INTRODUCTION AND PURPOSE
When a baby receives a diagnosis of clubfoot, parents are typically concerned about how the diagnosis and treatment will effect the child's attainment of normal gross motor milestones. Idiopathic clubfoot disorder is one of the most common orthopedic diagnoses in infants with an incidence varying from 0.6 per 1000 to 6.8 per 1000, depending on cultural group and location.1 Etiology of the disorder is unclear; however, there is recent identification of a genetic mutation that may be implicated in some cases.2
There is a paucity of evidence of the effect of any idiopathic orthopedic deformity on gross motor development in the first year of life in recent literature with the exception of infants with skeletal dysplasias. Crockett et al3 reported a significant delay in attainment of motor milestones in babies with diastrophic dysplasia. Ireland et al4 studied developmental milestones in Australasian children with achondroplasia and noted significant delays.
There is limited evidence of the effect of treated clubfoot disorder on motor skills in later childhood. Andriesse et al5 tested 20 children with treated clubfoot at age 7 years and found an increased prevalence of motor impairment as measured by the Movement Assessment Battery for Children. The degree of motor impairment did not correlate to the severity of the clubfoot or whether the disorder was unilateral or bilateral. The authors concluded that factors, in addition to clubfoot disorder, may be present that affect motor abilities.
The presence of a clubfoot and the methods and containment used to treat the disorder can be seen as constraints that potentially effect patterns of gross motor development. Treatment of clubfoot at Shriners Hospitals for Children—Spokane is performed by 1 of 2 methods. The first method consists of the Ponseti technique with casting and brace application.6 The second method is the French or physical therapy method of taping and splinting outlined by Dimeglio et al7 and further refined at Texas Scottish Rite Hospital.8 Both treatment methods typically incorporate heel cord tenotomy within the first 6 months of treatment. The choice of treatment method is made by the parent after education by hospital personnel. Regardless of which method is used for treatment, with a successful outcome the treated foot is plantigrade by the time a child is spontaneously pulling to stand.
The Ponseti method involves a series of lower extremity casts that encompass the baby's foot and extend to the upper thigh. These casts, changed weekly, continue until the forefoot is corrected, usually requiring 5 to 6 casts. The baby then undergoes a percutaneous heel cord tenotomy and is casted for another 3 weeks. At that point, the baby is fitted with an orthotic such as a Mitchell brace, using a metal bar between the baby's feet that are held in an everted position by shoes or sandals attached to the bar. This brace is worn full time for several months progressing to sleep time only.
Some parents express concerns regarding motor development effects of having both of the baby's legs restrained from independent movement by this brace. The use of long leg casts initially and Mitchell brace do not permit typical patterns of kicking in the early months of life. The Mitchell brace and similar devices limit movements in both lower extremities, even if the clubfoot is unilateral. Thelan9 demonstrated that 3-month-old babies were able to adapt kicking behavior to activate a mobile when their legs were tied together. A baby constrained by an external device such as a long leg cast or bilateral orthoses may be able to adapt to these constraints using novel patterns of movement and continue to progress in gross motor skill.
For babies undergoing the physical therapy method of clubfoot treatment, the constraints on typical patterns of gross motor development are different. The baby undergoes sessions of massage, stretching, and active facilitation of the baby's involved foot or feet by the parent and therapist. The foot is constrained in the position of maximal possible correction with taping and a fabricated ankle foot orthosis (AFO) splint encompassing the baby's foot extending to just below the knee. The splint is custom molded by the therapist and is made of Aquaplast (Sammons Preston, Cedarburg, Wisconsin). Movement is restricted for the ankle of the involved side(s). Movement is not restricted at hips or knees or in the uninvolved limb, and there is no bar connecting the lower extremities. The tape and splint are worn a minimum of 22 hours per day until the baby is beginning to pull to stand. When the baby begins standing, the tape and splint are discontinued except for sleep time if the baby's foot is well corrected, and an arch support or custom molded foot orthosis is worn in a shoe during awake time as needed.
With either method used for treatment of the clubfoot, typical early infant lower extremity movements are affected. Parents, medical, and early intervention providers would benefit from an understanding of typical gross motor development for a child with clubfoot. This understanding may help prevent over referral or under referral for motor-related early intervention services.
