Use of dual Euler angles to quantify the three-dimensional joint motion and its application to the ankle joint complex

Validity and Reliability of a Novel Instrument for the Measurement of Subtalar Joint Axis of Rotation

Inclination of the subtalar joint (STJ) in the sagittal and transverse planes may be highly associated with ankle pathology. However, the validity and reliability of measuring the inclination of the STJ axis of rotation (AoR) is not well established. This study aimed to develop a custom-made STJ locator (STJL) and evaluate its reliability and validity. To establish the reliability and validity of the measurement device for STJ AoR, 38 healthy male participants were recruited. For the reliability analysis, test–retest was used, and for validity analysis, Pearson’s correlation and Bland–Altman plot analyses were performed. In the reliability analysis of the STJL, a higher correlation was observed with the sagittal plane (0.930) and transverse plane (0.748) (standard error of measurement: 0.56–0.78; minimal detectable difference: 1.57–2.16). In the validity analysis between radiography and STJL, a significantly higher value of 0.798 was obtained with radiography (42.5) and STJL (43.5) with the sagittal plane. The custom-made STJL may be used in the clinical setting as its validity and intraclass correlation coefficient were high, indicating consistent measurements. Further studies including motion analysis are necessary to provide more information regarding the relationship between STJ AoR inclinations and STJ movements.

Effects of 4-week impairment-based rehabilitation on jump-landing biomechanics in chronic ankle instability patients

OBJECTIVE

To determine effects of 4-weeks of impairment-based rehabilitation on lower extremity neuromechanics during jump-landing.

DESIGN

Descriptive laboratory study.

PARTICIPANTS

Twenty-six CAI subjects (age = 21.4 ± 3.1 sex=(M = 7,F = 19), height = 169.0 ± 8.8 cm, weight = 71.0 ± 13.8 kg) completed 15 jump-landing trials prior to and following 12 supervised rehabilitation sessions.

MAIN OUTCOME MEASURES

Frontal and sagittal lower extremity kinematics and kinetics and sEMG amplitudes (anterior tibialis, peroneus brevis, peroneus longus, and medial gastrocnemius). Means and 90% confidence intervals (CIs) were calculated for 100 ms prior to and 200 ms following ground contact. Areas where pre- and post-rehabilitation CIs did not overlap were considered significantly different. Kinematic and kinetic peaks and kinematic excursion were compared with paired t-test (P ≤ 0.05).

RESULTS

Following rehabilitation, CAI subjects exhibited less ankle (2.1° (0.8, 3.4), P < 0.01) and hip (2.0° (0.5, 3.7), P = 0.01) frontal plane excursion and lower peak hip abduction (2.5° (0.0, 5.0), P = 0.05). There was less ankle (5.0° (1.7, 8.3), P < 0.01) and knee (3.4° (0.8, 6.0), P = 0.01) sagittal plane excursion following rehabilitation. There was decreased peroneus longus activity from 9 ms to 135 ms post ground contact and decreased peak plantar flexion moment (0.08 N∗m/kg (0.01, 0.13), P = 0.02) following rehabilitation.

CONCLUSION

Progressive impairment-based rehabilitation resulted in reductions in kinematic excursion and peroneus longus muscle activity, suggesting a more efficient landing strategy.

Postural Stability Evaluation of Patients Undergoing Vestibular Schwannoma Microsurgery Employing the Inertial Measurement Unit

The article focuses on a noninvasive method and system of quantifying postural stability of patients undergoing vestibular schwannoma microsurgery. Recent alternatives quantifying human postural stability are rather limited. The major drawback is that the posturography system can evaluate only two physical quantities of body movement and can be measured only on a transverse plane. A complex movement pattern can be, however, described more precisely while using three physical quantities of 3-D movement. This is the reason why an inertial measurement unit (Xsens MTx unit), through which we obtained 3-D data (three Euler angles or three orthogonal accelerations), was placed on the patient's trunk. Having employed this novel method based on the volume of irregular polyhedron of 3-D body movement during quiet standing, it was possible to evaluate postural stability. To identify and evaluate pathological balance control of patients undergoing vestibular schwannoma microsurgery, it was necessary to calculate the volume polyhedron using the 3-D Leibniz method and to plot three variables against each other. For the needs of this study, measurements and statistical analysis were made on nine patients. The results obtained by the inertial measurement unit showed no evidence of improvement in postural stability shortly after surgery (4 days). The results were consistent with the results obtained by the posturography system. The evaluated translation variables (acceleration) and rotary variables (angles) measured by the inertial measurement unit correlate strongly with the results of the posturography system. The proposed method and application of the inertial measurement unit for the purpose of measuring patients with vestibular schwannoma appear to be suitable for medical practice. Moreover, the inertial measurement unit is portable and, when compared to other traditional posturography systems, economically affordable. Inertial measurement units can alternatively be implemented in mobile phones or watches.

