Anastasiia Vladimirovna Sertakova1*, Musa Khamzatovich Timaev1, Sergey Alekseevich Kurkin1, Magomed Machrailovich Dokhov1, Sergey Anatolievich Rubashkin1, Ksenia Pavlovna Zvereva1, Vladimir Andreevich Gerasimov1 and Nina Yurievna Agafonova2
1Scientific Research Institute of Traumatology, Orthopedics and Neurosurgery at the Federal State-Funded Educational Institution of Higher Education “Saratov State Medical University Named After V.I. Razumovsky”, Saratov, Russia
2Federal State-Funded Educational Institution of Higher Education “National Research Saratov State University Named After N.G. Chernyshevsky”, Saratov, Bol'shaya Kazach'ya, Russia
*Corresponding Author: Anastasiia Vladimirovna Sertakova, Scientific Research Institute of Traumatology, Orthopedics and Neurosurgery at the Federal State-Funded Educational Institution of Higher Education “Saratov State Medical University Named After V.I. Razumovsky”, Saratov, Russia.
Received: June 16, 2021; Published: June 26, 2021
Introduction: Pediatric flatfoot (PFF) is a multifactorial group of foot diseases with varied disability in anatomy and function. Flatfoot can be flexible and rigid. We aim to select significant basic criteria for symptomatic flatfoot assessment.
Patients and Methods: To analyse the PFF criteria significance, the following were selected: clinical examination indicators and functional tests; OAFQuestionnairepro for QoL; 18 paired radiological indicators for both feet and 13 biomechanical spatio-temporal parameters, centre of mass and gravity, ground-reaction forces. Investigation was performed on 228 feet in 114 patients (75 boys, 39 girls, average age: 9,5 ± 0,9 years, aged 7 - 14 years) diagnosed with symptomatic flatfoot, confirmed by statistically significant criteria of instrumental examination methods selected in our study.
Results: The most significant radiological criteria in diagnosing PFF were talo-horizontal angle (р = 0,0002), medial longitudinal arch angle (р = 0,03) and medial longitudinal arch height (р = 0,05). The calcaneal pitch angle is included with p = 0.67, L, mm and V, mm/sec. with about 0.29, however, in their presence the proportion of correctly predicted cases increases, which is explained by the clinical significance of these indicators and the “tuning” of the mathematical model. Valid biomechanical indicators: stance phase, swing period in gait cycle, centre of mass and gravity parameters (p < 0,05). ENMG demonstrated significant changes in M-responses and F-waves, F/M ratio from the gastrocnemius muscle, reciprocity coefficients of the gastrocnemius and tibial muscles different from that of healthy children 4 - 5 times.
Keywords: Pediatric Flatfoot; Findings; Children
Flatfoot in children is a heterogeneous group of pathological conditions united by similar disorders in the anatomy of the skeleton of the foot and its biomechanical functions (stability, propulsion, shock absorption). Fundamental components of the deformity are a decrease in the height of the medial longitudinal arch and hindfoot valgus deformity with eversion and pronation of the calcaneus [1,2]. In addition, changes occur in the forefoot in the form of deviation and supination of the metatarsal bones, in the midfoot - dorsal displacement and lateralization of the scaphoid, in the hindfoot there are deformities in plantar flexion and medial deviation of the talus, dorsal flexion and external rotation of the calcaneus in relation to the talus [3,4]. Traditionally, flexible and rigid forms are distinguished, characterized, respectively, by a functional or anatomical decrease in the medial longitudinal arch height [3]. Children with FF have their own gait characteristics: pronation of the ankle and foot, depression of supination in the gait cycle, which reduces the efficiency of the swing phase during walking, excessive tension of the lower leg muscles and the valgus position of the knee joint [5,6].
