Comparison of screw-home mechanism in the unloaded living knee subjected to active and passive movements

2021 ◽  
pp. 1-7
Author(s):  
Jeong Woo Jeon ◽  
Jiheon Hong
Keyword(s):  
Knee Flexion ◽  
Measurement Unit ◽  
Tibial Rotation ◽  
Related Factors ◽  
Articular Surfaces ◽  
Flexion Extension ◽  
Waveform Similarity ◽  
Student’S T ◽  
The Stability ◽  
Passive Movements

BACKGROUND: The screw-home mechanism (SHM) plays an important role in the stability of the knee. Accordingly, the analysis of tibial rotation patterns can be used to elucidate the effect of SHM-related factors. OBJECTIVE: The purpose of this study was to compare the magnitude of the angle and the pattern of SHM between passive and active movements. METHODS: We studied twenty healthy males, of which the angle of knee flexion-extension and tibial longitudinal rotation (TLR) during active and passive movements were measured using the inertial measurement unit. Student’s t-tests were used to compare the magnitude of TLR. The waveform similarity was quantified using a coefficient of multiple correlation (CMC). RESULTS: Significant differences were found in the TLR between the active and passive movements (p< 0.05). The knee flexion-extension waveform similarity was excellent (CMC = 0.956). However, the waveform similarity of TLR was weak (CMC = 0.629). CONCLUSION: The SHM increased abruptly during the last 20∘ of the active (extension) movement compared with passive extension. The SHM occurred mainly owing to the geometry and shape of the articular surfaces of the knee joint. In addition, muscle contraction was considered to be an important factor in the articulation movement.

Unraveling Interlimb Interactions Underlying Bimanual Coordination

2005 ◽  
Vol 94 (5) ◽  
pp. 3112-3125 ◽  
Author(s):  
Arne Ridderikhoff ◽  
C. (Lieke) E. Peper ◽  
Peter J. Beek
Keyword(s):  
Bimanual Coordination ◽  
Feedforward Control ◽  
Emg Activity ◽  
Minor Role ◽  
Error Corrections ◽  
Flexion Extension ◽  
Contralateral Hand ◽  
Phase Coordination ◽  
The Stability ◽  
Passive Movements

Three sources of interlimb interactions have been postulated to underlie the stability characteristics of bimanual coordination but have never been evaluated in conjunction: integrated timing of feedforward control signals, phase entrainment by contralateral afference, and timing corrections based on the perceived error of relative phase. In this study, the relative contributions of these interactions were discerned through systematic comparisons of five tasks involving rhythmic flexion–extension movements about the wrist, performed bimanually (in-phase and antiphase coordination) or unimanually with or without comparable passive movements of the contralateral hand. The main findings were the following. 1) Contralateral passive movements during unimanual active movements induced phase entrainment to interlimb phasing of either 0° (in-phase) or 180° (antiphase). 2) Entrainment strength increased with the passive movements' amplitude, but was similar for in-phase and antiphase movements. 3) Coordination of unimanual active movements with passive movements of the contralateral hand (kinesthetic tracking) was characterized by similar bilateral EMG activity as observed in active bimanual coordination. 4) During kinesthetic tracking the timing of the movements of the active hand was modulated by afference-based error corrections, which were more pronounced during in-phase coordination. 5) Indications of in-phase coordination being more stable than antiphase coordination were most prominent during active bimanual coordination and marginal during kinesthetic tracking. Together the results indicated that phase entrainment by contralateral afference contributed equally to the stability of in-phase and antiphase coordination, and that differential stability of these patterns depended predominantly on integrated timing of feedforward signals, with only a minor role for afference-based error corrections.

scholarly journals Primary stability of the Activ L® intervertebral disc prosthesis in cadaver bone and comparison of the keel and spike anchoring concept

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Christoph von Schulze Pellengahr ◽  
Wolfram Teske ◽  
Saurabh Kapoor ◽  
Alexander Klein ◽  
Bernd Wegener ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Intervertebral Disc ◽  
Three Dimensional ◽  
Primary Stability ◽  
Longitudinal Axis ◽  
Axial Rotation ◽  
Mean Values ◽  
Flexion Extension ◽  
Student’S T ◽  
The Stability

