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Abstract

PURPOSE:

The aim of this study was to examine the relationship between gait analysis measures associated with crouch gait, functional health status and daily activity in ambulant cerebral palsy (CP).

METHODS:

Three-dimensional gait analysis was carried out on 35 ambulant participants with bilateral CP crouch gait (knee flexion at mid-stance (KFMS) $\geqslant$ 19 ${}^{0}$ ). KFMS, knee-flexion at initial contact, gait speed and step-lengths were extracted for analysis. Steps/day and sedentary time/day were assessed using an ActivPAL accelerometer. Functional health status was assessed using the five relevant domains of the Pediatric Outcomes Data Collection Instrument (PODCI) questionnaire. Associations between variables were assessed with correlation coefficients and multivariable linear regression.

RESULTS:

There were no significant correlations between KFMS and PODCI domains ( $\rho=-$ 0.008–0.110) or daily activity ( $\rho=-$ 0.297–0.237) variables. In contrast, multivariable analysis found that step-length was independently associated with the Sports and Physical Function ( $p=$ 0.030), Transfers and Basic Mobility ( $p=$ 0.041) and Global Function ( $<$ 0.001) domains of the PODCI assessment. Gait speed was independently associated with mean steps/day ( $p<$ 0.001).

CONCLUSIONS:

Step length and gait speed are more strongly associated with functional health status and daily activity than knee flexion during stance in children and adolescents with CP crouch gait.

Keywords

Cerebral palsy functional health status gait/balance activities of daily living

1. Introduction

Cerebral palsy (CP) is the most common cause of motor impairment in children [1]. The associated muscle tightness, weakness and impaired motor control often lead to difficulties during gait. There are numerous gait presentations associated with CP; however, crouch gait, defined as excessive knee flexion in stance phase, is one of the most common pathological patterns associated with bilateral CP [2]. This flexed knee posture during gait has been shown to increase the forces and demands on the knee joint [3, 4] and can potentially lead to joint degeneration and pain [5]. For these reasons, the correction of excessive knee flexion during gait is a significant focus of surgical intervention in those with CP. A number of surgical techniques have been shown to improve knee kinematics in crouch gait [6, 7, 8, 9]. It is recognised that the assessment of surgical outcomes should include outcome measures based on the International Classification of Functioning, Disability and Health (ICF) [10]. The impact of knee crouch, and its treatment on these domains is less clear. A recent long-term follow-up study by Boyer et al. [9] found that while distal femoral extension osteotomy (DFEO) and patellar tendon advancement (PTA) led to superior outcomes in terms of improving knee extension compared to alternative surgical intervention. This did not translate into better outcomes in terms of non-gait function, activity, participation, quality of life or knee pain.

The Pediatric Outcomes Data Collection Instrument (PODCI) is a measure of functional health status which has been found to be valid and reliable in children and adolescents with CP [11, 12]. The PODCI questionnaire yields scores in six domains: upper extremity function, transfers and basic mobility, sports and physical function, pain/comfort, happiness with physical condition and a global function score. A number of studies have reported improvement in the functional PODCI domains (sports and physical function, transfers and basic mobility and global function) following orthopaedic surgery in children with CP but no changes in the psycho-social domains (pain/comfort and happiness with physical condition) [13, 14, 15]. As none of these studies [13, 14, 15] reported on gait kinematics, it is not possible to ascertain if the reported post-operative improvements in PODCI domains were associated with improvement in specific gait kinematic variables post-operatively. In contrast, Stout 2008 [16] compared short-term outcomes in groups who had DFEO-only, DFEO+PTA and PTA-only and found that while stance-phase knee flexion was restored to normal range in the DFEO+PTA and PTA-only groups, none of the three groups demonstrated significant improvement in the transfers and basic mobility, sports and physical function or pain/comfort domains of the PODCI assessment. Thus, is appears that while orthopaedic intervention can potentially lead to improvements in the functional domains of the PODCI assessment. They do not seem to be related to changes in stance phase knee flexion.

Ambulatory children with CP have been shown to have significantly reduced levels of walking activity compared to typically developing peers [17]. On examining the relationship between gait kinematics and daily activity, Wilson et al. [18] found a moderate correlation ( $r=$ 0.58) between daily step counts and an overall gait kinematic summary score (Gait Deviation Index (GDI)). Nicholson et al. [19] confirmed a moderate correlation between GDI and stride counts ( $r=$ 0.49) in a cohort of participants with CP pre-operatively, although this correlation did not persist at surgical follow-up. However, neither study specifically examined the influence of knee kinematics. Thus, the potential relationship between crouch gait, as measured in the gait laboratory and activity levels is unclear.

