A Finite Helical Axis as a Landmark for Kinematic Reference of the Knee

1991 ◽  
Vol 113 (2) ◽  
pp. 215-222 ◽  
Author(s):  
R. A. Hart ◽  
C. D. Mote ◽  
H. B. Skinner
Keyword(s):  
Soft Tissue ◽  
Human Subjects ◽  
Helical Axis ◽  
Knee Motion ◽  
Axis Orientation ◽  
Motion Representation ◽  
Axial Translation ◽  
Six Degree Of Freedom ◽  
Finite Helical Axis

Reference coordinates based on the finite helical axis for flexion of the knee from 0 to 90 deg are proposed. Six degree-of-freedom tracking allows the use of such a helical axis as a kinematic landmark for knee motion representation. Data from five human subjects in vivo are presented as a path of finite helical axes for flexion of the knee from 20 to 80 deg. The finite helical axis rotates by an average of 11.4 deg, the centrode translates an average of 19.8 mm, and the total axial translation averages 0.1 mm during flexion from 20 to 80 deg. Error due to the transducer was measured on a fixed-pivot pendulum and found to be 1.0 deg and 1.9 mm rms for the helical axis orientation and position, respectively, and 0.1 mm for the axial translation. Reproducibility and soft tissue effects on the measurements were repeatable to 4.0 deg and 2.7 mm rms in orientation and position, respectively, and 0.1 mm for the axial translations. Soft tissue errors averaged 4.9 deg and 3.6 mmm in position and orientation, and 0.3 mm in the axial translations.

In vivo measurements of patellar tracking and finite helical axis using a static magnetic resonance based methodology

2014 ◽  
Vol 36 (12) ◽  
pp. 1611-1617 ◽  
Author(s):  
Jie Yao ◽  
Bin Yang ◽  
Wenxin Niu ◽  
Jianwei Zhou ◽  
Yuxing Wang ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Patellar Tracking ◽  
Helical Axis ◽  
In Vivo Measurements ◽  
Finite Helical Axis

scholarly journals The Envelope of Physiological Motion of the First Carpometacarpal Joint

2015 ◽  
Vol 137 (10) ◽  
Author(s):  
Joseph J. Crisco ◽  
Tarpit Patel ◽  
Eni Halilaj ◽  
Douglas C. Moore
Keyword(s):  
Hand Function ◽  
Helical Axis ◽  
Axis Orientation ◽  
Discrete Fourier Analysis ◽  
Joint Pathology ◽  
Physiological Motion ◽  
Thumb Carpometacarpal ◽  
Helical Axis Of Motion ◽  
Cmc Joint

Much of the hand's functional capacity is due to the versatility of the motions at the thumb carpometacarpal (CMC) joint, which are presently incompletely defined. The aim of this study was to develop a mathematical model to completely describe the envelope of physiological motion of the thumb CMC joint and then to examine if there were differences in the kinematic envelope between women and men. In vivo kinematics of the first metacarpal with respect to the trapezium were computed from computed tomography (CT) volume images of 44 subjects (20M, 24F, 40.3 ± 17.7 yr) with no signs of CMC joint pathology. Kinematics of the first metacarpal were described with respect to the trapezium using helical axis of motion (HAM) variables and then modeled with discrete Fourier analysis. Each HAM variable was fit in a cyclic domain as a function of screw axis orientation in the trapezial articular plane; the RMSE of the fits was 14.5 deg, 1.4 mm, and 0.8 mm for the elevation, location, and translation, respectively. After normalizing for the larger bone size in men, no differences in the kinematic variables between sexes could be identified. Analysis of the kinematic data also revealed notable coupling of the primary rotations of the thumb with translation and internal and external rotations. This study advances our basic understanding of thumb CMC joint function and provides a complete description of the CMC joint for incorporation into future models of hand function. From a clinical perspective, our findings provide a basis for evaluating CMC pathology, especially the mechanically mediated aspects of osteoarthritis (OA), and should be used to inform artificial joint design, where accurate replication of kinematics is essential for long-term success.

scholarly journals Relationship between patellofemoral finite helical axis and femoral trans-epicondylar axis using a static magnetic resonance-based methodology

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Zhenguo Yu ◽  
Hong Cai ◽  
Bin Yang ◽  
Jie Yao ◽  
Ke Zhang ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Knee Flexion ◽  
Spline Interpolation ◽  
Helical Axis ◽  
Mr Images ◽  
Full Extension ◽  
Epicondylar Axis ◽  
Maximum Angle ◽  
Finite Helical Axis