The purpose of this study was to assess the gross motor performance of babies treated for a clubfoot disorder using the Alberta Infant Motor Scale10 and parent report of attainment of 6 motor milestones. The scores attained on the Alberta Infant Motor Scale (AIMS) by the clubfoot group were compared to the group of babies who were typically developing (controls). The dates of attainment of motor milestones by the clubfoot group were also compared with the control group. The following hypotheses were tested in this study: the AIMS scores of the clubfoot group would be lower than those of the control group up to 15 months of age and attainment of motor milestones of the clubfoot group would be later than the control group based on parental report.
Approval for the study was obtained by the Institutional Review Board Spokane. The babies with a clubfoot diagnosis were recruited from the group of infants whose parents sought clubfoot treatment from Shriners Hospitals for Children—Spokane. Inclusion criteria included a clubfoot diagnosis unilateral or bilateral without other medical diagnoses and a gestational age of 36 weeks or more. The control group was recruited by word of mouth; parents in this group were interested in monitoring their child's gross motor development and were willing to bring the baby to our facility for motor assessment every 3 months. All babies were at least 36 weeks gestation at the time of birth. No incentives were given for participation in the study for either group. Written informed consent was obtained from the parents of the babies in the study. A total of 71 babies were recruited to participate (39 in the clubfoot group, 32 in the control group), with 52 completing the study. The primary reason for withdrawal was an inability to return for assessments within time parameters of the study. Two babies in the clubfoot group were excluded because of other medical diagnoses received after study enrollment. Three participants with clubfoot missed an assessment (1 at 9 months, 2 at 12 months), however, returned for the remaining assessments and were included in the study. Of the 52 participants who completed the study, 26 were babies diagnosed with and being treated for bilateral or unilateral clubfoot without other medical diagnoses and 26 babies were typically developing without medical diagnoses.
Of the 26 participants in the clubfoot group, 8 had bilateral involvement and 18 unilateral involvement. The Ponseti technique was used to treat 12 participants whereas 9 were treated using the French technique. The remaining 5 participants had treatment that included both techniques. Four of these participants began in the Ponseti method and then transitioned to the French method due to inability to comply with Ponseti bracing and parental choice. One participant began in the French method and transitioned to Ponseti due to parental choice.
For the clubfoot group, the severity of the clubfoot disorder was measured using the Dimeglio scale. This is a series of 4 measurements of the blockage of movement related to the disorder and the presence or absence of skin creases, cavus, and normal muscle tone in the baby's foot. These measurements were routinely done periodically before and during the treatment of clubfoot and result in a numeric score from 0 to 20 (Table 1). At initial presentation, the majority of treated clubfeet in this study were scored in the 11 to 18 range, considered severe to very severe.11 For babies with bilateral clubfoot, the greater of the 2 Dimeglio scores was used for analysis.
The AIMS assessments were conducted at the ages of 3, 6, 9, and 12 months. Fifteen- and 18-month assessments were conducted only if the baby had not yet started walking. Scheduling of the assessments was aimed at the actual date at the age of 3, 6, 9, 12, 15, 18 months but a 2-week window was allowed before and after if needed. For the clubfoot group, the motor assessments were conducted during a routine orthopedic follow up appointment.
The AIMS assessment was performed by 2 physical therapists, each with over 15 years of experience in pediatric physical therapy and each certified as a pediatric specialist by the American Board of Physical Therapy Specialties. The 2 therapists both scored the AIMS for 10 participants at a variety of ages (3–12 months). Comparing the scores between the 2 therapists resulted in an intraclass correlation of 0.99, indicating a high degree of agreement between the therapists. The assessments were performed at Shriners Hospitals for Children—Spokane and scoring was done at the time of the assessment, and the results of the AIMS were explained to the parent(s).
Parents were also requested to report the dates of 6 motor milestones, including rolling front to back, rolling back to front, sitting alone for 10 seconds, crawling, pulling to stand, and walking. Crawling was defined as reciprocal movements in hands and knees and walking was defined as multiple steps. They were given a magnetized tracking card to place on their refrigerator and were asked to write the date of the initial attainment of the milestones on the card. They were asked to bring the card when they had their AIMS assessment and the dates of any milestones attained in the previous 3-month period were given to the testing therapist. Most but not all participants complied with this request.
