|Year : 2022 | Volume
| Issue : 1 | Page : 16-22
Association of foot arch types with chronic low back pain among selected adults in Sri Lanka
Shanaz F Marikkar1, Desha Rajni Fernando2, H V. Yamuna Deepani Siriwardana3
1 Spinal Cord Injury and Rehabilitation Unit, Divisional Hospital Wariaypola, Sri Lanka
2 Diabetes Research Unit, Department of Clinical Medicine, Faculty of Medicine, University of Colombo, Sri Lanka
3 Department of Parasitology, Faculty of Medicine, University of Colombo, University of, Sri Lanka
|Date of Submission||18-Mar-2022|
|Date of Decision||12-May-2022|
|Date of Acceptance||13-May-2022|
|Date of Web Publication||22-Jul-2022|
Shanaz F Marikkar
Spinal Cord Injury and Rehabilitation Unit, Divisional Hospital Wariyapola, Wariyapola
Source of Support: None, Conflict of Interest: None
BACKGROUND: Abnormal foot posture has been extensively discussed as a risk factor for chronic low back pain (CLBP). The present study aimed at assessing the association of foot arch types with CLBP in a selected population.
METHODOLOGY: A descriptive study was conducted at the Department of Rheumatology and Rehabilitation Clinic of National Hospital of Sri Lanka with employing a 100 of patients diagnosed with CLBP (50 cases and 50 controls). The data were collected during December 1, 2019, and February 28, 2020. Foot arch type was detected using the arch index method. The modified Oswestry low back pain disability questionnaire was used to measure the disability level and Numerical Rating Scale (NRS) for pain. Chi-square test and Pearson's correlation tests were used for data analysis.
RESULTS: Out of the patients with CLBP, 82% (n = 41) were with normal foot arch (NFA), 16% (n = 8) with low foot arch (LFA), and 2% (n = 1) with high foot arch (HFA). In the control group, there were 94% (n = 47) with NFA, 4% (n = 2) with LFA, and 2% (n = 1) with HFA. Sample size was small to extract a significant P value for the observed difference between cases and controls with regard to the presence of LFA. The majority (66%) of the patients had severe disability followed with moderate disability (28%), minimal disability (4%), and crippled (2%). A positive correlation was found between disability level and the pain scale (P < 0.01).
CONCLUSIONS: Further research with large sample size is necessary to make firm conclusions on association of LFA type with low back pain. However, the pain and the disability level among the patients with CLBP seems to be highly correlated.
Keywords: Chronic low back pain, foot arch types, low back pain, risk factors for low back pain
|How to cite this article:|
Marikkar SF, Fernando DR, Deepani Siriwardana H V. Association of foot arch types with chronic low back pain among selected adults in Sri Lanka. Physiother - J Indian Assoc Physiother 2022;16:16-22
|How to cite this URL:|
Marikkar SF, Fernando DR, Deepani Siriwardana H V. Association of foot arch types with chronic low back pain among selected adults in Sri Lanka. Physiother - J Indian Assoc Physiother [serial online] 2022 [cited 2023 Feb 5];16:16-22. Available from: https://www.pjiap.org/text.asp?2022/16/1/16/351864
| Introduction|| |
Lower back pain (LBP) is a highly prevalent musculoskeletal disorder. The global point prevalence of LBP has been estimated to be 9.4% with considerably high proportions of persons who experienced LBP in different studies.,, Resultant health-care costs and productivity loss are also considered substantial. The lower back includes the fifth vertebrae (L1-L5) in the lumbar region, which supports much of the weight of the upper body. Chronic low back pain (CLBP) is defined as pain in the lower back that persists for 12 weeks or longer. It is also reported that the rural or suburbanized people are more prone to LBP than urbanized people.
Treatment of low back pain presents a considerable challenge, as a specific pathoanatomical diagnosis cannot be identified in most occasions. The entire human body acts as an integrated unit. Thus, the lower back does not exist in isolation. Alterations at any segment or body may cause consequence in spine. A complex array of risk factors is known to contribute to the condition, such as increased age, female sex, low educational status, obesity, occupation, and psychosocial factors. In addition to these well-established risk factors, postural variations, such as decreased lumbar lordosis and leg length inequality, have long been suspected to play a role in predisposition to low back pain by altering the stresses placed on soft tissue structures around the spine. Abnormal foot posture and function have also been implicated. Approximately 80% of the general population have alterations in the feet. Three types of foot arches have been described. They are low arch (flat feet; pes planus), normal arch (neutral foot), and high arch (pes cavus). A decrease in arch height leads to low arch (pes planus). The loss of arch height affects weight bearing of the foot, resulting in pain, irritation, or discomfort in the foot and other lower limb joints due to the synchrony in their biomechanics. Hence, unusual or prolonged stress in the foot can affect the biomechanics and functioning of proximal joints, which commonly translate into pain at the knee, hip, pelvis, and lower back. Therefore, it is necessary to know whether the feet are undergoing or generating changes which can ultimately lead to CLBP. Then, the hypothesis of the study was whether the changes in the height of the foot arch have an effect on the CLBP.