Abstract Background To manage patellofemoral joint disorders, a complete understanding of the in vivo patellofemoral kinematics is critical. However, as one of the parameters of joint kinematics, the location and orientation of the patellofemoral finite helical axis (FHA) remains unclear. The purpose of this study is to quantify the location and orientation of the patellar FHA, both in vivo and non-invasively at various flexion angles, and evaluate the relationship of the FHA and the trans-epicondylar axis (TEA). Methods The magnetic resonance (MR) images of 18 unilateral knees were collected at full extension, 30°, 60°, 90°, and maximum angle of knee flexion. Three-dimensional models of the knee joint at different flexion angles were created using the MR images, and then used to calculate the patellar tracking and FHA with a spline interpolation algorithm. By using a coordinate system based on the TEA, the FHA tracking was quantified. Six parameters concerning the location and orientation of the patellar FHA were analysed. Results The average patellar FHA drew an L-shaped tracking on the midsagittal plane moving from the posteroinferior to the anterosuperior side of the TEA with knee flexion. Before 90° flexion, the patellar rotational radius decreased slightly, with an average value of 5.65 ± 1.09 cm. During 20° to 90° knee flexion, the average angle between the patellar FHA and the TEA was approximately 10° and that between the FHA and the coronal plane was maintained at about 0°, while that between the FHA and the level plane fluctuated between − 10° and 10°. Conclusions This study quantitatively reported the continuous location and direction of the patellar FHA during knee flexion. The patellar FHA was close to but not coincident with the femoral TEA both in location and orientation, and the patellar rotational radius decreased slightly with knee flexion. These findings could provide a clear direction for further studies on the difference in patellofemoral FHA among various types of patellofemoral disorders, and provide a foundation for the application of FHA in surgical evaluation, preoperative planning and prosthesis design, thereby assisting in the diagnosis and treatment of patellofemoral disorders.

scholarly journals Relationship Between Patellofemoral Finite Helical Axis and Femoral Trans-Epicondyle Axis Using a Static Magnetic Resonance-Based Methodology

2020 ◽  
Author(s):  
Zhenguo Yu ◽  
Hong Cai ◽  
Bin Yang ◽  
Jie Yao ◽  
Ke Zhang ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Knee Flexion ◽  
Patellofemoral Joint ◽  
Spline Interpolation ◽  
Joint Kinematics ◽  
Helical Axis ◽  
Mr Images ◽  
Maximum Angle ◽  
Finite Helical Axis

Abstract Background: To manage patellofemoral joint disorders, a complete understanding of the in vivo patellofemoral kinematics is critical. However, as one of the parameters of joint kinematics, the location and orientation of patellofemoral finite helical axis (FHA) remains unclear. The purpose of this study is to quantify the location and orientation of the patellar FHA both in vivo and non-invasively at various flexion angles and to relate the FHA to the trans-epicondyle axis (TEA).Methods: The Magnetic resonance (MR) images of 18 unilateral knees were collected at full extension and at 30°, 60°, 90°, and maximum angle of knee flexion. Three-dimensional models of knee joint at different flexion angles were developed with the MR images, and were used to calculate the patellar tracking and FHA with a spline interpolation algorithm. By using a coordinate system based on the TEA, the FHA tracking was quantified. Six parameters concerning the location and orientation of the patellar FHA were analyzed.Results: The average patellar FHA of 18 knees drew an L-shaped tracking on the midsagittal plane moving from the posteroinferior side of the TEA to the anterosuperior with knee flexion. Before 90° flexion, the patellar rotational radius decreased slightly, with an average value of 5.65 ± 1.09 cm. During 20° to 90° knee flexion, the average angle between the patellar FHA and TEA was approximately 10° and that between the FHA and coronal plane was maintained at about 0°, while that between the FHA and level plane fluctuated between -10° and 10°.Conclusions: Patellar FHA was not fixed during flexion, which showed a close relationship with femoral TEA in both location and orientation. The results could help us better understand the patellofemoral joint kinematics and further deal with troublesome patellofemoral disorders.

