The Gait Deviation Index: a new comprehensive index of gait pathology

Walking Speed of Children and Adolescents With Cerebral Palsy: Laboratory Versus Daily Life

The purpose of this pilot study was to compare walking speed, an important component of gait, in the laboratory and daily life, in young individuals with cerebral palsy (CP) and with typical development (TD), and to quantify to what extent gait observed in clinical settings compares to gait in real life. Fifteen children, adolescents and young adults with CP (6 GMFCS I, 2 GMFCS II, and 7 GMFCS III) and 14 with TD were included. They wore 4 synchronized inertial sensors on their shanks and thighs while walking at their spontaneous self-selected speed in the laboratory, and then during 2 week-days and 1 weekend day in their daily environment. Walking speed was computed from shank angular velocity signals using a validated algorithm. The median of the speed distributions in the laboratory and daily life were compared at the group and individual levels using Wilcoxon tests and Spearman's correlation coefficients. The corresponding percentile of daily life speed equivalent to the speed in the laboratory was computed and observed at the group level. Daily-life walking speed was significantly lower compared to the laboratory for the CP group (0.91 [0.58-1.23] m/s vs 1.07 [0.73-1.28] m/s, p = 0.015), but not for TD (1.29 [1.24-1.40] m/s vs 1.29 [1.20-1.40] m/s, p = 0.715). Median speeds correlated highly in CP (p < 0.001, rho = 0.89), but not in TD. In children with CP, 60% of the daily life walking activity was at a slower speed than in-laboratory (corresponding percentile = 60). On the contrary, almost 60% of the daily life activity of TD was at a faster speed than in-laboratory (corresponding percentile = 42.5). Nevertheless, highly heterogeneous behaviors were observed within both populations and within subgroups of GMFCS level. At the group level, children with CP tend to under-perform during natural walking as compared to walking in a clinical environment. The heterogeneous behaviors at the individual level indicate that real-life gait performance cannot be directly inferred from in-laboratory capacity. This emphasizes the importance of completing clinical gait analysis with data from daily life, to better understand the overall function of children with CP.

Kinematic gait asymmetry assessment using joint angle data in patients with chronic stroke-A normalized cross-correlation approach

BACKGROUND

Gait asymmetry is an important characteristic often studied in stroke patients. Several methods have been used to define gait asymmetry using joint angles. However, these methods may require normative data from healthy individuals as reference points. This study used normalized cross-correlation (CC_norm) to define kinematic gait asymmetry in individuals after stroke and investigated the usefulness of this assessment.

RESEARCH QUESTION

Is the analysis of kinematic gait asymmetry based on joint angle data using CC_norm useful for gait assessment in patients with chronic stroke?

METHODS

The study involved 12 patients with chronic stroke. A motion analysis system was used to record gait speed, hip joint angles, knee joint angles, ankle joint angles, stance time, and swing time. The CC_norm was calculated using the flexion-extension joint angles of hip, knee, and ankle in the sagittal plane to assess the degree of kinematic gait asymmetry. The symmetry ratio (SR) was calculated using stance and swing times to assess the degree of temporal gait asymmetry. Clinical outcomes were measured using the Fugl-Meyer Assessment for the lower extremity (FMA-LE), Berg Balance Scale (BBS), and Functional Independence Measure (FIM).

RESULTS

Hip CC_norm was correlated with SR_swing (r=-0.612, p < 0.05). Knee CC_norm was correlated with SR_stance (r = 0.807, p < 0.01), SR_swing (r=-0.752, p < 0.05), gait speed (r = 0.654, p < 0.05), BBS (r = 0.717, p < 0.01), and FIM (r = 0.735, p < 0.01).

SIGNIFICANCE

Hip and knee joint CC_norm appear to be useful tools for the assessment of gait asymmetry in stroke patients. In addition, kinematic gait asymmetry of the knee joint could reflect physical function, balance, and activities of daily living. These findings underline the importance of using kinematic gait asymmetry assessment in chronic stroke patients.

Factors affecting GDI improvement after single event multilevel surgery in patients with cerebral palsy

BACKGROUND

Pathologic gait is common in patients with cerebral palsy (CP). Single-event multilevel surgery (SEMLS) is a combination of surgical procedures to improve pathologic gait in patients with CP. However, the effect of each procedure is difficult to predict. The gait deviation index (GDI) is useful in comparing pre- and postoperative improvement.

RESEARCH QUESTION

In this study, we evaluated the degree of GDI improvement in patients with CP and analyzed factors related to surgical outcomes.

METHODS

We screened patients seen between May 2003 and December 2019 via a clinical data warehouse to identify those with CP who had been followed up for >1 year and who had undergone SEMLS. The inclusion criteria were (1) CP patients with GMFCS levels I, II and III, (2) patients who underwent SEMLS, (3) and patients who underwent 3D gait analyses preoperatively and at least 1 year postoperatively. A linear mixed model was used to model GDI improvement, assess effects of covariates, and examine factors that contributed to improvement.

RESULTS

Overall, 544 patients were included. The average improvement in overall GDI was 8.9 ± 12.3, 9.6 ± 12.0, and 6.4 ± 8.6 in Gross Motor Function Classification System (GMFCS) levels I, II, and III, respectively. In GMFCS level II patients, GDI improvement decreased by 0.26 points with a 1-year delay in surgery (p = 0.0022). Within each group of GMFCS levels, femoral derotation osteotomy (FDO) was a significant factor in GDI improvement in GMFCS levels I and II. Rectus femoris transfer (RFT) and supracondylar extension osteotomy (SCO) were significant factors in GMFCS level II. No single procedure was shown to affect improvement in GMFCS level III.

SIGNIFICANCE

Postoperative GDI improved in all levels of GMFCS. Particular procedures especially affected postoperative improvement in GDI in levels I and II. Our data do not mean to set an indication for particular procedures; however, in GMFCS levels I, II patients, particular procedures, such as FDO, yielded a greater GDI improvement in our data set.

Improved Clinical and Functional Outcomes in Crouch Gait Following Minimally Invasive Hamstring Lengthening and Serial Casting in Children With Cerebral Palsy

BACKGROUND

Serial extension casting represents a novel solution for addressing residual knee flexion contractures following hamstring lengthening in children with cerebral palsy. The purpose of this study was to investigate postoperative changes in patients following hamstring lengthening with a serial casting protocol.

METHODS

Measures from preoperative and postoperative gait analyses were reviewed retrospectively for 19 patients with cerebral palsy who underwent hamstring lengthening followed by serial extension casting. Postoperative changes in clinical, functional, and kinematic parameters were assessed using paired parametric methods.

RESULTS

Improvements were measured in popliteal angle, knee contracture, peak stance phase knee extension, sagittal plane range of motion of the knee during walking, Gait Deviation Index, and pediatric outcomes data collection instrument Global score. Nearly 80% of the cohort (15/19 patients) demonstrated a significant or moderate response to the intervention, whereas 20% demonstrated no improvement. Of note, significantly increased anterior pelvic tilt was also observed.

CONCLUSIONS

Hamstring lengthening combined with a serial casting protocol was associated with significant postoperative improvements in a range of clinical (eg, knee contracture), functional (eg, pediatric outcomes data collection instrument Global), and kinematic (eg, knee extension in stance) parameters. Improvements following this minimally invasive surgery were comparable to outcomes from procedures with higher complication rates.

LEVEL OF EVIDENCE

This is a Level III Therapeutic Study (retrospective study investigating the results of a treatment).

Early Mobilization Rehabilitation Program for Children With Cerebral Palsy Undergoing Single-Event Multilevel Surgery

PURPOSE

This study investigates functional and technical outcomes to support an early mobilization approach to rehabilitation after single-event multilevel surgery (SEMLS) for children with cerebral palsy (CP), and disseminates innovative guidelines emphasizing early walking.

METHODS

Twenty-three participants with spastic diplegic CP ages 7 through 17 years, Gross Motor Function Classification System levels I to III, who underwent an early mobilization program after SEMLS were reviewed. Outcomes were examined from motion analysis data and clinical documentation.

RESULTS

All participants were able to return to school walking at discharge. At 1-year postoperatively, participants had returned to their prior walking level or better. Change in Gait Deviation Index and Pediatric Outcomes Data Collection Instrument indicated improvements in functional mobility and gait consistent with or greater than the literature.

CONCLUSION

This intensive early mobilization program restores participation in daily activities, walking, and school within the first month postoperatively.

