http://informahealthcare.com/idt ISSN 1748-3107 print/ISSN 1748-3115 online Disabil Rehabil Assist Technol, Early Online: 1–7 ! 2014 Informa UK Ltd. DOI: 10.3109/17483107.2014.908244
RESEARCH PAPER
Optimising the effects of rigid ankle foot orthoses on the gait of children with cerebral palsy (CP) – an exploratory trial
Disabil Rehabil Assist Technol Downloaded from informahealthcare.com by Gazi Univ. on 01/04/15 For personal use only.
Kavi C. Jagadamma1, Fiona J. Coutts1, Thomas H. Mercer1, Janet Herman2, Jacqueline Yirrell3, Lyndsay Forbes4, and Marietta L. van der Linden1 1
School of Health Sciences, Queen Margaret University, Edinburgh, UK, 2Anderson Gait Analysis Laboratory, Astley Ainsley Hospital, Edinburgh, UK, Department of Clinical Genetics, Western General Hospital, Edinburgh, UK, and 4Orthotics Department, Buchanan Orthotics, Glasgow, UK
3
Abstract
Keywords
Purpose: This exploratory trial investigated the effects of rigid ankle foot orthoses (AFO) with an optimally cast Angle of the Ankle in the AFO (AAAFO) on the gait of children with Cerebral Palsy (CP), and whether tuning of the AFO – Footwear Combination (AFO-FC) further affected gait. Methods: Eight children with CP underwent gait analysis and tuning of their AFO-FCs using a 3-D motion analysis system. Comparisons were carried out for selected gait parameters between three conditions – barefoot, non-tuned AFO-FC and tuned AFO-FC. Results: In comparison to barefoot gait, walking with a non-tuned AFO-FC produced significant (p50.05) improvements in several key gait parameters. Compared to the non-tuned AFO-FC, on average a tuned AFO-FC produced a significant reduction in peak knee extension and knee ROM during gait. However, when examined as case studies, it was observed that the type of gait pattern demonstrated while wearing a non-tuned AFO-FC affected the outcomes of tuning. Conclusions: The findings of the current study indicate the potential benefits of using rigid AFO-FC with optimal AAAFO and tuning of AFO-FCs. This study emphasises the need for categorising children with CP based on their gait patterns when investigating the effects of interventions such as AFOs.
AFO, ankle foot orthosis, cerebral palsy, gait, tuning History Received 28 August 2013 Revised 3 March 2014 Accepted 21 March 2014 Published online 21 April 2014
ä Implications for Rehabilitation
Rigid ankle foot orthoses (AFO) cast at an optimal angle to accommodate the length of gastrocnemius muscle may positively influence walking in children with Cerebral Palsy (CP). Tuning of the AFO-Footwear Combination (AFO-FC) has potential benefits to the walking of children with CP, depending on their gait abnormalities. When investigating the effects of interventions such as AFOs, it is important to categorise children with CP based on their gait abnormalities.
Introduction Cerebral Palsy (CP) is an umbrella term used to describe children with a group of disorders associated with injury to the developing brain. It has been reported that there is an incidence of CP ranging from 1.5 to 3 per 1000 live births in Europe [1]. Due to motor impairments such as alterations in muscle tone and loss of selective motor control, ambulatory children with CP commonly present with varying degrees of gait abnormalities, therefore they are prescribed rigid ankle foot orthoses (AFO) with the aim of improving their gait pattern. Several studies have investigated the effects of rigid AFOs, all of which have reported positive influences on at least one gait parameter. However, there is a lack
Address for correspondence: Dr Kavi C. Jagadamma, Lecturer, Physiotherapy Subject Area, School of Health Sciences, Queen Margaret University, Musselburgh, East Lothian EH21 6UU, UK. Tel: +44 131 474 0000. Fax: +44 131 474 0001. E-mail: [email protected]
of consistency among the studies in relation to which parameters were positively influenced. Some studies found that rigid AFOs influence temporal-spatial parameters and ankle joint kinematics of children with CP [2,3], while others found changes in proximal joint kinematics as well [4,5]. It has also been reported that rigid AFOs only influence ankle joint kinematics [6]. The ambiguity in the literature may be attributed to several factors, such as the lack of uniformity in study design [7], and poor biomechanical optimisation of AFOs, which has been suggested to have a vital role in effectiveness of AFO management [8,9]. It has been suggested that the design of AFOs and footwear can be optimised for children with CP. Biomechanical optimisation, or tuning, of the Ankle Foot Orthosis – Footwear Combination (AFO-FC) is a key consideration. Tuning involves modifying the alignment of AFO-FC using aids such as wedges, heels and rockers to optimise gait. The role of tuning of AFO-FCs was identified decades ago [8] and has been recommended for children with CP [10] and adults with stroke [11]. Although there have been only a few reports on the effects of tuning of AFOs,
Disabil Rehabil Assist Technol Downloaded from informahealthcare.com by Gazi Univ. on 01/04/15 For personal use only.
2
K. C. Jagadamma et al.
they have invariably reported improved gait parameters [13–15]. However, there is still a lack of evidence and consensus regarding the benefits of tuning of AFOs. A further consideration is the lack of consensus about the angle at which AFOs are cast, or in other words, Angle of the Ankle in AFO (AAAFO). Some authors have emphasised that the AAAFO is important, since a lack of available length of the gastrocnemius and soleus muscles at the ankle joint can prevent the knee joint from achieving adequate extension during gait [9,12]. However, this lacks empirical evidence. A search of the literature revealed 16 studies reporting the effects of rigid AFOs on the gait of children with CP, most of which have reported the AAAFO used. In the past, practice has been to use AFOs either cast at plantigrade or in dorsiflexion. However, recent recommendations have highlighted that research studies should state whether AAAFO has taken the length of gastrocnemius into consideration [10]. A further limitation of studies which have investigated the effects of tuning of AFO-FC is their comparison between tuned AFO-FC and barefoot [13–15] rather than a control condition, such as the non-tuned AFO-FC. Selected results from the dataset reported in this article have been published before, which compared between tuned AFO-FC and non-tuned AFO-FC to report the effects of tuning of mid-stance in five children whose knees hyperextended during gait [16]. Considering the lack of evidence, the current study had two aims. The first aim was to compare the gait of children with CP when wearing rigid AFOs with an optimally cast AAAFO, to their barefoot gait; the second aim was to explore whether tuning of these AFO-FC further influenced the gait of these children.
Disabil Rehabil Assist Technol, Early Online: 1–7
Table 1. Sample characteristics of the children with cerebral palsy. Age (years) Gender Diagnosis Participant Participant Participant Participant Participant Participant Participant Participant
1 5.6 2 12.5 3 7.8 4 7.2 5 6.2 6 12.5 7 8.3 8 11.8
Boy Girl Girl Boy Girl Girl Girl Boy
Orthosis-left Orthosis-right
Diplegia Dynamic AFO Hemiplegia Nil Diplegia Nil Diplegia Rigid AFO Hemiplegia Nil Diplegia Rigid AFO Hemiplegia Nil Hemiplegia Rigid AFO
Rigid AFO Rigid AFO Rigid AFO Rigid AFO Rigid AFO Rigid AFO Rigid AFO Nil
Table 2. Sample characteristics of healthy children. Number of participants 11
Mean age (SD) in years
Mean height (SD) in m
Mean weight (SD) in kg
10 (2.1)
1.44 (0.15)
38.5 (10.3)
Boys Girls 6
5
Methods Participants Ambulatory children with CP between 5 and 15 years of age who were using or prescribed rigid AFOs were recruited from the treatment lists of local physiotherapists. Children who had soft tissue or bony surgery in the previous year, botulinum toxin A or Baclofen in the previous 6 months, and who were diagnosed as having severe dystonia, ataxia or behavioural problems were excluded from the study. Eight children with CP participated in the study. Participant characteristics are given in Table 1. In total 10 legs with rigid AFOs were included in analysis. Eleven healthy children between 5 and 15 years of age were also recruited through personal contacts for reference gait data (Table 2). Ethical approval for the study was gained from the local UK NHS ethics committee and informed assent and consent were gained from the participants and their parents, respectively. Instrumentation All the rigid AFOs used by the participants were made of polypropylene and did not have any joints. The AFOs were custom-made for each participant by an orthotist. The thickness of polypropylene used varied (3, 4.5 or 6 mms) depending on the size and weight of the children, but was sufficient to keep the AFOs rigid at the ankle. The ankle angles of the AFOs were cast ranging from 90 (plantigrade) to varying degrees of plantar-flexion to accommodate any tightness present in the plantar-flexor muscles. All AFOs had their trim lines at the ankle, anterior to the malleoli; and had two straps, one at the proximal end of the shank and one at the ankle. When an AFO was cast in plantar-flexion, a heel wedge was added to align the midline of the shank of the AFO perpendicular to the floor when placed flat. Tuning was carried out with the participants’ own shoes. The wedges used for tuning were made of non-deformable Ethyl Vinyl Acetate (EVA) and the
Figure 1. Ankle Foot Orthosis-Footwear Combination (AFO-FC) with a wedge made of Ethyl Vinyl Acetate (EVA) and Point Loading Rocker (PLR) made of plastazote attached to the shoes.