The aim of this study was to examine the relationship between gait parameters related to knee crouch gait, functional health status and daily activity levels in children and adolescents ( $<$ 18 years old) with bilateral CP. Our hypothesis was that individuals with more severe crouch gait, as measured by knee flexion angle at mid-stance, would have lower measures of functional health status and reduced daily activity levels.

2. Method

2.1 Participants

The local host institution research ethics committee granted ethical approval for this study. Potential study participants were identified both prospectively and retrospectively. Participants were recruited prospectively from those being seen for routine clinical gait analysis between December 2014 and February 2017. The gait laboratory database was also used retrospectively to identify participants who met the inclusion criteria up to two years prior to December 2014. Willing participants were subsequently invited back to the laboratory for a research-only assessment. Inclusion criteria were a diagnosis of bilateral cerebral palsy GMFCS level I–III, age 4 to 17 years at the time of analysis and crouch gait. Crouch was defined as knee flexion greater or equal to two standard deviations above normal at mid-stance phase in at least one limb [20]. Based on a review of our laboratory database, this equated to a mid-stance knee flexion value of greater or equal to 19 ${}^{0}$ . Participants were excluded if they had surgery within one year prior to the gait analysis.

2.2 Data collection and analysis

Three-dimensional kinematic and kinetic data were captured using a four-camera Codamotion cx1 active marker system (Charnwood Dynamics, Leicestershire, UK). Kinematic data were sampled at a rate of 200 Hz while ground reaction forces were captured using two Kistler force plates at a sampling rate of 400 Hz. Infrared markers were placed on each participant’s lower limbs as per a modified Helen Hayes protocol [21]. All participants walked barefoot at a self-selected speed. Participants walked independently where possible. For those who routinely used a walking aid ( $n=$ 5), data were collected while the participant walked with hand-held assistance from a physiotherapist in place of the aid. This was to ensure full and accurate pick-up of gait analysis markers and reflects clinical practice. A minimum of four walking trials was recorded for each participant and, reflecting clinical practice, one representative walking trial was chosen from these for further analysis. To avoid dependence between sides, only one side was chosen for analysis [22]. If only one limb of a participant met the objective criteria, only that limb was included [20]; if both sides met the inclusion criteria, the more flexed limb was chosen for analysis [23]. The following gait parameters were extracted using Codamotion ODIN software (v1.06 Build 01 09): knee flexion at mid-stance ( ${}^{0}$ ), knee flexion at initial contact ( ${}^{0}$ ), normalised gait speed (gait speed (m/s)/height(m)) and normalised step length (step length(m)/height(m)).

Functional health status was assessed using the Pediatric Outcomes Data Collection Instrument (PODCI). The scores most relevant to gait and lower limb function were analysed in this study, namely: Transfers and Basic Mobility, Sports and Physical Function, Pain/Comfort, Happiness with Physical Condition and Global Function. Parents completed the questionnaire for all participants aged 10 years and under (Pediatric version). Older participants completed the questionnaire themselves where possible or with parent/guardian assistance when needed (Adolescent Self-Reported version). Questionnaires were completed by participants/parents at home in the days following gait analysis. The majority of questions in the PODCI questionnaire are scored using a 1–5 range with 1 indicating the most positive response. The scores for all individual questions comprising a scale are averaged and the mean of the rescaled values is then multiplied by a constant so that each scale has a final range of values between 0–100 [24].

Daily activity levels were assessed using an activPAL (PAL Technologies, Glasgow, UK) uni-axial accelerometer-based activity monitor, which has shown evidence of criterion validity in children, adolescents and young adults with CP [25, 26, 27]. Manufacturer’s recommendations for securing the thigh-mounted device were followed and wearing of the thigh mounted activity monitor was demonstrated to participants and parents/guardians. Participants were asked to remove the device only for night-time and for water-based activities [26]. A simple diary of physical activity was completed by each participant (or guardian) to both confirm appropriate wear time and provide an aid to interpretation of the output. Sedentary time (time sitting/lying) and the number of strides taken were determined. It was determined by the accelerometer based on limb position [25]. The monitor was worn for five consecutive days and the average of three days was used for analysis which has been shown to achieve a reliability coefficient of 0.70 in children with and without CP [28]. It has previously been shown that children with CP take more steps on school days compared to weekend days [29]. Therefore, in the current study, the mean of two weekdays and one weekend day was analysed to account for this difference and to best capture overall activity levels. School term time versus school holidays as well as seasonal variations in weather might also be expected to impact on daily activity levels [30, 31]. Therefore, while the time of year of the assessment (school term or summer) was not controlled in this study, the season (spring, summer, fall, winter) was included in the correlation analysis.

