Inter-trial and test-retest reliability of kinematic and kinetic gait parameters among subjects with adolescent idiopathic scoliosis

Gait analysis: An effective tool to mechanically monitor the bone regeneration of critical-sized defects in tissue engineering applications

INTRODUCTION

Tissue engineering has emerged as an innovative approach to treat critical-size bone defects using biocompatible scaffolds, thus avoiding complex distraction surgeries or limited stock grafts. Continuous regeneration monitoring is essential in critical-size cases due to the frequent appearance of non-unions. This work evaluates the potential clinical use of gait analysis for the mechanical assessment of a tissue engineering regeneration as an alternative to the traditional and hardly conclusive manual or radiological follow-up.

MATERIALS AND METHODS

The 15-mm metatarsal fragment of eight female merino sheep was surgically replaced by a bioceramic scaffold stabilized with an external fixator. Gait tests were performed weekly by making the sheep walk on an instrumented gangway. The evolution of different kinematic and dynamic parameters was analyzed for all the animal's limbs, as well as asymmetries between limbs. Finally, potential correlation in the recovery of the gait parameters was evaluated through the linear regression models.

RESULTS

After surgery, the operated limb has an altered way of carrying body weight while walking. Its loading capacity was significantly reduced as the stance phases were shorter and less impulsive. The non-operated limbs compensated for this mobility deficit. All parameters were normalizing during the consolidation phase while the bone callus was simultaneously mineralizing. The results also showed high levels of asymmetry between the operated limb and its contralateral, which exceeded 150% when analyzing the impulse after surgery. Gait recovery significantly correlated between symmetrical limbs.

CONCLUSIONS

Gait analysis was presented as an effective, low-cost tool capable of mechanically predicting the regeneration of critical-size defects treated by tissue engineering, as comparing regeneration processes or novel scaffolds. Despite the progressive normalization as the callus mineralized, the bearing capacity reduction and the asymmetry of the operated limb were more significant than in other orthopedic alternatives.

Hip loading asymmetry in Lenke type 1 idiopathic scoliosis: Effect of spinal fusion and sex

BACKGROUND

Thoracic curvatures are most common in patients with idiopathic scoliosis. The literature highlights an imbalance of hip joint moments in the frontal plane quantified with a symmetry index. Spinal arthrodesis can reduce this symmetry index which then tends towards 0. Furthermore, asymptomatic women present lower hip moment in the frontal plane than asymptomatic men. This difference could influence the symmetry index in the case of patients with idiopathic scoliosis. Therefore, the main objective of this study was to show a significant positive effect of spinal arthrodesis on the symmetry index. The secondary objective was to compare the symmetry index between sexes before spinal fusion.

METHOD

The retrospective study included 20 patients with Type-1 Lenke curve idiopathic scoliosis, who performed a gait analysis before and one year after spinal fusion. The gait analysis consisted of walking back and forth at spontaneous speed.

FINDINGS

While significantly lower curvatures were depicted, the symmetry index showed a significantly lower value after spinal fusion (p < 0.03). The symmetry index showed no significant difference between sexes (p > 0.05).

INTERPRETATION

The study shows the effect of surgical fusion on the symmetry index, although the latter remains significant compared to the norm. Literature reveals that spinal fusion tends to the symmetrisation of the body's center of mass and increases ranges of motion on the trunk and pelvis. This could favour symmetry of hip moment in the frontal plane. Future research should investigate other Type Lenke curves before and after surgery, and the effect of braces on this symmetry index.

The effect of prosthetic alignment on the stump temperature and ground reaction forces during gait in transfemoral amputees

BACKGROUND

Lower limb prosthetic alignment is a procedure mostly subjective. A prosthetic misaligned induces gait deviations and long-term joint diseases. The alignment effects for each lower limb and the stump stays uncertain.

RESEARCH OBJECTIVE

To identify the effect of the transfemoral alignment prosthesis on ground reaction forces and thermal images of the residual limb.

