Neto, Hugo Pasini PhD; Grecco, Luanda André Collange MS; Galli, Manuella PhD; Oliveira, Claudia Santos PhD
Cerebral palsy (CP) is a permanent, but not immutable, posture and movement disorder stemming from a nonprogressive brain abnormality due to hereditary factors or events during pregnancy, childbirth, the neonatal period, or the first 2 years of life. Cerebral palsy limits motor activities and is often accompanied by sensation, cognition, communication, perception, and behavioral disorders.1 According to a more current definition, CP is a nonprogressive chronic disease with a movement, posture, and motor function disorder stemming from lesions or abnormalities in the immature brain.2–4 Neuromotor impairment may involve different parts of the body, resulting in specific topographic classifications, such as quadriplegia, hemiplegia, and diplegia.5
Children with CP experience significant functional limitations due to excessive muscle weakness, kinematic joint abnormalities, and reduced postural reactions.6–9 Different therapeutic interventions seek to improve selective motor control and the coordination of muscle activity. One such intervention is the use of a positioning orthosis (brace), which, according to Lucareli et al,10 is used to facilitate and improve the gait pattern. Different types of orthoses may be prescribed for children with CP, such as an ankle-foot orthosis (AFO), which can help in alignment and gait quality. An AFO reduces plantar flexion of the ankle, leading to greater stability in the support phase of gait.11
There are different types of orthoses for different therapeutic indications. The rigid AFO is most often employed and maintains the ankle in a neutral position, thereby preventing plantar flexion contractures. Another option is the use of articulated orthoses, which allow dorsiflexion movement, thereby promoting the stretching of the posterior musculature and reportedly reducing electrical activity in this muscle group.12
The aim of this review was to compare the effects of rigid and articulated AFOs on gait in children with CP.
Searches were carried out in 4 databases (MEDLINE, PubMed, Embase, and PEDro) by using the following key words: cerebral palsy combined with rigid orthosis, articulated orthosis, and gait.
The papers located in the initial search were evaluated by 2 blinded evaluators on the basis of the following inclusion criteria: (1) design—controlled clinical trial; (2) population—children and adolescents with CP; (3) intervention—rigid or articulated AFOs; and (4) outcome—improved motor function and gait performance.
The papers selected were then analyzed with regard to methodological quality using the PEDro scale,13 which has 11 items for the assessment of the internal validity and statistical procedures in randomized controlled studies. Each adequately satisfied item contributes to a maximal score of 10 points (except item 1, which is not included in the scoring as it assesses external validity). The score of the articles provided in the web site of the databases was used. In cases in which this score was not provided, the manuscript was evaluated independently by 2 blinded researchers, with divergences between these 2 evaluators settled by a third evaluator.
The following items were used as the basis for scoring the papers: (1) Eligibility criteria: origin of subjects and list of requirements used to determine the subjects eligible for participation in the study; (2) Randomized allocation: random distribution of subjects into different groups; (3) Confidential allocation: the researcher who determined the eligibility of the subjects had no prior knowledge regarding to which group each subject would belong; (4) Similar prognosis: based on the initial prognosis, it would not be possible to predict clinically significant differences between groups; (3) Blinded subjects: the subjects had no knowledge regarding to which group they belonged; (4) Blinded therapists: the researcher who administered the therapeutic intervention had no knowledge regarding to which group each subject belonged; (5) Blinded evaluators: the researcher in charge of the evaluation had no knowledge regarding to which group each subject belonged; (6) Key results: the measurement of at least 1 key result among more than 85% of the subjects distributed among the different groups; (7) Comparisons between groups: data analysis of at least 1 of the key results; and (8) Results of precision and variability: presentation of measures of precision and variability for at least 1 of the key results.
The initial search of the databases resulted in 9 titles and abstracts addressing the comparison of rigid and articulate AFOs, 2 of which were case studies14,15 and did not achieve the necessary score on the PEDro scale to be a part of this review. Seven papers achieved a minimum of 3 points and were, therefore, considered methodologically adequate (Tables 1 and 2).
The 7 studies16–22 involved a total of 120 individuals. The majority of studies used the same volunteers for the experimental and control groups, alternating only the condition of the data collection. The number of participants ranged from 12 to 30 volunteers. The participants were children and adolescents with CP (spastic diplegia or hemiplegia), between 4 and 15 years of age.
The studies offer divergent results regarding the comparison of rigid and articulated AFOs. Some report significant differences in gait parameters, such as velocity, cadence, step length, and stride length, as well as kinetic and kinematic differences in the ankle and knee, whereas other studies found no significant differences between the 2 types of orthoses (Table 3).
The significant differences in the comparison between articulated and rigid orthoses were in the increase in peak dorsiflexion,16,19–22 reduction in double-support time,19 increase in gait speed,22 and reduction in energy expenditure22 with the use of the articulated orthosis (Table 3).
It should be stressed that this study considered only results regarding comparisons between rigid and articulated AFOs and did not address aspects related to the benefits of using an orthosis, as this topic is widely discussed in the literature.
All papers compared the effects of rigid and articulated AFOs during gait. Two studies included a third type of orthosis (posterior leaf spring),16,18 which was not considered in the presentation and discussion of the results of this study.