Point Loading Rockers (PLRs) were made of high density plastazote. Figure 1 shows an example of an AFO-FC along with a wedge and PLR. Tuning and gait assessment were carried out in a gait analysis laboratory with an eight camera Vicon three-dimensional (3-D) motion analysis system with a sampling frequency of 100 Hz (Vicon motion systems Ltd., Oxford, UK). The laboratory had two force plates (AMTI, Watertown, MA) with sampling frequency of 1000 Hz embedded in the middle of the walkway. For data collection, reflective markers were attached to the anatomical landmarks as specified by the Vicon Plug-In-Gait model which is based on the Helen Hayes gait model [17].
Optimising the use of AFOs for children with CP
DOI: 10.3109/17483107.2014.908244
Disabil Rehabil Assist Technol Downloaded from informahealthcare.com by Gazi Univ. on 01/04/15 For personal use only.
Procedure Gait analysis was performed while the participant walked barefoot and with the non-tuned AFO-FC at a self-determined speed. This was followed by the tuning process, during which gait data were captured for the tuned AFO-FC. The order of the gait analysis was kept the same for all participants and no randomisation of the order was attempted. The tuning procedure was based on previous suggestions by Owen [9] and Butler and Nene [18]. The key element of the procedure was mid-stance tuning, which began with measurement of the shank to vertical angle (SVA), which is the angle made by shank of the tibia to an imaginary vertical line perpendicular to the ground. The SVA was measured in standing using a goniometer. Wedges were attached to the shoes until a SVA of 12 was obtained, which is considered optimal [9]. The participant then walked with the modified AFO-FC until three clean foot strikes on the force plates were obtained. The orientation of the Ground Reaction Force (GRF) during mid-stance was then visually analysed on the Vicon Workstation display, to identify the orientation of the GRF in relation to the knee during mid-stance. Mid-stance was identified as the point where the ankle joint of the swinging leg crossed the weightbearing leg. No more wedges were added if the GRF passed through the centre of the knee. However, if the GRF did not pass through the centre of the knee, the procedure was repeated with more or fewer wedges until the GRF passed as close to the knee as possible during mid-stance. Following on from mid-stance, terminal stance tuning was attempted. This was only attempted for children whose GRF was not aligned posterior to the hip joint and anterior to the knee joint during terminal stance which was considered optimal, as this is the case in normal gait [9]. When the orientation of the GRF during terminal stance was not determined to be optimal, a PLR was added, with the apex of the rocker at 75% of the shoe length. The GRF orientation was then visually analysed using Vicon Workstation display and the length and thickness of PLR were modified until the alignment of the GRF was as optimal as possible. Once the prescription was finalised, the session was concluded. For comparison, gait data collected from 11 healthy children within the age range of 5 to 15 years were used. Analysis Three walks with clean force plate strikes for each condition compared were considered for analysis. Data processing was completed using Vicon Workstation software which makes use of Plug-In-Gait model to calculate temporal-spatial parameters, joint kinematics and kinetics. Selected joint kinematic and kinetic (external moments) data and Temporal-spatial parameters were compared between barefoot and non-tuned AFO-FC, and nontuned and tuned AFO-FC. Statistical data analysis was carried out using SPSS for Windows Version 16.0 using paired t-tests or Wilcoxon signed rank tests depending on the distribution of the data. Results were considered statistically significant if p50.05. Three way comparison using a repeated measures analysis of
3
variance was not employed because the comparison between tuned AFO-FC and barefoot was of no interest in the current study. It was acknowledged that the heterogeneity of the sample in terms of gait patterns may mask the effects of intervention in several variables when using statistical comparisons reliant on measures of central tendency. Hence, further analysis was carried out using case studies to identify any possible trends specific to gait patterns. Sagittal knee joint kinematics of all participants are presented in the current article as tuning predominantly influences the knee joint and gait patterns of children with CP are mainly determined by knee joint kinematics. Average healthy data are provided for reference in both group comparisons and case studies. Healthy data have not been included in the statistical comparisons for two reasons; first, the emphasis of the study is on comparing the effects of AFO and tuning in children with CP, and more so with the case studies than group comparisons. Second, a three-way comparison did not seem ideal with the small sample size of the current study. However, the authors have attempted to discuss the direction of change (improvement or deterioration) in variables using healthy data as a reference to help the reader understand the nature of change in selected variables.
Results Temporal-spatial parameters and SVA The means (SD) of the temporal-spatial parameters, with statistical comparisons for barefoot walking and walking with non-tuned AFO-FC, and walking with non-tuned AFO-FC and tuned AFO-FC, are given in Table 3. Stride length (p ¼ 0.01, t ¼ 3.92) and walking speed (p ¼ 0.04, Z ¼ 2.09) were significantly higher with non-tuned AFO-FC in comparison to barefoot, whereas none of the temporal-spatial parameters were significantly different between non-tuned and tuned AFO-FC. Kinematics and kinetics of the lower limb joints Table 4 provides the comparison of selected kinematic variables between barefoot and a non-tuned AFO-FC, and between a nontuned AFO-FC and tuned AFO-FC. In comparison to barefoot, knee ROM was 4 higher (p ¼ 0.02, t ¼ 2.69) and hip ROM was 5 higher (p ¼ 0.04, t ¼ 2.45) with the non-tuned AFO-FC. Comparing the kinematics between a non-tuned AFO-FC and a tuned AFO-FC, lower peak knee extension with tuned AFO-FC was seen compared to non-tuned AFO-FC (7.1 flexion versus 10.3 flexion) (p ¼ 0.04, t ¼ 2.33). Furthermore, knee ROM was lower by 6 with tuned AFO-FC compared to non-tuned (p ¼ 0.02, t ¼ 2.88). No differences were found in the hip and pelvis kinematics in any of the comparisons. Figure 2 indicates the key divisions of the gait cycle considered in this study [19]. Figure 3 shows the sagittal plane knee kinematics of all eight participants comparing barefoot, nontuned AFO-FC and tuned AFO-FC. Several key trends could be noted. In comparison to barefoot, the influence of non-tuned AFO-FC showed mixed effects on knee kinematics. In some
Table 3. Results of comparison of the temporal-spatial parameters between barefoot and non-tuned AFO-FC, and between non-tuned AFO-FC and tuned AFO-FC.
Cadence (steps/minute) Stride-length (m) Walking speed (m/s) a
Barefoot mean (SD)
Non-tuned AFO-FC Mean (SD)
Tuned AFO-FC Mean (SD)
Healthy mean (SD)
117.7 (27.0) 0.82 (0.3) 0.84 (0.4)
122.3 (14.7) 0.98 (0.2)a 0.99 (0.2)a,b
123.0 (9) 0.97 (0.2) 0.99 (0.2)
119.7 (15.5) 1.4 (0.2) 1.4 (0.2)
Significantly different with non-tuned AFO-FC in comparison to barefoot at p50.05. Wilcoxon signed-rank test was used for comparisons involving this variable, all other comparisons were made using paired t-test.
b
4
K. C. Jagadamma et al.
Disabil Rehabil Assist Technol, Early Online: 1–7
Table 4. Results of comparison of kinematic data points between barefoot and non-tuned AFO-FC, and between non-tuned AFOFC and tuned AFO-FC (n ¼ 10 legs). Barefoot Mean (SD) Peak anterior pelvic tilt Peak posterior pelvic tilt Pelvic tilt ROM Peak hip flexion Peak hip extension Peak hip flexion (stance) Hip ROM Knee flexion at initial contact Peak knee flexion (stance) Peak knee extension (stance) Peak knee flexion Knee ROM
21.8 13.4 8.4 44.2 3.4 38.8 40.8 19.1 22.4 7.6 52.5 45.0
Non-tuned AFO-FC Mean (SD)
(6.7) (7.1) (2.4) (9.7) (8.8) (10.9) (9.0) (8.2) (8.4) (9.9) (5.7) (12.6)
23.0 14.4 8.5 46.1 0.5 42.9 45.7 20.7 27.0 7.1 56.0 48.9
(8.3) (8.1) (2.6) (11.0) (8.1) (12.3) (6.2)a (12.4) (2.2) (12.2) (6.4)c (14.4)a
Tuned immediate Mean (SD) 22.9 14.3 8.5 46.8 2.6 44.7 44.2 22.1 29.7 10.3 53.4 43.1
(10.9) (9.8) (2.7) (13.7) (10.9) (12.8) (6.9) (9.1) (8.0) (9.5)b (6.9) (13.5)b
Healthy Mean (SD) 12.8 7.7 5.1 39.6 11.3 37.4 50.9 2.5 20.9 4.1 65.8 61.6
(5.5) (5.0) (0.9) (8.0) (5.7) (8.2) (6.2) (4.4) (6.2) (2.8) (5.2) (5.6)
For hip and knee kinematics positive values represent flexion and negative values represent extension. Significantly different with non-tuned AFO-FC in comparison to barefoot at p50.05. b Significantly different with tuned AFO-FC in comparison to non-tuned AFO-FC at p50.05. c Wilcoxon signed-rank test was used for comparisons involving this variable, all other comparisons were made using paired t-test.
