Determining the optimal flexion–extension axis of the elbow in vivo — a study of interobserver and intraobserver reliability

2000 ◽  
Vol 33 (9) ◽  
pp. 1139-1145 ◽  
Author(s):  
M Stokdijk ◽  
M Biegstraaten ◽  
W Ormel ◽  
Y.A de Boer ◽  
H.E.J Veeger ◽  
...  
Keyword(s):  
Intraobserver Reliability ◽  
Flexion Extension ◽  
Extension Axis

A Marker-Based Mean Finite Helical Axis Model to Determine Elbow Rotation Axes and Kinematics in Vivo

2010 ◽  
Vol 26 (3) ◽  
pp. 305-315 ◽  
Author(s):  
Aaron Chin ◽  
David Lloyd ◽  
Jacqueline Alderson ◽  
Bruce Elliott ◽  
Peter Mills
Keyword(s):  
Upper Limb ◽  
Cross Talk ◽  
Functional Model ◽  
Helical Axis ◽  
Rotation Axes ◽  
Model Following ◽  
Flexion Extension ◽  
Analysis Models ◽  
Extension Axis

The predominance of upper-limb elbow models have been based on earlier lower-limb motion analysis models. We developed and validated a functionally based 2 degree-of-freedom upper-limb model to measure rotations of the forearm using a marker-based approach. Data were collected from humans and a mechanical arm with known axes and ranges of angular motion in 3 planes. This upper-limb model was compared with an anatomically based model following the proposed ISB standardization. Location of the axes of rotation relative to each other was determined in vivo. Data indicated that the functional model was not influenced by cross-talk from adduction-abduction, accurately measuring flexion-extension and pronation-supination. The functional flexion-extension axis in vivo is angled at 6.6° to the anatomical line defined from the humeral medial to lateral epicondyles. The pronation-supination axis intersected the anatomically defined flexion-extension axis at 88.1°. Influence of cross-talk on flexion-extension kinematics in the anatomical model was indicated by strong correlation between flexion-extension and adduction-abduction angles for tasks performed by the subjects. The proposed functional model eliminated cross-talk by sharing a common flexion axis between the humerus and forearm. In doing so, errors due to misalignment of axes are minimized providing greater accuracy in kinematic data.

scholarly journals Identifying the Functional Flexion-extension Axis of the Knee: An In-Vivo Kinematics Study

PLoS ONE ◽  
2015 ◽  
Vol 10 (6) ◽  
pp. e0128877 ◽  
Author(s):  
Li Yin ◽  
Kaining Chen ◽  
Lin Guo ◽  
Liangjun Cheng ◽  
Fuyou Wang ◽  
...  
Keyword(s):  
In Vivo Kinematics ◽  
Flexion Extension ◽  
Extension Axis

scholarly journals Accuracy and repeatability of wrist joint angles in boxing using an electromagnetic tracking system

2019 ◽  
Vol 23 (1) ◽  
Author(s):  
Ian T. Gatt ◽  
Tom Allen ◽  
Jon Wheat
Keyword(s):  
Wrist Joint ◽  
Tracking System ◽  
Testing Procedure ◽  
Electromagnetic Tracking ◽  
Good Reliability ◽  
Flexion Extension ◽  
In Vivo Testing ◽  
Accuracy And Repeatability ◽  
Electromagnetic Tracking System

AbstractThe hand-wrist region is reported as the most common injury site in boxing. Boxers are at risk due to the amount of wrist motions when impacting training equipment or their opponents, yet we know relatively little about these motions. This paper describes a new method for quantifying wrist motion in boxing using an electromagnetic tracking system. Surrogate testing procedure utilising a polyamide hand and forearm shape, and in vivo testing procedure utilising 29 elite boxers, were used to assess the accuracy and repeatability of the system. 2D kinematic analysis was used to calculate wrist angles using photogrammetry, whilst the data from the electromagnetic tracking system was processed with visual 3D software. The electromagnetic tracking system agreed with the video-based system (paired t tests) in both the surrogate (< 0.2°) and quasi-static testing (< 6°). Both systems showed a good intraclass coefficient of reliability (ICCs > 0.9). In the punch testing, for both repeated jab and hook shots, the electromagnetic tracking system showed good reliability (ICCs > 0.8) and substantial reliability (ICCs > 0.6) for flexion–extension and radial-ulnar deviation angles, respectively. The results indicate that wrist kinematics during punching activities can be measured using an electromagnetic tracking system.