Table 1
Participant ( $n=$ 35) demographic, gait, quality of life and daily activity data

Variable	Value
Gender, male/female	21/14
Body Mass Index (kg/m ${}^{2}$ )	17.82 $\pm$ 3.02 (12.68–26.40)
Age at gait analysis (years)	9.82 $\pm$ 3.93 (4–17)
GMFCS	I $=$ 11, II $=$ 17, III $=$ 7
Gait Deviation Index	71.11 $\pm$ 11.42 (38.5–95.5)
Gait parameters
Knee flexion at mid-stance ( ${}^{0}$ )	22.00 $\pm$ 8.00 (19.00–51.00) ${}^{\wedge}$
Knee flexion at initial contact ( ${}^{0}$ )	32.91 $\pm$ 10.94 (10.08–60.02)
Normalised gait speed (speed/height)	0.72 $\pm$ 0.40 (0.11–1.16) ${}^{\wedge}$
Normalised step length (step length/height)	0.33 $\pm$ 0.09 (0.09–0.42) ${}^{\wedge}$
PODCI quality of life domains
Sports and physical function	57.61 $\pm$ 22.85 (4.55–90.83)
Transfers and basic mobility	86.00 $\pm$ 17.96 (9–100) ${}^{\wedge}$
Pain/Comfort	89.00 $\pm$ 24.22 (45.56–100) ${}^{\wedge}$
Happiness	90.00 $\pm$ 11.13 (25–100) ${}^{\wedge}$
Global function	82.34 $\pm$ 10.76 (39.86–96.16) ${}^{\wedge}$
Daily activity measures
Mean steps/day	5850.71 $\pm$ 3599.33 (233.33–14226.67)
Sedentary time/day (hours)	19.99 $\pm$ 1.54 (16.05–23.76)

Data are mean $\pm$ standard deviation (range) unless otherwise stated. ${}^{\wedge}$ Median $\pm$ interquartile range (range). GMFCS – Gross Motor Function Classification System; PODCI – Pediatric Outcomes Data Collection Instrument.

2.3 Statistical analysis

Shapiro-Wilks test of normality was conducted on all continuous variables and collinearity was assessed using variance inflation factors (VIF). For the purpose of statistical analysis, the averaged and rescaled PODCI scores (ranging 0–100) were treated as continuous variables. Parameters were considered non-collinear for VIF $<$ 10 [23, 32]. Correlation coefficients were calculated to investigate the relationship between gait variables associated with crouch gait and measures of functional health status and daily activity. Age and Gross Motor Function Classification System level (GMFCS) were included in the overall correlation analysis as a relationship between both PODCI scores and daily activity has previously been demonstrated in children with CP [12, 29]. Time of year (season) was included in the correlation analysis of daily activity measures [30, 31]. Where both variables were continuous and normally distributed, Pearson’s correlation coefficients were calculated. Otherwise non-parametric Spearman rank correlation coefficients were used. A Bonferroni correction for multiple comparisons was applied and an adjusted significance level was set at $p<$ 0.008. Separate multivariable linear regression analyses were then undertaken using the parameters significantly correlated with functional health status and daily activity as predictor variables. The relevant PODCI measures and daily activity measures were used as dependent variables. The correlations between PODCI domains and daily activity measures were separately examined using appropriate correlation coefficients and a Bonferroni adjusted significance level was set at $p<$ 0.010. All statistical analyses were conducted using Stata v13.1 software (StataCorp LP, USA).

3. Results

A total of 35 participants met the inclusion criteria for this study. All had knee flexion greater or equal to 19 ${}^{\circ}$ at mid-stance in one or both limbs. Participant demographic data and gait, QoL and activity parameters are summarised in Table 1.

Sports and physical function, sedentary time/day, mean steps/day, knee flexion at initial contact and age were normally distributed. Transfers and basic mobility, pain/comfort, happiness with physical condition, global Function, knee flexion at mid-stance, Normalised speed and normalised step length were not normally distributed ( $p\leqslant$ 0.01 in all cases).

The relevant correlation coefficients between gait, PODCI and daily activity variables and associated p-values are summarised in Figs 1 and 2. Analysis of variance inflation factors demonstrated no collinearity between any of the included parameters; values ranged from 1.18 to 5.82.

Figure 1.

Correlations between PODCI domains and gait parameters. r- Pearson’s correlation coefficient. $\rho$ - Spearman’s correlation coefficient. GMFCS – Gross Motor Function Classification System. ${}^{*}$ Significant correlations (Bonferroni adjusted $p$ -value $p<$ 0.008).

Figure 2.