METHODS

The effect of misalignment and nominal alignment was evaluated in sixteen transfemoral amputees. The nominal alignment was considered as the optimal alignment for each subject. Misalignment included random variations in the anterior-posterior and medial-lateral translation of the prosthetic foot and the angle of flexion-extension, abduction-adduction, and internal-external rotation of the socket and prosthetic foot. The control group consisted of fifteen non-amputee individuals. The ground reaction force parameters and stump temperature were analyzed for each alignment condition. The statistical analysis included the one-way ANOVA, Kruskal-Wallis, and multiple comparison tests.

RESULTS

The prosthesis did not produce statistically significant changes in the average temperature of residual limbs. However, the temperature distribution on the stump skin was different (P < 0.05). The transfemoral prosthesis misalignment produced an irregular heat diffusion on the anterior, posterior, and lateral sides of the stump contour compared to the nominal alignment (P < 0.05). The sound limb did not show differences between nominal alignments and misalignments for most ground reaction force parameters. For almost all GRF parameters, significant differences were observed for the prosthetic limb between misalignment and nominal alignment (P < 0.001). The symmetry indices of ground reaction force parameters of transfemoral amputees did not show any kind of significant improvements after aligning the prosthesis nominally.

SIGNIFICANCE

The stump's temperature distribution and the ground reaction force findings for the prosthetic limb provide a better understanding of the alignment procedure of the transfemoral prosthesis and improve the amputees' compliance to the prosthesis.

Effect of preferred walking speed on the upper body range of motion and mechanical work during gait before and after spinal fusion for patients with idiopathic scoliosis

BACKGROUND

Scoliosis may have an effect on gait parameters, the kinematics of the lower limbs and the spine, and mechanical work with specific gait speed. Imposed gait speed may influence these effects. Following spinal fusion in the case of idiopathic scoliosis, patients fear subsequent and considerable back stiffness and kinetic consequences. The aim of this retrospective study was to evaluate the upper body range of motion and mechanical work before and after spinal fusion in of free gait speed conditions.

METHODS

Twenty-two patients with idiopathic scoliosis and twenty-two asymptomatic controls were included. Patients were analyzed before and one year after spinal fusion. Based on full body modeling and motion capture, we measured gait speed, cadence, stride length, the mobility of the upper and lower spinal segments (in each plane), and mechanical work (with and without dimensionless scaling strategy).

FINDINGS

Patients walked significantly slower than controls. The same speed was noticed before and after fusion. Only the lower back kinematics in the frontal plane was reduced before fusion. Spinal fusion further reduced the mobility of the pelvis segment in the sagittal plane in comparison to controls. Scaling external work was associated with higher values for patients.

INTERPRETATION

Spinal fusion improves pelvic and thorax-pelvis mobility (during the stance phase) in the frontal plane. The impact of scoliosis on the upper body range of motion was limited on the thorax-pelvis, corresponding to a stiffening effect. With such restrictions, an increase in normalized external work was observed for similar normalized internal work.

Reproducibility of gait kinematics and kinetics in chronic stroke patients

BACKGROUND

The search for reliable techniques to assess gait in stroke patients is crucial for the design and follow-up of rehabilitation programs.

OBJECTIVE

To assess the reproducibility of kinematic and kinetic gait parameters in chronic stroke patients using a three-dimensional gait analysis system.

METHODS

Ten chronic stroke patients were assessed while walking along a 20 m walkway at their natural speed, using a gait analysis system of six infrared cameras and two force plates. Each patient performed 10 gait trials on 2 separate days. Inter-measurement agreement was assessed with the Coefficient of Multiple Correlation, while Root Mean Square Differences were used to quantify the variability of the trials.

RESULTS

The majority of kinetics and kinematics showed excellent reproducibility in all patients. Joints' power seemed to be more reliable compared with joints' angle and moment. Most parameters presented greater variability in non-paretic than the paretic leg, while they were less variable in the sagittal compared with the non-sagittal planes. Less than 10 trials were sufficient to obtain excellent reproducibility for most kinematic and kinetic parameters.

CONCLUSIONS

The reproducibility of movement assessment through three-dimensional gait analysis appears excellent in chronic stroke patients.

