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Purpose: To investigate the effects of a systematic tuning protocol for ankle foot orthosis footwear combinations (AFO-FC) using incrementing heel height on gait in children with cerebral palsy (CP). Methods: Eighteen children with CP (10.8 ± 3 years, Gross Motor Function Classification System (GMFCS) I–II) underwent 3D gait analysis on a treadmill, while the AFO heel surface was systematically incremented with wedges. Children were subdivided based on their gait pattern, i.e., knee hyperextension (EXT) and excessive knee flexion (FLEX). Outcome measures included sagittal hip and knee angles and moments, shank to vertical angle (SVA), foot to horizontal angle, and gait profile score (GPS). Results: For both groups, incrementing heel height resulted in increased knee flexion, more inclined SVA, and increased knee extension moments. This resulted in gait improvements for some children of the EXT-group, but not in FLEX. High variation was found between individuals and within-subject effects were not always consistent for kinematic and kinetics. Conclusions: A systematic AFO-FC tuning protocol using incremented heel height can be effective to improve gait in children with CP walking with EXT. The current results emphasise the importance of including kinematics as well as kinetics of multiple instances throughout the gait cycle for reliable interpretation of the effect of AFO tuning on gait.Implications for rehabilitation A systematic ankle foot orthosis footwear combinations (AFO-FC) tuning protocol using incremented heel height can improve gait in children walking with knee hyperextension. Tuning results in changes throughout the gait cycle. Little evidence is found for an optimal SVA of 10–12° at midstance. For clinical interpretation, both joint kinematic and kinetic parameters should be considered throughout the gait cycle and evaluation should not be based on SVA only.

Objective Hand orthoses are often prescribed for persons with chronic hand and wrist impairments. This study assessed the feasibility, in terms of production time and user satisfaction, of 3-dimensional printed hand orthoses compared with conventional hand orthoses for this population. Methods In this prospective case series, both a conventional hand orthosis and a 3-dimensional printed hand orthosis were manufactured for 10 participants. Production time (in minutes) of each orthosis was recorded. Each orthosis was worn for one week, after which participants completed a self-designed questionnaire on satisfaction, scored on a 5-point Likert scale. Functionality and orthosis preference were also assessed. Results The mean (standard deviation (SD)) production time for the 3-dimensional printed orthoses, of 112 (11.0) min, was significantly shorter compared with 239 (29.2) min for the conventional orthoses (95% confidence interval (95% CI) 71–182 min, p = 0.001). Satisfaction scores were similar for both orthoses, except for comfort item “fitting method”, which was rated significantly higher for scanning compared with casting (median [IQR] score: 5 [0.0]; 4 [2.0], p = 0.034). Functionality and orthosis preference were rated similar for both orthoses. CONCLUSION As the production time was halved, user satisfaction similar, and scanning experienced as slightly more comfortable than casting, 3-dimensional printed hand orthoses seem feasible and potentially beneficial for use in people with chronic hand and wrist impairments. LAY ABSTRACT Persons with chronic hand and wrist impairments often use an orthosis to make it easier to perform daily activities. Three-dimensional scanning and printing can facilitate the manufacturing of hand orthoses. This study compared 3-dimensional printed orthoses with conventional orthoses for persons with chronic hand and wrist impairments, with regard to production time and user satisfaction. Ten participants used a 3-dimensional printed orthosis, as well as a conventional orthosis, each for one week. The results showed that production time of 3-dimensional printed orthoses was half that of conventional orthoses. Satisfaction with both orthoses was similar, except for the “fitting method”, whereby fitting by 3-dimensional scanning was perceived as slightly more comfortable compared with conventional casting. Functionality and orthosis preference were rated similar for both orthoses. In conclusion, 3-dimensional printed orthoses appear to be a potential treatment option for persons with chronic hand and wrist impairments.