An Interlocking Ligamentous Spinal Disk Arthroplasty with Neural Network Infrastructure

2010 ◽  
Vol 7 ◽  
pp. 55-79 ◽  
Author(s):  
Philip Boughton ◽  
James Merhebi ◽  
C. Kim ◽  
G. Roger ◽  
Ashish D. Diwan ◽  
...  
Keyword(s):  
Neural Network ◽  
Finite Element ◽  
Axial Compression ◽  
Wire Array ◽  
Axial Strain ◽  
Compressive Strain ◽  
Niti Wire ◽  
Motion Segment ◽  
Flexion Extension

An elastomeric spinal disk prosthesis design (BioFI™) with vertebral interlocking anchors has been modified using an embedded TiNi wire array. Bioinert styrenic block copolymer (Kraton®) and polycarbonate urethane (Bionate®) thermoplastic elastomer (TPE) matrices were utilized. Fatigue resistant NiTi wire was pretreated to induce superelastic martensitic microstructure. Stent-like helical structures were produced for incorporation within homogenous TPE matrix. Composite prototypes were fabricated in a vacuum hot press using transfer moulding techniques. Implant prototypes were subject to axial compression using a BOSE ® ELF3400. The NiTi reinforced implants exhibited reduction in axial strain, compliance, and creep compared to TPE controls. The axial properties of the NiTi reinforced Bionate® BioFI™ implant best approximated those of a spinal disk followed by Kraton®-NiTi, Bionate® and Kraton® prototypes. An ovine lumbar segment biomechanical model was used to characterize the disk prosthesis prototypes. Specimens were subject to 7.5Nm pure moments in axial rotation, flexion-extension and lateral bending with a custom jig mounted on an Instron® 8874. The motion preserving ligamentous nature of this arthroplasty prototype was not inhibited by NiTi reinforcement. Joint stiffness for all prototypes was significantly less than the intact and discectomy controls. This was due to lack of vertebral anchor rigidity rather than BioFI™ motion segment matrix type or reinforcement. Implant stress profiles for axial compression and axial torsion conditions were obtained using finite element methods. The biomechanical testing and finite element modelling both support existing BioFI™ design specifications for higher modulus vertebral anchors, endplates and motion segment periphery with gradation to a low modulus core within the motion segment. This closer approximation of the native spinal disk form translates to improvements in prosthesis biomechanical fidelity and longevity. Axial compressive strain induced within a TiNi reinforced Kraton® BioFI™ was found to be linearly proportional to the NiTi helical coil electrical resistance. This neural network capability delivers opportunities to monitor and telemeterize in situ multiaxis joint structural performance and in vivo spine biomechanics.

scholarly journals In vivo intervertebral disc deformation: intratissue strain patterns within adjacent discs during flexion–extension

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Robert L. Wilson ◽  
Leah Bowen ◽  
Woong Kim ◽  
Luyao Cai ◽  
Stephanie Ellyse Schneider ◽  
...  
Keyword(s):  
Intervertebral Disc ◽  
Biomechanical Analysis ◽  
Resonance Imaging ◽  
Tissue Architecture ◽  
Mechanical Responses ◽  
Flexion Extension ◽  
Adjacent Disc ◽  
Shear Strains ◽  
Magnetic Resonance Imaging Mri

AbstractThe biomechanical function of the intervertebral disc (IVD) is a critical indicator of tissue health and pathology. The mechanical responses (displacements, strain) of the IVD to physiologic movement can be spatially complex and depend on tissue architecture, consisting of distinct compositional regions and integrity; however, IVD biomechanics are predominately uncharacterized in vivo. Here, we measured voxel-level displacement and strain patterns in adjacent IVDs in vivo by coupling magnetic resonance imaging (MRI) with cyclic motion of the cervical spine. Across adjacent disc segments, cervical flexion–extension of 10° resulted in first principal and maximum shear strains approaching 10%. Intratissue spatial analysis of the cervical IVDs, not possible with conventional techniques, revealed elevated maximum shear strains located in the posterior disc (nucleus pulposus) regions. IVD structure, based on relaxometric patterns of T2 and T1ρ images, did not correlate spatially with functional metrics of strain. Our approach enables a comprehensive IVD biomechanical analysis of voxel-level, intratissue strain patterns in adjacent discs in vivo, which are largely independent of MRI relaxometry. The spatial mapping of IVD biomechanics in vivo provides a functional assessment of adjacent IVDs in subjects, and provides foundational biomarkers for elastography, differentiation of disease state, and evaluation of treatment efficacy.

Friction in Hip Hemiendoprostheses. Review of Literature and Own Model Using Cadaveric Acetabula

2002 ◽  
Vol 12 (2) ◽  
pp. 126-134
Author(s):  
L.P. Müller ◽  
J. Degreif ◽  
H. Hely ◽  
D. Mehler ◽  
M. Otto ◽  
...  
Keyword(s):  
Animal Experiments ◽  
Calf Serum ◽  
Hip Joints ◽  
Hip Simulator ◽  
Total Endoprosthesis ◽  
Flexion Extension ◽  
Pin On Disc ◽  
On Line ◽  
Frictional Coefficients