Assessment of stability during gait in patients with spinal deformity-A preliminary analysis using the dynamic stability margin

Daily living activities are dynamic, requiring spinal motion through space. Current assessment of spinal deformities is based on static measurements from full-spine standing radiographs. Tools to assess dynamic stability during gait might be useful to enhance the standard evaluation. The aim of this study was to evaluate gait dynamic imbalance in patients with spinal deformity using the dynamic stability margin (DSM). Twelve normal subjects and 17 patients with spinal deformity were prospectively recruited. A kinematic 3D gait analysis was performed for the control group (CG) and the spinal deformity group (SDG). The DSM (distance between the extrapolated center of mass and the base of support) and time-distance parameters were calculated for the right and left side during gait. The relationship between DSM and step length was assessed using three variables: gait stability, symmetry, and consistency. Variables' accuracy was validated by a discriminant analysis. Patients with spinal deformity exhibited gait instability according to the DSM (0.25m versus 0.31m) with decreased velocity (1.1ms^-1 versus 1.3ms^-1) and decreased step length (0.32m versus 0.38m). According to the discriminant analysis, gait stability was the more accurate variable (area under the curve AUC=0.98) followed by gait symmetry and consistency. However, gait consistency showed 100% of specificity, sensitivity, and accuracy of precision. The DSM showed that patients with spinal malalignment exhibit decreased gait stability, symmetry, and consistency besides gait time-distance parameter changes. Additional work is required to determine how to apply the DSM for preoperative and postoperative spinal deformity management.

Lower Limb Loading during Gait in Patients Long Period after Total Hip Arthroplasty Revision

The aim of the study was to assess lower limb loading during walking after unilateral total hip arthroplasty (THA) revision. Twenty-three THA revision subjects (12 men, 11 women) were divided into three groups according to time since surgery as 1 to 6 years, 6 to 11 years, and over 11 years. Two force plates were used to measure the ground reaction force during the stance phase. On the operated limb, compared to nonoperated limb, we found lower first vertical peak in the group of 1 to 6 years after revision and lower propulsion peak in the group of 6 to 11 years since revision. In the group of 11 years since THA revision, no significant difference was found. With advancing years after surgery, the stance phase duration got reduced and propulsion peak increased in the operated limb; minimal vertical force decreased and the time of minimal vertical force increased in the nonoperated limb. The study findings suggest the tendency to a more gradual and safer weight acceptance on the operated limb during the first years after THA revision, followed by limitation of foot propulsion. Despite this fact, lower limb loading can be considered as symmetrical across the whole measured period.

Reliability of ground reaction forces in the aquatic environment

The aim of this study was to verify the reliability of the kinetic parameters of gait using an underwater force platform. A total of 49 healthy participants with a median age of 21years were included. The kinetic gait data were collected using a 0.6×0.6×0.1m aquatic force plate (Bertec®), set in a pool (15×13×1.30m) with a water depth of 1.20m and water temperature of 32.5°C. Participants walked 10m before reaching the platform, which was fixed to the ground. Participants were instructed to step onto the platform with their preferred limb and data from three valid attempts were used to calculate the average values. A 48-h interval between tests was used for the test-retest reliability. Data were analyzed using interclass correlation coefficients (ICC) and results demonstrated that reliability ranged from poor to excellent, with ICC scores of between 0.24 and 0.87 and mean differences between (d¯)=-0.01 and 0.002. The highest reliability values were found for the vertical (Fz) and the lowest for the mediolateral components (Fy). In conclusion, the force platform is reliable for assessing the vertical and anteroposterior components of power production rates in water, however, caution should be applied when using this instrument to evaluate the mediolateral component in this environment.

The gait standard deviation, a single measure of kinematic variability

Measurement of gait kinematic variability provides relevant clinical information in certain conditions affecting the neuromotor control of movement. In this article, we present a measure of overall gait kinematic variability, GaitSD, based on combination of waveforms' standard deviation. The waveform standard deviation is the common numerator in established indices of variability such as Kadaba's coefficient of multiple correlation or Winter's waveform coefficient of variation. Gait data were collected on typically developing children aged 6-17 years. Large number of strides was captured for each child, average 45 (SD: 11) for kinematics and 19 (SD: 5) for kinetics. We used a bootstrap procedure to determine the precision of GaitSD as a function of the number of strides processed. We compared the within-subject, stride-to-stride, variability with the, between-subject, variability of the normative pattern. Finally, we investigated the correlation between age and gait kinematic, kinetic and spatio-temporal variability. In typically developing children, the relative precision of GaitSD was 10% as soon as 6 strides were captured. As a comparison, spatio-temporal parameters required 30 strides to reach the same relative precision. The ratio stride-to-stride divided by normative pattern variability was smaller in kinematic variables (the smallest for pelvic tilt, 28%) than in kinetic and spatio-temporal variables (the largest for normalised stride length, 95%). GaitSD had a strong, negative correlation with age. We show that gait consistency may stabilise only at, or after, skeletal maturity.

