41.3 MPa. (3) In the first 60% of the gait cycle, the maximum stress distribution of the tibia cartilage in the meniscus tear model was much larger than that in the healthy model, and as the gait cycle grew, the contact range gradually spread to the outer edge of the cartilage. After 60% of the gait cycle, the stress on the tibia cartilage was small, and the distribution range of the maximum stress was also small. (4) The stress distribution of the healthy medial meniscus was basically the same in the two models, while the maximum stress distribution of the torn outer meniscus was wider than that of the healthy medial meniscus. A more severe stress concentration phenomenon occurred around the crack, and with the gait cycle, the stress concentration area gradually shifted toward the crack near the anterior corner of the meniscus. (5) These results suggest that the meniscus is an important load-bearing component in human knee joint. From the perspective of biomechanics, the hazard of the meniscus injury on the human knee joint can be observed more intuitively.

Surface Electromyographic Features of Lower Limb Muscles during Different Phases of Gait Cycle in Stroke Patients / 中国康复理论与实践

Objective:To explore the changes of surface electromyography (sEMG) signal during gait cycle and its various phases of the lower limbs of stroke patients, to guide targeted gait rehabilitation training for stroke patients. Methods:From January to June, 2018, 20 stroke patients and 20 healthy subjects were involved in this study. All the subjects were asked to walk naturally. At the same time, the sEMG signals of bilateral tibialis anterior (TA), rectus femoris (RF), gastrocnemius medial (GM) and biceps femoris (BF) were recorded by Noraxon wireless surface electromyography acquisition system. Results:The electromyographic activities of TA, RF, GM and BF of healthy subjects changed with the activity and static periodicity during gait cycle, and the muscles of the same name alternated, and they were disturbed in stroke patients. Conclusion:The surface electromyography can reflect the gait-related muscle damage in stroke patients and can be used to guide gait rehabilitation training.

Influence of Load Carriage during Military Walking on Lower Limb Gait Characteristics / 医用生物力学

Objective To evaluate the influence of different load carriages during military walking on the gait of lower limbs. Methods In a randomized cross-over design, 15 healthy young males were asked to perform self-paced walking with a normal uniform under a load carriage of 0 kg, 7.5 kg, 27 kg, and 50 kg for four times. The kinematics parameters of the pelvis, knee, and ankle were evaluated by the Vicon motion capture system and AMTI force plates. Results With increasing load carriage, the stride frequency relatively improved, whereas the stride reduced and the speed was maintained on the whole. The peak left/right hip flexion and extension angle and peak knee adduction angle were obviously affected by the load carriage, whereas the movement magnitudes could be maintained. The peak varus angle of the left ankle and peak valgus angle of the right ankle were also affected. The peak force and moment of the left/right knee and ankle increased. Conclusions With increasing load carriage, overall, the movement magnitudes of lower limb joints were maintained under the given loads, whereas the lower limb loads were increased, which could increase the potential risk of lower limb injuries.

Electromyographic analysis of the gait cycle phases of boxer dogs / Análise eletromiográfica do ciclo de marcha em cães da raça boxer

Systematic studies involving technologies such as surface electromyography (sEMG) may provide important data that enable veterinarians to recognize musculoskeletal, ligamentous, and neurological alterations. The aim of this study was to describe the gait cycle phases and the timing of muscle activation in healthy Boxer dogs during gait by means of sEMG. The gait cycle of seven Boxer dogs was evaluated and sEMG was recorded from the biceps brachii, triceps brachii, brachiocephalic, rectus femoris, semitendinosus, semimembranosus, and superficial gluteal muscles of the right hemibody. Circular monopolar Ag/AgCl electrodes were attached to the mean point between the motor point and the muscle insertion. The electromyographic signals were collected by an active interface with 20-fold gain in a bipolar differential configuration using a 16-channel signal conditioner (EMG Systems Brasil), while the dogs walked on a treadmill at a speed of 2m/s. Pearson's correlation was used for the statistical analysis. A positive correlation was found between the rectus femoris and biceps brachii (r= 0.81); superficial gluteal and triceps brachii (r= 0.69); semitendinosus-semimembranosus and biceps brachii (r= 0.76); and rectus femoris and semitendinosus and semimembranosus muscle groups (r=0.99). The biceps brachii and brachiocephalic muscles work in tandem to position the thoracic limb during the gait cycle, while the semitendinosus-semimembranosus group flexes the knee and, simultaneously with the quadriceps that flexes the hip, prevents the contact of the pelvic limb with the ground during the swing phase. The body is propelled forward by the triceps brachii muscle, which extends the elbow and flexes the shoulder at the final contact, while the superficial gluteal muscle extends the hip.(AU)