Disabil Rehabil Assist Technol Downloaded from informahealthcare.com by Gazi Univ. on 01/04/15 For personal use only.
a
Figure 2. Key divisions of the gait cycle [19]. Key to the figure: IC, initial contact; LR, loading response; MS, mid-stance; TS, terminal stance; PS, pre-swing; ISw, initial swing; MSw, mid-swing; TSw, terminal swing. Adapted with permission from the figure published in Whittlea˜ s Gait Analysis, 5th ed., Levine et al., pp. 36, Copyright Elsevier (2012).
participants (participants 1, 2, 5, 7 and 8), there was no reduction of knee hyperextension, or there was increased hyperextension of already extended/hyperextended knee during mid-stance and/or terminal stance phases of gait. In some participants (participant 3, right leg of participant 4) there was no reduction of abnormal knee flexion during stance, or further increase in flexion. The use of non-tuned AFO-FC influenced the overall gait patterns of participants. It is not common to categorise children according to gait patterns based on knee kinematics with their AFO(s). In this study, however, such a categorisation is attempted because in the current study the effects of tuning are investigated by comparing gait with the tuned AFO-FC against non-tuned AFO-FC and not barefoot. With the non-tuned AFO-FC, in participant 3 (right leg), and both legs of participant 4, a crouch knee gait pattern with increased knee flexion throughout the gait cycle was observed. Participants 1, 2, 5, 7 and 8 demonstrated an extended knee gait pattern in which the knee joint was positioned at less than 5 of flexion during mid to terminal stance. Both legs of participant 6 demonstrated a jump knee gait pattern featured by increased knee flexion during initial stance, followed by near normal to hyperextension during mid to terminal stance. It is clear from Table 4 that there were not many statistically significant
differences between tuned AFO-FC and non-tuned AFO-FC, and that on average the tuned AFO-FC resulted in knee kinematics further away from normal. However, the graphs in Figure 3 demonstrate different trends when gait patterns of the participants while wearing non-tuned AFO-FCs are taken into consideration. It can be seen that for the participants with an extended knee gait pattern (participants 1, 2, 5, 7 and 8), tuned AFO-FC produced reduction in peak knee extension which was closer to normal when compared with non-tuned AFO-FC. In participant 6, who demonstrated jump knee gait, the increased flexion in initial stance was reduced in both legs and the abnormal hyperextension during terminal stance of the right knee was reduced with tuned AFO-FC compared to non-tuned. However, for the participants with crouch knee gait (participant 3 and both legs of participant 4), the effects of tuning were restricted to a slightly lower peak knee flexion during stance for one leg (participant 4 right knee) with tuned AFO-FC compared to non-tuned. It is worth noting that among the participants with extended knee gait (participants 1, 2, 5, 7 and 8), in comparison to non-tuned AFO-FC, tuning produced abnormally high knee flexion during initial contact for all the participants and higher peak knee flexion during stance for three of the five participants (2, 5 and 7). Kinetics (external joint moments) of the lower limb joints Table 5 provides the comparison of peak external joint moments between barefoot and non-tuned AFO-FC, and between non-tuned AFO-FC and tuned AFO-FC. Peak hip flexion moments (p50.001, t ¼ 5.62), peak hip extension moments (p ¼ 0.01, Z ¼ 2.60), peak knee flexion moments (p ¼ 0.03, t ¼ 2.57), peak ankle plantar flexion moments (p ¼ 0.02, t ¼ 2.94) and peak ankle dorsi-flexion moments (p ¼ 0.04, t ¼ 2.48) were significantly higher with non-tuned AFO-FC compared to barefoot. With the tuned AFO-FC, peak knee extension moments were significantly lower (p ¼ 0.001, Z ¼ 2.80) and peak ankle plantar flexion moments were significantly higher (p ¼ 0.01, t ¼ 3.42) compared to non-tuned AFO-FC; both changes are towards the values of age-matched normal data.
Discussion The current study aimed to investigate the immediate effects of rigid AFOs with optimally cast AAAFOs on the gait of children with CP and whether tuning of AFO-FCs further influenced their gait. The significant difference in walking speed and stride
Optimising the use of AFOs for children with CP
5
Disabil Rehabil Assist Technol Downloaded from informahealthcare.com by Gazi Univ. on 01/04/15 For personal use only.
DOI: 10.3109/17483107.2014.908244
Figure 3. Graphs comparing knee kinematics in the sagittal plane between barefoot walking, walking with non-tuned AFO-FC and tuned AFO-FC during one complete gait cycle of all participants. First and second row includes legs which demonstrated an extended knee gait pattern, third row includes legs which demonstrated a crouch knee gait and the last row includes legs with a jump knee gait pattern.
length between barefoot and non-tuned AFO-FC in the current study corroborates the findings of many previous studies [4,5,20,21]. Higher walking speed and stride length with nontuned AFO-FC in comparison to barefoot in the current study are likely to be related to the changes in knee and hip Range of Motion (ROM) which is similar to the findings of Abel et al. [5]. In comparing non-tuned and tuned AFO-FC, none of the
temporal-spatial parameters were significantly different. However, it should be noted that in the current study, participants probably did not have sufficient time to become familiar with the prescription, which may have influenced the results. A case study on tuning of AFO-FC for an adult with hemiplegia supports such a possibility [22]; although there was no improvement in temporal-spatial parameters directly after tuning, similar to the
6
K. C. Jagadamma et al.
Disabil Rehabil Assist Technol, Early Online: 1–7
Table 5. Results of comparison of external joint moments (in Nm/kg) between barefoot and non-tuned AFO-FC, and between non-tuned AFO-FC and tuned AFO-FC (n ¼ 10). Barefoot Mean (SD) Peak Peak Peak Peak Peak Peak
hip flexion moments hip extension moments knee flexion moments knee extension moments ankle dorsi-flexion moments ankle plantar-flexion moments
0.77 0.34 0.26 0.38 0.84 0.01
(0.37) (0.19) (0.24) (0.28) (0.27) (0.05)
Non-tuned AFO-FC Mean (SD) 1.14 0.69 0.66 0.30 1.00 0.17
(0.44)a (0.21)a,c (0.41)a (0.13) (0.19)a (0.17)a
Tuned AFO-FC Mean (SD)
Healthy Mean (SD)
0.9 0.60 0.71 0.17 0.95 0.31
0.95 0.82 0.47 0.28 1.48 0.25
(0.4) (0.15) (0.24) (0.12)b,c (0.19) (0.13)b
(0.2) (0.1) (0.2) (0.1) (0.2) (0.1)
Positive values represent flexion moments and negative values represent extension moments. Significantly different with non-tuned AFO-FC in comparison to barefoot at p50.05. b Significantly different with tuned AFO-FC in comparison to non-tuned AFO-FC at p50.05. c Wilcoxon signed-rank test was used for comparisons involving this variable, all other comparisons were made using paired t-test.
Disabil Rehabil Assist Technol Downloaded from informahealthcare.com by Gazi Univ. on 01/04/15 For personal use only.
a
current study, walking speed and step length increased after three months. The current study reported higher hip and knee ROM with non-tuned AFO-FC compared to barefoot. While Abel et al. [5] reported an increase in hip ROM and knee ROM with rigid AFOs, a few other studies reported no significant changes [2,3,6,23]. In the current study, knee ROM was less with tuned AFO-FC compared to non-tuned, which may be attributed to the reduction in knee hyperextension in some participants and a reduced peak knee flexion in swing in others. On average participants had lower peak knee extension with tuned AFO-FC (10.3 of flexion) compared to non-tuned (7.1 of flexion). However, analysis of the knee kinematics of individual participants provided a different picture (Figure 3). The positive effects of tuning on knee kinematics were more obvious when participants were grouped based on their gait patterns while wearing non-tuned AFO-FCs. It could be assumed that tuning of AFO-FC normalised knee extension in the five participants who were identified as having an extended knee gait and one participant with jump knee gait. The normalisation of knee extension may be attributed to re-orientation of the GRF closer to the knee joint, as suggested by Butler and Nene [18]. However, it should be noted that the participants with crouch knee gait did not yield any clear benefits with tuning; this was also reported by Butler et al. [15], who identified children with crouch gait as non-tunable. The high (around 28 ) knee flexion at initial contact seen in both legs of the participant with jump knee gait (participant 6) was reduced, and hence was closer to normal (around 20 ) after tuning. In contrast, in those participants with extended knee gait, the use of tuned AFO-FC tended to produce an abnormal increase in knee flexion during initial stance, which was also reported previously by Butler et al. [15] in children with CP and Jagadamma et al. [22] in an adult with hemiplegia. Butler et al. [15] stated that the overall benefits of tuning compensates for this possible disadvantage. These findings demonstrate that the gait patterns of children with CP can influence the outcomes of tuning of AFO-FC, which was identified previously by Butler et al. [14]. Abnormal joint moments contribute to gait abnormalities in children with CP and one of the aims of tuning is to normalise these by optimising the orientation of GRF. Significantly higher peak dorsiflexion moments at the ankle during terminal stance were observed with non-tuned AFO-FC compared to barefoot in the current study, which is line with existing literature [2,3,5,24,25]. It is likely that the moment arm was smaller in barefoot due to the plantar flexed position of the ankle during terminal stance. Higher dorsiflexion moments could also be related to the higher walking speed when walking with an AFO. Tuning of AFO-FC did not further influence the peak dorsiflexion moments.