Canonical correlation between body-posture deviations and gait disorders in children with cerebral palsy

Children with Cerebral Palsy (CP) show the postural constraints while standing, and gait disorders, resulting from both primary and secondary impairments of brain injury. In our previous studies, several characteristic postural and gait patterns in children with unilateral as well as with bilateral CP were defined, and the relationship between these patterns was demonstrated. The purpose of present study was to identify which features of body posture deviation during standing were strongly related to gait deviations in independently ambulatory children with CP. For this aim we explored the cross-relationship between features of body posture while standing examined by surface topography and the selected gait parameters from three-dimensional instrumented gait analysis in one hundred twenty children with cerebral palsy, aged between 7 and 13 years, who were able to walk independently. First, our study documented that that sagittal misalignment of the spine curvature was significantly related to kinematic deviations such as deviations of pelvic tilt, inadequate swing phase and knee flexion, and peak dorsiflexion in stance. Second, the study shows that the static asymmetry of pelvis and trunk was significantly associated with kinematic deviations during gait cycle such as pelvic rotation, hip abduction in swing, ROM of knee flexion, peak dorsiflexion in stance. Based on obtained results and referring to our previous findings it can be assumed that the first model of the relationship between postural deviation and gait disturbances, called 'postural and gait complex of disorders in sagittal plane', is related to children with bilateral CP, whereas the second model 'postural and gait complex of disorders in coronal plane' to children with unilateral CP. The clinical applications of this study relate to the early recognition of particular features of postural deviation using surface topography, instead of more difficult and demanding expensive tools 3-D gait analysis.

Pre-operative gastrocnemius lengths in gait predict outcomes following gastrocnemius lengthening surgery in children with cerebral palsy

Equinus deformity is one of the most common gait deformities in children with cerebral palsy. We examined whether estimates of gastrocnemius length in gait could identify limbs likely to have short-term and long-term improvements in ankle kinematics following gastrocnemius lengthening surgery to correct equinus. We retrospectively analyzed data of 891 limbs that underwent a single-event multi-level surgery (SEMLS), and categorized outcomes based on the normalcy of ankle kinematics. Limbs with short gastrocnemius lengths that received a gastrocnemius lengthening surgery as part of a SEMLS (case limbs) were 2.2 times more likely than overtreated limbs (i.e., limbs who did not have short lengths, but still received a lengthening surgery) to have a good surgical outcome at the follow-up gait visit (good outcome rate of 71% vs. 33%). Case limbs were 1.2 times more likely than control limbs (i.e., limbs that had short gastrocnemius lengths but no lengthening surgery) to have a good outcome (71% vs. 59%). Three-fourths of the case limbs with a good outcome at the follow-up gait visit maintained this outcome over time, compared to only one-half of the overtreated limbs. Our results caution against over-prescription of gastrocnemius lengthening surgery and suggest gastrocnemius lengths can be used to identify good surgical candidates.

An Unsupervised Data-Driven Model to Classify Gait Patterns in Children with Cerebral Palsy

Ankle and foot orthoses are commonly prescribed to children with cerebral palsy (CP). It is unclear whether 3D gait analysis (3DGA) provides sufficient and reliable information for clinicians to be consistent when prescribing orthoses. Data-driven modeling can probe such questions by revealing non-intuitive relationships between variables such as 3DGA parameters and gait outcomes of orthoses use. The purpose of this study was to (1) develop a data-driven model to classify children with CP according to their gait biomechanics and (2) identify relationships between orthotics types and gait patterns. 3DGA data were acquired from walking trials of 25 typically developed children and 98 children with CP with additional prescribed orthoses. An unsupervised self-organizing map followed by k-means clustering was developed to group different gait patterns based on children's 3DGA. Model inputs were gait variable scores (GVSs) extracted from the gait profile score, measuring root mean square differences from TD children's gait cycle. The model identified five pathological gait patterns with statistical differences in GVSs. Only 43% of children improved their gait pattern when wearing an orthosis. Orthotics prescriptions were variable even in children with similar gait patterns. This study suggests that quantitative data-driven approaches may provide more clarity and specificity to support orthotics prescription.

Effectiveness of treadmill training on gait function in children with cerebral palsy: meta-analysis

The purpose of this review was to analysis the effects of treadmill training on gait function in children with cerebral palsy. Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane Central Register of Controlled Trials, Physiotherapy Evidence Database (PEDro), PubMed and Web of Science were searched. Investigating the effects of treadmill training on gait endurance, gait speed, limb support time, cadence, and step length in children with cerebral palsy. Similar outcomes were pooled by calculating the standardized mean difference. Of the eight studies, 179 participants were included. The average PEDro score was 6.25/10. The results of the sensitivity test for bias evaluation using the duval and tweedie's trim and fill method showed low publication bias. The test regarding the effect of treadmill training on overall gait function yielded a moderate effect size of 0.53, which was a statistically significant effect as its confidence interval did not include. The overall effect size of gait endurance was 0.85. The overall effect size of gait speed and limb support time were 0.52 and 0.73. The overall effect size of cadence and step length were 0.14 and 0.21, indicating a nonsignificant improvement. These findings suggested that treadmill training on cerebral palsy was effective for gait endurance, gait speed and limb support time than cadence and step length.

Comparison of gait characteristics between clinical and daily life settings in children with cerebral palsy

Gait assessments in standardized settings, as part of the clinical follow-up of children with cerebral palsy (CP), may not represent gait in daily life. This study aimed at comparing gait characteristics in laboratory and real life settings on the basis of multiple parameters in children with CP and with typical development (TD). Fifteen children with CP and 14 with TD wore 5 inertial sensors (chest, thighs and shanks) during in-laboratory gait assessments and during 3 days of daily life. Sixteen parameters belonging to 8 distinct domains were computed from the angular velocities and/or accelerations. Each parameter measured in the laboratory was compared to the same parameter measured in daily life for walking bouts defined by a travelled distance similar to the laboratory, using Wilcoxon paired tests and Spearman’s correlations. Most gait characteristics differed between both environments in both groups. Numerous high correlations were found between laboratory and daily life gait parameters for the CP group, whereas fewer correlations were found in the TD group. These results demonstrated that children with CP perform better in clinical settings. Such quantitative evidence may enhance clinicians’ understanding of the gap between capacity and performance in children with CP and improve their decision-making.

Endoscopic Transverse Gastrocsoleus Recession in Children With Cerebral Palsy

Aim: The aim of this study was to evaluate the surgical outcome, in terms of gait improvement, of endoscopic transverse Vulpius gastrocsoleus recession in children with cerebral palsy compared to the traditional open surgery. Methods: Twenty-seven children with cerebral palsy who had undergone endoscopic transverse Vulpius gastrocsoleus recession were reviewed. For the comparison of gait improvement, independent ambulatory spastic diplegic patients who had undergone only endoscopic transverse Vulpius gastrocsoleus recession on both legs were selected. Seven (14 legs) children were included and the median age was 7 years (6-9 years). Seven age-matched patients with the same inclusion/exclusion criteria who underwent open surgery were selected as the control group. Physical examination and gait parameters were evaluated and compared between groups, including the gait deviation index (GDI), and gait profile score (GPS). Results: There was no significant complication in twenty-seven children after endoscopic transverse Vulpius gastrocsoleus recession. However, one patient required a revision open surgery at postoperative 1 year 9 months due to the recurrence of equinus and the incomplete division of the midline raphe which was noted during surgery. When comparing gait improvements, there were no differences between the endoscopic and open surgery groups in ankle dorsiflexion angle, ankle kinetics, GDI, and GPS. The postoperative peak ankle dorsiflexion during stance phase was slightly higher in the open group. Conclusion: This is the first study that evaluates gait improvement exclusively for children with spastic diplegia after endoscopic transverse Vulpius gastrocsoleus recession. The gait improvements after endoscopic surgery were comparable to the open surgery, however, the possibility of reduced improvement in ankle kinematics should be considered.

Use of Wearable Sensor Technology in Gait, Balance, and Range of Motion Analysis

More than 8.6 million people suffer from neurological disorders that affect their gait and balance. Physical therapists provide interventions to improve patient’s functional outcomes, yet balance and gait are often evaluated in a subjective and observational manner. The use of quantitative methods allows for assessment and tracking of patient progress during and after rehabilitation or for early diagnosis of movement disorders. This paper surveys the state-of-the-art in wearable sensor technology in gait, balance, and range of motion research. It serves as a point of reference for future research, describing current solutions and challenges in the field. A two-level taxonomy of rehabilitation assessment is introduced with evaluation metrics and common algorithms utilized in wearable sensor systems.

The nature and extent of upper limb associated reactions during walking in people with acquired brain injury

BACKGROUND

Upper limb associated reactions (ARs) are common in people with acquired brain injury (ABI). Despite this, there is no gold-standard outcome measure and no kinematic description of this movement disorder. The aim of this study was to determine the upper limb kinematic variables most frequently affected by ARs in people with ABI compared with a healthy cohort at matched walking speed intention.

METHODS

A convenience sample of 36 healthy control adults (HCs) and 42 people with ABI who had upper limb ARs during walking were recruited and underwent assessment of their self-selected walking speed using the criterion-reference three dimensional motion analysis (3DMA) at Epworth Hospital, Melbourne. Shoulder flexion, abduction and rotation, elbow flexion, forearm rotation and wrist flexion were assessed. The mean angle, standard deviation (SD), peak joint angles and total joint angle range of motion (ROM) were calculated for each axis across the gait cycle. On a group level, ANCOVA was used to assess the between-group differences for each upper limb kinematic outcome variable. To quantify abnormality prevalence on an individual participant level, the percentage of ABI participants that were outside of the 95% confidence interval of the HC sample for each variable were calculated.