Abstract Background High primary stability is the key prerequisite for safe osseointegration of cementless intervertebral disc prostheses. The aim of our study was to determine the primary stability of intervertebral disc prostheses with two different anchoring concepts – keel and spike anchoring. Methods Ten ActivL intervertebral disc prostheses (5 x keel anchoring, 5 x spike anchoring) implanted in human cadaver lumbar spine specimens were tested in a spine movement simulator. Axial load flexion, extension, left and right bending and axial rotation motions were applied on the lumbar spine specimens through a defined three-dimensional movement program following ISO 2631 and ISO/CD 18192-1.3 standards. Tri-dimensional micromotions of the implants were measured for both anchor types and compared using Student’s T-test for significance after calculating 95 % confidence intervals. Results In the transverse axis, the keel anchoring concept showed statistically significant (p < 0.05) lower mean values of micromotions compared to the spike anchoring concept. The highest micromotion values for both types were observed in the longitudinal axis. In no case the threshold of 200 micrometers was exceeded. Conclusions Both fixation systems fulfill the required criteria of primary stability. Independent of the selected anchorage type an immediate postoperative active mobilization doesn’t compromise the stability of the prostheses.

Inertial measurement unit based knee flexion strength-power test for sprinters

2020 ◽  
Vol 15 (5-6) ◽  
pp. 738-744
Author(s):  
Ryu Nagahara ◽  
Munenori Murata
Keyword(s):  
Knee Flexion ◽  
Inertial Measurement Unit ◽  
Measurement Unit ◽  
Step Frequency ◽  
Inertial Measurement ◽  
Power Test ◽  
Fitness Evaluation ◽  
Flexion Extension ◽  
Flexion Strength ◽  
Positive Work

This study aimed to examine whether sprinting performance would be associated with knee flexion strength-power capabilities measured using a recently developed inertial measurement unit (IMU) based system. Sixteen male sprinters performed 60-m sprints and the IMU based knee flexion strength-power test which consisted of five serial knee flexion-extension motions in three conditions (unweighted, 0.75 or 1.5 kg ankle weighted) for both legs. Spatiotemporal variables during sprinting for a 50-m distance were obtained using a long force platform system. The knee flexion joint kinetic variables during the knee flexion strength-power test were collected using one IMU. Running acceleration during the entire sprinting was positively correlated with the knee flexion positive work measured using the unweighted right knee flexion strength-power test (r = .521–.721). Moreover, step frequencies at the 13th–16th, 17th–20th and 21st–22nd step sections and during the entire sprint were positively correlated with the knee flexion positive work measured using the unweighted right knee flexion strength-power test (r = .506–.566), while step length did not show any correlations with the knee flexion strength-power test variables. The results demonstrate that the greater right knee flexion strength-power capabilities measured using IMU based method in the unweighted condition are advantageous for better sprinting performance through higher step frequency. The IMU-based knee flexion strength-power test in the right leg unweighted condition will likely be useful for physical fitness evaluation of sprinters on the field setting.

A Comparison of Central Anatomic Single-Bundle Reconstruction and Anatomic Double-Bundle Reconstruction in Anteroposterior and Rotational Knee Stability: Intraoperative Biomechanical Evaluation

2020 ◽  
Author(s):  
Yasunari Ikuta ◽  
Atsuo Nakamae ◽  
Ryo Shimizu ◽  
Masakazu Ishikawa ◽  
Tomoyuki Nakasa ◽  
...  
Keyword(s):  
Acl Reconstruction ◽  
Knee Flexion ◽  
Double Bundle ◽  
Anterior Tibial Translation ◽  
Single Bundle ◽  
Tibial Rotation ◽  
Knee Stability ◽  
Flexion Extension ◽  
Anterior Tibial ◽  
Tibial Translation