The finding of significantly higher and closer to normal peak ankle plantar flexion moments during initial stance with nontuned AFO-FC compared to barefoot was contradictory to the existing literature. Abel et al. [5] and Lam et al. [25] did not report any significant differences during initial stance. This contradiction of the findings of the current study to those of previous studies may have been caused by the difference in the angle at which AFOs were cast in the current study; this may have had a positive influence on alignment during initial stance. It has been recommended that casting of AFOs to accommodate the tightness of gastrocnemius is vital for children with CP [10] and adults with stroke [11]. The peak plantar flexion moments were even higher with tuned AFO-FC compared to non-tuned in the current study. This may be attributed to the influence of more rigid heels in the tuned AFO-FCs. Wiest et al. [26] suggested that a harder heel produces higher torque on the tibia, i.e. a higher plantar flexion moment. Compared to the non-tuned AFO-FC, tuned AFO-FC produced significant reduction of the abnormally high peak knee extension moments. This is likely to be attributed to the fact that one of the aims of tuning is to bring the GRF closer to the knee joint. In two different studies, Butler et al. [13,27] also reported that tuning of AFOs reduced the moment arm at the knee joint. The findings of the current study suggest that rigid AFOs with optimally cast AAAFO can produce various positive influences on the gait of children with CP. Furthermore, tuning of AFO-FC has potential benefits, such as reduction of knee hyperextension, in the gait of children with CP, depending on their gait patterns. The small sample size limits the possibility of generalising the findings of the current study. However, the current findings may indicate the need for a different approach when investigating the effects of an intervention on the gait of children with CP who have different gait patterns. Furthermore, the positive trends suggest the need for an appropriately powered trial with a randomised controlled design. The possible disadvantages of increased flexion at initial stance after tuning in children with extended knee gait should be further investigated in future studies that address the long-term effects of tuning on gait, activity, participation and quality of life.
Conclusion The aims of the study were first to compare the gait of children with CP when wearing rigid AFOs with an optimally cast AAAFO, to their barefoot gait and second to explore whether tuning of these AFO-FC further influenced the gait of these children. The findings of the current study indicate potential benefits from using rigid non-tuned AFO-FC with optimal AAAFO when compared to barefoot, and possible benefits of
Optimising the use of AFOs for children with CP
DOI: 10.3109/17483107.2014.908244
tuning depending on the gait pattern of the child. Furthermore, this study emphasises the need for categorising children with CP based on their gait patterns while investigating effects of interventions such as AFOs. While generalisation of the current findings is limited, the exploratory nature of the study provides important insights which should be taken into account for future research.
Disabil Rehabil Assist Technol Downloaded from informahealthcare.com by Gazi Univ. on 01/04/15 For personal use only.
Acknowledgements
11. 12. 13.
We are thankful to Queen Margaret University, Edinburgh and Centre for Integrated Health Care Research (CIHR), Edinburgh for funding this study. We are also grateful to Dr Cathy Bulley, Queen Margaret University, Edinburgh for her help with the final stages of manuscript preparation.
14.
Declaration of interest
16.
The authors declare no conflicts of interests. The authors alone are responsible for the content and writing of this article.
15.
17.
References 1. Cans C. Surveillance of cerebral palsy in Europe: a collaboration of cerebral palsy surveys and registers. Dev Med Child Neurol 2000; 42:816–24. 2. Carlson WE, Vaughan CL, Damiano DL, Abel MF. Orhtotic management of gait in sapastic diplegia. Am J Phys Med Rehabil 1997;76:219–25. 3. Radtka SA, Skinner SR, Johanson ME. A comparison of gait with solid and hinged ankle-foot orthoses in children with spastic diplegic cerebral palsy. Gait Posture 2005;21:303–10. 4. Brunner R, Meier G, Ruepp T. Comparison of a stiff and a springtype ankle-foot orthosis to improve gait in spastic hemiplegic children. J Pediatr Orthopaed 1998;18:719–26. 5. Abel MF, Juhl GA, Vaughan CL, Damiano DL. Gait asseement of fixed ankle-foot orthoses in children with spastic diplegia. Arch Phys Med Rehabil 1998;79:126–33. 6. Smiley SJ, Jacobsen FS, Mielke C, et al. A comparison of the effects of solid, articulated, and posterior leaf-spring ankle-foot orthoses and shoes alone on gait and energy expenditure in children with spastic diplegic cerebral palsy. Orthopedics 2002;25:411–15. 7. Balaban B, Yasar E, Dal U, et al. The effect of hinged ankle-foot orthosis on gait and energy expenditure in spastic hemiplegic cerebral palsy. Disabil Rehabil 2007;29:139–44. 8. Meadows CB. The influence of polypropylene ankle-foot orthoses on the gait of cerebral palsied children [dissertation]. Strathclyde University; 1984. 9. Owen E. Tuning of ankle-foot orthosis combinations for children with cerebral palsy, spina bifida and other conditions. Proceedings of European Society of Movement Analysis in Adults and Children (ESMAC) Seminars, Warsaw; 2004. 10. Bowers RJ, Ross K. A review of the effectiveness of lowr limb orthoses used in cerebral palsy. In: Morris C, Condie D, eds.
18. 19. 20. 21.
22.
23. 24. 25. 26. 27.
7
International Society for Prosthetics and Orthotics. Recent developments in healthcare for cerebral palsy; implications and opportunities for orthotics; 2009 31st Oct. Copenhagen: ISPO; 2009:235–97. NHS Quality Improvement. Use of ankle foor orthoses following stroke – best practice statement. NHS Quality Improvement Scotland; 2009 Aug. Owen E. Proposed clinical algorithm for deciding the sagittal angle of the ankle in an ankle-foot orthoses footwear combination. Gait Posture 2005;22S:S38–9. Butler PB, Thompson N, Major RE. Improvement in walking performance of children with cerebral palsy: preliminary results. Dev Med Child Neurol 1992;34:567–76. Stallard J, Woollam PJ. Transportable two-dimensional gait assessment: routine service experience for orthotic provision. Disabil Rehabil 2003;25:254–8. Butler PB, Farmer SE, Stewart C, et al. The effect of fixed ankle foot orthoses in children with cerebral palsy. Disabil Rehabil: Assist Technol 2007;2:51–8. Jagadamma KC, Coutts FJ, Mercer TH, et al. Effects of tuning of ankle foot orthoses-footwear combination using wedges on stance phase knee hyperextension in children with cerebral palsy – preliminary results. Disabil Rehabil: Assist Technol 2009;4:406–13. Davis RB, o`unpuu S, Tyburski D, Gage JR. A gait analysis data collection and reduction technique. Human Mov Sci 1991;10: 575–87. Butler PB, Nene AV. The biomechanics of fixed ankle foot orthoses and their potentional in the management of cerebral palsied children. Physiotherapy 1991;77:81–7. Levine D, Richards J, Whittle MW. Whittle’s gait analysis. 5th ed. London: Elsevier Ltd.; 2012. Thompson NS, Taylor TC, McCarthy KR, et al. Effect of a rigid ankle-foot orthosis on hamstring length in children with hemiplegia. Dev Med Child Neurol 2002;44:51–7. White H, Jenkins J, Neace WP, et al. Clinically prescribed orthoses demonstrate an increase in velocity of gait in children with cerebral palsy: a retrospective study. Dev Med Child Neurol 2002;44: 227–332. Jagadamma KC, Owen E, Coutts FJ, et al. The effects of tuning an ankle-foot orthosis footwear combination on kinematics and kinetics of the knee joint of an adult with hemiplegia. Prosthet Orthot Int 2010;34:270–6. Radtka SA, Skinner SR, Dixon DM, Johanson ME. A comparison of gait with solid, dynamic, and no ankle-foot orthoses in children with spastic cerebral palsy. Phys Ther 1997;77:395–409. Rethlefsen S, Kay R, Dennis S, et al. The effects of fixed and articulated ankle-foot orthoses on gait patterns in subjects with cerebral palsy. J Pediatr Orthopaed 1999;19:470–4. Lam WK, Leong JCY, Li YH, et al. Biomechanical and electromyographic evaluation of ankle foot orthosis and dynamic ankle foot orthosis in spastic cerebral palsy. Gait Posture 2005;22:189–97. Wiest DR, Waters RL, Bontrager EL, Quigley MJ. The influence of heel design on a rigid ankle-foot orthosis. Orthot Prosthet 1979;33: 3–10. Butler PB, Farmer SE, Major RE. Improvement in gait parameters following late intervention in traumatic brain injury: a long-term follow-up report of a single case. Clin Rehabil 1997;11:220–6.