RESULTS

There were significant between-group differences for all elbow and shoulder abduction outcome variables (p < 0.01), most shoulder flexion variables (except for shoulder extension peak), forearm rotation SD and ROM and for wrist flexion ROM. Elbow flexion and shoulder abduction were the axes most frequently affected by ARs. Despite the elbow being the most prevalently affected (38/42, 90%), a large proportion of participants had abnormality, defined as ±1.96 SD of the HC mean, present at the shoulder (32/42, 76%), forearm (20/42, 48%) and wrist joints (10/42, 24%).

CONCLUSION

This study provides valuable information on ARs, and highlights the need for clinical assessment of ARs to include all of the major joints of the upper limb. This may inform the development of a criterion-reference outcome measure or classification system specific to ARs.

Association between Gait Deviation Index and Physical Function in Children with Bilateral Spastic Cerebral Palsy: A Cross-Sectional Study

This study examined the association between Gait Deviation Index (GDI) and the five-times-sit-to-stand test (FTSST) or gait speed results, which represent mobility and muscle strength of the lower extremities in ambulatory children with Gross Motor Function Classification System (GMFCS) level I and II spastic cerebral palsy. In this cross-sectional, observational study, three-dimensional gait analysis data were obtained during gait trials to evaluate the GDI in 35 children (age 5–16 years) with spastic palsy. Motor function was evaluated using FTSST and gait speed. Gross motor function was evaluated using GMFCS. Children with GMFCS level II spastic cerebral palsy demonstrated lower GDI (p < 0.001) and poorer FTSST (p = 0.031) than those with GMFCS level I spastic cerebral palsy. Correlation analysis showed that FTSST results were significantly correlated with GDI (r = −0.624; p < 0.001). Motor function may be important for the maintenance of gait quality in patients with GMFCS level I and II spastic cerebral palsy and should not be ignored. In conclusion, reduction in gait impairment may affect the values of FTSST and GDI in patients with spastic cerebral palsy who can ambulate without an assistive device.

Application of the Gait Deviation Index in the analysis of post-stroke hemiparetic gait

Due to the complexity and volume of kinematic data from 3-dimensional gait analysis, the Gait Deviation Index (GDI) was introduced as a summary measure providing a global picture of gait kinematic data, however previously it was not validated as an outcome measure in individuals after stroke. The present study investigated the concurrent validity of the GDI as an outcome measure of gait defects at a chronic stage of recovery post-stroke, through comparisons with conventional measures of gait. Those enrolled included 65 individuals after stroke and 65 healthy individuals without gait disorders, matched for age and gender. The kinematic gait parameters were measured using a movement analysis system. Walking speed, walking distance, number of steps, self-reliant mobility, cadence, step length, and single support time were evaluated. Strong correlation was found between cadence and mGDI as well as GDI for the affected leg (0.7 ≤ |R| < 0.9; p < 0.001). Moderate correlations were found between walking speed, number of steps, step length affected leg and mGDI as well as GDI for the affected leg (0.5 ≤ |R| < 0.7; p < 0.001). Low correlations were found between walking distance, self-reliant mobility, single support time affected leg and mGDI as well as GDI for the affected leg (0.3 ≤ |R| < 0.5; p < 0.001; p < 0.005). The findings confirm the concurrent validity of the GDI, but only for the affected leg and mGDI in post-stroke patients. On the other hand, the GDI for unaffected leg may be useful in efforts to identify any compensatory mechanisms developing in post-stroke gait patterns. Trial registration: anzctr.org.au, ID:ACTRN12617000436370. Registered 24 March 2017.

The Gait Deviation Index as an indicator of gait abnormality among degenerative spinal pathologies

INTRODUCTION

The Gait Deviation Index (GDI) is a composite measure of gait abnormality derived from lower-limb joint range-of-motion which is increasingly being reported for clinical gait analysis among neurologic and orthopedic patients. A GDI score of 100 is representative of healthy individuals and decreasing scores represent a greater abnormality. Preliminary data is needed to help assess the utility of GDI as a measure of compromised gait among spine patients and to provide reference values for commonly treated pathologies.

METHODS

GDI scores were obtained from healthy adults and four symptomatic degeneration groups: cervical spondylotic myelopathy (CSM), adult degenerative scoliosis (ADS), and single-level lumbar degeneration (LD). Clinical gait analysis was done using a three-dimensional motion tracking system. Evaluations were done 1 week prior to surgical intervention for degeneration groups. Two-sample t-tests were used to compare degenerative cohorts to healthy controls and for inter-cohort comparisons. Pearson correlations were used to test for significant relationships between GDI and walking speed.

RESULTS

Degenerative cohorts all showed significantly lower (worse) GDI scores compared to healthy (all p < 0.001). CSM patients showed the best GDI scores with an average of 90, and LD patients showed the worst GDI scores with an average of 86. Worsening GDI significantly correlated with decreased walking speed among ADS patients.

CONCLUSION

Composite metrics like GDI provide a tempting means to summarize nuanced and complex gait characteristics into a single, comparable value among cohorts. The results of this study provide preliminary GDI scores for common degenerative spine pathologies. These slides can be retrieved under Electronic Supplementary Material.

The Pediatric Temporal-spatial Deviation Index: quantifying gait impairment for children with cerebral palsy

AIM

To develop an easily-administered metric to quantify gait impairment in children and to assess its use in children with cerebral palsy (CP).

METHOD

The Pediatric Temporal-spatial Deviation Index (TDI) was developed from gait data collected from 75 typically developing children (37 males, 38 females; mean age 9y 4mo; interquartile range [IQR] 8-10y) and 17 children diagnosed with spastic CP (nine males, eight females; mean age 9y 9mo; IQR 9-11y), in Gross Motor Function Classification System (GMFCS) levels I to III, aged 7 to 11 years. Children walked on a pressure-sensitive mat. Children with CP also completed 3D gait analysis. The Kaiser-Meyer-Olkin test of sampling adequacy was used for temporal-spatial feature selection. Principal components obtained from temporal-spatial gait parameters quantified deviation from typically developing gait. Deviation was normalized to a Pediatric TDI score mean (standard deviation [SD]) of 100 (10). The Pediatric TDI for children with CP was compared to 3D motion capture-based Gait Deviation Index (GDI).

RESULTS

The Pediatric TDI was significantly lower for children with CP compared to typically developing children (p<0.001), correlated with average GDI (r=0.610, p=0.009), and demonstrated sensitivity (0.78) and specificity (0.88) to gait function, assessed with GDI.

INTERPRETATION

The Pediatric TDI is an easily administered, revealing gait metric that can be used in children with CP in pediatric clinics and for research. Detection of gait abnormalities in the clinic can expedite diagnosis and treatment. What this paper adds The Pediatric Temporal-spatial Deviation Index (TDI) is a single-score index of gait deviation, based on nine parameters. The Pediatric TDI was more revealing than single temporal-spatial gait parameters. The Pediatric TDI is quick and simple to administer in the clinic.

Human Gait Analysis Metric for Gait Retraining

The combined gait asymmetry metric (CGAM) provides a method to synthesize human gait motion. The metric is weighted to balance each parameter's effect by normalizing the data so all parameters are more equally weighted. It is designed to combine spatial, temporal, kinematic, and kinetic gait parameter asymmetries. It can also combine subsets of the different gait parameters to provide a more thorough analysis. The single number quantifying gait could assist robotic rehabilitation methods to optimize the resulting gait patterns. CGAM will help define quantitative thresholds for achievable balanced overall gait asymmetry. The study presented here compares the combined gait parameters with clinical measures such as timed up and go (TUG), six-minute walk test (6MWT), and gait velocity. The comparisons are made on gait data collected on individuals with stroke before and after twelve sessions of rehabilitation. Step length, step time, and swing time showed a strong correlation to CGAM, but the double limb support asymmetry has nearly no correlation with CGAM and ground reaction force asymmetry has a weak correlation. The CGAM scores were moderately correlated with TUG and strongly correlated to 6MWT and gait velocity.

Compensatory sagittal plane ankle gait mechanics: Are they present in patients with a weak or stiff hip?

INTRODUCTION

Simulations suggest that subjects with reduced hip range of motion (ROM) and/or weakness can achieve more normal walking mechanics through compensations at the ankle. The aims of this study were to assess whether subjects with reduced hip ROM (Stiff hip) or hip flexor weakness (Weak hip) exhibit ankle compensations during walking and investigate redistribution of power in the lower extremity joints.