Correlations between ActivPal measures of daily activity and gait parameters. r- Pearson’s correlation coefficient. $\rho$ - Spearman’s correlation coefficient. GMFCS – Gross Motor Function Classification System. ${}^{*}$ Significant correlations (Bonferroni adjusted $p$ -value $p<$ 0.008).

There were no significant correlations (Bonferroni adjusted $p$ -value $p<$ 0.008) between knee flexion at mid-stance and any of the PODCI or daily activity measures. In contrast, normalised step length significantly correlated with three PODCI domains:ports and physical function (Spearman $\rho=$ 0.524; $p=$ 0.001), transfers and basic mobility (Spearman $\rho=$ 0.565; $p<$ 0.001) and global function (Spearman $\rho=$ 0.486; $p=$ 0.003). Knee flexion at initial contact demonstrated a significant correlation with transfers and basic mobility (Spearman $\rho=-$ 0.508; $p=$ 0.002). There were no significant correlations between pain/comfort or happiness with physical condition and any of the gait variables. There was a significant correlation between mean steps/day and normalised gait speed (Spearman $\rho=$ 0.561; $p=$ 0.001). However, sedentary time/day was not associated with any of the gait variables. There was no significant correlation between season and either mean steps/day (Spearman $\rho=$ 0.236; $p=$ 0.173) or sedentary time/day (Spearman $\rho=-$ 0.315; $p=$ 0.065). Age was found to be associated with transfers and basic mobility (Spearman $\rho=$ 0.545; $p=$ 0.001) while GMFCS level was associated with sports and physical function (Spearman $\rho=-$ 0.495; $p=$ 0.003) and transfers and basic mobility (Spearman $\rho=-$ 0.458; $p=$ 0.006).

Table 2

Multivariable linear regression analyses of functional health status and daily activity measures

	$\beta$ coefficients		Standard error		$p$ -value
PODCI quality of life domains
A) Sports and physical function
Normalised step length (step length/height)	190.	51	83.	86	0.	030 ${}^{*}$
GMFCS
II	$-$ 1.	24	8.	57	0.	886
III	3.	93	18.	96	0.	837
Intercept	$-$ 1.	57	31.	99	0.	961
b) Transfers and basic mobility
Normalised step length (step length/height)	112.	40	52.	46	0.	041 ${}^{*}$
Knee flexion at ground contact	$-$ 0.	31	0.	24	0.	213
Age	2.	46	0.	59	$<$ 0.	001 ${}^{*}$
GMFCS
II	9.	33	5.	27	0.	087
III	$-$ 0.	80	11.	23	0.	944
Intercept	29.	81	24.	18	0.	227
c) Global Function
Normalised step length (step length/height)	116.	28	24.	53	$<$ 0.	001 ${}^{*}$
Intercept	40.	66	7.	85	$<$ 0.	001 ${}^{*}$
Daily activity measures
a) Mean steps/day
Normalised gait speed (speed/height)	8028.	75	1945.	05	$<$ 0.	001 ${}^{*}$
Intercept	805.	57	1321.	13	0.	546

PODCI – Pediatric Outcomes Data Collection Instrument; GMFCS – Gross Motor Function Classification System. ${}^{*}$ Significant values ( $p<$ 0.05) in bold.

The separate multivariable linear regression analyses are summarised in Table 2. The analysis found that normalised step-length was independently associated with three PODCI domains (sports and physical function, transfers and basic mobility and global function). Normalised gait speed was significantly associated with steps/day.

Figure 3.

Correlations between ActivPal measures of daily activity and PODCI domains. r- Pearson’s correlation coefficient. $\rho$ - Spearman’s correlation coefficient. ${}^{*}$ Significant correlations (Bonferroni adjusted $p$ -value $p<$ 0.010).

Correlation coefficients between PODCI and daily activity variables and associated $p$ -values are summarised in Fig. 3. There was a significant correlation (Bonferroni adjusted $p$ -value $p<$ 0.010) between mean steps/day and the sports and physical function domain of the PODCI assessment (Pearson $r=$ 0.433; $p=$ 0.009).

4. Discussion

As crouch gait has been shown to increase the forces and demands on the knee joint [3, 4], our hypothesis was that, as a result, those with more severe crouch would have lower measures of functional health status and reduced daily activity levels. However, our analysis demonstrates that there was no correlation between knee flexion angle at mid-stance and any of the PODCI domains or daily activity measures analysed.