Previous research showed that an Inertial Measurement Unit (IMU) on the anterior side of the shank can accurately measure the Shank-to-Vertical Angle (SVA), which is a clinically-used parameter to guide tuning of ankle-foot orthoses (AFOs). However, in this context it is specifically important that differences in the SVA are detected during the tuning process, i.e., when adjusting heel height. This study investigated the validity of the SVA as measured by an IMU and its responsiveness to changes in AFO-footwear combination (AFO-FC) heel height in persons with incomplete spinal cord injury (iSCI). Additionally, the effect of heel height on knee flexion-extension angle and internal moment was evaluated. Twelve persons with an iSCI walked with their own AFO-FC in three different conditions: (1) without a heel wedge (refHH), (2) with 5 mm heel wedge (lowHH) and (3) with 10 mm heel wedge (highHH). Walking was recorded by a single IMU on the anterior side of the shank and a 3D gait analysis (3DGA) simultaneously. To estimate validity, a paired t-test and intraclass correlation coefficient (ICC) between the SVAIMU and SVA3DGA were calculated for the refHH. A repeated measures ANOVA was performed to evaluate the differences between the heel heights. A good validity with a mean difference smaller than 1 and an ICC above 0.9 was found for the SVA during midstance phase and at midstance. Significant differences between the heel heights were found for changes in SVAIMU (p = 0.036) and knee moment (p = 0.020) during the midstance phase and in SVAIMU (p = 0.042) and SVA3DGA (p = 0.006) at midstance. Post-hoc analysis revealed a significant difference between the ref and high heel height condition for the SVAIMU (p = 0.005) and knee moment (p = 0.006) during the midstance phase and for the SVAIMU (p = 0.010) and SVA3DGA (p = 0.006) at the instant of midstance. The SVA measured with an IMU is valid and responsive to changing heel heights and equivalent to the gold standard 3DGA. The knee joint angle and knee joint moment showed concomitant changes compared to SVA as a result of changing heel height.

Ankle-Foot Orthoses (AFOs) are commonly prescribed to promote gait in children with cerebral palsy (CP). The AFO prescription process is however largely dependent on clinical experience, resulting in confusing results regarding treatment efficacy. To maximize efficacy, the AFO's mechanical properties should be tuned to the patient's underlying impairments. This study aimed to investigate whether the efficacy of a ventral shell AFO (vAFO) to reduce knee flexion and walking energy cost could be improved by individually optimizing AFO stiffness in children with CP walking with excessive knee flexion. Secondarily, the effect of the optimized vAFO on daily walking activity was investigated. Fifteen children with spastic CP were prescribed with a hinged vAFO with adjustable stiffness. Effects of a rigid, stiff, and flexible setting on knee angle and the net energy cost (EC) [Jkg(-1)m(-1)] were assessed to individually select the optimal stiffness. After three months, net EC, daily walking activity [stridesmin(-1)] and knee angle [deg] while walking with the optimized vAFO were compared to walking with shoes-only. A near significant 9% (p=0.077) decrease in net EC (-0.5Jkg(-1)m(-1)) was found for walking with the optimized vAFO compared to shoes-only. Daily activity remained unchanged. Knee flexion in stance was reduced by 2.4° (p=0.006). These results show that children with CP who walk with excessive knee flexion show a small, but significant reduction of knee flexion in stance as a result of wearing individually optimized vAFOs. Data suggest that this also improves gait efficiency for which an individual approach to AFO prescription is emphasized.

Background Ankle–foot orthoses can be prescribed to improve gait in children with cerebral palsy. Before evaluating the effects of ankle–foot orthoses on gait, a period to adapt or acclimatize is usually applied. It is however unknown whether an acclimatization period is actually needed to reliably evaluate the effect of a new orthosis on gait. This study aimed to investigate whether specific gait parameters in children with cerebral palsy would change within an acclimatization period after being provided with new ankle–foot orthoses. Methods Ten children with cerebral palsy, walking with excessive knee flexion in midstance (8 boys; mean (SD) 10.2 (1.9) years; Gross Motor Function Classification System levels I–II) were provided with ventral shell ankle–foot orthoses. The orthoses were worn in combination with the child's own shoes and tuned, based on ground reaction force alignment with respect to the lower limb joints. Directly after tuning (T0) and four weeks later (T1), 3D-gait analysis was performed using an optoelectronic motion capture system and a force plate. From this assessment, ten spatiotemporal, kinematic and kinetic gait parameters were derived for the most affected leg. Differences in parameters between T0 and T1 were analyzed using paired t-tests or Wilcoxon signed rank tests (P Findings Over the course of four weeks, no significant differences (P ≥ 0.080) were observed for any investigated parameter. Interpretation These results imply that the biomechanical effect of ventral shell ankle–foot orthoses on gait in independent walking children with cerebral palsy is immediately apparent, i.e., there is no further change after acclimatization.