Estudos sistemáticos que envolvem uso de tecnologias, como a eletromiografia de superfície (EMGs), podem fornecer dados importantes que capacitam os clínicos a diferenciar as alterações musculoesqueléticas, ligamentares ou neurológicas. Objetiva-se com este trabalho descrever as fases da marcha canina e o momento de ativação dos músculos de cães saudáveis da raça Boxer durante a marcha, por meio da eletromiografia de superfície. Avaliou-se a marcha de sete cães da raça Boxer, e o sinal elétrico da eletromiografia de superfície foi coletado do bíceps braquial, do tríceps braquial, do braquiocefálico, do reto femoral, do semitendinoso/semimembranoso e do glúteo superficial do hemicorpo direito. Os eletrodos monopolares circulares de prata com cloreto de prata (Ag/AgCl) foram posicionados no ponto médio entre a placa motora e a inserção desses músculos. Os sinais eletromiográficos foram capturados e adquiridos por uma interface ativa com ganho de 20x em configuração diferencial bipolar e por um condicionador de sinais (EMG Systems Brasil) de 16 canais, enquanto os cães caminharam em esteira com velocidade de 2m/s. Para análise estatística, foi aplicado teste de correlação de Pearson. Verificou-se correlação positiva entre os músculos retofemoral e bíceps braquial (r= 0,81); glúteo superficial e tríceps braquial (r= 0,69); semitendinoso/semimembranoso e bíceps braquial (r= 0,76); e entre o músculo reto femoral e o grupo muscular semitendinoso e semimembranoso (r=0,99). Os músculos bíceps braquial e braquiocefálico do mesmo membro trabalham em sinergia para posicionar o membro torácico durante o ciclo de marcha, enquanto o grupo muscular semitendinoso/semimembranoso flexiona o joelho e, simultaneamente com o quadríceps, que flexiona o quadril, impede que o membro pélvico entre em contato com o solo no balanço. Para impulsionar o corpo à frente, o músculo tríceps braquial estende o cotovelo e flexiona o ombro no contato final e o glúteo superficial estende o quadril.(AU)

Three-dimensional Hindlimb Gait Data Toolkit for Healthy and Spinal Cord Injured Rhesus Monkey / 中国康复理论与实践

@#Objective To establish a three- dimensional hindlimb gait data toolkit (THGT) for healthy and spinal cord injured (SCI) non-human primate (rhesus monkey) based on Matlab to realize upload of original data, automatic gait division, calculation and drawing of multiple gait parameters, etc. Methods Vicon system was used to collect three-dimensional hindlimb gait data of healthy and SCI (after 6 weeks) rhesus monkey to obtain the kinematics data of both hindlimbs in continuous strides. It was analyzed with THGT to process the gait division, calculation and drawing of multiple gait parameters. Results THGT read the data, distinguished cycles of gait, calculated 140 kinds of gait parameters and drew graphs of the results. Conclusion THGT extends the universality of the Vicon data, realizes automatically gait division and friendly interactive interface, and puts out the visible results.

Three-dimensional Hindlimb Gait Data Toolkit for Healthy and Spinal Cord Injured Rhesus Monkey / 中国康复理论与实践

Objective To establish a three-dimensional hindlimb gait data toolkit (THGT) for healthy and spinal cord injured (SCI) non-human primate (rhesus monkey) based on Matlab to realize upload of original data, automatic gait division, calculation and drawing of multiple gait parameters, etc. Methods Vicon system was used to collect three-dimensional hindlimb gait data of healthy and SCI (after 6 weeks) rhesus monkey to obtain the kinematics data of both hindlimbs in continuous strides. It was analyzed with THGT to process the gait division, calculation and drawing of multiple gait parameters. Results THGT read the data, distinguished cycles of gait, calculated 140 kinds of gait parameters and drew graphs of the results. Conclusion THGT extends the universality of the Vicon data, realizes automatically gait division and friendly interactive interface, and puts out the visible results.