parent’s concern about foot problems. In most cases, the young patients have a
flatfoot deformity and complain of no or only moderate pain.
Although there is no universally accepted definition for flatfoot, the
deformity is characterized by increased eversion of the subtalar complex during
weight-bearing with plantar flexion of talus and calcaneus, a dorsiflexed and
abducted navicular and a supinated forefoot. The clinically recognizable low or
absent longitudinal arch results from the malalignment of different subtalar
joints. While flat feet are often flexible in the beginning (normal foot morphology
and arch height without weight bearing), the pathology can become fixed
or rigid (marked deformity with and without weight-bearing) after some years
due to secondary structural changes.
Flatfoot is not a pathologic condition per se: normally developing infants
have flexible flatfeet and gradually develop a normal arch during the first
decade of life. Reduction of the physiologic subcutaneous fat pad under the
medial row as well as a slowly maturing bony arch by longitudinal and slightly
oblique growth of calcaneus and metatarsals normally result in a gradual development
of the ‘normal’ foot. There are some risk factors, however, which can
affect this process of maturation and lead to marked pronation deformities:
Major contributing factors are ligamentous laxity, rotational deformities,
equinus, tarsal coalitions and obesity. Especially an excessive elevation of body
weight can be very detrimental to the development of a pediatric foot, as
the constant mechanical overload during weight-bearing forces the subtalar
complex in increased eversion.
Numerous surveys of pediatric foot deformities have looked at an association
with elevated body weight. Riddiford-Harland et al. [6] calculated the
BMI of 431 children from Australian primary schools and took static weightbearing
footprints of each participant. They found a significant difference in
measured parameters (footprint angle and indices) between obese and non-obese
subjects and concluded that excess body mass appears to have detrimental
effects on the foot structure of prepubescent children. Bordin et al. [7] evaluated
the incidence of flat foot by photo-podoscopic examination in 243 primary
school pupils and calculated the Cole index (ideal ratio between the ideal BMI
at the 50 degrees percentile of weight and height as function of age, sex and real
BMI) of all participants from anthropometric data. The incidence of flat foot
in the study group was 16.4% and the frequency of obesity and overweight
was found to be 27.3% (Cole index 120). An analysis of variance showed a
significant difference between the Cole index in subjects with flat feet and
normal feet.
In our recent investigation [3] we determined the clinical prevalence of flat
foot in a study group of 411 children (215 girls and 196 boys) with a mean age
of 14.5 years ( 9–17 years) who required in- or outpatient pediatric treatment
due to severe obesity (individual BMI more than 2.8 standard deviations
over age-specific mean values [8]). The mean BMI in this study group was
32.9 kg/m2. We found flat feet in 77 children (18.9%), 66 participants (16.1%)
had flexible and 11 participants (2.7%) fixed deformities which did not resolve
with off-weight-bearing. Due to the lack of a control group it is very difficult
to interpret these data, although the prevalence of flat foot was somewhat higher
in a subgroup of extremely obese patients (mean BMI 35.2 kg/m2).
It might be interesting to compare the results of our investigation with data
from a German field study in 345 high school pupils (age 10–13 years): with
clinical examination the authors determined a prevalence of flat foot of 19.1%,
but could not find a correlation between body weight and foot deformity [9].
One recent study confined the analysis not only to static measures, but
looked also at the plantar pressure patterns in prepubescent children [10].
The investigators obtained foot plantar pressures using a mini-emed pressure
platform in 13 obese (mean BMI 25.5 kg/m2) and 13 non-obese children (mean
BMI 16.9 kg/m2) matched for gender, age (mean age 8.1 years) and height. The
calculation of force and pressure during static and dynamic loaded and
unloaded conditions revealed interesting differences in gait pattern: Although
rearfoot dynamic forces of obese study participants were significantly higher
than those of controls, these forces were experienced over significantly higher
mean peak areas of contact. Therefore, rearfoot pressures experienced by the
two groups did not differ. However, the mean peak dynamic forefoot pressures
generated by the obese study participants were significantly higher than
those generated by the non-obese subjects. The authors conclude that foot
discomfort-associated structural changes and increased forefoot plantar
pressures in the obese foot may hinder obese children from participating in
physical activity.
Another investigation looked at foot mechanics during walking in obese
and non-obese female adults [11]. The severely obese participants (BMI
41.14 kg/m2) had significantly greater forefoot abduction and rearfoot motion
than normal weight females.
There are also some investigations, where no correlation between foot
deformity and body weight could be demonstrated. In a survey of 2,300 children
from India, Rao and Joseph [12] found no difference of mean BMI values
in participants with and without flat foot deformity. Jerosch and Mamsch [9]
also could not find a correlation in their investigation of German high school
pupils. Garcia-Rodriguez et al. [13] report an increased prevalence of flat foot
only in their 4- and 5-year-old group of overweight Spanish children, whereas
in elder participants no such correlation could be established.
It is very difficult to discuss these results as different study designs and a
lack of valid data regarding inter- and intra-observer reliability of clinical investigations
impairs comparability. Even the studies which found higher prevalence
rates of flat foot in obese children when compared to non-obese children
cannot conclude the clinical relevance of their results without any doubt. Due
to the lack of valid data regarding the natural history of flat foot, not every
deformity must be considered as a pathological one which requires treatment.
Only few investigators look at associations of foot trouble and body weight in
adulthood and if they do so, it is very difficult to recall the time of exposure to
obesity as a potential risk factor [14]. Bruckner and Rosler [15] for example,
who performed a cross-sectional evaluation of 103 women and report a dependence
of painful foot deformities on body weight, have difficulties in attributing
the symptoms to a clearly defined causal pathology.
Although most studies seem to indicate a correlation between high body
weight and foot deformities in children as well as in adults, further investigations
into possible consequences of obesity, particularly any effects on pain
development and discomfort, are necessary therefore.
0 komentar:
Posting Komentar