The impact of foot orthoses on gait in children with Osteogenesis Imperfecta type I, III and IV - a cross-sectional study.

BACKGROUND: For children with Osteogenesis Imperfecta (OI), a rare genetic bone disease, walking can be difficult to carry out due to a combination of bone fragility and deformity, muscle weakness, joint hypermobility, and pain. Bisphosphonate treatment has facilitated more children being able to walk, but for many, foot and ankle hypermobility is a limiting factor. Current evidence on foot orthoses in children with OI is sparse. This study aimed to evaluate gait characteristics in children with OI walking barefoot as compared to walking with foot orthoses. METHODS: Twenty-three children with OI and hypermobility (mean age 8.3 ± 3.0 years) were included in this cross-sectional study. Children conducted three-dimensional gait analysis barefoot, and with foot orthoses and appropriate foot wear (stable yet light-weight), respectively. Walking speed, step length, lower limb kinematics and kinetics were collected. Differences in gait characteristics between test conditions were evaluated using paired sample t-tests. RESULTS: When walking with foot orthoses, the external foot progression angle was reduced, peak ankle dorsiflexion angle increased, and peak plantarflexion moment increased as compared to barefoot. No difference was found in walking speed between test conditions, however, children with OI walked with longer steps with foot orthoses as compared to barefoot. CONCLUSION: The observed gait alterations suggest that foot orthoses, aiming to support the foot and ankle joint, contributed to reduced overall foot rotation as measured by external foot progression, increased peak plantarflexion moment, and increased step length. In a wider perspective, the ability to walk provides the opportunity to be physically active, and thereby increase skeletal loading and prevent fractures, thus, foot orthoses may be an important treatment option to consider in children with OI. LEVEL OF EVIDENCE: III.

Validation of algorithms for calculating spatiotemporal gait parameters during continuous turning using lumbar and foot mounted inertial measurement units.

Spatiotemporal gait parameters such as step time and walking speed can be used to quantify gait performance and determine physical function. Inertial measurement units (IMUs) allow for the measurement of spatiotemporal gait parameters in unconstrained environments but must be validated against a gold standard. While many IMU systems and algorithms have been validated during treadmill walking and overground walking in a straight line, fewer studies have validated algorithms during more complex walking conditions such as continuous turning in different directions. This study explored the concurrent validity in a population of healthy adults (range 26-52 years) of three different algorithms using lumbar and foot mounted IMUs to calculate spatiotemporal gait parameters: two methods utilizing an inverted pendulum model, and one method based on strapdown integration. IMU data was compared to a Vicon twelve-camera optoelectronic system, using data collected from 9 participants performing straight walking and continuous walking trials at different speeds, resulting in 162 walking trials in total. Intraclass correlation coefficients (ICCA,1) for absolute agreement were calculated between the algorithm outputs and Vicon output. Temporal parameters were comparable in all methods and ranged from moderate to excellent, except double support time which was poor. Strapdown integration performed better for estimating spatial parameters than pendulum models during straight walking, but worse during turning. Selecting the most appropriate model should take into consideration both speed and walking condition.

Evaluation of Knee Position Sense in Children with Motor Disabilities and Children with Typical Development: A Cross-Sectional Study.

BACKGROUND: In children with motor disabilities, knee position during walking is often of concern in rehabilitation. This study aimed to investigate knee joint position sense. Thirty-seven children with Cerebral Palsy (CP), 21 with Myelomeningocele (MMC), 19 with Arthrogryposis (AMC), and 42 TD children participated in the study. Knee joint position sense, i.e., the difference between the criterion angle and the reproduced angle (JPS-error), was assessed in sitting while 3D motion capture was recorded at flexed knee 70 (Knee70), 45 (Knee45), and 20 (Knee20) degrees, and after three seconds at maintained criterion angle (CAM) and maintained reproduced angle (RAM). No differences were found between the groups in JPS-error, CAM, and RAM. At Knee70, CAM differed between the right and left legs in the TD group (p = 0.014) and RAM in the MMC group (p = 0.021). In the CP group, CAM was greater than RAM at Knee70 in the left leg (p = 0.002), at Knee45 in both legs (p = 0.004, p = 0.025), and at Knee20 in the right leg (p = 0.038). Difficulties in maintaining the knee position at CAM in the CP group sheds light on the need for complementary judgments of limb proprioception in space to explore the potential influence on knee position during walking.

Biomechanical analysis of lifting on stable versus unstable surfaces-a laboratory-based proof-of-concept study.

BACKGROUND: Many workers performing manual handling tasks suffer from musculoskeletal disorders (MSD). Previous research has identified several loading aspects associated with manual handling, but it is still unknown if lifting on an unstable surface is associated with increased biomechanical loading of different body parts. AIM: This proof-of-concept study aims to study what kinematic and kinetic movement parameters, such as movement time, joint angles, torque, and muscle activity are feasible and of importance when studying the effect of lifting on surfaces with varying degrees of stability in an experimental set-up. METHODS: Measurements were taken during three different surface conditions: stable, slightly unstable, and unstable. The participants were instructed to lift a box from the floor and place it on a table in front of them. The weight of the box varied from 0.5 to 15.5 kg. By using a motion capture system (VICON) with 28 reflective markers placed on the participants and one on the box, one Kistler force plate for measuring force levels and center of pressure movements (CoP), and four electromyographic transmitters (EMG), we analyzed the downward and upward phases of the lifting movement, using the Friedman's test for repeated measures. RESULTS: Statistically significant results with less joint movements in the lower and upper back were seen with increased instability during both the downward and upward phases. The decrease in trunk movements with increased instability resulted in a somewhat more flexed knee position during the movement, a lower torque in the lower back, and a decrease in CoP movements, but no differences in movement time or muscle activity in back and knee muscles. CONCLUSION: Lifting while standing on unstable surfaces resulted in an alteration of both kinematics and kinetics parameters; however, further studies regarding whether this is an additional risk factor for developing lower back pain are needed. Muscle activity levels were not altered due to instability and due to the complexity of the measurement, and we suggest not including EMG measures in future experiments of this type.

Comparative analysis of power, work and muscle activation during weight-stack and iso-inertial flywheel resistance exercise in young adults with cerebral palsy.

INTRODUCTION: The development of efficient resistance exercise protocols to counteract muscle dysfunction in cerebral palsy is warranted. Whether individuals with cerebral palsy are able to perform iso-inertial resistance (flywheel) exercise in a comparable manner to typically developed subjects has never been experimentally tested. DESIGN: A comparative, controlled study. SUBJECTS: Eight young ambulatory adults with cerebral palsy (mean age 19 years; Gross Motor Function Classification System (GMFCS) I-III) and 8 typically developed control subjects (mean age 21 years). METHODS: Subjects performed acute bouts on the weight-stack and flywheel leg-press device, respectively. Range of motion, electromyography, power, work and muscle thickness (ultrasound) data were collected. RESULTS: Subjects with cerebral palsy were able to produce a greater eccentric/concentric peak power ratio on the flywheel (p < 0.05 vs ratio in weight-stack), however absolute values were lower (p < 0.05 vs weight-stack). Typically developed subjects produced more power per mm of thigh muscle than the cerebral palsy group, independent of leg, device and action. DISCUSSION: Subjects with cerebral palsy could not elicit the eccentric overload seen in typically developed subjects. Furthermore, peak power production per mm muscle was markedly reduced in both legs in subjects with cerebral palsy. In conclusion, this comparative study of weight-stack and flywheel exercise does not support the implementation of the current iso-inertial protocol for young adults with cerebral palsy.