A Computational Analysis of Error in Locating the Rotational Axes of the Tibiofemoral Joint With an Instrumented Spatial Linkage

Author(s):  
Daniel P. Bonny ◽  
Stephen M. Howell ◽  
Maury L. Hull

A method to measure the two kinematic axes of the tibiofemoral joint, the flexion-extension (F-E) axis and longitudinal rotation (LR) axis [1], was developed by Gatti [2]. This method used an instrumented spatial linkage (ISL), a series of six instrumented revolute joints that can measure motion between two rigid bodies. While Gatti’s method demonstrated success in locating the F-E and LR axes, defining the axes and their errors using anatomically relevant coordinate systems would improve clinical relevance. While errors due to revolute joint transducer resolution were computed, errors due to nonlinearity and hysteresis in the transducers were not examined, and errors due to different applied tibiofemoral motions were not examined. Thus the objective was to computationally determine, using anatomically relevant coordinate systems, the errors in locating the F-E and LR axes due to nonlinearity and hysteresis in the revolute joint transducers for three different simulations of applied tibiofemoral motion.

Author(s):  
Daniel P. Bonny ◽  
S. M. Howell ◽  
M. L. Hull

The two kinematic axes of the tibiofemoral joint, the flexion-extension (F-E) and longitudinal rotation (LR) axes [1], are unrelated to the anatomic landmarks often used to align prostheses during total knee arthroplasty (TKA) [1, 2]. As a result, conventional TKA changes the position and orientation of the joint line, thus changing the position and orientation of the F-E and LR axes and consequently the kinematics of the knee. However, the extent to which TKA changes these axes is unknown. An instrument that can measure the locations of and any changes to these axes is an instrumented spatial linkage (ISL), a series of six instrumented revolute joints that can measure the six degrees of freedom of motion (DOF) between two rigid bodies without constraining motion. Previously, we computationally determined how best to design and use an ISL such that rotational and translational errors in locating the F-E and LR axes were minimized [3]. However, this ISL was not constructed and therefore its ability to measure changes in the axes has not been validated. Therefore the objective was to construct the ISL and quantify the errors in measuring changes in position and orientation of the F-E axis.


2021 ◽  
Vol 29 (2) ◽  
pp. 230949902110258
Author(s):  
Seungbum Chae ◽  
Junho Nam ◽  
Il-Jung Park ◽  
Steven S. Shin ◽  
Michelle H. McGarry ◽  
...  

Purpose: This study compares the kinematic changes after the procedures for scapholunate interosseous ligament (SLIL) reconstruction—the modified Brunelli technique (MBT) and Mark Henry’s technique (MHT). Methods: Ten cadaveric wrists were used. The scapholunate (SL) interval and angle and radiolunate (RL) angle were recorded using the MicroScribe system. The SL interval was measured by dividing the volar and dorsal portions. Four motions of the wrist were performed—neutral, flexion, extension, and clenched fist (CF) positions—and compared among five conditions: (1) intact wrist, (2) volar SLIL resection, (3) whole SLIL resection, (4) MBT reconstruction, and (5) MHT reconstruction. Results: Under the whole SLIL resection condition, the dorsal SL intervals were widened in all positions. In all positions, the dorsal SL intervals were restored after MBT and MHT. The volar SL interval widened in the extension position after volar SLIL resection. The volar SL interval was not restored in the extension position after MBT and MHT. The SL angle increased in the neutral and CF positions under the whole SLIL resection condition. The SL angle was not restored in the neutral and CF positions after MBT and MHT. The RL angle increased in the neutral and CF positions under the whole SLIL resection condition. The RL angle was not restored in the neutral and CF positions after MBT and MHT. Conclusion: The MBT and MHT may restore the dorsal SL interval. No significant differences in restoration of the SL interval between MBT and MHT were found in the cadaveric models. Clinical relevance: No significant differences between MBT and MHT were found in the cadaveric models for SLIL reconstruction. When considering the complications due to volar incision and additional procedures in MHT, MBT may be a more efficient technique in terms of operative time and injury of the anterior structures during surgery, but further research is needed.


