Between-day repeatability of knee kinematics during functional tasks recorded using flexible electrogoniometry (original) (raw)
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Journal of Musculoskeletal Research, 2013
Purpose: The increasing use of electrogoniometry (ELG) in clinical research requires the validation of different instrumentation. The purpose of this investigation was to examine the concurrent validity of an ELG system during activities of daily living. Methods: A total of 10 asymptomatic participants gave informed consent to participate. A Biometrics SG150 electrogoniometer was directly compared to a 12 camera three-dimensional motion analysis system during walking, stair ascent, stair descent, sit to stand, and stand to sit activities for the measurement of the right knee angle. Analysis of validity was undertaken by linear regression. Standard error of estimate (SEE), standardized SEE (SSEE), and Pearson's correlation coefficient r were computed for paired trials between systems for each functional activity. Results: The 95% confidence interval of SEE was reasonable between systems across walking (LCI = 2.43°; UCI = 2.91°), stair ascent (LCI = 2.09°; UCI = 2.42°), stair desc...
Variability of walking and other daily activities in patients with total knee replacement
Gait & Posture, 2009
Background: Three-dimensional motion analysis has provided important information about functional outcome for patients who have undergone total knee replacement, yet many comparisons to control populations are inconclusive. Some of these findings may be explained by variability in patients' repeated performance, however this has not been previously reported. Therefore the objective of this study was to determine the variability of repeated performance in patients who have undergone total knee replacement during walking and selected activities of daily living using three-dimensional motion analysis. Methods: The variability of kinematic and kinetic parameters over six repetitions of walking at comfortable and fast speeds, lunging, stair ascent and descent, squatting and standing up from sitting were measured using motion analysis. Variability was calculated using both the coefficient of variation, and the group average of the range of data within each subject. Findings: During level walking the within-subject difference was less than 3.28 or 0.9 Nm/kg and coefficients of variation ranged from 2% to 29%. When patients performed other activities of daily living the within-subject difference was up to 8.28 or 1.3 Nm/kg and coefficients of variation were between 0.5% and 50.5%. Interpretation: Although patients walked and performed the activities with reasonable consistency, the variability of their performance appeared to be related to the size of the group mean for each parameter. Comparison of patient groups on parameters with small mean values requires larger sample sizes to prevent intra-subject variability from obscuring differences between groups.
Gait & Posture, 2002
The functional ranges of movement of the knee were investigated in a group of patients with knee osteoarthritis (n= 42, mean age 70 years) before, 4 months and at 18-24 months after total knee arthroplasty and then compared with age matched normal subjects (n=20, mean age 67 years). Flexible electrogoniometry was used to record the maximum flexion-extension angle, the minimum flexion-extension angle and flexion-extension excursions of both knees during eleven functional activities along with the active and passive knee joint range of motion measured using a manual goniometer. Over the eleven functional activities the patients pre-operatively exhibited 28% less knee joint excursion than normal age matched subjects. By 18 -24 months following total knee arthroplasty only 2% of this deficit was recovered. Statistically this recovery was only significant in level walking, slope ascent and slope descent. A greater range of movement was measured in a non-weight bearing position than was used in weight bearing functional activity. It is concluded that total knee arthroplasty gives rise to little improvement in knee motion during functional activities and that functional range of movement of the knee remains limited when compared to normal knee function for a minimum of 18 months following operation.
Clinical Biomechanics, 2010
Background: Patients with knee osteoarthritis often feel unstable, suffering from buckling (giving way) or even falling. This study aimed at characterising such instability, and following it over time. Methods: We investigated treadmill walking in knee osteoarthritis, focusing on angular velocity of sagittal plane knee movements. Knee osteoarthritis patients were followed 1 year after replacement surgery, and were compared to healthy peers. Subjects walked at increasing speeds, and maximum speed was registered. To quantify stability, we calculated short-term (k S ) and long-term (k L ) Lyapunov exponents (the exponential rate of divergence, in state space, of trajectories originating from nearest neighbours), as well as the variability of knee movements, the latter just after heel contact. At each measurement session, patients reported how often they had fallen in the preceding period. Findings: Patients had lower maximum walking speed than controls, and walked with reduced variability, post-operatively even more so. Variability was positively related to number of falls. Pre-operatively, patients had higher k S at the unaffected side, which post-operatively normalized. Interpretation: Slow walking may serve being more cautions. Reducing variability of sagittal knee kinematics appears to reduce fall risk, perhaps involving paying more attention and/or using cocontraction. The pre-operatively higher unaffected side k S could result from attempts to reduce the kinematic demands on the affected leg, ''letting go" the unaffected leg. One year after the operation, this problem with unaffected k S had disappeared, suggesting recovery. Further study should include short-term and long-term stability, as well as a quantitative measure of perceived instability.