RESEARCH PAPER
Optimising the effects of rigid ankle foot orthoses on the gait of children with cerebral palsy (CP) – an exploratory trial
Disabil Rehabil Assist Technol Downloaded from informahealthcare.com by Gazi Univ. on 01/04/15 For personal use only.
Kavi C. Jagadamma1, Fiona J. Coutts1, Thomas H. Mercer1, Janet Herman2, Jacqueline Yirrell3, Lyndsay Forbes4, and Marietta L. van der Linden1 1
School of Health Sciences, Queen Margaret University, Edinburgh, UK, 2Anderson Gait Analysis Laboratory, Astley Ainsley Hospital, Edinburgh, UK, Department of Clinical Genetics, Western General Hospital, Edinburgh, UK, and 4Orthotics Department, Buchanan Orthotics, Glasgow, UK
3
Abstract
Keywords
Purpose: This exploratory trial investigated the effects of rigid ankle foot orthoses (AFO) with an optimally cast Angle of the Ankle in the AFO (AAAFO) on the gait of children with Cerebral Palsy (CP), and whether tuning of the AFO – Footwear Combination (AFO-FC) further affected gait. Methods: Eight children with CP underwent gait analysis and tuning of their AFO-FCs using a 3-D motion analysis system. Comparisons were carried out for selected gait parameters between three conditions – barefoot, non-tuned AFO-FC and tuned AFO-FC. Results: In comparison to barefoot gait, walking with a non-tuned AFO-FC produced significant (p50.05) improvements in several key gait parameters. Compared to the non-tuned AFO-FC, on average a tuned AFO-FC produced a significant reduction in peak knee extension and knee ROM during gait. However, when examined as case studies, it was observed that the type of gait pattern demonstrated while wearing a non-tuned AFO-FC affected the outcomes of tuning. Conclusions: The findings of the current study indicate the potential benefits of using rigid AFO-FC with optimal AAAFO and tuning of AFO-FCs. This study emphasises the need for categorising children with CP based on their gait patterns when investigating the effects of interventions such as AFOs.
AFO, ankle foot orthosis, cerebral palsy, gait, tuning History Received 28 August 2013 Revised 3 March 2014 Accepted 21 March 2014 Published online 21 April 2014
ä Implications for Rehabilitation
Rigid ankle foot orthoses (AFO) cast at an optimal angle to accommodate the length of gastrocnemius muscle may positively influence walking in children with Cerebral Palsy (CP). Tuning of the AFO-Footwear Combination (AFO-FC) has potential benefits to the walking of children with CP, depending on their gait abnormalities. When investigating the effects of interventions such as AFOs, it is important to categorise children with CP based on their gait abnormalities.
Introduction Cerebral Palsy (CP) is an umbrella term used to describe children with a group of disorders associated with injury to the developing brain. It has been reported that there is an incidence of CP ranging from 1.5 to 3 per 1000 live births in Europe [1]. Due to motor impairments such as alterations in muscle tone and loss of selective motor control, ambulatory children with CP commonly present with varying degrees of gait abnormalities, therefore they are prescribed rigid ankle foot orthoses (AFO) with the aim of improving their gait pattern. Several studies have investigated the effects of rigid AFOs, all of which have reported positive influences on at least one gait parameter. However, there is a lack
Address for correspondence: Dr Kavi C. Jagadamma, Lecturer, Physiotherapy Subject Area, School of Health Sciences, Queen Margaret University, Musselburgh, East Lothian EH21 6UU, UK. Tel: +44 131 474 0000. Fax: +44 131 474 0001. E-mail: [email protected]
of consistency among the studies in relation to which parameters were positively influenced. Some studies found that rigid AFOs influence temporal-spatial parameters and ankle joint kinematics of children with CP [2,3], while others found changes in proximal joint kinematics as well [4,5]. It has also been reported that rigid AFOs only influence ankle joint kinematics [6]. The ambiguity in the literature may be attributed to several factors, such as the lack of uniformity in study design [7], and poor biomechanical optimisation of AFOs, which has been suggested to have a vital role in effectiveness of AFO management [8,9]. It has been suggested that the design of AFOs and footwear can be optimised for children with CP. Biomechanical optimisation, or tuning, of the Ankle Foot Orthosis – Footwear Combination (AFO-FC) is a key consideration. Tuning involves modifying the alignment of AFO-FC using aids such as wedges, heels and rockers to optimise gait. The role of tuning of AFO-FCs was identified decades ago [8] and has been recommended for children with CP [10] and adults with stroke [11]. Although there have been only a few reports on the effects of tuning of AFOs,
Disabil Rehabil Assist Technol Downloaded from informahealthcare.com by Gazi Univ. on 01/04/15 For personal use only.
2
K. C. Jagadamma et al.
they have invariably reported improved gait parameters [13–15]. However, there is still a lack of evidence and consensus regarding the benefits of tuning of AFOs. A further consideration is the lack of consensus about the angle at which AFOs are cast, or in other words, Angle of the Ankle in AFO (AAAFO). Some authors have emphasised that the AAAFO is important, since a lack of available length of the gastrocnemius and soleus muscles at the ankle joint can prevent the knee joint from achieving adequate extension during gait [9,12]. However, this lacks empirical evidence. A search of the literature revealed 16 studies reporting the effects of rigid AFOs on the gait of children with CP, most of which have reported the AAAFO used. In the past, practice has been to use AFOs either cast at plantigrade or in dorsiflexion. However, recent recommendations have highlighted that research studies should state whether AAAFO has taken the length of gastrocnemius into consideration [10]. A further limitation of studies which have investigated the effects of tuning of AFO-FC is their comparison between tuned AFO-FC and barefoot [13–15] rather than a control condition, such as the non-tuned AFO-FC. Selected results from the dataset reported in this article have been published before, which compared between tuned AFO-FC and non-tuned AFO-FC to report the effects of tuning of mid-stance in five children whose knees hyperextended during gait [16]. Considering the lack of evidence, the current study had two aims. The first aim was to compare the gait of children with CP when wearing rigid AFOs with an optimally cast AAAFO, to their barefoot gait; the second aim was to explore whether tuning of these AFO-FC further influenced the gait of these children.
Disabil Rehabil Assist Technol, Early Online: 1–7
Table 1. Sample characteristics of the children with cerebral palsy. Age (years) Gender Diagnosis Participant Participant Participant Participant Participant Participant Participant Participant
1 5.6 2 12.5 3 7.8 4 7.2 5 6.2 6 12.5 7 8.3 8 11.8
Boy Girl Girl Boy Girl Girl Girl Boy
Orthosis-left Orthosis-right
Diplegia Dynamic AFO Hemiplegia Nil Diplegia Nil Diplegia Rigid AFO Hemiplegia Nil Diplegia Rigid AFO Hemiplegia Nil Hemiplegia Rigid AFO
Rigid AFO Rigid AFO Rigid AFO Rigid AFO Rigid AFO Rigid AFO Rigid AFO Nil
Table 2. Sample characteristics of healthy children. Number of participants 11
Mean age (SD) in years
Mean height (SD) in m
Mean weight (SD) in kg
10 (2.1)
1.44 (0.15)
38.5 (10.3)
Boys Girls 6
5
Methods Participants Ambulatory children with CP between 5 and 15 years of age who were using or prescribed rigid AFOs were recruited from the treatment lists of local physiotherapists. Children who had soft tissue or bony surgery in the previous year, botulinum toxin A or Baclofen in the previous 6 months, and who were diagnosed as having severe dystonia, ataxia or behavioural problems were excluded from the study. Eight children with CP participated in the study. Participant characteristics are given in Table 1. In total 10 legs with rigid AFOs were included in analysis. Eleven healthy children between 5 and 15 years of age were also recruited through personal contacts for reference gait data (Table 2). Ethical approval for the study was gained from the local UK NHS ethics committee and informed assent and consent were gained from the participants and their parents, respectively. Instrumentation All the rigid AFOs used by the participants were made of polypropylene and did not have any joints. The AFOs were custom-made for each participant by an orthotist. The thickness of polypropylene used varied (3, 4.5 or 6 mms) depending on the size and weight of the children, but was sufficient to keep the AFOs rigid at the ankle. The ankle angles of the AFOs were cast ranging from 90 (plantigrade) to varying degrees of plantar-flexion to accommodate any tightness present in the plantar-flexor muscles. All AFOs had their trim lines at the ankle, anterior to the malleoli; and had two straps, one at the proximal end of the shank and one at the ankle. When an AFO was cast in plantar-flexion, a heel wedge was added to align the midline of the shank of the AFO perpendicular to the floor when placed flat. Tuning was carried out with the participants’ own shoes. The wedges used for tuning were made of non-deformable Ethyl Vinyl Acetate (EVA) and the
Figure 1. Ankle Foot Orthosis-Footwear Combination (AFO-FC) with a wedge made of Ethyl Vinyl Acetate (EVA) and Point Loading Rocker (PLR) made of plastazote attached to the shoes.