The effectiveness of an Ankle-Foot Orthosis footwear combination (AFO-FC) may be partly dependent on the alignment of the ground reaction force with respect to lower limb joint rotation centers, reflected by joint angles and moments. Adjusting (i.e. tuning) the AFO-FC's properties could affect this alignment, which may be guided by monitoring the Shank-to-Vertical-Angle. This study aimed to investigate whether the Shank-to-Vertical-Angle during walking responds to variations in heel height and footplate stiffness, and if this would reflect changes in joint angles and net moments in healthy adults. Ten subjects walked on an instrumented treadmill and performed six trials while walking with bilateral rigid Ankle-Foot Orthoses. The AFO-FC heel height was increased, aiming to impose a Shank-to-Vertical-Angle of 5°, 11° and 20°, and combined with a flexible or stiff footplate. For each trial, the Shank-to-Vertical-Angle, joint flexion-extension angles and net joint moments of the right leg at midstance were averaged over 25 gait cycles. The Shank-to-Vertical-Angle significantly increased with increasing heel height (p< 0.001), resulting in an increase in knee flexion angle and internal knee extensor moment (p < 0.001). The stiff footplate reduced the effect of heel height on the internal knee extensor moment (p = 0.030), while the internal ankle plantar flexion moment increased (p = 0.035). Effects of heel height and footplate stiffness on the hip joint were limited. Our results support the potential to use the Shank-to-Vertical-Angle as a parameter to evaluate AFO-FC tuning, as it is responsive to changes in heel height and reflects concomitant changes in the lower limb angles and moments.

Introduction Rigid Ankle-Foot Orthoses (AFOs) are commonly prescribed to counteract excessive knee flexion during the stance phase of gait in children with cerebral palsy (CP). While rigid AFOs may normalize knee kinematics and kinetics effectively, it has the disadvantage of impeding push-off power. A spring-like AFO may enhance push-off power, which may come at the cost of reducing the knee flexion less effectively. Optimizing this trade-off between enhancing push-off power and normalizing knee flexion in stance is expected to maximize gait efficiency. This study investigated the effects of varying AFO stiffness on gait biomechanics and efficiency in children with CP who walk with excessive knee flexion in stance. Fifteen children with spastic CP (11 boys, 10±2 years) were prescribed with a ventral shell spring-hinged AFO (vAFO). The hinge was set into a rigid, or spring-like setting, using both a stiff and flexible performance. At baseline (i.e. shoes-only) and for each vAFO, a 3D-gait analysis and 6-minute walk test with breath-gas analysis were performed at comfortable speed. Lower limb joint kinematics and kinetics were calculated. From the 6-minute walk test, walking speed and the net energy cost were determined. A generalized estimation equation (p

A rigid ventral shelf ankle foot orthosis (AFO) may improve gait in children with spastic cerebral palsy (SCP) whose gait is characterized by excessive knee flexion in stance. However, these AFOs can also impede ankle range of motion (ROM) and thereby inhibit push-off power. A more spring-like AFO can enhance push-off and may potentially reduce walking energy cost. The recent development of an adjustable spring-hinged AFO now allows adjustment of AFO stiffness, enabling tuning toward optimal gait performance. This study aims to quantify the mechanical properties of this spring-hinged AFO for each of its springs and settings. Using an AFO stiffness tester, two AFO hinges and their accompanying springs were measured. The springs showed a stiffness range of 0.01−1.82 N·m·deg−1. The moment-threshold increased with increasing stiffness (1.13–12.1 N·m), while ROM decreased (4.91–16.5°). Energy was returned by all springs (11.5–116.3 J). These results suggest that the two stiffest available springs should improve joint kinematics and enhance push-off in children with SCP walking with excessive knee flexion.