2018 ◽  
Vol 51 (4) ◽  
pp. 1059-1068 ◽  
Author(s):  
Pascal Parois ◽  
James Arnold ◽  
Richard Cooper

Crystallographic restraints are widely used during refinement of small-molecule and macromolecular crystal structures. They can be especially useful for introducing additional observations and information into structure refinements against low-quality or low-resolution data (e.g. data obtained at high pressure) or to retain physically meaningful parameter values in disordered or unstable refinements. However, despite the fact that the anisotropic displacement parameters (ADPs) often constitute more than half of the total model parameters determined in a structure analysis, there are relatively few useful restraints for them, examples being Hirshfeld rigid-bond restraints, direct equivalence of parameters and SHELXL RIGU-type restraints. Conversely, geometric parameters can be subject to a multitude of restraints (e.g. absolute or relative distance, angle, planarity, chiral volume, and geometric similarity). This article presents a series of new ADP restraints implemented in CRYSTALS [Parois, Cooper & Thompson (2015), Chem. Cent. J. 9, 30] to give more control over ADPs by restraining, in a variety of ways, the directions and magnitudes of the principal axes of the ellipsoids in locally defined coordinate systems. The use of these new ADPs results in more realistic models, as well as a better user experience, through restraints that are more efficient and faster to set up. The use of these restraints is recommended to preserve physically meaningful relationships between displacement parameters in a structural model for rigid bodies, rotationally disordered groups and low-completeness data.


2021 ◽  
Author(s):  
Xingyu Liu ◽  
Lihong Lu ◽  
Kewei Bian ◽  
Arthur Brown ◽  
Haojie Mao

Abstract Background Laboratory animal experiments are an invaluable tool for studying mild traumatic brain injury (mTBI)/concussion. Among them, rodent neurotrauma experiments have been most widely used, as transgenic and gene targeting technologies in mice allow us to test the roles of different genes in recovery from brain injury. Furthermore, the clinical relevance of rodent concussion studies can be improved by using these technologies to study concussions in animals that carry the human versions of genes known to play a role in neurological disease. However, delivering concussion injuries to the mice that are relevant to real-world human head impacts is challenging, as the mouse and human heads are dramatically different in shape and size. In the vast majority of mouse concussion experiments, the pathological and behavioral consequences of the injuries are evaluated without considering whether the injury model produces brain stretches (maximum principal strains) of the same magnitude as those experienced by human brains undergoing similar impacts. Methods We conducted a total of 201 computational simulations to understand both human and mouse brain strains that are directly linked to neuronal damage during closed-head concussive impacts. To represent real-world human head impacts we simulated mouse head impacts with durations of 1.5 ms (Type 1 scaling), followed by simulations with durations between 1 and 2 ms (Type 2), and finally, simulations with durations from 0.75 to 4.5 ms (Type 3) to develop scaling between human and mouse, as well as to reveal the predicted effects of small and large changes in impact durations on brain strain. Results Guided by these simulations we calculated that peak rotational velocities in mice could be achieved by scaling human peak rotational velocities with factors of 5.8, 4.6, and 6.8, for flexion/extension, lateral bending, and axial rotation, respectively, to reach equal brain strains between human and mouse. The effects of impact durations on scaling were also calculated and longer-duration mouse head impacts needed larger scaling factors to reach equal strain. Conclusions The scaling method will help us to create brain injury in the mouse with brain strain loading equivalent to those experienced in real-world human head impacts.


Robotica ◽  
2013 ◽  
Vol 32 (6) ◽  
pp. 889-905 ◽  
Author(s):  
Chin-Hsing Kuo ◽  
Jian S. Dai ◽  
Giovanni Legnani

SUMMARYA non-overconstrained three-DOF parallel orientation mechanism that is kinematically equivalent to the Agile Eye is presented in this paper. The output link (end-effector) of the mechanism is connected to the base by one spherical joint and by another three identical legs. Each leg comprises of, in turns from base, a revolute joint, a universal joint, and three prismatic joints. The three lower revolute joints are active joints, while all other joints are passive ones. Based on a special configuration, some three projective angles of the end-effector coordinates are fully decoupled with respect to the input actuated joints, that is, by actuating any revolute joint the end-effector rotates in such a way that the corresponding projective angle changes with the same angular displacement. The fully decoupled motion is analyzed geometrically and proved theoretically. Besides, the inverse and direct kinematics solutions of the mechanism are provided based on the geometric reasoning and theoretical proof.