Point Loading Rockers (PLRs) were made of high density plastazote. Figure 1 shows an example of an AFO-FC along with a wedge and PLR. Tuning and gait assessment were carried out in a gait analysis laboratory with an eight camera Vicon three-dimensional (3-D) motion analysis system with a sampling frequency of 100 Hz (Vicon motion systems Ltd., Oxford, UK). The laboratory had two force plates (AMTI, Watertown, MA) with sampling frequency of 1000 Hz embedded in the middle of the walkway. For data collection, reflective markers were attached to the anatomical landmarks as specified by the Vicon Plug-In-Gait model which is based on the Helen Hayes gait model [17].
Optimising the use of AFOs for children with CP
DOI: 10.3109/17483107.2014.908244
Disabil Rehabil Assist Technol Downloaded from informahealthcare.com by Gazi Univ. on 01/04/15 For personal use only.
Procedure Gait analysis was performed while the participant walked barefoot and with the non-tuned AFO-FC at a self-determined speed. This was followed by the tuning process, during which gait data were captured for the tuned AFO-FC. The order of the gait analysis was kept the same for all participants and no randomisation of the order was attempted. The tuning procedure was based on previous suggestions by Owen [9] and Butler and Nene [18]. The key element of the procedure was mid-stance tuning, which began with measurement of the shank to vertical angle (SVA), which is the angle made by shank of the tibia to an imaginary vertical line perpendicular to the ground. The SVA was measured in standing using a goniometer. Wedges were attached to the shoes until a SVA of 12 was obtained, which is considered optimal [9]. The participant then walked with the modified AFO-FC until three clean foot strikes on the force plates were obtained. The orientation of the Ground Reaction Force (GRF) during mid-stance was then visually analysed on the Vicon Workstation display, to identify the orientation of the GRF in relation to the knee during mid-stance. Mid-stance was identified as the point where the ankle joint of the swinging leg crossed the weightbearing leg. No more wedges were added if the GRF passed through the centre of the knee. However, if the GRF did not pass through the centre of the knee, the procedure was repeated with more or fewer wedges until the GRF passed as close to the knee as possible during mid-stance. Following on from mid-stance, terminal stance tuning was attempted. This was only attempted for children whose GRF was not aligned posterior to the hip joint and anterior to the knee joint during terminal stance which was considered optimal, as this is the case in normal gait [9]. When the orientation of the GRF during terminal stance was not determined to be optimal, a PLR was added, with the apex of the rocker at 75% of the shoe length. The GRF orientation was then visually analysed using Vicon Workstation display and the length and thickness of PLR were modified until the alignment of the GRF was as optimal as possible. Once the prescription was finalised, the session was concluded. For comparison, gait data collected from 11 healthy children within the age range of 5 to 15 years were used. Analysis Three walks with clean force plate strikes for each condition compared were considered for analysis. Data processing was completed using Vicon Workstation software which makes use of Plug-In-Gait model to calculate temporal-spatial parameters, joint kinematics and kinetics. Selected joint kinematic and kinetic (external moments) data and Temporal-spatial parameters were compared between barefoot and non-tuned AFO-FC, and nontuned and tuned AFO-FC. Statistical data analysis was carried out using SPSS for Windows Version 16.0 using paired t-tests or Wilcoxon signed rank tests depending on the distribution of the data. Results were considered statistically significant if p50.05. Three way comparison using a repeated measures analysis of
3
variance was not employed because the comparison between tuned AFO-FC and barefoot was of no interest in the current study. It was acknowledged that the heterogeneity of the sample in terms of gait patterns may mask the effects of intervention in several variables when using statistical comparisons reliant on measures of central tendency. Hence, further analysis was carried out using case studies to identify any possible trends specific to gait patterns. Sagittal knee joint kinematics of all participants are presented in the current article as tuning predominantly influences the knee joint and gait patterns of children with CP are mainly determined by knee joint kinematics. Average healthy data are provided for reference in both group comparisons and case studies. Healthy data have not been included in the statistical comparisons for two reasons; first, the emphasis of the study is on comparing the effects of AFO and tuning in children with CP, and more so with the case studies than group comparisons. Second, a three-way comparison did not seem ideal with the small sample size of the current study. However, the authors have attempted to discuss the direction of change (improvement or deterioration) in variables using healthy data as a reference to help the reader understand the nature of change in selected variables.
Results Temporal-spatial parameters and SVA The means (SD) of the temporal-spatial parameters, with statistical comparisons for barefoot walking and walking with non-tuned AFO-FC, and walking with non-tuned AFO-FC and tuned AFO-FC, are given in Table 3. Stride length (p ¼ 0.01, t ¼ 3.92) and walking speed (p ¼ 0.04, Z ¼ 2.09) were significantly higher with non-tuned AFO-FC in comparison to barefoot, whereas none of the temporal-spatial parameters were significantly different between non-tuned and tuned AFO-FC. Kinematics and kinetics of the lower limb joints Table 4 provides the comparison of selected kinematic variables between barefoot and a non-tuned AFO-FC, and between a nontuned AFO-FC and tuned AFO-FC. In comparison to barefoot, knee ROM was 4 higher (p ¼ 0.02, t ¼ 2.69) and hip ROM was 5 higher (p ¼ 0.04, t ¼ 2.45) with the non-tuned AFO-FC. Comparing the kinematics between a non-tuned AFO-FC and a tuned AFO-FC, lower peak knee extension with tuned AFO-FC was seen compared to non-tuned AFO-FC (7.1 flexion versus 10.3 flexion) (p ¼ 0.04, t ¼ 2.33). Furthermore, knee ROM was lower by 6 with tuned AFO-FC compared to non-tuned (p ¼ 0.02, t ¼ 2.88). No differences were found in the hip and pelvis kinematics in any of the comparisons. Figure 2 indicates the key divisions of the gait cycle considered in this study [19]. Figure 3 shows the sagittal plane knee kinematics of all eight participants comparing barefoot, nontuned AFO-FC and tuned AFO-FC. Several key trends could be noted. In comparison to barefoot, the influence of non-tuned AFO-FC showed mixed effects on knee kinematics. In some
Table 3. Results of comparison of the temporal-spatial parameters between barefoot and non-tuned AFO-FC, and between non-tuned AFO-FC and tuned AFO-FC.
Cadence (steps/minute) Stride-length (m) Walking speed (m/s) a
Barefoot mean (SD)
Non-tuned AFO-FC Mean (SD)
Tuned AFO-FC Mean (SD)
Healthy mean (SD)
117.7 (27.0) 0.82 (0.3) 0.84 (0.4)
122.3 (14.7) 0.98 (0.2)a 0.99 (0.2)a,b
123.0 (9) 0.97 (0.2) 0.99 (0.2)
119.7 (15.5) 1.4 (0.2) 1.4 (0.2)
Significantly different with non-tuned AFO-FC in comparison to barefoot at p50.05. Wilcoxon signed-rank test was used for comparisons involving this variable, all other comparisons were made using paired t-test.
b
4
K. C. Jagadamma et al.
Disabil Rehabil Assist Technol, Early Online: 1–7
Table 4. Results of comparison of kinematic data points between barefoot and non-tuned AFO-FC, and between non-tuned AFOFC and tuned AFO-FC (n ¼ 10 legs). Barefoot Mean (SD) Peak anterior pelvic tilt Peak posterior pelvic tilt Pelvic tilt ROM Peak hip flexion Peak hip extension Peak hip flexion (stance) Hip ROM Knee flexion at initial contact Peak knee flexion (stance) Peak knee extension (stance) Peak knee flexion Knee ROM
21.8 13.4 8.4 44.2 3.4 38.8 40.8 19.1 22.4 7.6 52.5 45.0
Non-tuned AFO-FC Mean (SD)
(6.7) (7.1) (2.4) (9.7) (8.8) (10.9) (9.0) (8.2) (8.4) (9.9) (5.7) (12.6)
23.0 14.4 8.5 46.1 0.5 42.9 45.7 20.7 27.0 7.1 56.0 48.9
(8.3) (8.1) (2.6) (11.0) (8.1) (12.3) (6.2)a (12.4) (2.2) (12.2) (6.4)c (14.4)a
Tuned immediate Mean (SD) 22.9 14.3 8.5 46.8 2.6 44.7 44.2 22.1 29.7 10.3 53.4 43.1
(10.9) (9.8) (2.7) (13.7) (10.9) (12.8) (6.9) (9.1) (8.0) (9.5)b (6.9) (13.5)b
Healthy Mean (SD) 12.8 7.7 5.1 39.6 11.3 37.4 50.9 2.5 20.9 4.1 65.8 61.6
(5.5) (5.0) (0.9) (8.0) (5.7) (8.2) (6.2) (4.4) (6.2) (2.8) (5.2) (5.6)
For hip and knee kinematics positive values represent flexion and negative values represent extension. Significantly different with non-tuned AFO-FC in comparison to barefoot at p50.05. b Significantly different with tuned AFO-FC in comparison to non-tuned AFO-FC at p50.05. c Wilcoxon signed-rank test was used for comparisons involving this variable, all other comparisons were made using paired t-test.