Journal of applied biomechanics, 2012
Results from instrumented gait analysis vary between test situations. Subject characteristics and the biomechanical model can influence the total amount of variability. The purpose of this study was to quantify reliability of gait data in general, and with respect to the applied model, and investigated population group. Reliability was compared between a functional and a predictive gait model in subjects with knee osteoarthritis and healthy controls. Day-to-day consistency for sagittal plane variables was comparable between models and population groups. Transversal plane variables relative to joint excursion showed larger inconsistency for repeated measures, even for a more sophisticated biomechanical approach. In conclusion, the presented reliability data of sagittal plane kinematics should be used for a reasonable interpretation of results derived in clinical gait analysis. Variables of the transversal plane should not be used as long as sources of error are not sufficiently minim...
PLOS ONE, 2023
Recovery of function is among a patient's main expectations when undergoing total knee arthroplasty (TKA). However, normal gait knee function is not always completely restored, which can affect patient satisfaction and quality of life. Computer-assisted surgery (CAS) allows surgeons to evaluate passive knee kinematics intra-operatively. Understanding associations between knee kinematics measured during surgery and during daily activities, such as walking, could help define criteria for success based on knee function and not only on the correct alignment of the implant or the leg. This preliminary study compared passive knee kinematics measured during surgery with active kinematics measured during walking. Eight patients underwent a treadmill gait analysis using the KneeKG™ system both before surgery and three months afterwards. Knee kinematics were measured during CAS both before and after TKA implantation. The anatomical axes of the KneeKG™ and CAS systems were homogenised using a two-level, multi-body kinematics optimisation with a kinematic chain based on the calibration measured during CAS. A Bland-Altman analysis was performed before and after TKA for adduction-abduction angle, internal-external rotation, and anterior-posterior displacement over the whole gait cycle, at the single stance phase and at the swing phase. Homogenising the anatomical axes between CAS and treadmill gait led to limited median bias and limits of agreement (post-surgery-0.6 ± 3.6 deg,-2.7 ± 3.6 deg, and-0.2 ± 2.4 mm for adduction-abduction, internal-external rotation and anterior-posterior displacement, respectively). At the individual level, correlations between the two systems were mostly weak (R 2 < 0.3) over the whole gait cycle, indicating low kinematic consistency between the two measurements. However, correlations were better at the phase level, especially the swing phase. The multiple sources of differences did not enable us to conclude whether they came from anatomical and biomechanical differences or from measurement system errors.
Test-retest and inter-rater reliability of gait measures
Gait & Posture, 2006
supine, knee extended and the angle between pelvis and trunk of 1508. The subjects were studied 1 day before and 1 day after the knee surgery in both lower limbs. Every subject has performed both exercises twice, for a total number of eight exercises. There was 1 min of pause between two successive exercises and the sequence of execution among the eight exercises has been randomised. It has been used the pocket EMG (BTS) and bipolar electrodes to record the surface electromyography. The electrodes were positioned on the rectus femoris, vastus medialis and vastus lateralis of the quadriceps. It was recorded the eventual pain during the execution of exercises using a visual analogic scale (VAS) after every exercise. Nonparametric tests were used for the statistical analysis using the SPSS software.
Physical Therapy
Following total knee arthroplasty (TKA), quadriceps femoris muscle strength (force-generating capacity) and functional test scores improve but continue to be lower than those in people without injury. Analysis of the sit-to-stand (STS) task demonstrated side-to-side differences in subjects with TKA, as well as differences between subjects with TKA and control subjects. It was hypothesized that, when using a self-selected starting position, subjects 1 year following TKA would show improvements in strength and movement patterns but would continue to show asymmetries of angles and moments at the hips and knees. Twenty-four subjects (12 subjects with unilateral TKA and 12 control subjects) were recruited; those with TKA were tested 3 months and 1 year following surgery. Motion analysis of an STS task was synchronized with 2 force platforms and electromyography. Outcome measures included joint angles and moments, electromyography, vertical ground reaction forces, muscle strength, and fun...