Instead, the current results suggest that step-length is better associated with functional health status rather than the more specific kinematic angle of knee flexion during stance. While knee flexion contributes to step-length, it has also been suggested that factors such as selective motor control also influence step-length [33]. Normalised step-length was found to be independently associated with the three functional PODCI domains (sports and physical function, transfers and basic mobility and global function). Knee flexion in stance was not related to functional health status or daily activity levels. It is consistent with the findings of Steele et al. [34] who recently reported that knee flexion in stance also demonstrated poor correlation with energy expenditure of gait. These authors further noted that oxygen consumption during gait better correlated with knee flexion angle at initial contact which the authors hypothesised may in turn lead to shorter step lengths. The fact that step-length is better associated with functional health status potentially has important implications in treatment planning in children with CP crouch gait. While gait analysis has proven its effectiveness and usefulness in surgical planning in those with CP [35, 36, 37, 38], the current study suggests that surgical interventions targeted at improving specific gait kinematics may not directly influence activity and participation. While correlation does not imply causation, our results suggest that to best improve functional health status, step-length should be considered. This possibly re-enforces the importance of appropriate orthoses where indicated as Ankle Foot Orthoses (AFOs) have been shown to improve spatiotemporal parameters such as speed and step length in addition to the beneficial effects of surgery [39, 40]. The current results suggest that further research is warranted about a potential relationship between improvements in the spatiotemporal parameters of gait with AFOs and potential changes in functional health status.

In terms of daily activity, we found moderate correlations between mean steps/day and both normalised gait speed and sports and physical function. It is probably not surprising that the more functional walkers in terms of speed were also the most active. There was no association between daily activity and any of the specific kinematic values, which differs somewhat from the findings of both Wilson et al. [18] and Nicholson et al. [19]. They both report a moderate correlation between step/stride count and an overall gait kinematic summary score (GDI). This may suggest that kinematic values other than those examined in this study have more of an influence on step counts and daily activity.

There are a number of limitations that should be considered when interpreting the results of this study. Our population size of 35 potentially limits the wider interpretation of the results. However, the sample size is broadly in line with, or larger than, similar studies on participants with CP [23, 41] and in all our regression analyses, the number of fitted variables is less than one-tenth of the number of observations as recommended [42]. This study specifically examined children and adolescents with ambulant bilateral CP and therefore, the generalizability of the results to older, more involved participants is somewhat limited. The majority of participants in this study were GMFCS I and II and only a limited number of GMFCS III participants were included as might be expected in a study of participants with ambulant CP. Accordingly, Fig. 1 highlights that the knee flexion at mid-stance values are somewhat skewed to the left with a smaller number of participants in more severe crouch greater than 40 ${}^{0}$ . This is similarly the case for mean steps/day as plotted in Fig. 2 and reported in Table 1. There was a large range of recorded values with the relatively small number of participants who were GMFCS level III likely having significantly reduced step counts compared to less involved participants [29, 43]. Likewise, a ceiling effect is seen in some domains of the PODCI assessment, particularly pain/comfort, which again reflects the relatively high levels of function in this population of ambulant CP participants. The mean age of participants in this study was 9.82 years and all participants were under 18 years of age. Based on retrospective gait studies, it has long been suggested that crouch severity increases with age [2, 44]. While a recent prospective study has highlighted that this is not the case in all those with CP crouch gait [45], the findings of this study should not necessarily be extrapolated to older, more involved people with CP.

The gait kinematics analysed in this study were collected barefoot as per routine clinical analysis protocols and therefore may not fully reflect community ambulation in this population. As highlighted above, the spatiotemporal parameters of gait would be expected to improve with orthoses [39, 40]. Therefore, future work is warranted to examine step length during community-based assessment to examine their impact on daily activity and functional health status. Additionally, routine walking aids were not used during gait data collection and the five participants who routinely used a walking aid (3 posterior walker, 2 bilateral crutches) were instead assessed with hand-held assistance. Krautwurst et al. [46] have highlighted that gait data collected without a walking aid is likely to be more flexed than gait with routine walking aid. While the hand-held support provided may have mitigated this to some degree, it is still likely that gait data as assessed in the clinical gait laboratory is likely to have differed somewhat compared to routine day to day walking.

A control group, not walking in crouch, might have potentially strengthened the findings and theoretically, as functional PODCI domains and daily activity levels do not appear to be related to knee flexion, the non-crouch group would have demonstrated similar functional health status and daily activity levels. However, as crouch gait has been suggested to progress with age in children with CP [44], a non-crouch control group would potentially be younger which in turn influences both PODCI scores and daily activity levels [12, 29].

5. Conclusion

The results of this study confirm that functional gait variables are associated with the functional domains of the PODCI assessment (sports and physical function, transfers and basic mobility and global function), although not the psycho-social domains (pain/comfort and happiness with physical condition). Analysis of specific gait parameters suggest that it is step length rather than knee flexion in stance which is best associated with functional health status in children/adolescents with CP crouch gait. This highlights the importance of considering spatiotemporal measures of gait when assessing walking function in CP and examining the potential impact of footwear and orthoses on these parameters.