Also, the eversion of the calcaneus during walking and the lack of adaptation of the kinematic parameters of the gait (step length, step time, walking speed, etc.) are noted in children. Pediatric FF is an important problem in orthopedics, because there is still no agreement between different orthopedic schools on the limits of foot mobility and the age of the child for the validity of the diagnosis; optimal methods of conservative and surgical treatment; timing of surgeries and further rehabilitation [7]. Thus, disagreements regarding the definition have led to the fact that the majority of orthopedists identify FF as a foot disease without uniform classification criteria [1-3]. Epidemiological data is inaccurate due to a moderate number of studies in the “case-control” format only and diagnostics at the level of graphiс plantoscopy without assessing the quality of life, biomechanics of the foot and the state of the neuromuscular apparatus of the foot and lower leg, physical activity and other parameters [4,5]. Even the instrumental criteria (radiological parameters assessing the joints of the foot bones) have a wide range of values. For example, standard parameters of the talo-calcaneal angle alone (measurements in sagittal plane) [6] vary between 10° and 55°: Dobbs and Beaty use between 30° and 55°, Grissom between 25° and 50°, and Templeton between 15° and 50°, and Beatson and Pearson reported a range between 10° and 50°. Vanderwilde reported a linear decrease with age, averaging 42° in the 6-month-old and decreasing to 24° in the 9+year old (ranging between 12° and 35°); Radler reported 23° ± 4 in the 7 - 14-year group. Although, there are about 30 currently known radiological parameters describing the anatomy of the foot [6]. Despite the variety of diagnostic tools, there are practically no clearly defined criteria that сould serve as reference points for solving the problem of assessing the degree of the FF disorder, as well as the results of surgical correction of the deformity. In our study, we analyzed various criteria for assessing FF in children that exist and are currently used. We combined the results into an algorithm of statistically significant parameters that allow us to determine the severity of FF disorders as well as to predict the course of the pathological process and, possibly, treatment tactics.
A retrospective analytical case-control study was conducted, which included patients diagnosed with flatfoot (observation group) and patients with a neutral foot (control group) with stratification based on age (variation series: 7 - 16 years old) taking into account the full ossification of the weight-bearing foot skeleton. Children were examined using a combination of the following techniques: clinical method, survey method using OAFQPro, X-ray and computed tomography (in cases of suspected abnormal foot bone development in the form of tarsal coalitions), biomechanical and electroneuromyography methods. When interviewing patients a child version of the questionnaire was used (for ages of 7 - 17 years old). The survey was also offered to parents, however, they refused for personal reasons (“providing the child with autonomous decision making”). All data is presented as a percentage scale. The following complaints were focused on clinically: foot pain, fatigue when walking and increased physical activity, impaired gait, deformation of all parts of the foot, as well as local pain on palpation and callosity on the weight-bearing areas. Among specialized functional tests were the following: a single-stage passive correction test (the doctor passively returns the foot position to neutral in the absence of load), tiptoe standing test (with the patient standing on his toes, position of the vertical axis of the calcaneal tuber is fixed-its position up to the middle line is determined positive by 1st variant; if the calcaneal tuber maintains the pronated valgus position when on tiptoes- 2nd variant; if the child cannot stand on his toes on his own - 3rd variant), Jack test (the doctor performs passive extension of the 1st toe which leads to increased excavation of the medial longitudinal arch - the test is positive), Thompson test (passive dorsiflexion of the ankle joint with moderate effort while maintaining the foot in neutral position, if dorsiflexion is limited to 90 degrees - Achilles tendon shortening is noted), arch flattening test under load (in a standing position a decrease in the medial longitudinal arch height is noted). 18 parameters in the form of paired dependent variables for both feet were measured with an X-ray. Their selection was conducted based on the analysis of the most frequently used indicators, since there are no generally accepted criteria to compare with. According to the standard technique, the following were measured under load in the form of patient’s own body mass: talo-calcaneal angle (TCA) in anterior plane (AP) and sagittal plane (SP); talo-1st-metatarsal angle (T1MA) in AP/SP; talo-horizontal angle (THA) in SP; talo-tibial angle (TTA) in SP; medial longitudinal arch angle (MLAA) and calcaneal pitch angle (CPA) in SP; medial longitudinal arch height (MLAH) in mm. All angles are formed by the longitudinal axis of the bones or the axis of the bone and the tangent surface line. A biomechanical study recorded the results (a total of 13 parameters from two feet) of temporal step characteristics: step cycle in sec.; stance period - swing period - period of single and double support in %; gait rhythm coefficient in c.u. Among