Effects of simulated crouch gait on foot kinematics and kinetics in healthy children.

Identification of secondary and tertiary impairments in neurologically induced gait deviations, such as crouch gait, is not always straightforward, but essential in order to decide upon the most efficient medical treatment in patients with cerebral palsy (CP). Until now, exact intersegmental dependency of the development of foot deformities has not been investigated. Therefore, the aim of this study was to explore if an artificially induced bilateral knee flexion contracture causes compensatory mechanisms in foot motion during gait in healthy children. Three-dimensional kinematic and kinetic data from 30 healthy children (mean age 10.6 years) were derived from the Oxford Foot model (OFM). Participants walked first in an artificially induced crouch gait (limitation of knee extension to 40°) and then normally. Walking speed was kept the same in both conditions. Analysis revealed small but significant (p<0.05) differences between the two conditions in hindfoot and forefoot kinematics in all three planes during the stance phase as well as for all peak internal moments within the foot. In general the foot tended to compensate for an artificial knee flexion contracture with an increase in maximal dorsiflexion, eversion and external rotation of the hindfoot, which also allowed increased foot motion in other foot segments. The results of this study showed that an isolated proximal joint contracture had an influence on foot position during stance in healthy children. Further interpretation of the data in relation to CP children will be possible as soon as comparable OFM data of pathological crouch gait is available.

Balzer J ，Schelldorfer S ，Bauer C ，van der Linden ML ... -  《-》

Threshold of equinus which alters biomechanical gait parameters in children.

The main aim of this study was to define the threshold angle of equinus beyond which significant changes in 3D lower limb kinematics and kinetics occur in typically developing children and to describe these changes.A customized orthosis was fitted on the right ankle of 10 typically developing children and was adjusted to +10° ankle dorsiflexion, 0°, -10°, -20° plantarflexion and maximum plantarflexion. Gait was analyzed using an optoelectronic system. A gait velocity of 1m/s was imposed.Most of the kinematic and kinetic changes were significantly altered from the -10° condition. In the sagittal plane, the results showed increased knee flexion at initial contact, increased knee flexion or hyperextension in stance, increased hip flexion at initial contact and increased anterior pelvic tilt. Other changes included increased knee varus, reduced hip adduction and more internal foot progression. The ankle plantarflexion moment was bi-phasic during stance, peak ankle power generation was reduced, peak knee extension moment was decreased and hip extension moments increased. On the contralateral side, there was a significant increase in ankle plantarflexion at initial contact and a significant decrease in knee flexion during swing phaseat maximum plantarflexion.Although slight modifications occurred for smaller degrees of equinus, the results suggest that significant kinematic and kinetic changes occurred during gait in both limbs from 10° of plantarflexion. The results of this study also provide some indications regarding the primary causes of gait deviations and secondary compensatory strategiesin children with a clinical dorsiflexion limitation.

Houx L ，Lempereur M ，Rémy-Néris O ，Brochard S ... -  《-》

The efficacy of the floor-reaction ankle-foot orthosis in children with cerebral palsy.

Rogozinski BM ，Davids JR ，Davis RB 3rd ，Jameson GG ，Blackhurst DW ... -  《-》

On the imitation of CP gait patterns by healthy subjects.

The comparison of gait imitated by healthy subjects with real pathological CP gaits is expected to contribute to a better distinction between primary deviations directly induced by neurological troubles and secondary compensatory deviations in relation with the biomechanics of the pathological gait. However, the ability of healthy subjects for imitating typical CP gaits such as "jump" or "crouch" gaits still remains to be determined. The present study proposes to investigate healthy subjects imitating these typical CP gait patterns. 10 healthy adult subjects performed three types of gait: one "normal" and two imitated "jump" and "crouch" gaits. Kinematics and kinetics of the hip, knee and ankle were computed in the sagittal plane. Rectified normalized EMG was also analysed. Our data were compared with reference data. For the statistical analysis, the coefficient of multicorrelation has been used. It has been demonstrated that healthy subjects were able to voluntarily modify their gait pattern with a high level of intra-session and inter-subject reproducibility as quantified by a CMC values higher than 0.76 for all parameters. The comparison with literature reference data showed that healthy subjects not could perfectly reproduce a CP gait, however could only simulate the main characteristics of "crouch" and "jump" gaits pattern. As a perspective, pathological gaits imitated by healthy subjects could be used as valuable additional material to analyse the relationship between a voluntarily modified posture and the altered muscle activation to explore a new paradigm on pathological gait pattern analysis and musculoskeletal modelling.

Rezgui T ，Megrot F ，Fradet L ，Marin F ... -  《-》

Ground reaction and solid ankle-foot orthoses are equivalent for the correction of crouch gait in children with cerebral palsy.

To investigate any performance differences between the solid ankle-foot orthosis (SAFO) and ground reaction ankle-foot orthosis (GRAFO) designs for correcting crouch gait in children diagnosed with cerebral palsy (CP). We retrospectively analyzed 147 individuals seen at our center who: (1) were diagnosed with diplegic CP, (2) walked with crouch gait, (3) had bilateral SAFO or GRAFO prescription, and (4) had three-dimensional gait analysis collected for both barefoot and orthosis walking conditions. Overall, no performance gap was identified between the SAFO and GRAFO groups (p=0.828). A series of bootstrapped stepwise regression analyses indicated that ankle-foot orthosis (AFO) design was not predictive of crouch gait improvements. Improvements in crouch gait were instead shown to be predicted by AFO neutral angle and four patient factors: amount of dorsiflexion in stance, level of knee flexion contracture, age, and severity of crouch. Our results show that the SAFO and GRAFO designs are equally effective at correcting crouch gait for individuals diagnosed with CP. No performance difference was detected between solid ankle-foot orthoses and ground reaction ankle-foot orthoses designs for crouch gait correction. Crouch gait improvement from ankle-foot orthoses (AFO) is influenced by AFO neutral angle. Other factors of influence include: dorsiflexion in stance, level of knee flexion contracture, age, and severity of crouch.

Ries AJ ，Schwartz MH 《-》