Several authors suggest that individuals with low back pain are more likely to have pes planus (low-arched or pronated) feet. A retrospective study reported that those with moderate or severe pes planus (determined by clinical observation) were almost twice as likely to report a history of intermittent low back pain. In contrast, evidence also indicated that those with low back pain were more likely to have a cavus (high-arched or supinated) foot posture. Previously, some researchers have suggested that abnormalities such as flatfoot are associated with changes in gait and effects associated with lumbar region. Despite this lack of evidence, an association between foot posture, function, and low back pain is biomechanically and physiologically plausible. Several studies have surveyed the relationship between flatfoot and sometimes contradictory results were also obtained. One of the latest studies conducted with pregnant women in the Nigerian community aimed at assessing the arch height index of and its correlation with foot pain, anterior knee pain, and LBP. They did not find any relationship between foot arch heights and intensities of the foot, anterior knee, and lower back pain.
Since a complex array of risk factors is known to be contributed to the condition, detecting the effect of foot arch types on CLBP would be helpful in identifying the people at risk of CLBP; thereby, it would be easy for the patients to seek for medical advice before achieving the severe disability level. With the evidence found in earlier studies, examination of different foot arches in patients with CLBP and healthy individuals would be assisted in improving the methods of treating patients with CLBP. Further, a limited number of the latest world literatures are available on explaining the mechanism and relation between foot arch and CLBP. Furthermore, there are no researches done in Sri Lanka to find the relationship between the foot arch type and CLBP. The present study aimed at comparing the types of foot arch between patients with CLBP and healthy individuals and to identify the association between the disability score and the score of numerical rating pain scale (NRS) of CLBP.
| Methodology|| |
This hospital-based case–control study was carried out in the general and special units of the Department of Rheumatology and Rehabilitation (DRR) of National Hospital Sri Lanka (NHSL). This unit is the premier clinical setting of the government for Rheumatology and Rehabilitation, in Colombo district as well as in Sri Lanka where the majority of patients with CLBP attend daily clinics.
Clinically diagnosed patients with CLBP aged between 40 and 60 years were selected as cases. A consultant rheumatologist diagnosed the patients for CLBP using the ICD-10 code. Patients with CLBP due to trauma or other obvious mechanical causes, patients in a foot cast after a surgery, and patients with the presence of any spinal pathology and neuropathology and the presence of any diagnosed pathology of back muscles other than CLBP were excluded. The control group included the gender- and age-matched healthy persons who accompanied patients to the DRR clinic in NHSL during the study period. Due to the limited resources and limited time constraint related to this undergraduate study, 50 subjects within the inclusion criteria were selected to each of the case and control groups.
The data were collected during December 1, 2019, and February 28, 2020. An interviewer-administered questionnaire was used. Participants who were filtered through the inclusion and exclusion criteria were then selected for further investigations. Interview was conducted in a preferred language of the participant (either Sinhala or Tamil). A data collection form consisted of questions on sociodemographic features and clinical and diagnosis aspects of back pain.
CLBP and impact of pain intensity on daily activities were assessed according to the modified Oswestry low back pain disability questionnaire (MODQ). Cronbach's α coefficient which is used to measure the reliability was 0.69 for the MODQ. This was a self-administered questionnaire that compromises of ten sections. Disability score was calculated by evaluating the effect of pain on the personal care, lifting, walking, sitting, standing, sleeping, social life, traveling, and employment. Each question had to be marked on a five-point Likert scale: 0 being no pain and 5 being the greatest pain when involved in activities. The score of disability is the summation of rating scale. The numerical rating scale (NRS) is the simplest and most commonly used numeric scale in which the individual rates the pain from 0 (no pain) to 10 (worst pain). The NRS was used to assess the pain at the data collection. Intraclass correlation coefficient which used to test–retest the reliability was 0.991 for NRS.
Determination of foot arch type
Foot arch type was detected using arch index (AI) method. The type of foot arch was assessed using the AI method. From the maximum peak pressure image of the participant's bipedal relaxed stance, AI was calculated as the ratio of the area of the middle third of the foot print to the entire foot print area excluding toes. Patients had to be in standing position (50% of bodyweight to each foot). Bilateral foot print was taken onto a graph paper using an easily removable ink and calculated the surface area in each third of foot [Figure 1]. Straight line was drawn between the center of the heel (K) and the tip of the second toe (J). Next perpendicular line was drawn tangential to the most anterior point of the main body of the foot print and their point of intersection was marked (L). Then, the distance between L and K was equally divided into three parts. Finally, foot print was divided as anterior, middle, and posterior parts.
|Figure 1: Illustration of measuring foot arch type using AI method. AI: Arch Index|
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AI = middle/(anterior + middle + posterior)
AI = B/(A + B + C)
Each measurement was taken two times for each foot and the mean value was used for the analysis. According to the standard values for AI [Table 1], foot arches were categorized as high, normal, and low arch. The average of the left and right feet was considered to classify the foot arch type.