Disabil Rehabil Assist Technol Downloaded from informahealthcare.com by Gazi Univ. on 01/04/15 For personal use only.
a
Figure 2. Key divisions of the gait cycle [19]. Key to the figure: IC, initial contact; LR, loading response; MS, mid-stance; TS, terminal stance; PS, pre-swing; ISw, initial swing; MSw, mid-swing; TSw, terminal swing. Adapted with permission from the figure published in Whittlea˜ s Gait Analysis, 5th ed., Levine et al., pp. 36, Copyright Elsevier (2012).
participants (participants 1, 2, 5, 7 and 8), there was no reduction of knee hyperextension, or there was increased hyperextension of already extended/hyperextended knee during mid-stance and/or terminal stance phases of gait. In some participants (participant 3, right leg of participant 4) there was no reduction of abnormal knee flexion during stance, or further increase in flexion. The use of non-tuned AFO-FC influenced the overall gait patterns of participants. It is not common to categorise children according to gait patterns based on knee kinematics with their AFO(s). In this study, however, such a categorisation is attempted because in the current study the effects of tuning are investigated by comparing gait with the tuned AFO-FC against non-tuned AFO-FC and not barefoot. With the non-tuned AFO-FC, in participant 3 (right leg), and both legs of participant 4, a crouch knee gait pattern with increased knee flexion throughout the gait cycle was observed. Participants 1, 2, 5, 7 and 8 demonstrated an extended knee gait pattern in which the knee joint was positioned at less than 5 of flexion during mid to terminal stance. Both legs of participant 6 demonstrated a jump knee gait pattern featured by increased knee flexion during initial stance, followed by near normal to hyperextension during mid to terminal stance. It is clear from Table 4 that there were not many statistically significant
differences between tuned AFO-FC and non-tuned AFO-FC, and that on average the tuned AFO-FC resulted in knee kinematics further away from normal. However, the graphs in Figure 3 demonstrate different trends when gait patterns of the participants while wearing non-tuned AFO-FCs are taken into consideration. It can be seen that for the participants with an extended knee gait pattern (participants 1, 2, 5, 7 and 8), tuned AFO-FC produced reduction in peak knee extension which was closer to normal when compared with non-tuned AFO-FC. In participant 6, who demonstrated jump knee gait, the increased flexion in initial stance was reduced in both legs and the abnormal hyperextension during terminal stance of the right knee was reduced with tuned AFO-FC compared to non-tuned. However, for the participants with crouch knee gait (participant 3 and both legs of participant 4), the effects of tuning were restricted to a slightly lower peak knee flexion during stance for one leg (participant 4 right knee) with tuned AFO-FC compared to non-tuned. It is worth noting that among the participants with extended knee gait (participants 1, 2, 5, 7 and 8), in comparison to non-tuned AFO-FC, tuning produced abnormally high knee flexion during initial contact for all the participants and higher peak knee flexion during stance for three of the five participants (2, 5 and 7). Kinetics (external joint moments) of the lower limb joints Table 5 provides the comparison of peak external joint moments between barefoot and non-tuned AFO-FC, and between non-tuned AFO-FC and tuned AFO-FC. Peak hip flexion moments (p50.001, t ¼ 5.62), peak hip extension moments (p ¼ 0.01, Z ¼ 2.60), peak knee flexion moments (p ¼ 0.03, t ¼ 2.57), peak ankle plantar flexion moments (p ¼ 0.02, t ¼ 2.94) and peak ankle dorsi-flexion moments (p ¼ 0.04, t ¼ 2.48) were significantly higher with non-tuned AFO-FC compared to barefoot. With the tuned AFO-FC, peak knee extension moments were significantly lower (p ¼ 0.001, Z ¼ 2.80) and peak ankle plantar flexion moments were significantly higher (p ¼ 0.01, t ¼ 3.42) compared to non-tuned AFO-FC; both changes are towards the values of age-matched normal data.
Discussion The current study aimed to investigate the immediate effects of rigid AFOs with optimally cast AAAFOs on the gait of children with CP and whether tuning of AFO-FCs further influenced their gait. The significant difference in walking speed and stride
Optimising the use of AFOs for children with CP
5
Disabil Rehabil Assist Technol Downloaded from informahealthcare.com by Gazi Univ. on 01/04/15 For personal use only.
DOI: 10.3109/17483107.2014.908244
Figure 3. Graphs comparing knee kinematics in the sagittal plane between barefoot walking, walking with non-tuned AFO-FC and tuned AFO-FC during one complete gait cycle of all participants. First and second row includes legs which demonstrated an extended knee gait pattern, third row includes legs which demonstrated a crouch knee gait and the last row includes legs with a jump knee gait pattern.
length between barefoot and non-tuned AFO-FC in the current study corroborates the findings of many previous studies [4,5,20,21]. Higher walking speed and stride length with nontuned AFO-FC in comparison to barefoot in the current study are likely to be related to the changes in knee and hip Range of Motion (ROM) which is similar to the findings of Abel et al. [5]. In comparing non-tuned and tuned AFO-FC, none of the
temporal-spatial parameters were significantly different. However, it should be noted that in the current study, participants probably did not have sufficient time to become familiar with the prescription, which may have influenced the results. A case study on tuning of AFO-FC for an adult with hemiplegia supports such a possibility [22]; although there was no improvement in temporal-spatial parameters directly after tuning, similar to the
6
K. C. Jagadamma et al.
Disabil Rehabil Assist Technol, Early Online: 1–7
Table 5. Results of comparison of external joint moments (in Nm/kg) between barefoot and non-tuned AFO-FC, and between non-tuned AFO-FC and tuned AFO-FC (n ¼ 10). Barefoot Mean (SD) Peak Peak Peak Peak Peak Peak
hip flexion moments hip extension moments knee flexion moments knee extension moments ankle dorsi-flexion moments ankle plantar-flexion moments
0.77 0.34 0.26 0.38 0.84 0.01
(0.37) (0.19) (0.24) (0.28) (0.27) (0.05)
Non-tuned AFO-FC Mean (SD) 1.14 0.69 0.66 0.30 1.00 0.17
(0.44)a (0.21)a,c (0.41)a (0.13) (0.19)a (0.17)a
Tuned AFO-FC Mean (SD)
Healthy Mean (SD)
0.9 0.60 0.71 0.17 0.95 0.31
0.95 0.82 0.47 0.28 1.48 0.25
(0.4) (0.15) (0.24) (0.12)b,c (0.19) (0.13)b
(0.2) (0.1) (0.2) (0.1) (0.2) (0.1)
Positive values represent flexion moments and negative values represent extension moments. Significantly different with non-tuned AFO-FC in comparison to barefoot at p50.05. b Significantly different with tuned AFO-FC in comparison to non-tuned AFO-FC at p50.05. c Wilcoxon signed-rank test was used for comparisons involving this variable, all other comparisons were made using paired t-test.
Disabil Rehabil Assist Technol Downloaded from informahealthcare.com by Gazi Univ. on 01/04/15 For personal use only.
a
current study, walking speed and step length increased after three months. The current study reported higher hip and knee ROM with non-tuned AFO-FC compared to barefoot. While Abel et al. [5] reported an increase in hip ROM and knee ROM with rigid AFOs, a few other studies reported no significant changes [2,3,6,23]. In the current study, knee ROM was less with tuned AFO-FC compared to non-tuned, which may be attributed to the reduction in knee hyperextension in some participants and a reduced peak knee flexion in swing in others. On average participants had lower peak knee extension with tuned AFO-FC (10.3 of flexion) compared to non-tuned (7.1 of flexion). However, analysis of the knee kinematics of individual participants provided a different picture (Figure 3). The positive effects of tuning on knee kinematics were more obvious when participants were grouped based on their gait patterns while wearing non-tuned AFO-FCs. It could be assumed that tuning of AFO-FC normalised knee extension in the five participants who were identified as having an extended knee gait and one participant with jump knee gait. The normalisation of knee extension may be attributed to re-orientation of the GRF closer to the knee joint, as suggested by Butler and Nene [18]. However, it should be noted that the participants with crouch knee gait did not yield any clear benefits with tuning; this was also reported by Butler et al. [15], who identified children with crouch gait as non-tunable. The high (around 28 ) knee flexion at initial contact seen in both legs of the participant with jump knee gait (participant 6) was reduced, and hence was closer to normal (around 20 ) after tuning. In contrast, in those participants with extended knee gait, the use of tuned AFO-FC tended to produce an abnormal increase in knee flexion during initial stance, which was also reported previously by Butler et al. [15] in children with CP and Jagadamma et al. [22] in an adult with hemiplegia. Butler et al. [15] stated that the overall benefits of tuning compensates for this possible disadvantage. These findings demonstrate that the gait patterns of children with CP can influence the outcomes of tuning of AFO-FC, which was identified previously by Butler et al. [14]. Abnormal joint moments contribute to gait abnormalities in children with CP and one of the aims of tuning is to normalise these by optimising the orientation of GRF. Significantly higher peak dorsiflexion moments at the ankle during terminal stance were observed with non-tuned AFO-FC compared to barefoot in the current study, which is line with existing literature [2,3,5,24,25]. It is likely that the moment arm was smaller in barefoot due to the plantar flexed position of the ankle during terminal stance. Higher dorsiflexion moments could also be related to the higher walking speed when walking with an AFO. Tuning of AFO-FC did not further influence the peak dorsiflexion moments.