Quantification of Trunk Postural Stability Using Convex Polyhedron of the Time-Series Accelerometer Data

Techniques to quantify postural stability usually rely on the evaluation of only two variables, that is, two coordinates of COP. However, by using three variables, that is, three components of acceleration vector, it is possible to describe human movement more precisely. For this purpose, a single three-axis accelerometer was used, making it possible to evaluate 3D movement by use of a novel method, convex polyhedron (CP), together with a traditional method, based on area of the confidence ellipse (ACE). Ten patients (Pts) with cerebellar ataxia and eleven healthy individuals of control group (CG) participated in the study. The results show a significant increase of volume of the CP (CPV) in Pts or CG standing on foam surface with eyes open (EO) and eyes closed (EC) after the EC phase. Significant difference between Pts and CG was found in all cases as well. Correlation coefficient indicates strong correlation between the CPV and ACE in most cases of patient examinations, thus confirming the possibility of quantification of postural instability by the introduced method of CPV.

BIOMECHANICAL MODEL FOR KINETIC AND KINEMATIC DESCRIPTION OF GAIT DURING SECOND TRIMESTER OF PREGNANCY TO STUDY THE EFFECTS OF BIOMECHANICAL LOAD ON THE MUSCULOSKELETAL SYSTEM

Walking is daily physical activity and a common way of exercise during pregnancy, but morphological changes can modify the gait pattern. Biomechanical models can help in evaluating joint mechanical loads and kinetics and kinematics during gait, and provide patterns. This study aimed to describe the gait pattern during the second trimester of pregnancy and give an orientation for biomechanical modeling for pregnant women. The ankle and hip joints seem to be more overloaded, mainly in the sagittal and frontal planes, respectively. Results show that pregnant women have a similar walking pattern to the normal gait. This model construction was revealed to be appropriate for describing gait during the second trimester of pregnancy.

Comparison of two stretching methods and optimization of stretching protocol for the piriformis muscle

Piriformis syndrome is an uncommon diagnosis for a non-discogenic form of sciatica whose treatment has traditionally focused on stretching the piriformis muscle (PiM). Conventional stretches include hip flexion, adduction, and external rotation. Using three-dimensional modeling, we quantified the amount of (PiM) elongation resulting from two conventional stretches and we investigated by use of a computational model alternate stretching protocols that would optimize PiM stretching. Seven subjects underwent three CT scans: one supine, one with hip flexion, adduction, then external rotation (ADD stretch), and one with hip flexion, external rotation, then adduction (ExR stretch). Three-dimensional bone models were constructed from the CT scans. PiM elongation during these stretches, femoral neck inclination, femoral head anteversion, and trochanteric anteversion were measured. A computer program was developed to map PiM length over a range of hip joint positions and was validated against the measured scans. ExR and ADD stretches elongated the PiM similarly by approximately 12%. Femoral head and greater trochanter anteversion influenced PiM elongation. Placing the hip joints in 115° of hip flexion, 40° of external rotation and 25° of adduction or 120° of hip flexion, 50° of external rotation and 30° of adduction increased PiM elongation by 30-40% compared to conventional stretches (15.1 and 15.3% increases in PiM muscle length, respectively). ExR and ADD stretches elongate the PiM similarly and therefore may have similar clinical effectiveness. The optimized stretches led to larger increases in PiM length and may be more easily performed by some patients due to increased hip flexion.

Multi-rigid image segmentation and registration for the analysis of joint motion from three-dimensional magnetic resonance imaging

We report an image segmentation and registration method for studying joint morphology and kinematics from in vivo magnetic resonance imaging (MRI) scans and its application to the analysis of foot and ankle joint motion. Using an MRI-compatible positioning device, a foot was scanned in a single neutral and seven other positions ranging from maximum plantar flexion, inversion, and internal rotation to maximum dorsiflexion, eversion, and external rotation. A segmentation method combining graph cuts and level set was developed. In the subsequent registration step, a separate rigid body transformation for each bone was obtained by registering the neutral position dataset to each of the other ones, which produced an accurate description of the motion between them. The segmentation algorithm allowed a user to interactively delineate 14 foot bones in the neutral position volume in less than 30 min total (user and computer processing unit [CPU]) time. Registration to the seven other positions took approximately 10 additional minutes of user time and 5.25 h of CPU time. For validation, our results were compared with those obtained from 3DViewnix, a semiautomatic segmentation program. We achieved excellent agreement, with volume overlap ratios greater than 88% for all bones excluding the intermediate cuneiform and the lesser metatarsals. For the registration of the neutral scan to the seven other positions, the average overlap ratio is 94.25%, while the minimum overlap ratio is 89.49% for the tibia between the neutral position and position 1, which might be due to different fields of view (FOV). To process a single foot in eight positions, our tool requires only minimal user interaction time (less than 30 min total), a level of improvement that has the potential to make joint motion analysis from MRI practical in research and clinical applications.