Background Ankle-Foot-Orthoses with a ventral shell, also known as Floor Reaction Orthoses (FROs), are often used to reduce gait-related problems in children with spastic cerebral palsy (SCP), walking with excessive knee flexion. However, current evidence for the effectiveness (e.g. in terms of walking energy cost) of FROs is both limited and inconclusive. Much of this ambiguity may be due to a mismatch between the FRO ankle stiffness and the patient’s gait deviations. The primary aim of this study is to evaluate the effect of FROs optimised for ankle stiffness on the walking energy cost in children with SCP, compared to walking with shoes alone. In addition, effects on various secondary outcome measures will be evaluated in order to identify possible working mechanisms and potential predictors of FRO treatment success. Method/Design A pre-post experimental study design will include 32 children with SCP, walking with excessive knee flexion in midstance, recruited from our university hospital and affiliated rehabilitation centres. All participants will receive a newly designed FRO, allowing ankle stiffness to be varied into three configurations by means of a hinge. Gait biomechanics will be assessed for each FRO configuration. The FRO that results in the greatest reduction in knee flexion during the single stance phase will be selected as the subject’s optimal FRO. Subsequently, the effects of wearing this optimal FRO will be evaluated after 12–20 weeks. The primary study parameter will be walking energy cost, with the most important secondary outcomes being intensity of participation, daily activity, walking speed and gait biomechanics. Discussion The AFO-CP trial will be the first experimental study to evaluate the effect of individually optimised FROs on mobility and participation. The evaluation will include outcome measures at all levels of the International Classification of Functioning, Disability and Health, providing a unique set of data with which to assess relationships between outcome measures. This will give insights into working mechanisms of FROs and will help to identify predictors of treatment success, both of which will contribute to improving FRO treatment in SCP in term. Trial registration This study is registered in the Dutch Trial Register as NTR3418.

Introduction and aim: In patients with post polio syndrome (PPS), gait is frequently hampered by excessive and/or abrupt ankle dorsiflexion, caused by weakness of the plantar flexors. This can lead to instability and fatigue due to a reduced walking efficiency [1]. To provide stability and increase walking efficiency, patients with plantar flexor weakness can be prescribed with a spring-like dorsiflexion stopped ankle-foot orthosis (DS-AFO). In patients with stroke and MS presenting spastic leg paresis, it has been shown that walking with such an AFO can optimize walking efficiency by choosing the correct ankle stiffness [2]. A similar principal might also apply to patientswith flaccid paresis. The aimof this studywas to evaluate the effect of different degrees of DS-AFO ankle stiffness on walking efficiency and gait biomechanics in patients with PPS and plantar flexor weakness. Patients/materials and methods: One male patient with PPS and mild plantar flexor weakness participated (age: 67 years, MRC score plantar flexors: 4+, gait pattern: excessive ankle range of motion combined with persistent knee flexion during stance). For this patient a custommade foot partwith calf casingwas fabricated, in which five interchangeable carbon leaf springs with a different degree of stiffness (k) could be placed (range: k1: 0.8Nm/deg to k5: 7.3Nm/deg, as measured with the BRUCE device [3]). The patient was first assessed for gait biomechanics (Vicon MX, AMTI force plates) at comfortable speed while walking with the DS-AFO (5 springs, tested in random order). Each measurement started after the patient indicated to be customized to the new spring. After each condition, satisfaction was rated with a visual analogue scale. Subsequently, walking efficiency was assessed (Cosmed) during a 6-min walk test for the most satisfying DS-AFO spring, the stiffest and themost compliant spring. Gait biomechanics andwalking efficiency were also assessed for the patients’ own DS-AFO and for walking with shoes alone. Results: The patient rated DS-AFO-k3 (2.5Nm/deg) asmost satisfying: ‘It supported, butdidnot constrain toomuch’.Walkingwith this DS-AFO resulted in the highest comfortable gait speed (10% higher compared to shoes alone) and it increasedwalking efficiency with 2.5% compared to walking with shoes alone and to walking with his ownDS-AFO (Fig. 1). However,most efficient gaitwas seen with the stiffest spring (k5 =7.3Nm/deg): +4.1% compared to walking with shoes alone. Regarding gait biomechanics, ankle range of motion (range: k1: 33◦ to k5: 19◦) and ankle power during push-off (range: k1: 2.1W/kg to k5: 1.2W/kg) reduced with increasing stiffness. Only the three stiffest springs resulted in a decreased knee flexion during terminal stance (all about −4.8◦), compared to the two most compliant springs. Discussion and conclusions: The results of this case study indicate that for this patient with PPS and plantar flexor weakness optimizing DS-AFO ankle stiffness was useful for improving gait with respect to walking efficiency. Walking with the stiffest DSAFO (k5 =7.3) resulted in the most efficient gait, and, although the improvements were small, gait efficiency and reduction of knee flexion seemed to be related. However, the most efficient DS-AFO wasnot considered themost satisfyingDS-AFO. Sinceplantar flexor weakness from themeasuredpatientwas onlymild, a high stiffness may not be optimal. This is the first result from an ongoing project; we expect that a broader range in plantar flexorweaknesswill yield more precise relations onhowDS-AFOmechanics andpatient characteristics interact towards gait performance. Ultimately, this will serve DS-AFO stiffness selection in patients with PPS.