At each 3-month interval, the AIMS scores for the clubfoot group were compared with the control group with the nonparametric Mann-Whitney U test. Within the clubfoot group, AIMS scores were compared for subgroups of unilateral versus bilateral involvement and treatment type (Ponseti vs French techniques) using the Mann-Whitney U test. Mean age of motor milestones obtained through parent report was compared between clubfoot and control groups using the Student t test. For the clubfoot group, the initial Dimeglio score was analyzed with respect to the AIMS at 9 months of age to determine if there is a relationship between clubfoot severity and attainment of gross motor development. Finally, control group AIMS scores were compared with standardized reported values using the Student t test; a nonparametric test could not be used because of the lack of raw data for the standardized values. An α level of .05 was used in all analyses.
At 3 and 6 months, there was no difference in gross motor development between babies with clubfoot and controls as measured by the AIMS (Table 2). At 9 and 12 months, scores for babies with clubfoot were significantly lower than controls (P < .05, Table 1). At 15 months, the clubfoot group AIMS scores trended lower with P = .06 but did not reach significance. This may be due to the ceiling effect of the AIMS score and the study design, as the values at 15 and 18 months represent slower developing babies of both the control and clubfoot groups as those who have walked at 12 months did not undergo the 15- and 18-month assessments.
Twenty-one babies with clubfoot were not walking at or before 12 months, so they did not complete the study at that time and had an AIMS assessment at the 15-month period. This was 81% of the clubfoot group (21 of 26). Twelve babies who were typically developing were not walking at or before 12 months and were tested at 15 months. This represented 48% (12 of 25) of the typically developing group. The percentage of babies with clubfoot not walking at 12 months or earlier (81%) was significantly higher than control group babies (48%), P = .014.
Comparing babies with bilateral clubfoot versus unilateral clubfoot, there was no significant difference in AIMS score at any point in time (Table 3). When comparing babies who underwent Ponseti treatment to those who underwent French treatment, there were no significant differences at any age tested (Table 4). The 5 babies who underwent both methods of treatment were not included in this comparison.
For the parent-reported dates of when the babies attained the 6 specific motor skills, there were no significant differences in attainment of rolling in either direction and sitting alone. However, for the remainder of the motor skills (crawling, pulling to stand, and walking), the babies with clubfoot attained the skill significantly later than the control group of babies who were typically developing (Table 5). The mean age of parent-reported attainment of independent walking in the clubfoot group was 13.9 months, whereas in the control group it was 12.0 months.
There was a very low correlation (R2 = 0.046) between the severity of the clubfoot disorder (Dimeglio score) and the AIMS score at 9 months (Figure). This implies that the severity of the disorder at initial presentation does not affect the attainment of early gross motor skills. The 9-month scores were chosen for analysis because the most significant difference in AIMS score between the groups was at 9 months. Analysis of correlation of Dimeglio score with AIMS score was not performed on other age-level data due to the lack of significant correlation at 9 months.
The group of babies diagnosed with clubfoot in our study did present with a mild delay in the attainment of gross motor skills when compared with a group of babies who were typically developing. This delay did not become apparent until the babies were 9 months of age when they begin activities that required them to be in a more upright position with less surface support. During treatment of clubfoot, the most extensive physical constraints to typical development of gross motor skills such as full-time use of splints and braces occur in the first 3 months but delay in attainment of gross motor skill is not apparent until later. There are many possible reasons for the mild delay that are not clear from our data. The delay may be related to the constraints on motor movements caused by the restriction inherent in any clubfoot treatment method such as the use of braces or splints. There may be changes in the development of the baby's foot position and function in the upright position that affect balance and equilibrium or strength of the baby's foot and ankle muscle groups. It is also possible that the presence of clubfoot disorder may be a marker for underlying mild motor development dysfunction or that there are other inherent factors associated with clubfoot deformity that negatively affect gross motor proficiency. There may be a link between 1 or more of the multifactorial components of clubfoot etiology identified in the literature with consequences that negatively affect the development of gross motor skills. These components include genetic mutations and a variety of histopathologies related to retractive fibrotic responses and neuromyogenic imbalances.12,13
Although the differences in AIMS scores between the control and clubfoot groups were significant at the 9- and 12-month level, it is important to note that the median score for the clubfoot group would not be considered suspicious or at risk for gross motor delay. The median of the 9-month clubfoot group was at the 19th percentile; the median of the 12-month clubfoot group was at the 28th percentile. Scores at or below the 10th percentile on the AIMS are considered suspect for motor delay. In the control group, 4 of 26 or 15% who completed the study scored below the 10th percentile, with 9 of 26 or 35% of the clubfoot group scoring below the 10th percentile at 9 months of age.