Normal Six-Degree-of-Freedom Motions of Knee Joint During Level Walking

1996 ◽  
Vol 118 (2) ◽  
pp. 258-261 ◽  
Author(s):  
Xue Mei Li ◽  
Bo Liu ◽  
Bo Deng ◽  
Shi Ming Zhang
Keyword(s):  
Degree Of Freedom ◽  
Joint Measurement ◽  
Knee Motion ◽  
In Vivo Test ◽  
In Vivo Measurement ◽  
Level Walking ◽  
Flexion Extension ◽  
Posterior Translation ◽  
Six Degree Of Freedom

The purpose of this study was to find an effective way for in vivo measurement of joint motion and give the normal knee motion according to this method. The joint model proposed by Grood and Suntay (1983) was chosen; the origin of the tibia was modified for the convenience of in vivo test. A computerized 6 degree-of-freedom electrogoniometer (EGM) was used in the measurement. Repeated tests on one subject were performed to establish the reliability of the method. Knee motions obtained from 42 males during level walking were expressed as flexion-extension, abduction-adduction, external-internal rotation, lateral-medial translation, anterior-posterior translation, and superior-inferior translation. The results showed that, with the proper choice of the origin of the tibia, the EGM could depend much less on external landmarks and be more effective for the joint measurement.

Evaluation of 99mTc-Label led Vitamin K4 as an Agent for Testicular Imaging

1991 ◽  
Vol 30 (01) ◽  
pp. 35-39 ◽  
Author(s):  
H. S. Durak ◽  
M. Kitapgi ◽  
B. E. Caner ◽  
R. Senekowitsch ◽  
M. T. Ercan
Keyword(s):  
Soft Tissue ◽  
Room Temperature ◽  
Normal Subjects ◽  
Left Testis ◽  
Wide Range ◽  
Activity Ratios ◽  
The Right ◽  
Radioactivity Levels

Vitamin K4 was labelled with 99mTc with an efficiency higher than 97%. The compound was stable up to 24 h at room temperature, and its biodistribution in NMRI mice indicated its in vivo stability. Blood radioactivity levels were high over a wide range. 10% of the injected activity remained in blood after 24 h. Excretion was mostly via kidneys. Only the liver and kidneys concentrated appreciable amounts of radioactivity. Testis/soft tissue ratios were 1.4 and 1.57 at 6 and 24 h, respectively. Testis/blood ratios were lower than 1. In vitro studies with mouse blood indicated that 33.9 ±9.6% of the radioactivity was associated with RBCs; it was washed out almost completely with saline. Protein binding was 28.7 ±6.3% as determined by TCA precipitation. Blood clearance of 99mTc-l<4 in normal subjects showed a slow decrease of radioactivity, reaching a plateau after 16 h at 20% of the injected activity. In scintigraphic images in men the testes could be well visualized. The right/left testis ratio was 1.08 ±0.13. Testis/soft tissue and testis/blood activity ratios were highest at 3 h. These ratios were higher than those obtained with pertechnetate at 20 min post injection.99mTc-l<4 appears to be a promising radiopharmaceutical for the scintigraphic visualization of testes.

Pharmacological treatment with L-DOPA may reduce striatal dopamine transporter binding in in vivo imaging studies

2016 ◽  
Vol 55 (01) ◽  
pp. 21-28 ◽  
Author(s):  
C. Antke ◽  
H. Hautzel ◽  
H.-W. Mueller ◽  
S. Nikolaus
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Binding Sites ◽  
Human Subjects ◽  
Synaptic Cleft ◽  
Presynaptic Terminal ◽  
Imaging Studies ◽  
Psychiatric Conditions ◽  
Da Release

SummaryNumerous neurologic and psychiatric conditions are treated with pharmacological compounds, which lead to an increase of synaptic dopamine (DA) levels. One example is the DA precursor L-3,4-dihydroxyphenylalanine (L-DOPA), which is converted to DA in the presynaptic terminal. If the increase of DA concentrations in the synaptic cleft leads to competition with exogenous radioligands for presynaptic binding sites, this may have implications for DA transporter (DAT) imaging studies in patients under DAergic medication.This paper gives an overview on those findings, which, so far, have been obtained on DAT binding in human Parkinson’s disease after treatment with L-DOPA. Findings, moreover, are related to results obtained on rats, mice or non-human primates. Results indicate that DAT imaging may be reduced in the striata of healthy animals, in the unlesioned striata of animal models of unilateral Parkinson’s disease and in less severly impaired striata of Parkinsonian patients, if animal or human subjects are under acute or subchronic treatment with L-DOPA. If also striatal DAT binding is susceptible to alterations of synaptic DA levels, this may allow to quantify DA reuptake in analogy to DA release by assessing the competition between endogenous DA and the administered exogenous DAT radioligand.

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