AbstractPostoperative anterior and rotational stability are still controversial when compared with single-bundle (SB) and double-bundle (DB) anterior cruciate ligament (ACL) reconstruction. This study aimed to compare the central anatomical SB and anatomical DB ACL reconstruction in intraoperative knee kinematics during continuous knee flexion-extension. A total of 34 patients who underwent ACL reconstruction using the hamstring tendon were evaluated intraoperatively before and immediately after ACL reconstruction using OrthoPilot ACL Navigation System Version 3.0. The patients were prospectively randomized into the central anatomical SB (17 knees) and the anatomical DB reconstruction (17 knees) groups. The tibial translation and rotation were continuously measured during knee flexion-extension under conventional knee motion, anterior tibial load (100N), and internal-external torque (3 N·m). The anterior tibial translation and total range of tibial rotation were calculated from the measurement values from 20 to 50 degrees at each 5-degree point. The anterior tibial translation (p = 0.59; two-factor repeated measures analysis of variance; η 2G = 0.0077) and total range of tibial rotation (p = 0.95; η 2G = 0.0001) at each knee flexion angle showed no significant difference between the central anatomical SB and anatomical DB reconstruction groups. It is suggested that the central anatomical SB reconstruction is comparable with the anatomical DB reconstruction in biomechanical anteroposterior and rotational knee stability at time 0.

Cardiovascular and Metabolic Responses to Electrical Stimulation-Induced Leg Exercise in Spinal Cord Injury

1997 ◽  
Vol 36 (04/05) ◽  
pp. 372-375 ◽  
Author(s):  
J. R. Sutton ◽  
A. J. Thomas ◽  
G. M. Davis
Keyword(s):  
Spinal Cord ◽  
Heart Rate ◽  
Spinal Cord Injury ◽  
Cardiac Output ◽  
Electrical Stimulation ◽  
Knee Flexion ◽  
Flexion Extension ◽  
Cord Injury ◽  
Leg Exercise ◽  
Leg Muscle

Abstract:Electrical stimulation-induced leg muscle contractions provide a useful model for examining the role of leg muscle neural afferents during low-intensity exercise in persons with spinal cord-injury and their able-bodied cohorts. Eight persons with paraplegia (SCI) and 8 non-disabled subjects (CONTROL) performed passive knee flexion/extension (PAS), electrical stimulation-induced knee flexion/extension (ES) and voluntary knee flexion/extension (VOL) on an isokinetic dynamometer. In CONTROLS, exercise heart rate was significantly increased during ES (94 ± 6 bpm) and VOL (85 ± 4 bpm) over PAS (69 ± 4 bpm), but no changes were observed in SCI individuals. Stroke volume was significantly augmented in SCI during ES (59 ± 5 ml) compared to PAS (46 ± 4 ml). The results of this study suggest that, in able-bodied humans, Group III and IV leg muscle afferents contribute to increased cardiac output during exercise primarily via augmented heart rate. In contrast, SCI achieve raised cardiac output during ES leg exercise via increased venous return in the absence of any change in heart rate.

scholarly journals Terrain classification and adaptive locomotion for a hexapod robot Qingzhui

2021 ◽  
Author(s):  
Yue Zhao ◽  
Feng Gao ◽  
Qiao Sun ◽  
Yunpeng Yin
Keyword(s):  
Legged Robots ◽  
Measurement Unit ◽  
Support Vector ◽  
Hexapod Robot ◽  
Terrain Classification ◽  
Adaptive Locomotion ◽  
Joint Torques ◽  
Active Compliance ◽  
Outdoor Environments ◽  
The Stability

AbstractLegged robots have potential advantages in mobility compared with wheeled robots in outdoor environments. The knowledge of various ground properties and adaptive locomotion based on different surface materials plays an important role in improving the stability of legged robots. A terrain classification and adaptive locomotion method for a hexapod robot named Qingzhui is proposed in this paper. First, a force-based terrain classification method is suggested. Ground contact force is calculated by collecting joint torques and inertial measurement unit information. Ground substrates are classified with the feature vector extracted from the collected data using the support vector machine algorithm. Then, an adaptive locomotion on different ground properties is proposed. The dynamic alternating tripod trotting gait is developed to control the robot, and the parameters of active compliance control change with the terrain. Finally, the method is integrated on a hexapod robot and tested by real experiments. Our method is shown effective for the hexapod robot to walk on concrete, wood, grass, and foam. The strategies and experimental results can be a valuable reference for other legged robots applied in outdoor environments.