the stabilometric indicators (recording the position and movements of the common center of pressure on the weight-bearing plane when standing) the following were noted: the average position of the CoP (centre of preassure) relative to the frontal (X) and sagittal (Y) planes, mm (L, mm), the area of the statokinesiogram characterizing the CoP fluctuation area (S, mm2), average fluctuation velocity of CoP (characterizes the path traveled by CoP in a unit of time, V mm/s.); LFS parameter (ratio of the length of the statokinesiogram to its area, mm-1 or 1/mm). An ENMG study was carried out with registration of the activity of the lower leg and foot muscles; calculating the amplitudes and frequencies of their various movements, as well as the activation coefficient (AC) and reciprocity coefficient (RC). AC is the ratio of the amplitude during the period of involuntary activation of the muscle to its own amplitude in full arbitrary voltage mode. RC shows the muscle activation degree in percentage in relation to the value of the antagonist muscle activity. The data was recorded from the tibial and peroneal nerves with the recording of M-responses from the muscles of the foot and lower leg. The following indicators were determined: the amplitude of the M-response - the total potential of muscle fibers obtained from the muscle during stimulation of the nerve innervating it in dynamics. Latent period - the time delay from the moment of stimulation to the occurrence of the M-response. F-wave amplitude - the total potential of the motor response of the muscle to the reverse discharge resulting from the antidromic stimulation of the motor neuron. F-wave latency - an indicator of the time of the pulse in both directions. For the selection of homogeneous groups, the criteria for inclusion, non-inclusion and exclusion in the study were defined.
Inclusion criteria:The period of inclusion of patients in the study was from January 1, 2018 to December 31, 2019. All patients (one group with foot pathology and the other with neutral foot) received the planned scope of diagnostic methods. Investigation was performed on 228 feet, 114 patients (75 boys, 39 girls, average age 9.5 ± 0.9 years, ages: 7 - 16 years) diagnosed with symptomatic flatfoot, confirmed by statistically significant criteria of instrumental examination methods selected as a result of our study. The control group consisted of 64 children (23 girls, 41 boys aged 7 - 14 years, average age: 9,3 ± 0,4 years) with neutral foot. The criteria for neutral foot position were the lack of complaints from children and their parents on foot pathology; negative functional tests and clinical signs of foot pathology in the child; normal radiological parameters (according to Vanderwilde and Bogdanov) of the child's foot, where medial longitudinal arch angle, medial longitudinal arch height and calcaneal pitch angle were especially taken into account; as well as normal indicators of biomechanical and electroneuromyographic studies, which are standardized for children aged 7 - 16 years.
Most patients complained of fatigue when walking up to 1000m and local foot pain (78%, 89 people). Physical examination showed tenderness to palpation in the projection of the talo-navicular joint (plantar of the midfoot) in 87% (99), callosity and supination of the forefoot in 14% and valgus position of the calcaneus in 70 children (62%). Among the screening functional tests, the most significant were tiptoe test (88%), arch flattening test under load (76%), single-step passive correction (even partial) and Jack’s test (50%). When assessing QoL, children with FF showed meaningful differences in the subscales “physical development” and “footwear selection” (76,1 [57,3; 82,3], р < 0,05) in contrast to healthy children (91,5 [76,3; 95,2]). Overall, the difference was 11-14% for OAFQ. Aspects such as “emotional development”, “school and physical activity”, “family/friends relationships” did not differ in patients with FF and were comparable to those of healthy children. Thus, the quality of life is moderately diminished in terms of “physical development” and “footwear selection”, which causes inconvenience only in certain aspects of the child’s life. Due to modern trends in the development of our society, these problems are often manageable. For example, children lead a hypodynamic lifestyle which is virtual reality oriented; at school, the problem is also easy to solve by reducing requirements for physical training. There is also no problem with footwear selection due to the wide selection of orthopedic products on the market. The presence of flatfoot practically does not affect children in terms of emotional development or social function; as a rule, an inferiority complex over their physical appearance is not formed. On the one hand, this ensures a favourable course of disease with minimal quality of life violations at various stages of childhood as well as no concerns for the children and their parents. However, therein lies the danger: the presence of an oligosymptomatic pathology without significant violations of the quality of life reduces the child's chances of receiving a full treatment of flatfoot. When the symptoms of the disease are clearly manifested in adults, orthopedic traumatologists can no longer offer highly effective methods of treatment, only symptomatic ones. In addition, the overlooked form of the rigid flatfoot does not allow the use of minimally invasive surgical correction for adults, while it would have been an option for a child.