Kinematic and electromyographic analyses of a karate punch

The aims of this study were: (i) to present the kinematic and electromyographic patterns of the choku-zuki punch performed by 18 experienced karatekas from the Portuguese team, and (ii) to compare it with the execution of 19 participants without any karate experience. The kinematic and electromyographic data were collected from the arm and forearm during the execution of the specific punch. A two-way analysis of variance (ANOVA) was used with significant level set at p≤0.05. We found that the kinematic and neuromuscular activity in this punch occurs within 400ms. Muscle activities and kinematic analysis presented a sequence of activation bracing a near-distal end, with the arm muscles showing greater intensity of activation than muscles in the forearm. In the skill performance, the arm, flexion and internal rotation, and the forearm extension and pronation movements were executed with smaller amplitude in the karate group. Based on the results of this study, the two groups' presented distinct kinematic and electromyographic patterns during the performance of the choku-zuki punch.

New method of measuring wrist joint position sense avoiding cutaneous and visual inputs

BACKGROUND

Aspects of afferent inputs, generally termed proprioception, are being increasingly studied. Extraneous factors such as cutaneous inputs can dramatically interfere while trying to design studies in order to determine the participation of the different structures involved in proprioception in the wrist position sense. We tried to determine validity and repeatability of a new wrist joint position measurement device using methodology designed to minimize extraneous factors and isolate muscle and joint inputs.

METHODS

In order to test the reliability of the system, eighty young-adult subjects without musculoskeletal or neurologic impairments affecting the right upper extremity were tested using a custom made motion tracking system. Testing consisted of two conditions: active reproduction of active placement and passive reproduction of passive placement. Subjects performed two repetitions of each target position (10, 20, and 30 degrees of flexion and extension) presented in a random order. Test- retest reliability was then tested.

RESULTS

The average constant error in the passive condition was -0.7 degrees +/- 4.7 degrees as compared to the active condition at 3.7 degrees +/- 5.1 degrees. Average absolute error in the passive condition was 4.9 degrees +/- 2.9 degrees compared to the active condition in which absolute error was 5.9 degrees +/- 3.5 degrees.

DISCUSSION

Test-retest repeatability in both conditions was less than the 5 degrees magnitude typical of clinical goniometry. Errors in the active condition (less than 2 degrees ) were slightly smaller than the passive condition, and the passive condition was also associated with poorer consistency between apparatus sensors and skin sensors.

CONCLUSIONS

The current system for measurement of wrist joint proprioception allows the researcher to decrease extraneous influences that may affect joint position sense awareness, and will help in future study aiming to determine precisely the role of the different structure involved in proprioception.

In vivo tests of an improved method for functional location of the subtalar joint axis

The subtalar joint is important in frontal plane movement and posture of the hindfoot. Abnormal subtalar joint moments caused by muscle forces and the ground reaction force acting on the foot are thought to play a role in various foot deformities. Calculating joint moments typically requires knowledge of the location of the joint axis; however, location of the subtalar axis from measured movement is difficult because the talus cannot be tracked using skin-mounted markers. The accuracy of a novel technique for locating the subtalar axis was assessed in vivo using magnetic resonance imaging. The method was also tested with skin-mounted markers and video motion analysis. The technique involves applying forces to the foot that cause pure subtalar joint motion (with negligible talocrural joint motion), and then using helical axis decomposition of the resulting tibiocalcaneal motion. The resulting subtalar axis estimates differed by 6 degrees on average from the true best-fit subtalar axes in the MRI tests. Motion was found to have been applied primarily about the subtalar joint with an average of only 3 degrees of talocrural joint motion. The proposed method provides a potential means for obtaining subject-specific subtalar axis estimates which can then be used in inverse dynamic analyses and subject-specific musculoskeletal models.

Estimation of the axis of a screw motion from noisy data—A new method based on Plücker lines

The problems of estimating the motion and orientation parameters of a body segment from two n point-set patterns are analyzed using the Plücker coordinates of a line (Plücker lines). The aim is to find algorithms less complex than those in conventional use, and thus facilitating more accurate computation of the unknown parameters. All conventional techniques use point transformation to calculate the screw axis. In this paper, we present a novel technique that directly estimates the axis of a screw motion as a Plücker line. The Plücker line can be transformed via the dual-number coordinate transformation matrix. This method is compared with Schwartz and Rozumalski [2005. A new method for estimating joint parameters from motion data. Journal of Biomechanics 38, 107-116] in simulations of random measurement errors and systematic skin movements. Simulation results indicate that the methods based on Plücker lines (Plücker line method) are superior in terms of extremely good results in the determination of the screw axis direction and position as well as a concise derivation of mathematical statements. This investigation yielded practical results, which can be used to locate the axis of a screw motion in a noisy environment. Developing the dual transformation matrix (DTM) from noisy data and determining the screw axis from a given DTM is done in a manner analogous to that for handling simple rotations. A more robust approach to solve for the dual vector associated with DTM is also addressed by using the eigenvector and the singular value decomposition.