Dynamic balance assessment during gait in spinal pathologies - a literature review

The role of the spine as a gait stabilizer is essential. Dynamic assessment, while walking, might provide complementary data to improve spinal deformity management. The aim of this paper was to review spine dynamic behavior and the various methods that have been used to assess gait dynamic balance in order to explore the consequences of spinal deformities while walking. A review was performed by obtaining publications from five electronic databases. All papers reporting pathological or non-pathological spine dynamic behavior during gait and dynamic balance assessment methods were included. Sixty articles were selected. Results varied widely according to pathologies, study conditions, and balance assessment techniques. Three methods assessing dynamic stability during gait were identified: local-orbital dynamic stability, tri-axial accelerometry, and dynamic stability margin. Data from conventional gait analysis techniques were established essentially for scoliosis and low back pain, but they do not assess specific consequences on gait dynamic balance. Three techniques investigate gait dynamic balance and have been validated in normal subjects. Further investigations need to be performed for validation in spinal pathologies as well as the value for clinical practice.

LEVEL OF EVIDENCE

Level IV.

Repeatability of kinematic, kinetic, and electromyographic data in normal adult gait

The repeatability of gait variables is an important consideration in the clinical use of results of quantitative gait analysis. Statistical measures were used to evaluate repeatability of kinematic, kinetic, and electromyographic data waveforms and spatiotemporal parameters of 40 normal subjects. Subjects were evaluated three times on each test day and on three different test days while walking at their preferred or natural speed. Intrasubject repeatability was excellent for kinematic data in the sagittal plane both within a test day as well as between test days. For joint angle motion in the frontal and transverse planes, the repeatability was good within a test day and poor between test days. Poor between-day repeatability of joint angle motion in the frontal and transverse planes was noted to be partly due to variabilities in the alignment of markers. Vertical reaction and fore-aft shear forces were more repeatable than the mediolateral shear force. Sagittal plane joint moments were more repeatable than frontal or transverse plane moments. For electromyographic data, repeatability within a day was slightly better than between test days. In general, the results demonstrate that with the subjects walking at their natural or preferred speed, the gait variables are quite repeatable. These observations suggest that it may be reasonable to base significant clinical decisions on the results of a single gait evaluation.

Learning effect on the dynamical strategies in sitting position on seesaw motion for idiopathic scoliosis patients

Our study meant to determine, for idiopathic scoliosis patients, the biomechanical processes involved in postural regulation when self-imposed disturbances occur in seated position in both directions during successive trials. 12 female adolescents with right thoracic scoliosis (SG) and 15 control adolescents (CG) were included in this study. Ground reaction forces were studied using a force platform while the subjects were maintaining their balance in sitting position on a seesaw. Every test is recorded with eyes opened, arms on shoulders and legs free. The force platform data (AP and ML forces data) obtained were processed to determine the following normalized force parameters: delta value (difference between maxima and minima), maximal and minimal force values (peak and occurrence), and the variability of AP and ML forces. We used a variance analysis (ANOVA test) to analyze and compare 3 trials and groups. Our results show that, whatever the directions of destabilization (AP versus ML), SG was always in a learning situation. Indeed, the first test is always less stable than the second and third trials. However, for CG, adaptability between the tests is only highlighted during ML imbalance. Significant differences of strategies between the groups are only visible for the AP force component. For all conditions imposed, scoliotic patients perform specific trunk balance strategies. Clinical tests and rehabilitation methods should include the learning effect within the spatio-temporal adaptation to ground reaction forces.