An analysis of the significance of existing instrumental diagnostic criteria by the principal component analysis method (18 radiological and 13 biomechanical) identified following factors: factor 1 “X-ray parameter” (MLAA, CPA, medial longitudinal arch height in SP); factor 2 “Spatio-temporal parameter” (one-stance and swing phase, sec.); factor 3 “Centre of mass and gravity parameter” (L, mm; V, mm/s); factor 4 “X-ray parameter” (TCA, THA in SP); factor 5 (TTA, SP). Later on, the second factorisation, which was based on the newly discovered data, left only the first four factors, according to which clustering was done. Most significant statistically was dividing patients into 4 clusters. In the final logit analysis carried out in the Gretl software package, the most significant criteria for assessing changes characteristic of flatfoot in children were identified (See table 1). The result is the cutoff scores for the diagnostic indicators for each group of patients by type of FF.
Parameters |
Coefficient |
St. error |
z |
p-value |
|
THA°, SP |
0.975819 |
0,266907 |
3.6560 |
0,266907 |
*** |
MLAA°, SP |
1,12431 |
0.542984 |
1,12431 |
0,03840 |
** |
Height of MLA, mm |
-1,14936 |
0,594188 |
-1,9343 |
0,05307 |
* |
CPA°, SP |
-0,152643 |
0,355145 |
-0,4298 |
0,66734 |
|
Single-support period, sec. |
11,736 |
5,8223 |
2,0157 |
0,04383 |
** |
Swing_period, sec. |
11,9675 |
5,87331 |
2,0376 |
0,04159 |
** |
L, mm |
-105.329 |
101.594 |
-1.0368 |
0.29985 |
|
V, mm/sec. |
112.2 |
106.1 |
1.0575 |
0.29029 |
|
cut1 |
-7.20219 |
1.49543 |
-4.8161 |
0.00001 |
*** |
cut2 |
-1.03575 |
1.09384 |
-0.9469 |
0.34369 |
|
cut3 |
2.21992 |
1.07165 |
2.0715 |
0.03831 |
** |
cut4 |
4.22801 |
1.14509 |
3.6923 |
0.00022 |
*** |
Table 4: Model 1: The ordered logit model, observations used: 1-114. The dependent variable: CLUSTER. Standard errors are calculated based on the Hessian.
Note: Number of 'correctly predicted' cases = 88 (77.3%). Likelihood ratio criterion: Chi-square (8) = 198.933 [0.0000]. Coefficient - coefficient in the regression equation of the variable “Cluster number” (CLUSTER) on the variables from the list, St. Error - St. coefficient error in the regression equation, z - the value of z-statistics having a standard normal distribution, P-value - the probability of the observed value if the coefficient in the regression equation is statistically not significantly different from zero. Cut1, cut2, cut3, cut4 - values of the cut off scores for the indicators, according to the value of the variable “Cluster number” (CLUSTER) calculated with the equation.