METHODS

Retrospective gait data were reviewed (IRB-approved hip registry). Preoperative kinematic/kinetic walking data were collected in patients with: adolescent hip dysplasia (AHD), femoral acetabular impingement (FAI), and Legg-Calvé Perthes disease (Perthes). AHD patients with significantly weak hip flexors on their affected side were included (Weak hip group). The Gait Profile Score (GPS) was calculated on the affected side of the FAI and Perthes groups to identify patients who had a Stiff hip. Patients who had undergone a hip arthrodesis (Fusion) were also included (Stiff hip group). Ankle kinematics/kinetics were compared to healthy participants (Control). The total positive work of sagittal plane hip, knee and ankle power were compared along with the distribution of power.

RESULTS

Patients in the Weak/Stiff hip groups did not walk with greater ankle plantarflexion, peak push-off power or positive ankle work on their affected sides compared to Control. Ankle work contribution (percentage of total positive work) on the affected or unaffected sides was greater in the Perthes and Hip Fusion patients compared to Control. Significant gait abnormalities on the unaffected side were observed.

CONCLUSIONS

Patients with a weak or stiff hip did exhibit altered ankle mechanics during walking. Greater percent ankle work contribution appeared to correspond with hip stiffness. In patients with hip pathology the redistribution of power among the lower extremity joints can highlight the importance of preserving ankle function.

Measures of knee and gait function and radiographic severity of knee osteoarthritis - A cross-sectional study

BACKGROUND

Pain reports show at most weak to moderate relationship with structural findings of knee osteoarthritis (OA). Less is known about the relationship between measures of knee and gait function and structural findings of knee OA.

RESEARCH QUESTION

To test the hypothesis that patient-reported, performance-based and three-dimensional knee and gait measures can distinguish between individuals with varying degrees of radiographic knee OA severity.

METHODS

To increase the spectrum of radiographic severity baseline data of individuals included in a cohort study and in a randomized controlled trial respectively were included in this cross-sectional study. Individuals completed the Knee injury and Osteoarthritis Outcome Score (KOOS), Single Limb Mini Squat (SLMS) test, and three-dimensional gait analysis. Radiographic severity was dichotomized into mild (Kellgren Lawrence (KL) 1-2) or severe (KL 3-4) knee OA. Proxies for medial knee joint loading were peak knee adduction moment (KAM) and KAM impulse, and summary measures of overall gait function were the Gait Deviation Index for kinematics (GDI) and kinetics (GDI-kinetic). Area under the receiver operating characteristic curves (AUC) and logistic regressions were used to evaluate whether KOOS-scores, SLMS test, peak KAM, KAM impulse, and GDI-scores could discriminate radiographic severity of knee OA.

RESULTS

The sample (n = 115) consisted of 60% women, mean age 61 years (SD 8). Good discriminating abilities (AUC > 0.7) were demonstrated for all measures of knee function and gait, except for GDI and GDI-kinetic (0.62 and 0.36, respectively). Odds ratios from logistic regressions largely supported the AUC findings.

SIGNIFICANCE

With the exception of gait summary measures, discriminating abilities were demonstrated by all measures of knee and gait function. Given the interest in interpreting OA as a multi-factorial disease, this information may assist researchers in selecting the most appropriate outcomes for biomechanical studies.

Rectus Femoris Transfer Surgery Worsens Crouch Gait in Children With Cerebral Palsy at GMFCS Levels III and IV

BACKGROUND

Previous study has shown that children with cerebral palsy (CP) functioning at Gross Motor Function Classification System (GMFCS) levels III and IV do not benefit from distal rectus femoris transfer (DRFT) due to lack of improvement in stance knee extension. The fate of knees in such subjects who do not undergo DRFT is unknown. The purpose of this study was to compare knee kinematic outcomes in patients with CP and stiff knee gait who underwent single-event multilevel surgery with and without DRFT.

METHODS

Preoperative and postoperative gait analysis data were retrospectively reviewed for ambulatory (GMFCS levels I to IV) patients with CP with crouch and stiff knee gait whom underwent single-event multilevel surgery, including hamstring lengthening either with DRFT (N=34) or without DRFT (N=40). Statistical analyses included t tests and χ tests, and multiple regression analysis was performed to adjust for covariates. Data were stratified by GMFCS level groups I/II and III/IV.

RESULTS

Improved maximum knee extension in stance was seen for both the DRFT (P=0.0002) and no DRFT groups (P≤0.0006) at GMFCS levels I/II, and the no DRFT group at GMFCS levels III/IV (P=0.02). Excessive stance knee flexion persisted for those at GMFCS level III/IV after DRFT. Maximum knee flexion in swing was maintained after DRFT, but significantly decreased in the no DRFT group (P<0.002) for both GMFCS groups. Change in total knee range of motion improved after DRFT only in the GMFCS I/II group subjects with unilateral involvement (P=0.01). Timing of maximum knee flexion in swing improved for all patients regardless of DRFT or GMFCS level group (P<0.0001).

CONCLUSIONS

In patients with CP functioning at GMFCS levels III and IV, DRFT results in persistent crouch postoperatively. Given the importance of maintaining upright posture in these patients, we do not recommend DRFT in patients functioning at GMFCS levels III and IV.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Gait analysis for individually tailored interdisciplinary interventions in children with cerebral palsy: a randomized controlled trial

AIM

To test the hypothesis that improvements in gait and function following individualized interdisciplinary interventions consisting of physical therapy, orthotics, spasticity management, and orthopaedic surgery using instrumented gait analysis are superior to 'usual care' in children with cerebral palsy (CP).

METHOD

This was a prospective, single-blind, parallel-group, randomized controlled trial investigating the effectiveness of interventions based on the use of gait analysis. Primary outcome was gait (Gait Deviation Index) and secondary outcomes were walking and patient-reported outcome measures of function, disability, and health-related quality of life. Follow-ups were done at 26 weeks (questionnaires) and at the primary end point of 52 weeks (all outcomes).

RESULTS

Sixty participants with CP (39 males, 21 females, mean age 6y 10mo, standard deviation 1y 3mo, range 5y-9y 1mo) in Gross Motor Function Classification System levels I or II, were randomized to interventions with or without gait analysis. No significant or clinically relevant between-group differences in change scores of the primary or secondary outcomes were found. The recommended categories of interventions were dominated by non-surgical interventions and were applied in 36% to 86% of the participants.

INTERPRETATION

Interventions using gait analysis were not superior to 'usual care' on gait, walking, or patient-reported outcomes in a sample of relatively young and independently walking children with CP not expected to need surgery.

WHAT THIS PAPER ADDS

Gait analysis in children with cerebral palsy in Gross Motor Function Classification System levels I or II recommends interdisciplinary interventions. Compliance to interventions recommended after gait analysis was low. No statistically significant advantages were identified for the intervention group versus the control group.

Gait Pattern of Adults with Cerebral Palsy and Spastic Diplegia More Than 15 Years after Being Treated with an Interval Surgery Approach: Implications for Low-Resource Settings

BACKGROUND

Single-event multilevel surgery (SEMLS) approach is regarded as the golden standard in developed countries to improve gait and functional mobility in children with cerebral palsy (CP). However, this approach is not always feasible in developing countries. Therefore, orthopedic surgery based on an interval surgery approach (ISA) is still commonly used in developing countries, although little is known about the long term outcomes of an ISA. Therefore, the aim of this study was to describe the gait patterns of adults with CP, who have been treated with ISA, which started more than 15 years ago.

MATERIALS AND METHODS

Thirty adults with CP and spastic diplegia, who received ISA treatment 21.6-33.7 years ago, were recruited for this study and participated in three-dimensional gait analysis. Twenty kinematic and nondimensional temporal-distance parameters were captured, while the overall gait deviation index (GDI) was also calculated. Data of the adults with CP were compared to normative data of typically developing (TD) adults.

RESULTS

Although all adults with CP were still ambulant, their gait parameters significantly differed from TD adults, with a lower GDI in the adults with CP. The CP gait patterns were characterized by excessive hip flexion and hip internal rotation as well as a stiff-knee gait.

CONCLUSION

Although different to TD adults, the gait patterns observed in the adult with CP treated with ISA is in line with other studies. Gait patterns suggest that derotation osteotomies potentially could have improved the long term gait patterns. Although SEMLS might be the preferred treatment method, potentially resulting in better outcomes, ISA can also be used to treat children with CP in developing countries as India and South Africa, where a SEMLS approach is not always feasible.

Distal Femoral Shortening Osteotomy for Severe Knee Flexion Contracture and Crouch Gait in Cerebral Palsy

Although there have been advancements of surgical techniques to correct gait abnormalities seen in patients with cerebral palsy, the crouch gait remains one of the most difficult problems to treat. The purpose of this retrospective study was to examine our results of distal femoral shortening osteotomy (DFSO) and patellar tendon advancement (PTA), performed in patients with crouch gait associated with severe knee flexion contracture. A total of 33 patients with a mean fixed knee contracture of 38° were included in the study. The mean age at the time of surgery was 12.2 years and the mean follow-up was 26.9 months. The measurements of clinical, radiological, and gait parameters were performed before and after surgery. The mean degrees of knee flexion contracture, Koshino index of patella height, and Gait Deviation Index were found to be significantly improved at the time of final follow-up. The maximum knee extension during the stance phase improved by an average of 25°, and the range of knee motion during gait increased postoperatively. On the other hand, the mean anterior pelvic tilt increased by 9.9°. Also, the maximum knee flexion during the swing phase decreased and the timing of peak knee flexion was observed to be delayed. We conclude that combined procedure of DFSO and PTA is an effective and safe surgical method for treating severe knee flexion contracture and crouch gait. However, the surgeons should be aware of the development of increased anterior pelvic tilt and stiff knee gait after the index operation.