Our data did not address whether a baby with clubfoot and mild gross motor delay should receive treatment, monitoring, or no intervention for the delay. If the differences in gross motor function persist through childhood, early intervention may be appropriate. Further study in this area is needed with data collected on gross motor skill of children with clubfoot disorder as they approach school age. The fact that our data suggest that babies with clubfoot disorder may perform slightly less well on the AIMS than babies who are typically developing does not lead to a specific guideline for identifying a true motor delay that would require early intervention services. No babies involved in the study were receiving any form of developmental therapy services at the time of the study. Further study using different testing measures would be beneficial.
The control group that was used as the standardized norm for the AIMS was obtained before the initiation of the “back to sleep” program in the United Stated.10 The effect of time spent in the supine position versus the prone position has been shown to be significant in the attainment of motor skills,14 and we questioned whether the norms are still applicable at each 3-month interval. An analysis was performed to examine the AIMS scores of our group of babies who were typically developing compared with the standardization sample of the AIMS. The current study control group scored significantly lower at the 3-month age group only. There were no significant differences at 6, 9, 12, or 15 months of age (Table 6). These data indicate that any “back to sleep” slowing on gross motor skill development may be transient. Another possible explanation is that any effect of the supine sleeping position may be ameliorated by motivated parents who are highly interested in their baby's gross motor development.
Despite the differences in physical restraints in the Ponseti and French methods used to treat clubfoot disorder at our facility, there was no difference in our assessment of the attainment of gross motor skills in these 2 groups. This information may assist parents who have difficulty complying with brace wear following Ponseti treatment due to concerns about effects of lack of independent movement of the lower extremities on attainment of gross motor milestones.
All but one of the babies in the clubfoot group was walking by age 18 months. These data may reassure parents with initial concerns about future walking ability at the time of diagnosis of clubfoot.
This study is limited by its small sample size. It would be beneficial to continue this study with a larger number of participants and at other facilities to determine if results are similar. Another limitation is lack of a randomization in the recruitment of control group participants. These children were recruited by word of mouth and included families who had sufficient interest in their baby's gross motor development to bring the baby to our facility for assessments every 3 months. This group of parents may also be motivated to do more activities with their child to foster development of gross motor skills. In addition, parents may have learned general developmental principles by participating in the assessment with their baby every 3 months. This effect may have been stronger in the control group babies due to the probable high level of parental interest in development. A third possible limitation is the nature of the gross motor assessment chosen to monitor attainment of gross motor skill. Once babies are walking, the AIMS ceiling is generally reached. The study may have benefited from the use of an additional standardized test, without such a low ceiling. In addition, it would be beneficial to do further assessment with a tool that covers the toddler period and beyond to determine whether or not the latency of acquisition of gross motor skills continues as the child matures.
Babies with idiopathic clubfoot performed significantly lower on a motor development assessment test at age 9 and 12 months than babies in a typically developing control group, when progression of gross motor skills demands moving into an upright position against gravity. They are also more likely to walk later than their peers who are typically developing. The rate of attainment of motor skills is not related to severity of the clubfoot, laterality, or method of treatment. Families can be counseled that babies with idiopathic clubfoot will likely walk later than typically expected and be reassured that walking will likely occur by age 15 to 18 months.
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activities of daily living; child development/physiology; clubfoot; clubfoot/surgery; comparative study; motor activity/physiology; orthopedic procedures/methods; plaster casts; physical therapy/methods; psychomotor performance© 2011 Lippincott Williams & Wilkins, Inc.