The calcaneal pitch angle is included in the model with a significance of p = 0.67, L, mm and V, mm/sec. with a significance of about 0.29, however, in their presence the proportion of correctly predicted cases has increased, which is explained by the clinical significance of these indicators and the “tuning” of the mathematical model. ENMG analysis demonstrated the following patterns in children with FF: regardless of symptoms and age, all patients recorded M-responses reduced in amplitude (2.7 ± 0.8 mV, normal - 7.5 ± 2.3 mV) and irregular late neuronal responses (F-waves, not more than 40 mv, at normal 140 mv) from the short toe extensor of the peroneal nerve from 2 sides M-responses and F-waves values of the tibial nerve recorded from the foot muscles corresponded to the norm (9.2 ± 2.4 mV). The main data changes of muscle and neuronal responses were noted during abduction from the lower leg muscles. Thus, high-amplitude M-responses (13.4 ± 1.6 mv, normal - 7.7 ± 0.8 mv) and F-waves (1603 ± 235.4 mv, normal - 360 ± 115 mv) were recorded from the gastrocnemius muscles, exceeding the data of healthy children 4 - 6 times. The most pronounced deviations in the F/M waves amplitude ratio, an indicator characterizing the level of motor neuron activity, were noted in children with mild symptoms and the X-ray picture (20%, maximum normal - 5 - 10%). In children with severe damage, the level of motor neuron activity is paradoxically reduced, but remains high. In the analysis of indicators of total EMG of the anterior tibial and gastrocnemius muscles, pronounced deviations of the average values of the amplitude in most cases were not detected. The frequency characteristics of EMG curves of the gastrocnemius muscles changed upwards (433 fluctuations per unit time, normal fluctuations - 284). When studying the relationship between the antagonist muscles of the lower leg by calculating the activation coefficients (AC) and reciprocity coefficients (RC), a deviation of the indicators upwards was revealed in almost all cases, but to different degrees of severity. The greatest deviations of AC (100 - 84,2%) were observed in patients with FF with mild deformity in the gastrocnemius muscle, while deviations of the reciprocity coefficient (65 - 70%) prevailed according to the anterior tibial muscle in patients with moderate and severe deformity of the feet. Thus, the most sensitive criteria among the recorded ENMG indicators were the amplitude of the M-response and the F-wave of the gastrocnemius muscle, mV; F/M ratio in %; RC of the anterior tibial muscle in %; RC of the gastrocnemius muscle in %, which made it possible to diagnose mild, moderate and severe disorders in children with FF with an accuracy of 88.2% in the statistical analysis (Figure 1).
Figure 1: Note. Ampl - Amplitude; GCM - Gastrocnemius Muscle; ATM - Anterior Tibial Muscle. All data is converted into a percentage scale.
Clinical data and functional tests made it possible to conduct the initial diagnosis in relation to FF, where qualitative abnormalities were confirmed in the child. This demonstrates how important it is that these tests are used by both pediatricians and pediatric orthopedists in their practice [8,9]. The quality of life in children with FF differed from that of children with a neutral foot within 10 - 14% in terms of physical development and the difficulties with footwear selection in our study. Meanwhile, the children’s psychoemotional state and social skills were not affected, while the statistical significance was regarded as moderate due to the small sample size. There are a number of publications devoted to assessing the quality of life in children with FF. Thus, a study by Damayanti., et al. who examined QOL in 120 children using PedsQL (79 with normal foot and 41 with FF at the age of 5-18 years, average age of 8.7 ± 2.5 years), showed the absence of its decrease in children ≥ 11 years and moderate impairment in a group younger than 11 years [10]. Notably, the regression analysis explained only 16 - 27% of the results obtained from the questionnaire. The authors attribute this to the lack of an integral QOL assessment from the questionnaire; in particular, PedsQL does not take into account the importance of lifestyle, dosage of physical activity, sleep hours, and a number of other criteria. Similar results were also obtained by Kothari., et al. [11] using the OAFQ and HRQOL questionnaires. Despite data inconsistency, the authors are convinced that the screening assessment using the questionnaire method allows us to question the “physiological nature” of FF in children and encourage further clinical and instrumental examination. Only a single study demonstrated a correlation between the intensity of pain, fatigue in the lower extremities after exercise and difficulties with footwear selection with the degree of flattening of the arch [12], but it did not indicate statistical significance. However, the assessment of QOL in adult patients with FF showed heterogeneous results as well, where the data did not change according to some questionnaires, but for the others they correlated with the main diagnosis, which is illustrated in the work of Gonzalez-Martin., et al [13]. The authors studied 835 people with FF aged 40 - 64 