The science of tribology concerning hip arthroplasty has mainly dealt with total endoprosthesis, whereas measurement values of hemiendoprosthetic implants are rare. The small amount of experimental tribologic data concerning hemiendoprosthetic implants in the form of pendulum trials, animal experiments, in vivo measurements on human hip joints and pin on disc studies will be reviewed in the following work. The reported frictional coefficients in these studies were between 0.014–0.57. In order to test the friction coefficients of different femur head hemiendoprostheses (unipolar ceramic- and metal heads) against fresh cadaveric acetabula, the HEPFlEx-hip simulator (Hemi-EndoProsthesis Flexion Extension) was developed. In the simulator, the various hemiendoprosthetic heads are placed on a special cone and tested against a cadaver acetabulum cast in MCP 47 woodmetal. The plane of movement of the apparatus is uniaxial with a flexion-extension movement of ± 35 degrees. The force is produced pneumatically with amounts of up to 5 kN. Newborn calf serum serves as a lubricant. A PC collects the data from torque-, force-, and angle-sensors on-line and allows the simultaneous processing and visualization of the data. The frictional coefficients produced by the different head materials and the relevance of the play between the hemiendoprothesis head size and acetabulum can be determined. Preliminary results showed that the mean friction coefficient at 1 kN loading was μ=0.024–0.063 for ceramic against cartilage and μ=0.033–0.075 for metal against cartilage.

In Vivo Motion Characteristics of the Lower Cervical Spine During Dynamic Weight-Bearing Flexion-Extension

2015 ◽  
Vol 15 (10) ◽  
pp. S183-S184
Author(s):  
Sean J. Driscoll ◽  
Haiqing Mao ◽  
Shaobai Wang ◽  
Weiye Zhong ◽  
Guoan Li ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Weight Bearing ◽  
Lower Cervical Spine ◽  
Dynamic Weight ◽  
Flexion Extension ◽  
Motion Characteristics

The Functional Flexion-Extension Axis of the Knee Corresponds to the Surgical Epicondylar Axis

2005 ◽  
Vol 20 (8) ◽  
pp. 1060-1067 ◽  
Author(s):  
Taiyo Asano ◽  
Masao Akagi ◽  
Takashi Nakamura
Keyword(s):  
Epicondylar Axis ◽  
Flexion Extension ◽  
Extension Axis

scholarly journals Ranges of Cervical Intervertebral Disc Deformation during an In Vivo Dynamic Flexion-Extension of the Neck

2016 ◽  
Vol 16 (10) ◽  
pp. S259
Author(s):  
Yan Yu ◽  
Thomas D. Cha ◽  
Gregory Moore ◽  
Haiqing Mao ◽  
Tsung-Yuan Tsai ◽  
...  
Keyword(s):  
Intervertebral Disc ◽  
Flexion Extension

scholarly journals Gender Differences in Capitate Kinematics are Eliminated After Accounting for Variation in Carpal Size

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Michael J. Rainbow ◽  
Joseph J. Crisco ◽  
Douglas C. Moore ◽  
Scott W. Wolfe
Keyword(s):  
Gender Differences ◽  
Wrist Joint ◽  
Carpal Bone ◽  
Ulnar Deviation ◽  
Rotation Axes ◽  
Flexion Extension ◽  
Optical Motion ◽  
Joint Center ◽  
Best Fit

Previous studies have found gender differences in carpal kinematics, and there are discrepancies in the literature on the location of the flexion∕extension and radio-ulnar deviation rotation axes of the wrist. It has been postulated that these differences are due to carpal bone size differences rather than gender and that they may be resolved by normalizing the kinematics by carpal size. The purpose of this study was to determine if differences in radio-capitate kinematics are a function of size or gender. We also sought to determine if a best-fit pivot point (PvP) describes the radio-capitate joint as a ball-and-socket articulation. By using an in vivo markerless bone registration technique applied to computed tomography scans of 26 male and 28 female wrists, we applied scaling derived from capitate length to radio-capitate kinematics, characterized by a best-fit PvP. We determined if radio-capitate kinematics behave as a ball-and-socket articulation by examining the error in the best-fit PvP. Scaling PvP location completely removed gender differences (P=0.3). This verifies that differences in radio-capitate kinematics are due to size and not gender. The radio-capitate joint did not behave as a perfect ball and socket because helical axes representing anatomical motions such as flexion-extension, radio-ulnar deviation, dart throwers, and antidart throwers, were located at distances up to 4.5mm from the PvP. Although the best-fit PvP did not yield a single center of rotation, it was still consistently found within the proximal pole of the capitate, and rms errors of the best-fit PvP calculation were on the order of 2mm. Therefore, the ball-and-socket model of the wrist joint center using the best-fit PvP is appropriate when considering gross motion of the hand with respect to the forearm such as in optical motion capture models. However, the ball-and-socket model of the wrist is an insufficient description of the complex motion of the capitate with respect to the radius. These findings may aid in the design of wrist external fixation and orthotics.

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