Gait Deviations in Children With Osteogenesis Imperfecta Type I

BACKGROUND

Osteogenesis imperfecta (OI) is a congenital connective tissue disorder often characterized by orthopaedic complications that impact normal gait. As such, mobility is of particular interest in the OI population as it is associated with multiple aspects of participation and quality of life. The purpose of the current study was to identify and describe common gait deviations in a large sample of individuals with type I OI and speculate the etiology with a goal of improving function.

METHODS

Gait analysis was performed on 44 subjects with type I (11.7±3.08 y old) and 30 typically developing controls (9.54±3.1 y old ). Spatial temporal, kinematic, and kinetic gait data were calculated from the Vicon Plug-in-Gait Model. Musculoskeletal modeling of the muscle tendon lengths (MTL) was done in OpenSim 3.3 to evaluate the MTL of the gastrocnemius and gluteus maximus. The gait deviation index, a dimensionless parameter that evaluates the deviation of 9 kinematic gait parameters from a control database, was also calculated.

RESULTS

Walking speed, single support time, stride, and step length were lower and double support time was higher in the OI group. The gait deviation index score was lower and external hip rotation angle was higher in the OI group. Peak hip flexor, knee extensor and ankle plantarflexor moments, and power generation at the ankle were lower in the OI group. MTL analysis revealed no significant length discrepancies between the OI group and the typically developing group.

CONCLUSIONS

Together, these findings provide a comprehensive description of gait characteristics among a group of individuals with type I OI. Such data inform clinicians about specific gait deviations in this population allowing clinicians to recommend more focused interventions.

LEVEL OF EVIDENCE

Level III-case-control study.

Gait Characteristics of Children with Spastic Cerebral Palsy during Inclined Treadmill Walking under a Virtual Reality Environment

OBJECTIVE

To investigate gait characteristics in children with spastic cerebral palsy during inclined treadmill walking under a virtual reality environment.

METHODS

Ten spastic cerebral palsy (CP) children and ten typically developing (TD) children were asked to walk at their comfortable speed on a treadmill at a ground level and 10° inclined. Three-dimensional kinematic data and ground reaction force data were captured in a computer-assisted rehabilitation environment system. Kinetic parameters and dynamic balance parameters were calculated using a standard biomechanical approach.

RESULTS

During uphill walking, both groups decreased walking speed and stride length and increased peak pelvis tilt, ankle dorsiflexion, and hip flexion. Compared with TD children, CP children had decreased walking speed and stride length, decreased peak hip abduction moment, increased stance phase percentage, increased peak ankle dorsiflexion and knee flexion, and increased peak hip extension moment. The peak trunk rotation angle, ankle angle at initial contact, and stride length showed a significant group∗walking condition interaction effect.

CONCLUSIONS

CP children showed similar adjustments for most gait parameters during uphill walking as TD children. With a lower walking speed, CP children could maintain similar dynamic balance as TD children. Uphill walking magnifies the existing abnormal gait patterns of the cerebral palsy children. We suggest that during a treadmill training with an inclination, the walking speed should be carefully controlled in the case of improving peak joint loading too much.

Choice of the Acetabular Component Placement in Dysplastic Hip Patients

Total hip arthroplasty (THA) in patients with hip dysplasia is a challenging surgical operation. Many orthopedic surgeons concur that the anatomical placement of the acetabular components of endoprostheses (AC-EPs) during THA yields the best result. However, there are advocates of the high rotation center of the hip joint after replacement surgery. In our study, we compared the outcomes of THA based on the placement of acetabular cups to identify the most favorable site for AC-EPs in patients with varying grades of dysplastic osteoarthritis. Our study included 88 patients with dysplastic hip osteoarthritis who underwent 106 THAs during a three-year period using cementless fixation endoprostheses. Functional results were assessed by Merle d’Aubigne and Postel’s method and by instrumental gait analysis (IGA). Gait deviation index was calculated based on IGA to compare results in different acetabular component placement groups. Functional assessment of patients by Merle d’Aubigne and Postel’s grading method and IGA showed no significant difference in results due to the placement of the acetabular component. Most complications were found in the severe dysplasia patients group with the anatomical placement of the AC-EP. The appropriate location of cementless acetabular cups during THA in dysplastic hips depends on the grade of dysplasia, expected elongation of the leg, and the potential for adequate bone coverage for the AC-EP. In cases of severe dysplasia, the placement of the AC-EP in the secondary socket can provide a good functional outcome and reduce the risk of complications.

Evaluating shear and normal force with the use of an instrumented transtibial socket: A case study

Patients with transtibial amputation experience ulcers on their residual limb. The loading between the device and underlying material plays a role in loads transmitted to the skin. The objective was to evaluate normal and shear forces at the socket/liner interface during walking. A 53 year old male (85.45 kg and 177.8 cm) with a transtibial amputation participated in this case study. A transtibial prosthesis was instrumented with a load cell to measure normal and shear forces at the socket interface. Three conditions were evaluated during walking: gel liner, additional three ply sock and a hole in the gel liner. Shear and normal forces were highest with the addition of a three ply. Longitudinal shear stresses ranged from 0.4-7.66 kPa, transverse shear stresses ranged from 0.01-7.79 kPa and normal stresses ranged from 2.7-61.9 kPa. Increased shear and normal forces can cause a significant decrease in blood perfusion, linked to an increased risk of ulcer formation. Experimental force results are also important for future work involving finite element modeling of the skin/liner/device interface.

Lower limb sagittal gait kinematics can be predicted based on walking speed, gender, age and BMI

Clinical gait analysis attempts to provide, in a pathological context, an objective record that quantifies the magnitude of deviations from normal gait. However, the identification of deviations is highly dependent with the characteristics of the normative database used. In particular, a mismatch between patient characteristics and an asymptomatic population database in terms of walking speed, demographic and anthropometric parameters may lead to misinterpretation during the clinical process. Rather than developing a new normative data repository that may require considerable of resources and time, this study aims to assess a method for predicting lower limb sagittal kinematics using multiple regression models based on walking speed, gender, age and BMI as predictors. With this approach, we were able to predict kinematics with an error within 1 standard deviation of the mean of the original waveforms recorded on fifty-four participants. Furthermore, the proposed approach allowed us to estimate the relative contribution to angular variations of each predictor, independently from the others. It appeared that a mismatch in walking speed, but also age, sex and BMI may lead to errors higher than 5° on lower limb sagittal kinematics and should thus be taken into account before any clinical interpretation.

Valgus Hip Osteotomy in Children With Spondyloepiphyseal Dysplasia Congenita: Midterm Results

BACKGROUND

Coxa vara has been frequently reported in spondyloepiphyseal dysplasia congenita (SEDC), and proximal femoral osteotomy has been described as a useful treatment. The aim of this study was to discuss the clinical, radiographic, and gait outcomes after valgus extension osteotomy of the proximal femur. Changes of lumbar lordosis, associated with coxa vara correction, are reported as well as the outcome differences between different ages.

METHODS

Records of children with SEDC, who were followed at our institution between 2004 and 2014, were reviewed; and children had hip surgery were identified. Hip pain and passive range of motion, radiographic neck shaft angle (NSA), and Hilgenreiner trochanteric (H-T) angle, sagittal spinopelvic parameters, and gait data were recorded. Preoperative and last follow-up data were compared. Outcomes were also compared between 3 age groups.

RESULTS

Of the 79 children with SEDC, 26 children (12 boys and 14 girls) had hip osteotomy in 48 hips. Mean age at surgery was 9.6 years and the mean follow-up was 5 years. Preoperative hip pain was noted in 30 hips. At the last follow-up, 3 hips were painful at the extreme range of motion. Passive range of motion, NSA, and H-T improved postoperatively. Although NSA was maintained over the follow-up, H-T deterioration was noted. Spinopelvic measurements changed significantly and gait data remained stable except pelvic tilt that reduced significantly after surgery. The changes of radiographic measurements in each age group were similar to the total group of patients.

CONCLUSIONS

In children with SEDC, surgical correction of coxa vara, by proximal femoral valgus osteotomy, is an effective treatment that improves hip pain and range of motion in addition to the radiographic alignment of the proximal femur and the sagittal spinopelvic alignment. Children are expected to maintain their level of function after surgery and to have good results over the midterm regardless of their age at surgery.