2017 ◽  
Vol 31 (01) ◽  
pp. 068-074
Author(s):  
Swithin Razu ◽  
Keiichi Kuroki ◽  
James Cook ◽  
Trent Guess

AbstractThe function and importance of the anterior intermeniscal ligament (AIML) of the knee are not fully known. The purpose of this study was to evaluate the biomechanical and sensorimotor function of the AIML. Computational analysis was used to assess AIML and tibiomeniscofemoral biomechanics under combined translational and rotational loading applied during dynamic knee flexion–extension. Histologic and immunohistochemical examination was used to identify and characterize neural elements in the tissue. The computational models were created from anatomy and passive motion of two female subjects and histologic examinations were conducted on AIMLs retrieved from 10 fresh-frozen cadaveric knees. It was found that AIML strain increased with compressive knee loading and that external rotation of the tibia unloads the AIML, suppressing the relationship between AIML strain and compressive knee loads. Extensive neural elements were located throughout the AIML tissue and these elements were distributed across the three AIML anatomical types. The AIMLs have a beneficial influence on knee biomechanics with decreased meniscal load sharing with AIML loss. The AIML plays a significant biomechanical and neurologic role in the sensorimotor functions of the knee. The major role for the AIML may primarily involve its neurologic function.


2009 ◽  
Vol 3 (2) ◽  
Author(s):  
J. Bryndza ◽  
A. Weiser ◽  
M. Paliwal

Arthritis, degenerative disc disease, spinal stenosis, and other ailments lead to the deterioration of the facet joints of the spine, causing pain and immobility in patients. Dynamic stabilization and arthroplasty of the facet joints have advantages over traditional fusion methods by eliminating pain while maintaining normal mobility and function. In the present work, a novel dynamic stabilization spine implant design was developed using computational analysis, and the final design was fabricated and mechanically tested. A model of a fused L4–L5 Functional Spinal Unit (FSU) was developed using Pro/Engineer (PTC Corporation, Needham, MA). The model was imported into commercial finite element analysis software Ansys (Ansys Inc., Canonsburg, PA), and meshed with the material properties of bone, intervertebral disc, and titanium alloy. Physiological loads (600N axial load, 10 N-m moment) were applied to the model construct following the protocol developed by others. The model was subjected to flexion/extension, axial rotation, and lateral bending, and was validated with the results reported by Kim et al. The validated FSU was used as a base to design and evaluate novel spine implant designs, using finite element anlysis. A comparison of the flexion-extension curve of six designs and an intact spine was carried out. Range of motion of the new designs showed up to 4 degrees in flexion and extension, compared to less than one degree flexion/extension in a fused spine. The design that reproduced normal range of motion best was optimized, fabricated and prepared for mechanical testing. The finalized dynamic stabilization design with spring insert was implanted into a L4-L5 FSU sawbone (Pacific Research Laboratories, Vashon, WA) using Stryker Xia pedicle screws. The construct was potted using PMMA, and was subjected to flexion/extension, axial rotation, and lateral bending loads using MTS mechanical testing machine. The stiffness of the design was assessed and compared with computational analysis results.


1990 ◽  
Vol 112 (2) ◽  
pp. 183-189 ◽  
Author(s):  
K. Soong ◽  
B. S. Thompson

A comprehensive analytical investigation of the dynamic response of a general planar kinematic chain comprising an assemblage of articulating interconnected rigid-bodies with bearing clearances in the revolute joints is presented. The equations governing the dynamical behavior of this general mechanical system are established by incorporating a four-mode model of the phenomenological behavior of the principal elements of each revolute joint into the generalized form of Lagrange’s equations. The proposed methodology is then employed to predict the dynamic behavior of a planar slider-crank mechanism with radial clearance in the gudgeon-pin joint prior to comparing these theoretical predictions with the corresponding response-data from a complementary experimental investigation.


Author(s):  
Wei Wang ◽  
Dongmei Wang ◽  
Mariska Wesseling ◽  
Bin Xue ◽  
Feiyue Li

This study aimed to find an optimal measurement protocol of elbow and forearm kinematics using different modelling and tracking methods. Kinematic data of elbow flexion/extension and forearm pronation/supination was acquired using optical motion capture from 12 healthy male volunteers. Segment coordinate systems for humerus, forearm, radius, ulna, and hand were defined. Different tracking methods, using anatomical markers or rigid or point maker clusters, were used to compute the three-dimensional rotations. Marker placement errors were assessed to evaluate the rigid body assumption. Multiple comparisons demonstrated statistical differences between tracking methods: compared to using only anatomical markers, tracking using clusters reduced the estimated range of pronation/supination by 14.9%–43.2%, while it estimated increased flexion/extension by 5.3%–9.1%. The study suggests using only anatomical markers exerts the optimal estimation of elbow and forearm kinematics. Modelling using the coordinate systems of the humerus and forearm and of the humerus and ulna, respectively, demonstrated good consistency with literature and are correspondingly regarded as the most appropriate approach for measuring pronation/supination and flexion/extension. The results are valuable in establishing a measurement protocol for analysing elbow and forearm kinematics, avoiding confusions and misinterpretations in communicating results from different methodologies.


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