Loading rate patterns in scoliotic children during gait: the impact of the schoolbag carriage and the importance of its position

PURPOSE

Concerns have been raised regarding the effects of schoolbag carriage on adolescent schoolchildren and particularly those with a pre-existing spinal deformity. The purpose of this study was to determine the effect of school backpack loads in scoliotic and healthy school-age children during walking, in terms of peak vertical ground reaction forces and loading rates. We hypothesized that walking with a loaded backpack would have a greater effect on gait kinetics of scoliotic compared to healthy.

METHODS

Eight children with idiopathic scoliosis and eight healthy children were assessed. Kinetic data were collected using two AMTI OR6-7 force-plates, while the subjects walked freely along a 6-m walkway under three walking conditions: (1) without a schoolbag, (2) carrying a schoolbag bilaterally (over both shoulders-symmetrical load) and (3) carrying a schoolbag unilaterally (over each shoulder-asymmetrical load). Kinetic data were collected and four parameters were calculated; peak ground reaction force at the first maximum force peak (F1), time needed to reach F1 (T1), loading rate of F1 (LRF1) and total contact time (T2).

RESULTS

We found no significant differences between the scoliotic and healthy children for any of the kinetic variables examined. In addition, the position of the bag did not seem to have any effect on loading rate.

CONCLUSIONS

The results of this study indicate that in terms of kinetic parameters during normal gait, the schoolbag load (symmetrical or asymmetrical) does not have a different effect on children with mild adolescent idiopathic scoliosis compared to normal controls.

Reliability of instrumented movement analysis as outcome measure in Charcot-Marie-Tooth disease: results from a multitask locomotor protocol

Some neurodegenerative diseases at early stage may not drastically affect basic gait ability, whereas more demanding locomotor tasks are more prone to disease-induced abnormalities. In this study, we evaluated the interday test-retest reliability, 4-6 weeks apart, of instrumented movement analysis on a group of 20 subjects with Charcot-Marie-Tooth (CMT) disease considering a set of kinematic and kinetic curves and related parameters obtained during natural walking (NW) and faster walking, heel and toe-walking, step ascending and descending. Results showed that the reliability was good for NW, with the exception of trunk curves, pelvic tilt and EMG profiles (moderate reliability), and trunk ROM in sagittal/transverse plane (poor reliability). Comparing our results with literature, CMT patients did not present a greater variability during NW than healthy subjects or patients with diseases of CNS. Additional locomotor tasks showed a slight reduction of reliability, although the moderate-to-good level shown in NW was almost never reduced to poor. Most of SEM values (absolute measurement errors) were smaller than 5°, a clinically acceptable threshold. In particular THS, an ankle joint related parameter computed across heel and toe-walking tasks, showed an optimal reliability (ICC=0.95, SEM=2.7°) and correlation with CMT clinical scores. Toe and heel-walking and step ascending tasks maximised the number of parameters with a moderate-to-good correlation with patients' clinical status. We concluded that, in addition to natural walking, more challenging locomotor tasks are good candidates to provide reliable and sensitive outcome measures for CMT patients.

Intertrial and test-retest reliabilities of Timed Bridge tests among frail older adults

The objective of this study was to assess the reliability of three versions of the Timed Bridge test (TB test) using the generalizability theory. A convenience sample of 30 frail older adults, from 65 to 94 years of age, performed three different TB Tests: 1) hold test (TB-Static); 2) five-repetitions dynamic test (TB-5rep); and 3) 60-second dynamic test (TB-60s). The tests were repeated twice on two occasions separated by a 48-hour interval. For each trial, the height of the bridge, the time of execution or the number of repetitions, the pain, and perceived effort were recorded. The intertrial and test-retest reliability for bridge heights were excellent. For the duration and the number of repetitions, a good intertrial reliability was found (0.83 <Phi< 0.94; SEMs 11.1 s, 2.9 s, and 4.2 rep), and the test-retest reliability was good for the TB-60 s and moderate for TB-Static and for the TB-5rep. The different tests were generally well tolerated by the subjects. The level of exertion perceived by the participants was light for the TB-5rep and moderate for the TB-Static and TB-60 s. The TB tests were simple to execute, showed good clinical applicability, and provided reliable measurements in a geriatric population.