Forces at the Anterior Meniscus Attachments Strongly Increase Under Dynamic Knee Joint Loading

2021 ◽  
Vol 49 (4) ◽  
pp. 994-1004
Author(s):  
Andreas Martin Seitz ◽  
Florian Schall ◽  
Steffen Paul Hacker ◽  
Stefan van Drongelen ◽  
Sebastian Wolf ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Muscle Force ◽  
Meniscal Tear ◽  
In Vitro Tests ◽  
Jump Landing ◽  
Medial Meniscectomy ◽  
Attachment Structures ◽  
Flexion Extension ◽  
Longitudinal Tear

Background: The anatomic appearance and biomechanical and clinical importance of the anterior meniscus roots are well described. However, little is known about the loads that act on these attachment structures under physiological joint loads and movements. Hypotheses: As compared with uniaxial loading conditions under static knee flexion angles or at very low flexion-extension speeds, more realistic continuous movement simulations in combination with physiological muscle force simulations lead to significantly higher anterior meniscus attachment forces. This increase is even more pronounced in combination with a longitudinal meniscal tear or after total medial meniscectomy. Study Design: Controlled laboratory study. Methods: A validated Oxford Rig–like knee simulator was used to perform a slow squat, a fast squat, and jump landing maneuvers on 9 cadaveric human knee joints, with and without muscle force simulation. The strains in the anterior medial and lateral meniscal periphery and the respective attachments were determined in 3 states: intact meniscus, medial longitudinal tear, and total medial meniscectomy. To determine the attachment forces, a subsequent in situ tensile test was performed. Results: Muscle force simulation resulted in a significant strain increase at the anterior meniscus attachments of up to 308% ( P < .038) and the anterior meniscal periphery of up to 276%. This corresponded to significantly increased forces ( P < .038) acting in the anteromedial attachment with a maximum force of 140 N, as determined during the jump landing simulation. Meniscus attachment strains and forces were significantly influenced ( P = .008) by the longitudinal tear and meniscectomy during the drop jump simulation. Conclusion: Medial and lateral anterior meniscus attachment strains and forces were significantly increased with physiological muscle force simulation, corroborating our hypothesis. Therefore, in vitro tests applying uniaxial loads combined with static knee flexion angles or very low flexion-extension speeds appear to underestimate meniscus attachment forces. Clinical Relevance: The data of the present study might help to optimize the anchoring of meniscal allografts and artificial meniscal substitutes to the tibial plateau. Furthermore, this is the first in vitro study to indicate reasonable minimum stability requirements regarding the reattachment of torn anterior meniscus roots.

scholarly journals Accent Stabilizes 1:2 Sensorimotor Synchronization of Rhythmic Knee Flexion-Extension Movement in Upright Stance

2019 ◽  
Vol 10 ◽  
Author(s):  
Takahide Etani ◽  
Akito Miura ◽  
Masahiro Okano ◽  
Masahiro Shinya ◽  
Kazutoshi Kudo
Keyword(s):  
Knee Flexion ◽  
Sensorimotor Synchronization ◽  
Upright Stance ◽  
Flexion Extension

scholarly journals Inertial sensor-based knee flexion/extension angle estimation

2009 ◽  
Vol 42 (16) ◽  
pp. 2678-2685 ◽  
Author(s):  
Glen Cooper ◽  
Ian Sheret ◽  
Louise McMillian ◽  
Konstantinos Siliverdis ◽  
Ning Sha ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Inertial Sensor ◽  
Angle Estimation ◽  
Flexion Extension
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