Footnotes

Acknowledgments

The lead author is a research fellow funded by the Health Research Board of Ireland [HPF-2014-650].

Conflict of interest

The authors have no conflict of interest to report.

References

Oskoui

, Coutinho

, Dykeman

, Jette

, Pringsheim

. An update on the prevalence of cerebral palsy: a systematic review and meta-analysis. Dev Med Child Neurol.2013; 55(6): 509–19. doi: 10.1111/dmcn.12080.

Rethlefsen

, Blumstein

, Kay

, Dorey

, Wren

. Prevalence of specific gait abnormalities in children with cerebral palsy revisited: influence of age, prior surgery, and Gross Motor Function Classification System level. Dev Med Child Neurol.2017; 59(1): 79–88. doi: 10.1111/dmcn.13205.

Steele

, Demers

, Schwartz

, Delp

. Compressive tibiofemoral force during crouch gait. Gait Posture.2012; 35(4): 556–60. doi: 10.1016/j.gaitpost.2011.11.023.

Steele

, van der Krogt

, Schwartz

, Delp

. How much muscle strength is required to walk in a crouch gait? J Biomech.2012; 45(15): 2564–9. doi: 10.1016/j.jbiomech..

O’Sullivan

, Walsh

, Kiernan

, O’Brien

. The knee kinematic pattern associated with disruption of the knee extensor mechanism in ambulant patients with diplegic cerebral palsy. Clin Anat.2010; 23(5): 586–92. doi: 10.1002/ca.20976.

Galey

, Lerner

, Bulea

, Zimbler

, Damiano

. Effectiveness of surgical and non-surgical management of crouch gait in cerebral palsy: a systematic review. Gait Posture.2017; 54: 93–105. doi: 10.1016/j.gaitpost.2017.02.024.

Putz

, Wolf

, Mertens

, Geisbusch

, Gantz

, Braatz

, et al. Effects of multilevel surgery on a flexed knee gait in adults with cerebral palsy. Bone Joint J.2017; 99-b(9): 1256–64. doi: 10.1302/0301-620x.99b9.bjj-2016-1155.r1.

Healy

, Schwartz

, Stout

, Gage

, Novacheck

. Is simultaneous hamstring lengthening necessary when performing distal femoral extension osteotomy and patellar tendon advancement? Gait Posture2011; 33(1): 1–5. doi: 10.1016/j.gaitpost.2010.08.014.

Boyer

, Stout

, Laine

, Gutknecht

, Araujo de Oliveira

, Munger

, et al. Long-term outcomes of distal femoral extension osteotomy and patellar tendon advancement in individuals with cerebral palsy. J Bone Joint Surg Am.2018 Jan 3; 100(1): 31–41. doi: 10.2106/JBJS.17.00480.

10.

Dreher

, Thomason

, Svehlik

, Doderlein

, Wolf

, Putz

, et al. Long-term development of gait after multilevel surgery in children with cerebral palsy: a multicentre cohort study. Dev Med Child Neurol.2018; 60(1): 88–93. doi: 10.1111/dmcn.13618.

11.

Daltroy

, Liang

, Fossel

, Goldberg

. The POSNA pediatric musculoskeletal functional health questionnaire: report on reliability, validity, and sensitivity to change. Pediatric outcomes instrument development group. Pediatric orthopaedic society of north america. J Pediatr Orthop. Sep-Oct 1998; 18(5): 561–71. doi: 10.1097/00004694-199809000-00001.

12.

Barnes

, Linton

, Sullivan

, Bagley

, Oeffinger

, Abel

, et al. Pediatric outcomes data collection instrument scores in ambulatory children with cerebral palsy: an analysis by age groups and severity level. J Pediatr Orthop.2008; 28(1): 97–102. doi: 10.1097/bpo.0b013e31815a60e6.

13.

Lee

, Chung

, Park

, Lee

, Choi

, Cho

, et al. Level of improvement determined by PODCI is related to parental satisfaction after single-event multilevel surgery in children with cerebral palsy. J Pediatr Orthop.2010; 30(4): 396–402. doi: 10.1097/BPO.0b013e3181da855f.

14.

Damiano

, Gilgannon

, Abel

. Responsiveness and uniqueness of the pediatric outcomes data collection instrument compared to the gross motor function measure for measuring orthopaedic and neurosurgical outcomes in cerebral palsy. J Pediatr Orthop.2005; 25(5): 641–5. doi: 10.1097/01.bpo.0000167079.83835.22.