LEVEL OF EVIDENCE

Level IV-therapeutic study.

Gait profile score identifies changes in gait kinematics in nonfaller, faller and recurrent faller older adults women

BACKGROUND

Quantification of differences in gait kinematics between young and older adults provides insight on age-related gait changes and can contribute to the investigation of risk of falls. Gait Profile Score (GPS) is an index that indicates gait quality, using kinematic gait data, but so far it has not been used in an elderly population without neurological conditions.

RESEARCH QUESTION

Is the Gait Profile Score (GPS) an index that shows reliability for use in old adults? Does this index detect changes in gait quality observed by kinematic data between nonfaller, faller and recurrent faller older adults?

METHODS

Forty-nine women (mean age 72,43 ± 6,44; 27 faller and 22 nonfaller) were included in the study. Intra-session reliability was obtained from the intraclass correlation coefficient (ICC) between the five strides of each session.

RESULTS

Overall value of GPS shows no difference between nonfaller (6.65 ± 1.59º), faller (6.67 ± 2.05º) and recurrent faller (6.62 ± 0.86º) older adult. In all groups larger values of Gait Variable Scores (GVS) were observed in the hip and knee joints. Intra-session ICC values the GVS and GPS presented high stability, ranging from 0.80 to 0.99. MDC lower values in GPS were observed in the faller (0.39; ICC - 0.97) and recurrent faller (0.69; ICC - 0.90).

SIGNIFICANCE

Due to the high reliability, GPS has proven to be a valid method to analyze the gait quality of faller and nonfaller older woman. The most sensitive indexes (GPS and GVS) are the gear changes in fallers and recurrent fallers.

Are we supererestimating gait assessments of patients with idiopathic normal-pressure hydrocephalus?

INTRODUCTION

Idiopathic normal pressure hydrocephalus (iNPH) is a syndrome characterized by a triad composed of cognitive alteration, urinary incontinence, and gait impairment associated with ventricular enlargement and normal cerebrospinal fluid pressure. Gait impairment is among the earliest symptoms; however, the reliability of the evaluation is not well-established and no consensus has been reaching regarding variables that should be analyzed and which parameters should be considered to accurately assess post-intervention improvement.

RESEARCH QUESTION

Are the degree of repeatability, standard error of measurement, and minimum detectable change considered to detect changes in gait variables in iNPH patients?

METHODS

A total of 84 iNPH patients with a mean age of 77.1 (±6.4) years were analyzed. Gait deviation index (GDI), speed, cadence, cycle time, stride length, single support, and first and second double support were chosen as the variables to be analyzed. Statistical analysis was performed by an independent evaluator, with gait repeatability assessed by the intraclass correlation coefficient (ICC) and the standard error of measure (SEM).

RESULTS

ICC values were 0.76-0.85 with excellent repeatability, while SEM demonstrated that the variables with best repeatability were the GDI (mean, 4.94; 95% confidence interval (CI), 4.63-5.43), representing a 7.65% mean relative error of the measurement (mean, 0.05 m; 95% CI, 0.05-0.06), and stride length (mean 0.05 m; 95% CI, 0.05-0.06), with a 7.69% mean relative error.

SIGNIFICANCE

We concluded that GDI and stride length were the variables with the best repeatability and lower variability in the gait of iNPH patients.

Center of mass in analysis of dynamic stability during gait following stroke: A systematic review

BACKGROUND

The Center of mass (CoM) analysis reveals important aspects of gait dynamic stability of stroke patients, but the variety of methods and measures represents a challenge for planning new studies.

RESEARCH QUESTION

How have the CoM measures been calculated and employed to investigate gait stability after a stroke? Three issues were addressed: (i) the methodological aspects of the calculation of CoM measures; (ii) the purposes and (iii) the conclusions of the studies on gait stability that employed those measures.

METHODS

PubMed and Science Direct databases have been searched to collect original articles produced until July 2017. A set of 26 studies were selected according to criteria involving their methodological quality.

RESULTS

A compromise between accuracy and feasibility in CoM calculation could be reached using the segmental method with 7-9 segments. Regarding their purposes, two types of studies were identified: clinical and research oriented. From the first ones, we highlighted: the margin of stability (MoS) in the mediolateral (ML) direction, and the angular momentum in the frontal plane could be indicators of dynamical stability; the MoS in the anteroposterior (AP) direction might be able to detect the risk of falls and the symmetry of vertical CoM displacement could be used to analyze energy expenditure during gait. These and other CoM measures are potentially useful in clinical settings, but their psychometric properties are still to be determined. The research oriented studies allowed to clarify that stability is not improved by widening the step in stroke patients and that the impaired control of the non-paretic limb might be the main source of instability.

SIGNIFICANCE

This review provides recommendations on the methods for estimating CoM and its measures, identifies the potential usefulness of CoM parameters and indicates issues that could be addressed in future studies.

Individuals with knee osteoarthritis present increased gait pattern deviations as measured by a knee-specific gait deviation index

BACKGROUND

A biomechanical analysis can provide valuable information on osteoarthritis (OA) gait, but important multidimensional interactions are often ignored. The Gait Deviation Index (GDI) was designed to address the issue of data complexity in gait analyses by providing a single, encompassing, value for one's deviation from a normative reference group.

RESEARCH QUESTION

The primary aim of this study was to examine differences in a knee-specific GDI among young adults, and older individuals with and without knee OA. Secondarily, we aimed to examine these differences while controlling for gait speed.

METHOD

Sagittal and frontal plane knee joint angles and moments were used in the computation of a GDI among young adults, and older individuals with and without knee OA. The GDI was calculated such that scores ≥100% were considered typical young-healthy gait and a 10% decrease below 100 equated to 1 standard deviation from typical gait. Scores were first examined using a one-way analysis of variance, and examined again after correcting for gait speed.

RESULTS

The GDI was calculated for three groups: young-healthy adults (n = 52), older individuals without knee OA (n = 56), and individuals with knee OA (n = 191). Those with knee osteoarthritis exhibited a mean GDI of 87.2 (11.1), which was significantly lower than young adults (99.6 (10.6); p < 0.001) and older individuals without knee OA (94.3 (11.0); p < 0.001). Differences in GDI remained consistent after controlling for gait speed. Knee OA gait waveforms displayed significant variability across similar GDIs, specifically in frontal plane patterns.

CONCLUSION

Those with knee osteoarthritis exhibited lower (worse) GDIs compared to those without knee osteoarthritis and young, healthy individuals. After correcting for gait speed, these findings did not change. The GDI highlighted the significant variability in gait waveforms within individuals with knee OA, but the clinical utility of the GDI score itself remains limited.

Comparing the effects of two spasticity management strategies on the long-term outcomes of individuals with bilateral spastic cerebral palsy: a multicentre cohort study protocol

INTRODUCTION

Spasticity is one of the primary pathologies associated with cerebral palsy (CP), yet no definitive evidence exists to guide the appropriate level of spasticity management for an individual. Spasticity management strategies often differ by center. On one end of this strategy spectrum is a highly-interventional approach, characterized by treatments such as a selective dorsal rhizotomy (SDR), intrathecal baclofen pump (ITB), and anti-spasticity injections and medications. On the other end of the spectrum is a less interventional approach, involving minimal use of these treatments, and no SDR.

METHODS AND ANALYSIS

A retrospectively-matched, multi-center study protocol is described that comprehensively compares the long-term outcomes of a highly-interventional versus a minimally-interventional spasticity management strategy. We will analyze two groups of adults with spastic bilateral CP (≥21 years). In one group are individuals who underwent an SDR between the ages of 4 and 10 years, along with ongoing spasticity management during childhood and adolescence. In the other group are individuals who received minimal spasticity management and did not undergo an SDR. Individuals with prolonged use of an intrathecal baclofen (ITB) pump will be excluded. The two groups will be matched for spasticity and other important clinical characteristics at baseline. This study design improves on many of the limitations found in the existing outcome literature.

ETHICS AND DISSEMINATION

This study received necessary approval from the University of Minnesota and Western Institutional Review Boards. Results will be disseminated via peer-reviewed publications and conference presentations.

TRIAL REGISTRATION NUMBER

NCT03789786.

Defining gait patterns using Parallel Factor 2 (PARAFAC2): A new analysis of previously published data

Three-dimensional gait analysis (3D-GA) is commonly used to answer clinical questions of the form "which joints and what variables are most affected during when". When studying high-dimensional datasets, traditional dimension reduction methods (e.g. principal components analysis) require "data flattening", which may make the ensuing solutions difficult to interpret. The aim of the present study is to present a case study of how a multi-dimensional dimension reduction technique, Parallel Factor 2 (PARAFAC2), provides a clinically interpretable set of solutions to typical biomechanical datasets where different variables are collected during walking and running. Three-dimensional kinematic and kinetic data used for the present analyses came from two publicly available datasets on walking (n = 33) and running (n = 28). For each dataset, a four-dimensional array was constructed as follows: Mode A was time normalized cycle points; mode B was the number of participants multiplied by the number of speed conditions tested; mode C was the number of joint degrees of freedom, and mode D was variable (angle, velocity, moment, power). Five factors for walking and four factors for running were extracted which explained 79.23% and 84.64% of their dataset's variance. The factor which explains the greatest variance was swing-phase sagittal plane knee kinematics (walking), and kinematics and kinetics (running). Qualitatively, all extracted factors increased in magnitude with greater speed in both walking and running. This study is a proof of concept that PARAFAC2 is useful for performing dimension reduction and producing clinically interpretable solutions to guide clinical decision making.