The finding of significantly higher and closer to normal peak ankle plantar flexion moments during initial stance with nontuned AFO-FC compared to barefoot was contradictory to the existing literature. Abel et al. [5] and Lam et al. [25] did not report any significant differences during initial stance. This contradiction of the findings of the current study to those of previous studies may have been caused by the difference in the angle at which AFOs were cast in the current study; this may have had a positive influence on alignment during initial stance. It has been recommended that casting of AFOs to accommodate the tightness of gastrocnemius is vital for children with CP [10] and adults with stroke [11]. The peak plantar flexion moments were even higher with tuned AFO-FC compared to non-tuned in the current study. This may be attributed to the influence of more rigid heels in the tuned AFO-FCs. Wiest et al. [26] suggested that a harder heel produces higher torque on the tibia, i.e. a higher plantar flexion moment. Compared to the non-tuned AFO-FC, tuned AFO-FC produced significant reduction of the abnormally high peak knee extension moments. This is likely to be attributed to the fact that one of the aims of tuning is to bring the GRF closer to the knee joint. In two different studies, Butler et al. [13,27] also reported that tuning of AFOs reduced the moment arm at the knee joint. The findings of the current study suggest that rigid AFOs with optimally cast AAAFO can produce various positive influences on the gait of children with CP. Furthermore, tuning of AFO-FC has potential benefits, such as reduction of knee hyperextension, in the gait of children with CP, depending on their gait patterns. The small sample size limits the possibility of generalising the findings of the current study. However, the current findings may indicate the need for a different approach when investigating the effects of an intervention on the gait of children with CP who have different gait patterns. Furthermore, the positive trends suggest the need for an appropriately powered trial with a randomised controlled design. The possible disadvantages of increased flexion at initial stance after tuning in children with extended knee gait should be further investigated in future studies that address the long-term effects of tuning on gait, activity, participation and quality of life.
Conclusion The aims of the study were first to compare the gait of children with CP when wearing rigid AFOs with an optimally cast AAAFO, to their barefoot gait and second to explore whether tuning of these AFO-FC further influenced the gait of these children. The findings of the current study indicate potential benefits from using rigid non-tuned AFO-FC with optimal AAAFO when compared to barefoot, and possible benefits of
Optimising the use of AFOs for children with CP
DOI: 10.3109/17483107.2014.908244
tuning depending on the gait pattern of the child. Furthermore, this study emphasises the need for categorising children with CP based on their gait patterns while investigating effects of interventions such as AFOs. While generalisation of the current findings is limited, the exploratory nature of the study provides important insights which should be taken into account for future research.
Disabil Rehabil Assist Technol Downloaded from informahealthcare.com by Gazi Univ. on 01/04/15 For personal use only.
Acknowledgements
11. 12. 13.
We are thankful to Queen Margaret University, Edinburgh and Centre for Integrated Health Care Research (CIHR), Edinburgh for funding this study. We are also grateful to Dr Cathy Bulley, Queen Margaret University, Edinburgh for her help with the final stages of manuscript preparation.
14.
Declaration of interest
16.
The authors declare no conflicts of interests. The authors alone are responsible for the content and writing of this article.
15.
17.
References 1. Cans C. Surveillance of cerebral palsy in Europe: a collaboration of cerebral palsy surveys and registers. Dev Med Child Neurol 2000; 42:816–24. 2. Carlson WE, Vaughan CL, Damiano DL, Abel MF. Orhtotic management of gait in sapastic diplegia. Am J Phys Med Rehabil 1997;76:219–25. 3. Radtka SA, Skinner SR, Johanson ME. A comparison of gait with solid and hinged ankle-foot orthoses in children with spastic diplegic cerebral palsy. Gait Posture 2005;21:303–10. 4. Brunner R, Meier G, Ruepp T. Comparison of a stiff and a springtype ankle-foot orthosis to improve gait in spastic hemiplegic children. J Pediatr Orthopaed 1998;18:719–26. 5. Abel MF, Juhl GA, Vaughan CL, Damiano DL. Gait asseement of fixed ankle-foot orthoses in children with spastic diplegia. Arch Phys Med Rehabil 1998;79:126–33. 6. Smiley SJ, Jacobsen FS, Mielke C, et al. A comparison of the effects of solid, articulated, and posterior leaf-spring ankle-foot orthoses and shoes alone on gait and energy expenditure in children with spastic diplegic cerebral palsy. Orthopedics 2002;25:411–15. 7. Balaban B, Yasar E, Dal U, et al. The effect of hinged ankle-foot orthosis on gait and energy expenditure in spastic hemiplegic cerebral palsy. Disabil Rehabil 2007;29:139–44. 8. Meadows CB. The influence of polypropylene ankle-foot orthoses on the gait of cerebral palsied children [dissertation]. Strathclyde University; 1984. 9. Owen E. Tuning of ankle-foot orthosis combinations for children with cerebral palsy, spina bifida and other conditions. Proceedings of European Society of Movement Analysis in Adults and Children (ESMAC) Seminars, Warsaw; 2004. 10. Bowers RJ, Ross K. A review of the effectiveness of lowr limb orthoses used in cerebral palsy. In: Morris C, Condie D, eds.
18. 19. 20. 21.
22.
23. 24. 25. 26. 27.
7
International Society for Prosthetics and Orthotics. Recent developments in healthcare for cerebral palsy; implications and opportunities for orthotics; 2009 31st Oct. Copenhagen: ISPO; 2009:235–97. NHS Quality Improvement. Use of ankle foor orthoses following stroke – best practice statement. NHS Quality Improvement Scotland; 2009 Aug. Owen E. Proposed clinical algorithm for deciding the sagittal angle of the ankle in an ankle-foot orthoses footwear combination. Gait Posture 2005;22S:S38–9. Butler PB, Thompson N, Major RE. Improvement in walking performance of children with cerebral palsy: preliminary results. Dev Med Child Neurol 1992;34:567–76. Stallard J, Woollam PJ. Transportable two-dimensional gait assessment: routine service experience for orthotic provision. Disabil Rehabil 2003;25:254–8. Butler PB, Farmer SE, Stewart C, et al. The effect of fixed ankle foot orthoses in children with cerebral palsy. Disabil Rehabil: Assist Technol 2007;2:51–8. Jagadamma KC, Coutts FJ, Mercer TH, et al. Effects of tuning of ankle foot orthoses-footwear combination using wedges on stance phase knee hyperextension in children with cerebral palsy – preliminary results. Disabil Rehabil: Assist Technol 2009;4:406–13. Davis RB, o`unpuu S, Tyburski D, Gage JR. A gait analysis data collection and reduction technique. Human Mov Sci 1991;10: 575–87. Butler PB, Nene AV. The biomechanics of fixed ankle foot orthoses and their potentional in the management of cerebral palsied children. Physiotherapy 1991;77:81–7. Levine D, Richards J, Whittle MW. Whittle’s gait analysis. 5th ed. London: Elsevier Ltd.; 2012. Thompson NS, Taylor TC, McCarthy KR, et al. Effect of a rigid ankle-foot orthosis on hamstring length in children with hemiplegia. Dev Med Child Neurol 2002;44:51–7. White H, Jenkins J, Neace WP, et al. Clinically prescribed orthoses demonstrate an increase in velocity of gait in children with cerebral palsy: a retrospective study. Dev Med Child Neurol 2002;44: 227–332. Jagadamma KC, Owen E, Coutts FJ, et al. The effects of tuning an ankle-foot orthosis footwear combination on kinematics and kinetics of the knee joint of an adult with hemiplegia. Prosthet Orthot Int 2010;34:270–6. Radtka SA, Skinner SR, Dixon DM, Johanson ME. A comparison of gait with solid, dynamic, and no ankle-foot orthoses in children with spastic cerebral palsy. Phys Ther 1997;77:395–409. Rethlefsen S, Kay R, Dennis S, et al. The effects of fixed and articulated ankle-foot orthoses on gait patterns in subjects with cerebral palsy. J Pediatr Orthopaed 1999;19:470–4. Lam WK, Leong JCY, Li YH, et al. Biomechanical and electromyographic evaluation of ankle foot orthosis and dynamic ankle foot orthosis in spastic cerebral palsy. Gait Posture 2005;22:189–97. Wiest DR, Waters RL, Bontrager EL, Quigley MJ. The influence of heel design on a rigid ankle-foot orthosis. Orthot Prosthet 1979;33: 3–10. Butler PB, Farmer SE, Major RE. Improvement in gait parameters following late intervention in traumatic brain injury: a long-term follow-up report of a single case. Clin Rehabil 1997;11:220–6.