years and 390 people over 65 years of age, taking into account comorbid status and body mass index using questionnaires SF-36, FHS, FFI, etc., resulting in incomplete data. Today, there is no uniform radiological classification of pediatric foot, however, various methods for radiographic analysis with measuring the angular and linear parameters of the relative position of bone-joint formations in all parts of the foot have been proposed [10,14]. Most Western orthopedic surgeons use the works of Vanderwilde R., et al. [15], who proposed 11 most optimal criteria for pediatric FF based on the analysis of 74 radiographs of children. In Russia, orthopedists widely use the criteria of Bogdanov F.R. [16], Zhokha KK., et al [17]. The most significant radiological indicators have been widely used in a great number of modern studies, but their statistical significance and validity are not indicated; while others demonstrate too wide a range of values, which contradicts statistical laws. In our work, out of 18 analysed parameters, 4 significant criteria were identified (talo-horizontal angle, medial longitudinal arch angle, medial longitudinal arch height and calcaneal pitch angle), the totality of which confirms more than 77% of cases of FF. The study revealed some interesting facts. Thus, the values of the talo-calcaneal angle often used in FF assessment cannot be interpreted in the practice of a clinician, since it is necessary to know the exact anatomical position of the calcaneus in relation to the horizontal weight-bearing surface of the foot. CPA statistically does not possess high accuracy, but adding that to other parameters increases the accuracy of determining the deviations of the foot. In terms of biomechanical parameters, the greatest changes were demonstrated by spatio-temporal parameters, centre of mass and gravity, ground-reaction forces. The obtained data is consistent with the experience of other studies. For example, Kerr., et al. [18] notes altered chaotic movements of the feet in the transverse surface in statics, gait velocity decline, as well as violations of goniometry in the hip, knee and ankle joints in patients with FF. Also in other works, qualitative deviations of the pushing function of the foot (the moment of “stance-swing” of the heel and toe) towards slowdown and incomplete moment as well as propulsive movements were revealed [19-21]. ENMG data showed significant disturbances in the innervation and functioning of the lower leg muscles, particularly, the anterior tibial and gastrocnemius, which was reflected in an increase in the amplitudes of M-responses, F-wave values and F/M ratio, reciprocity coefficient. Our final picture demonstrated changes characteristic of damage in the rubrospinal tract, which is responsible for the regulation of reciprocal postural movements, their focus and adjustment. Perhaps it is the ENMG findings that can make a significant contribution towards the choice of surgical tactics for the treatment of FF, since the detected changes are practically impossible to correct at the age of 7 - 14. Unfortunately, we found very few publications devoted to the state of the neuromuscular apparatus with flatfoot in children, which prevents us from getting the complete picture [22,23]. The main limitation of the study that may affect its results is the average patient group size. In our study, a biomechanical evaluation of the goniometry of the joints of the lower limb was not performed.
Currently, the problem of FF in children is relevant in many aspects. For example, there is no data on the prevalence of pathology in the population due to inaccurate classification criteria. Diagnostic criteria are not unified and the applied methods of treatment of FF are controversial. Our study provides an analysis of the existing diverse criteria for evaluating FF in children with an emphasis on statistical reliability. Such a verification made it possible to single out the most sensitive indicators as well as exclude the ones worsening the picture or simply insignificant. Particular attention was paid to the ENMG analysis, which demonstrated qualitative changes in the descending pathways of the brain responsible for the control of striated muscles. In the future, for the credibility of the results obtained and their practical application, it is planned to create a database of distinguished foot parameters in children, both flat and neutral (healthy), resembling the type of neural network, which will greatly facilitate the assessment of the severity of changes in FF and allow for choosing a treatment method for a child.
Data will be provided on request.
The authors declare that there is no conflict of interest regarding the publication of this paper.
The study was carried out as part of state assignment No. 154018-01 “Development of a decision support system for the treatment of static foot deformity in children” (state registration number R&D AAAA-A18-118020290180-6 from 02.02.2018).
Citation: Anastasiia Vladimirovna Sertakova., et al “Probable Criteria of Symptomatic Pediatric Flatfoot and Findings: Case-Control Study".Acta Scientific Orthopaedics 4.7 (2021): 47-54.
Copyright: © 2021 Anastasiia Vladimirovna Sertakova., et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.