Passive motion characteristics of the talocrural and the subtalar joint by dual Euler angles

The objective of this study is to validate previous descriptions of hindfoot kinematics using dual Euler angle methods in a passive cadaveric model. The dual Euler angle method was chosen so as to facilitate description of the translational and rotational movement occurring at both the ankle and subtalar joints. A non-metal experimental set-up was fabricated to generate motion in foot cadaver specimens. Three-dimensional kinematic data of the ankle joint complex was collected from ten knee-below foot cadaver specimens using a 'Flock of Birds' electromagnetic tracking device. The data correlates well with previously published kinematic descriptions of the ankle subtalar joint complex. Both the ankle and subtalar joint show 6 degree of freedom motion and multiaxial characteristics. The motions of the talocrural joint, the talocalcaneal joint, and the gross motion between the foot and the shank were analyzed. During dorsiflexion-plantarflexion the motion of the calcaneus with respect to the tibia occurs mainly at the ankle joint, with little motion at the subtalar joint. The subtalar joint contributes more than the ankle joint during inversion-eversion.

The analysis of golf swing as a kinematic chain using dual Euler angle algorithm

The manner in which anatomical rotation from an individual segment contributes to the position and velocity of the endpoint can be informative in the arena of many athletic events whose goals are to attain the maximal velocity of the most distal segment. This study presents a new method of velocity analysis using dual Euler angles and its application in studying rotational contribution from upper extremity segments to club head speed during a golf swing. Dual Euler angle describes 3D movement as a series of ordered screw motions about each orthogonal axis in a streamlined matrix form-the dual transformation matrix- and allows the translation and rotation component to be described in the same moving frame. Applying this method in biomechanics is a novel idea and the authors have previously applied the methodology to clinical studies on its use in displacement analysis. The focus of this paper is velocity analysis and applications in sports biomechanics. In this study, electrogoniometers (Biometrics, UK) with a frequency of 1000 Hz were attached to a subject during the execution of the swing to obtain the joint angles throughout the motion. The velocity of the club head was then analyzed using the dual velocity which specifies the velocity distribution of a rigid body in screw motion at any point in time as the dual vector. The contributions of each segment to the club-head velocity were also compared. In order to evaluate this method, the calculated position and velocity of the club head were compared to the values obtained from video image analysis. The results indicated that there is good agreement between calculated values and video data, suggesting the suitability of using the Dual Euler method in analyzing a kinematic chain motion.

Determining Dual Euler Angles of the Ankle Complex in vivo Using “Flock of Birds” Electromagnetic Tracking Device

The dual Euler angles method has been proposed as an alternative approach to describe the general spatial human joint motion. In this study, the dual Euler angles method was applied to study the three-dimensional motion of the ankle complex. The methodology for obtaining dual Euler angles of the ankle complex was developed by using a “Flock of Birds” electromagnetic tracking device. The repeatability of the methodology was studied based on the intertester and intratester variability analysis. Finally kinematic coupling characteristics of the ankle complex during dorsiflexion–plantarflexion, eversion–inversion, and abduction–adduction were analyzed according to the parameters of the dual Euler angles.

Analysis of passive motion characteristics of the ankle joint complex using dual Euler angle parameters

OBJECTIVE

To apply the dual Euler angles method to investigate the passive motion characteristics of the human ankle joint complex.

DESIGN

Three-dimensional kinematic data of the ankle joint complex was collected from 10 knee-below foot cadaver specimens.

BACKGROUND

Besides the Euler angles and screw axis methods, the dual Euler angles method has been proposed as an alternative approach to quantify general spatial human joint motion. The dual Euler angles method provides a way to combine rotational and translational joint motions and to interpret motions in Cartesian coordinate systems, which can avoid the problems caused by the use of the joint coordinate system due to non-orthogonality.

METHODS

A non-metal experimental setup was fabricated to generate motion in foot cadaver specimens. The kinematic data during passive dorsiflexion-plantarflexion was measured using an electromagnetic tracking device.

RESULTS

The kinematic coupling characteristics and the respective contribution of the ankle joint and the subtalar joint to the gross motion of the foot with respect to the shank were analyzed based on dual Euler angle parameters. The results obtained in this study are generally in agreement with the observations reported previously.

CONCLUSIONS

The dual Euler angles method is suitable for analyzing the motion characteristics of the ankle joint complex. The motion at the ankle joint complex involves rotations about and translations along three axes.