15.

Cuomo

, Gamradt

, Kim

, Pirpiris

, Gates

, McCarthy

, et al. Health-related quality of life outcomes improve after multilevel surgery in ambulatory children with cerebral palsy. J Pediatr Orthop.2007; 27(6): 653–7. doi: 10.1097/BPO.0b013e3180dca147.

16.

Stout

, Gage

, Schwartz

, Novacheck

. Distal femoral extension osteotomy and patellar tendon advancement to treat persistent crouch gait in cerebral palsy. J Bone Joint Surg Am.2008; 90(11): 2470–84. doi: 10.2106/JBJS.G.00327.

17.

Bjornson

, Belza

, Kartin

, Logsdon

, McLaughlin

. Ambulatory physical activity performance in youth with cerebral palsy and youth who are developing typically. Phys Ther.2007; 87(3): 248–57. doi: 10.2522/ptj.20060157.

18.

Wilson

, Signal

, Naude

, Taylor

, Stott

. Gait deviation index correlates with daily step activity in children with cerebral palsy. Arch Phys Med Rehabil.2015; 96(10): 1924–7. doi: 10.1016/j.apmr.2015.05.024.

19.

Nicholson

, Lennon

, Church

, Miller

. Gait analysis parameters and walking activity pre- and postoperatively in children with cerebral palsy. Pediatr Phys Ther.2018; 30(3): 203–07. doi: 10.1097/pep.0000000000000512.

20.

Ries

, Schwartz

. Ground reaction and solid ankle-foot orthoses are equivalent for the correction of crouch gait in children with cerebral palsy. Dev Med Child Neurol.2019; 61(2): 219–25. doi: 10.1111/dmcn.13999.

21.

Kiernan

, Hosking

, O’Brien

. Is adult gait less susceptible than paediatric gait to hip joint centre regression equation error? Gait Posture2016; 45: 133–6. doi: 10.1016/j.gaitpost.2016.01.023.

22.

Dreher

, Vegvari

, Wolf

, Geisbusch

, Gantz

, Wenz

, et al. Development of knee function after hamstring lengthening as a part of multilevel surgery in children with spastic diplegia: a long-term outcome study. J Bone Joint Surg Am.2012; 94(2): 121–30. doi: 10.2106/JBJS.J.00890.

23.

Rha

, Cahill-Rowley

, Young

, Torburn

, Stephenson

, Rose

. Biomechanical and clinical correlates of stance-phase knee flexion in persons with spastic cerebral palsy. PM R.2016; 8(1): 11–8; quiz 18. doi: 10.1016/j.pmrj.2015.06.003.

24.

Opheim

, McGinley

, Olsson

, Stanghelle

, Jahnsen

. Walking deterioration and gait analysis in adults with spastic bilateral cerebral palsy. Gait Posture.2013; 37(2): 165–71. doi: 10.1016/j.gaitpost.2012.06.032.

25.

Bania

, Taylor

, Baker

, Graham

, Karimi

, Dodd

. Gross motor function is an important predictor of daily physical activity in young people with bilateral spastic cerebral palsy. Dev Med Child Neurol.2014; 56(12): 1163–71. doi: 10.1111/dmcn.12548.

26.

Bania

. Measuring physical activity in young people with cerebral palsy: validity and reliability of the ActivPAL monitor. Physiother Res Int.2014; 19(3): 186–92. doi: 10.1002/pri.1584.

27.

Tang

, Richardson

, Maxwell

, Spence

, Stansfield

. Evaluation of an activity monitor for the objective measurement of free-living physical activity in children with cerebral palsy. Arch Phys Med Rehabil.2013; 94(12): 2549–58. doi: 10.1016/j.apmr.2013.07.019.

28.

Ryan

, Forde

, Hussey

, Gormley

. Comparison of patterns of physical activity and sedentary behavior between children with cerebral palsy and children with typical development. Phys Ther.2015; 95(12): 1609–16. doi: 10.2522/ptj.20140337.

29.

van Wely

, Becher

, Balemans

, Dallmeijer

. Ambulatory activity of children with cerebral palsy: which characteristics are important? Dev Med Child Neurol.2012; 54(5): 436–42. doi: 10.1111/j.1469-8749.2012.04251.x.

30.

Brazendale

, Beets

, Weaver

, Pate

, Turner-McGrievy

, Kaczynski

, et al. Understanding differences between summer vs. school obesogenic behaviors of children: the structured days hypothesis. Int J Behav Nutr Phys Act.2017; 14(1): 100-100. doi: 10.1186/s12966.

31.