Effect of a Combined Stretching and Strength Training Program on Gait Function in Children with Cerebral Palsy, GMFCS Level I & II: A Randomized Controlled Trial

Background and objectives: Ambulant children with cerebral palsy (CP) often develop impaired gait, and reduced active knee extension is often a part of the problem. This study aimed to evaluate the effect of a combined intervention program including stretching and progressive resistance exercise (PRE) targeting active knee extension on gait function, in children with spastic CP. Materials and methods: Thirty-seven children (21 boys, 16 girls, mean age 10.2 (±2.3) years), classified by Gross Motor Function Classification System I-III, were randomized to an intervention (n = 17) and a comparison group (n = 20). The intervention group received a 16-week combined exercise program (3 sessions per week) including stretching of hamstrings and PRE targeting the lower extremities, followed by a 16-week maintenance program (1 session per week). The comparison group received care as usual. Gait function was evaluated by three-dimensional gait analysis (3DGA); knee, hip and pelvic kinematics in the sagittal plane, step length and speed, Gait Deviation Index (GDI), and Six-Minute Walk test (6MWT) at 0, 16, and 32 weeks. Results: There were no statistically significant differences between the intervention group and the comparison group for any of the gait parameters measured at 16 and 32 weeks. There was a significant increase in gait distance measured by 6MWT within both groups; however, no differences between the groups were found. Conclusion: A 16-week combined stretching and PRE program followed by a 16-week maintenance program did not improve gait function in ambulant children with CP.

Anterior Guided Growth of the Distal Femur for Knee Flexion Contracture: Clinical, Radiographic, and Motion Analysis Results

BACKGROUND

Fixed knee flexion deformity is common in children with neuromuscular disorders. Anterior guided growth (AGG) of the distal femur can achieve gradual correction in patients who are skeletally immature. Little outcome data are available on this procedure.

METHODS

This is a retrospective matched cohort study. Forty-two knees (26 patients) underwent AGG surgery at our institution between 2007 and 2017. All patients underwent instrumented 3-dimensional gait analysis (3DGA). A nonsurgical control group of 49 knees (43 patients) was selected that matched for age, severity of preoperative knee contracture, and 3DGA parameters. Clinical, radiographic, and 3DGA outcomes were assessed and compared.

RESULTS

Average preoperative knee flexion deformity in AGG group was 13±8 degrees. Following AGG, deformity improved by 8±7 degrees (P<0.001) as measured radiographically and by 7±7 degrees (P<0.001) as measured on physical examination. Average rate of correction was 0.7±0.6 degrees per month or 8±8 degrees per year. The 3DGA parameters such as minimum stance phase knee flexion and knee flexion at initial contact were also significantly improved following AGG. In contrast, flexion deformity as measured radiographically worsened by 3±3 degrees (P=0.002) in the control group. Twelve knees (29%) had failure of correction. Predictors of failure included older age, lower level of function, and greater severity of preoperative deformity. The age at time of surgery and the anteroposterior position of plate fixation relative to the distal femoral physis were associated with rate of correction.

CONCLUSIONS

In children with neuromuscular disorders, AGG of the distal femur is effective in improving degree of fixed knee flexion deformity as well as objective gait parameters. A significant portion of knees experience inadequate correction. Addressing factors associated with correction failure (ie, age and plate placement) may improve the procedure's success.

LEVEL OF EVIDENCE

Level III-case control study.

Kinetic-based indexes for the functional evaluation of gait in diplegic children: a preliminary report

We evaluated the feasibility of a set of indexes based on ground reaction forces to discriminate between the degree of severity of spastic diplegia, identified via Gross Motor Function Classification System (GMFCS). A stepwise discriminant ordinal regression analysis performed on a sample of 58 children returned a subset of variables related to the ratio between braking and propulsive vertical forces and anteroposterior timings. Rather, parameters concerning bilateral symmetry were poorly discriminating. The relative simplicity of the selected indexes allows for their easy implementation on existing gait analysis applications for screening purposes.

Correlations between patient-perceived outcome and objectively-measured biomechanical change following Total Knee Replacement

BACKGROUND

Total Knee Replacement (TKR) surgery is being utilised in a younger, more active population with greater functional expectations. Understanding whether patient-perceived measures of function reflect objective biomechanical measures is critical in understanding whether functional limitations can be adequately captured within a clinical setting.

RESEARCH QUESTION

Do changes in objective gait biomechanics measures reflect patient-reported outcome measures at approximately 12 months following TKR surgery?

METHODS

Three-dimensional gait analysis was performed on 41 patients with OA who were scheduled for TKR surgery, 22 of which have returned for a (9-24 month) follow-up assessment. Principal Component Analysis was used to define features of variation between OA subjects and an additional 31 non-pathological control subjects. These were used to train the Cardiff Classifier, an objective classification technique, and subsequently quantify changes following TKR surgery. Patient-perceived changes were also assessed using the Oxford Knee Score (OKS), Knee Outcome Survey (KOS), and Pain Audit Collection System scores (PACS). Pearson and Spearman correlation coefficients were calculated to establish the relationship between changes in objectively-measured and perceived outcome.

RESULTS

Objective measures of biomechanical change were strongly correlated to changes in OKS(r=-0.695, p < 0.001) and KOS(r=-.810, p < 0.001) assessed outcomes. Pain (PACS) was only related to biomechanical function post-operatively (r=-.623, p = 0.003).

SIGNIFICANCE

In this biomechanics study, the relationship between changes in objective function and patient-reported measures pre to post TKR surgery is stronger than in studies which did not include biomechanics metrics. Quality of movement may hold more significance for a patient's perception of improvement than functional measures which consider only the time taken or distance travelled during functional activities.

How normal is normal: Consequences of stride to stride variability, treadmill walking and age when using normative paediatric gait data

Background: In the process of 3D-gait analysis interpretation, gait deviations in children with cerebral palsy are identified through comparison with reference data of typically developing children (TD). Generally, TD-data are presented based on averaged normalized curves of numerous strides for different ages and walking velocities. In patients however, often only a limited number of strides are available which are compared to group-averaged reference curves. Research question: To investigate the consequences of ignoring stride-to-stride variation when averaged normalized curves are used as a reference paediatric dataset. To illustrate implications for clinical practice, we investigated how many individual strides of TD-children would be classified as abnormal, when compared to averaged normalized curves from the reference group, and how this is affected by age and treadmill versus overground walking. Methods: Ninety TD-datasets were collected. Children (4-18y) walked on a 10 m-walkway (n = 49) or instrumented treadmill (n = 41). Joint kinematic and kinetic curves and clinically relevant outcome parameters were established. Individual strides were considered abnormal if they exceeded the group average more than 2SD. In addition, the Edinburgh Visual Gait Score, Gait Profile Score (GPS) and stride-to-stride variability were calculated. Generalized estimation equation analyses were used to investigate effects of age, overground/treadmill and their interaction. Results: Of all 2532 analysed strides, on average 28% were classified as abnormal for joint kinematic curves, 50% for moments, and 51% for powers. Younger children showed a greater percentage of abnormal strides, greater GPS and more variability (p < 0.001). The effect of age was similar between treadmill and overground, but variability was lower on the treadmill. Significance: Our findings indicate that due to stride-to-stride variability, even in TD-children a substantial number of strides can be classified as abnormal, when compared to group averaged normalized curves. Consequently, in patients, comparing a single stride to such a reference curve may lead to potential overestimation of gait deviations.

Leaving hip rotation out of a conventional 3D gait model improves discrimination of pathological gait in cerebral palsy: A novel neural network analysis

BACKGROUND

Complex clinical gait analysis results can be expressed as single number gait deviations by applying multivariate processing methods. The original Movement Deviation Profile (MDP) quantifies the deviation of abnormal gait using the most trusted nine dynamic joint angles of lower limbs.

RESEARCH QUESTION

Which subset of joint angles maximises the ability of the MDP to separate abnormal gait from normality? What is the effect of using the best subset in a large group of patients, and in individuals?

METHODS

A self-organising neural network was trained using normal gait data from 166 controls, and then the MDP of 1923 patients with cerebral palsy (3846 legs) was calculated. The same procedure was repeated with 511 combinations of the nine joint angles. The standardised distances of abnormal gait from normality were then calculated as log-transformed Z-scores to select the best combination. A mixed design ANOVA was used to assess how removing the least discriminating angle improved the separation of patients from controls. The effect of using the optimal subset of angles was also quantified for each individual leg by comparing the change in MDP to the independent FAQ levels of patients.