Gait performance was the parameter used for comparisons in all papers, which mainly investigated kinematic variations in the ankle, knee, and hip joints as well as differences in temporal-distance gait parameters, such as velocity, cadence, step length, and stride length. Moreover, 3 papers included an analysis of electromyographic activity in muscles related to gait, determining the degree of muscle activation in the different phases of gait with different orthoses.17,19,20 Other variables analyzed included energy expenditure with different orthoses16,18,22 and the preference of the individuals regarding the choice of orthosis.18
According to Cury et al,11 orthoses are part of the daily routine of children with CP and offer benefits mainly in locomotion in outdoor environments. The author also stated that orthoses significantly enhance gait quality in children with CP when compared with a control group, regardless of the topographic pattern of involvement.
The studies analyzed in this systematic review address gait characteristics with the use of rigid and articulated orthoses and offer divergent results regarding differences in gait parameters (velocity, cadence, step length, and stride length) between these 2 types of orthosis. It should be stressed that both types of orthosis lead to an improvement in gait parameters when compared to a control group without the use of an orthosis.
Buckon et al,16 Radtka et al,17 and Smiley et al18 found no significant differences in gait parameters between orthoses. In contrast, Rethlefsen et al21 found significant differences between 3 types of orthosis (rigid, articulated, and posterior leaf spring). The discrepancies in the results may be related to methodological differences between studies. Rethlefsen et al19 collected data with 3 orthoses in a single session, whereas the other studies cited allowed an adaptation period for the participants with different orthoses before data acquisition.
In agreement with other findings, Rowkes et al23 compared gait with and without an articulated orthosis in 10 children with hemiplegic CP and found changes in all gait parameters, stressing the improvement in step length, cadence, and gait speed as well as greater hip flexion upon initial contact and a reduction in plantar flexion in the swing phase. The authors concluded that this type of orthosis offers children a more functional gait.
However, Rethlefsen et al19 found that a rigid orthosis allowed greater stability during gait and suggest that this type of orthosis be used for patients with more severe impairment, as it assists in the prevention of muscle contractures. The authors state that the articulated orthosis, while achieving a more functional gait pattern, should be used with patients who have better hip and knee control.
It should be stressed that the results described by Rowkes et al23 were obtained from a gait analysis of children with hemiplegia, whereas Rethlefsen et al19 analyzed children with diplegia. This may explain the differences in the findings regarding the significant increase in the quality of the gait variables, as these 2 conditions present different impairments.
Other studies comparing the use of rigid and articulated orthosis during locomotion on stairs report a significant increase in the quality of gait parameters as well as the kinetic and kinematic aspects of lower limb joints with the use of an articulated orthosis.24 Moreover, Wilson et al24 report that an articulated orthosis offers a better transition between sitting and standing. More complex tasks require a greater range of motion in the joints, which respond more efficiently when allowed to move freely. Therefore, a rigid orthosis is more limiting for certain tasks and an articulated orthosis offers greater functional freedom for other tasks. However, these biomechanical advantages may not be made evident in gait analyses.
Another conflicting finding in the studies was the change in the kinematics of the ankle. Five of the papers reported better ankle dorsiflexion with the use of an articulated orthosis,16,17,20–22 whereas 2 papers reported no difference between orthoses with regard to this parameter.18,19 Among the inclusion criteria in the majority of the studies, the following are cited: absence of muscle shortening in flexor muscles of the hip or knee; contracture of less than 15° in the hip;20 and 10° of hip extension or 5° of dorsiflexion with the knees extended.17 The 2 papers that reported no significant differences between the orthoses did not include these criteria, which may explain the discrepancy in the results.
According to Radtka et al,17 the improvement in dorsiflexion achieved with an articulated orthosis (especially in the final support phase of gait) in comparison to a rigid orthosis constitutes an important clinical benefit, as this type of orthosis allows a more functional gait pattern.15,25 This corroborates findings described by Middleton et al,14 who published a case study and concluded that an articulated orthosis offers a more natural, symmetric gait pattern. This type of orthosis may, therefore, be an important resource for the prevention of deformities in plantar flexion.17 The maximal dorsiflexion allowed by an articulated orthosis may promote an increase in knee flexion, thereby increasing energy expenditure and negatively affecting gait.17 According to Carmick,15 a change from a rigid orthosis to an articulated orthosis is enough to alter the entire biomechanics of the body.
Regarding the knee kinematics, no significant differences are found between articulated and rigid orthoses during gait. However, the results demonstrate a tendency toward greater knee flexion upon initial contact among subjects using an articulated orthosis. One explanation for this is that muscle shortening in the triceps surae group, together with the distal fixation generated by the orthosis, may lead to a compensation in knee flexion due to the biarticular characteristic of this muscle group.18,22
There are a large number of studies that report the advantages of rigid and articulated orthoses, but few have compared the effects of these types of orthosis on gait. Moreover, methodological differences hinder the comparison of the results between studies. There is evidence supporting the use of an articulated AFO by children with CP due to the improved function this type of orthosis provides. However, other studies point out the advantages of a rigid orthosis for children with greater impairment related to spasticity and contractures.
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adolescent; cerebral palsy; child; gait; orthoses; systematic review
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