Niiler

, Nicholson

, Fischer

, Lennon

. Factors influencing post-surgical variability in StepWatch data in youth with cerebral palsy. Gait Posture.2019; 72: 234–38. doi: 10.1016/j.gaitpost.2019.06.017.

32.

Hair

, Anderson

, Tatham

Black

. Multivariate Data Analysis. 3rd ed ed: Macmillan Publishing Company, New York, 1995.

33.

Steele

, Shuman

, Schwartz

. Crouch severity is a poor predictor of elevated oxygen consumption in cerebral palsy. J Biomech.2017; 60: 170–74. doi: 10.1016/j.jbiomech.2017.06.036.

34.

Zhou

, Lowe

, Cahill-Rowley

, Mahtani

, Young

, Rose

. Influence of impaired selective motor control on gait in children with cerebral palsy. J Child Orthop.2019; 13(1): 73–81. doi: 10.1302/1863-2548.13.180013.

35.

Gough

, Shortland

. Can clinical gait analysis guide the management of ambulant children with bilateral spastic cerebral palsy? JJ Pediatr Orthop.2008; 28(8): 879–83. doi: 10.1097/BPO.0b013e31818e197c.

36.

Wren

, Otsuka

, Bowen

, Scaduto

, Chan

, Dennis

, et al. Outcomes of lower extremity orthopedic surgery in ambulatory children with cerebral palsy with and without gait analysis: results of a randomized controlled trial. Gait Posture.2013; 38(2): 236–41. doi: 10.1016/j.gaitpost.2012.11.018.

37.

Baker

, Esquenazi

, Benedetti

, Desloovere

. Gait analysis: clinical facts. Eur J Phys Rehabil Med.2016; 52(4): 560-74.

38.

Laracca

, Stewart

, Postans

, Roberts

. The effects of surgical lengthening of hamstring muscles in children with cerebral palsy – the consequences of pre-operative muscle length measurement. Gait Posture.2014; 39(3): 847–51. doi: 10.1016/j.gaitpost.2013.11.010.

39.

Schwarze

, Block

, Kunz

, Alimusaj

, Heitzmann

DWW

, Putz

, et al. The added value of orthotic management in the context of multi-level surgery in children with cerebral palsy. Gait Posture.2019; 68: 525–30. doi: 10.1016/j.gaitpost.2019.01.006.

40.

Skaaret

, Steen

, Terjesen

, Holm

. Impact of ankle-foot orthoses on gait 1 year after lower limb surgery in children with bilateral cerebral palsy. Prosthet Orthot Int.2019 Feb; 43(1): 12–20. doi: 10.1177/0309364618791615.

41.

Noble

, Gough

, Shortland

. Selective motor control and gross motor function in bilateral spastic cerebral palsy. Dev Med Child Neurol.2019; 61(1): 57–61. doi: 10.1111/dmcn.14024.

42.

Prescott

. Editorial: avoid being tripped up by statistics: statistical guidance for a successful research paper. Gait Posture.2019 Jul; 72: 240–249. doi: 10.1016/j.gaitpost.2018.06.172.

43.

Shkedy Rabani

, Harries

, Namoora

, Al-Jarrah

, Karniel

, Bar-Haim

. Duration and patterns of habitual physical activity in adolescents and young adults with cerebral palsy. Dev Med Child Neurol.2014; 56(7): 673–80. doi: 10.1111/dmcn.12394.

44.

O’Sullivan

, Horgan

, O’Brien

, French

. The natural history of crouch gait in bilateral cerebral palsy: a systematic review. Res Dev Disabil.2018; 80: 84–92. doi: 10.1016/j.ridd.2018.06.013.

45.

O’Sullivan

, French

, Horgan

. A prospective assessment of the progression of flexed-knee gait over repeated gait analyses in the absence of surgical intervention in bilateral cerebral palsy. Gait Posture2020; 79: 133–38. doi: 10.1016/j.gaitpost.2020.04.021.

46.

Krautwurst

, Dreher

, Wolf

. The impact of walking devices on kinematics in patients with spastic bilateral cerebral palsy. Gait Posture2016; 46: 184–7. doi: 10.1016/j.gaitpost.2016.03.014.

The association between gait analysis measures associated with crouch gait,functional health status and daily activity levels in cerebral palsy

Abstract

PURPOSE:

METHODS:

RESULTS:

CONCLUSIONS:

Keywords

1. Introduction

2. Method

2.1 Participants

2.2 Data collection and analysis

Table 1 Participant ( n = 35) demographic, gait, quality of life and daily activity data

3. Results

5. Conclusion

Footnotes

Acknowledgments

Conflict of interest

References

Table 1
Participant ( $n=$ 35) demographic, gait, quality of life and daily activity data