RESULTS

Removal of hip rotation significantly (p<0.0005) increased the separation of the patient group from normality (ΔZ-score 0.24) and also at FAQ levels 7-10 (ΔZ-score 0.38, 0.27, 0.22, 0.14). The MDP of individual patients changed in a wider range of -4.65 to 1.12 Z-scores and their change matched their independent FAQ scores, with less functional patients moving further from, and more functional patients moving closer to normality.

SIGNIFICANCE

In existing gait databases we recommend excluding hip rotation from data used to calculate the MDP. Alternatively, the calculation of hip rotation can be improved by post-hoc correction, but the ultimate solution is to use more accurate and reliable models of hip rotation.

3-D lower extremity bone morphology in ambulant children with cerebral palsy and its relation to gait

Changes in lower-extremity bone morphology are potential mid- to long-term secondary consequences of cerebral palsy (CP), affecting activity. Little is known about the 3-D morphology of lower-extremity bones in children with CP and the association with gait deviations. The main aim of this study was to describe and compare 3-D lower-extremity bone morphology in ambulant children with unilateral or bilateral CP. Secondary aims were to determine whether certain bone parameters were related to the unilateral or bilateral CP and to quantify the association between bone parameters and gait deviations. Among 105 ambulant children with CP (aged 3 to 17 years), 48 had bilateral CP (Bilat-CP) and 57 had unilateral CP (Unilat-CP); the unaffected limb of children with Unilat-CP was used as control limbs. Fifteen bone parameters were calculated by EOS® biplanar radiography, and the Gait Deviation Index (GDI) was calculated by 3-D gait analysis. Data were compared by descriptive and comparative statistical analysis (Anova, principal component analysis [PCA] and focused-PCA). Mean (SD) neck shaft angle was significantly greater for Unilat-CP than control limbs (134.9° [5.9] vs. 131.3° [5]). Mean mechanical tibial angle was significantly smaller (85.8° [6.7] vs. 89° [4.6]) and mean femoral torsion was significantly greater (29.4° [1.6] vs. 19.1° [11.8]) for Bilat-CP than control limbs. On PCA of the main determinants of 3-D bone morphology, bone shape was more complex with Bilat-CP, with changes in all 3 dimensions of space, than Unilat-CP and control limbs. Few bone parameters were correlated with the GDI in any limbs. In ambulant children with CP, femoral and tibial growth are not affected by the condition. The unilateral or bilateral nature of CP must be considered during treatment to prevent bone deformities and bone morphology affecting gait quality.

Multilevel Surgery for Children With Cerebral Palsy: A Meta-analysis

CONTEXT

Multilevel surgery (MLS) is standard care for reducing musculoskeletal disorders among children with spastic cerebral palsy (CP).

OBJECTIVE

To summarize the literature examining effects of MLS and satisfaction with MLS for children with CP.

DATA SOURCES

Medline, Embase, Cumulative Index to Nursing and Allied Health Literature, and Cochrane Central Register of Controlled Trials were searched.

STUDY SELECTION

Studies in which authors reported effects of or satisfaction with MLS in children with CP were selected.

DATA EXTRACTION

Two authors screened and extracted data on gross motor function, gait speed, gait (eg, Gait Profile Score), range of motion, strength, spasticity, participation, quality of life, satisfaction, and adverse events.

RESULTS

Seventy-four studies (3551 participants) were identified. One was a randomized controlled trial (RCT) (n = 19); the remainder were cohort studies. Pooled analysis of cohort studies revealed that MLS did not have a long-term effect on gross motor function (standardized mean difference [SMD]: 0.38; 95% confidence interval [CI]: -0.25 to 1.01) or gait speed (SMD: 0.12; 95% CI: -0.01 to 0.25) but did improve gait (SMD: -0.80; 95% CI: -0.95 to -0.65). The RCT also revealed no effect of MLS on gross motor function but improvements in the Gait Profile Score at 1 year. Participation and quality of life were reported in only 5 studies, and adverse events were adequately reported in 17 studies.

LIMITATIONS

Data were largely from cohort studies.

CONCLUSIONS

Findings reveal that gait, but not gross motor function, improves after MLS. RCTs and improved reporting of studies of MLS are required.

Muscle synergies demonstrate only minimal changes after treatment in cerebral palsy

BACKGROUND

Children with cerebral palsy (CP) have altered synergies compared to typically-developing peers, reflecting different neuromuscular control strategies used to move. While these children receive a variety of treatments to improve gait, whether synergies change after treatment, or are associated with treatment outcomes, remains unknown.

METHODS

We evaluated synergies for 147 children with CP before and after three common treatments: botulinum toxin type-A injection (n = 52), selective dorsal rhizotomy (n = 38), and multi-level orthopaedic surgery (n = 57). Changes in synergy complexity were measured by the number of synergies required to explain > 90% of the total variance in electromyography data and total variance accounted for by one synergy. Synergy weights and activations before and after treatment were compared using the cosine similarity relative to average synergies of 31 typically-developing (TD) peers.

RESULTS

There were minimal changes in synergies after treatment despite changes in walking patterns. Number of synergies did not change significantly for any treatment group. Total variance accounted for by one synergy increased (i.e., moved further from TD peers) after botulinum toxin type-A injection (1.3%) and selective dorsal rhizotomy (1.9%), but the change was small. Synergy weights did not change for any treatment group (average 0.001 ± 0.10), but synergy activations after selective dorsal rhizotomy did change and were less similar to TD peers (- 0.03 ± 0.07). Only changes in synergy activations were associated with changes in gait kinematics or walking speed after treatment. Children with synergy activations more similar to TD peers after treatment had greater improvements in gait.

CONCLUSIONS

While many of these children received significant surgical procedures and prolonged rehabilitation, the minimal changes in synergies after treatment highlight the challenges in altering neuromuscular control in CP. Development of treatment strategies that directly target impaired control or are optimized to an individual's unique control may be required to improve walking function.

Changes of and interrelationships between performance-based function and gait and patient-reported function 1 year after total hip arthroplasty

Background

The aim of this prospective study is to evaluate the degree of improvement in, and interrelationships between, performance-based function, gait, and patient-reported function 1 year after total hip arthroplasty (THA) in patients with primary hip osteoarthritis (OA).

Materials and methods

Thirty-four patients with hip OA, with a mean age of 67 years (standard deviation, SD 9 years), and 25 age- and gender-matched healthy controls performed three performance-based functional tests, instrumented three-dimensional gait analysis, and completed the Hip disability and Osteoarthritis Outcome Score prior to and 1 year after THA. Effect sizes with 95 % confidence intervals were calculated as measures of the magnitude of improvement in performance after surgery.

Results

Performance-based function displayed large improvements 1 year after THA. Overall gait patterns, quantified using a kinematic and a kinetic gait index, respectively, revealed moderate improvements in kinematics of the operated limb and kinetics of the contralateral limb. Patient-reported function displayed the largest improvement after surgery.

Conclusions

The findings of this study suggest that objectively measured improvements in performance-based function and gait are not in line with patient-reported functional improvements, highlighting the importance of using both subjective and objective methods for evaluating function following THA.

Level of evidence

III.

Gait Profile Score in able-bodied and post-stroke individuals adjusted for the effect of gait speed

BACKGROUND

The Gait Profile Score (GPS) measures the quality of an individual's walking by calculating the difference between the kinematic pattern and the average walking pattern of healthy individuals.

RESEARCH QUESTIONS

The purposes of this study were to quantify the effect of speed on the GPS and to determine whether the prediction of gait patterns at a specific speed would make the GPS outcome insensitive to gait speed in the evaluation of post-stroke individuals.

METHODS

The GPS was calculated for able-bodied individuals walking at different speeds and for the comparison of post-stroke individuals with able-bodied individuals using the original experimental data (standard GPS) and the predicted gait patterns at a given speed (GPS velocity, GPS^v). We employed standard gait analysis for data collection of the subjects. Sixteen participants with a stroke history were recruited for the post-stroke group, and 15 age-matched, able-bodied participants formed the control group.

RESULTS

Gait speed significantly affects the GPS and the method to predict the gait patterns at any speed is able to mitigate the effects of gait speed on the GPS. Overall, the gap between the GPS and GPS^v values across the post-stroke individuals was small (0.5° on average, range from 0.0° to 1.4°) and not statistically significant. However, there was a significant negative linear relationship in the absolute difference between the GPS and GPS^v values for the participants of the post-stroke group with gait speed, indicating that a larger difference between the speeds of the post-stroke participant and the reference dataset resulted in a larger difference between the GPS and GPS^v.

SIGNIFICANCE

The modified version of the GPS, the GPS^v, is effective in reducing the impact of gait speed on GPS; however, the observed difference between the two methods was only around 1° for the slowest individuals in comparison to the reference dataset.