The data were analysed using the IBM Statistical Package for the Social Sciences (SPSS) trial version 24.0. Demographic characteristics of the study participants were presented with descriptive statistics. An association between the foot arch types and two groups (cases and controls) was assessed by Chi-square test. A relationship between the disability score and the NRS was evaluated with Pearson's correlation test [Table 2]. To investigate the level of significance for this study was chosen at a P < 0.05.
Ethical clearance was obtained under the undergraduate research study program, from the Ethics Reviewing Committee of the Faculty of Medicine, University of Colombo, Sri Lanka. Written informed consent was obtained before the recruitment.
| Results|| |
The study employed a sample of 100 participants (n = 50 cases and n = 50 controls). The response rate was 100%.
Demographic characteristics of the study population
The majority of the cases were female (n = 32, 64%). Gender distribution was similar among both cases and controls. The mean age of the CLBP group was 52.94 years (standard deviation [SD], ±3.59) and 51.94 years (SD, ±4.16) in controls. The mean height and weight of the patients with CLBP were 157.62 cm (SD, ±5.16) and 64.16 kg (SD, ±7.31), respectively. In the control group, they were 157.26 cm (SD, ±5.03) and 62.48 kg (SD, ±7.09). No significance differences (P > 0.05) were found between the CLBP group and the control group with regard to the mean height and weight.
Distribution of foot arch types of the study participants
There were 82% (n = 41) of participants with normal foot arch (NFA), 16% (n = 8) with low foot arch (LFA), and 2% (n = 1) of high foot arch among the patients with CLBP. There were 94% (n = 47) of participants with NFA, 4% (n = 2) with LFA, and 2% (n = 1) of high foot arch in the control group. Both cases and controls had NFA in majority. Foot AI values were not obviously different between left and right feet among patients with CLBP (P = 0.293). This was not different (P = 0.317) between left and right feet of the control group too. A clear difference was observed between cases and controls with regard to presence of LFA, though sample size was small to extract a significant P value (P = 0.091). However, the prevalence of LFA among cases was found to be significantly higher than that among controls (P = 0.04). LFA was more frequently observed among females in both patients and controls. There was no significant association between foot arch types with gender in patients with CLBP (P = 0.2307). The distribution of the calculated bilateral foot arch types of the two groups is shown in [Figure 2].
|Figure 2: Frequency distribution of foot arch types among study participants|
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Distributions of disability levels and NRS among patients with chronic low back pain
The mean value of the disability score of patients with CLBP was 22.88 (SD + 5.89). Among the total 50 patients with CLBP, 4% (n = 2) had minimal disability, 28% (n = 14) had moderate disability, 66% (n = 33) had severe disability, and 2% (n = 1) were crippled [Figure 3]. Further, the mean numerical rating scale for pain (NRS) score for the patients with CLBP was 4.76 (SD, ±1.44). The correlation between back pain disability score and NRS was statistically significant (r = 0.54, P = 0.000) [Figure 4]. [Table 3] describes the cross-tabulation of foot arch types and disability level.
|Figure 3: Distribution of disability levels of chronic lower back pain among patients with CLBP. CLBP: Chronic low back pain|
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|Figure 4: Correlation between back pain disability score and NRS score in patients with CLBP. NRS: Numerical rating scale, CLBP: Chronic low back pain|
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|Table 3: Frequencies of the types of foot arch related to the levels of disability among patients with chronic low back pain|
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| Discussion|| |
Aim of the study
The aim of this preliminary study was to explore the association between CLBP and types of foot arch in affected individuals. This study also aimed to identify the association of severity of pain with a level of disability among the patients.
Cases and control groups
There were 50 patients with CLBP attended to the clinic at the DRR of NHSL. The control group of the study included gender- and age-matched healthy persons who accompanied patients to the DRR clinic in NHSL during the study period. There was no obvious difference in age among cases and controls. There was no difference in height and weight among cases and controls also (P > 0.05). However, some other studies have indicated the significantly higher weight and body mass index of patients with CLBP when compared with the same in apparently healthy individuals. This deviation may be due to the contrasting biopsychosocial factors of different study populations.
Foot arch type and chronic low back pain
The present study found no significant association between deviated foot arch types with CLBP (P = 0.091). Some other studies have also made similar observations,, while a significant association of foot arch type and CLBP had been reported at some other occasions., The interaction between bilateral foot posture and lumbar-pelvic alignment when standing was considered as a cause for this. When the foot is experimentally made into either low- or high-arched position using wedges, there is an increased anterior or posterior pelvic tilt which ultimately causes low back pain. Large studies including adequate sample sizes may provide more information.
Furthermore, low-arched foot type was more prevalent in patients with CLBP than among controls in this study. Similar results with small alterations and deviations have been found among patients with CLBP in other studies.,, This is explained in relation to biokinematic factors in the human body. Previous studies have interpreted that there is a possibility of kinematic changes induced by low-arched foot, which leads to increment in the already greater anterior pelvic tilt, thereby increasing the risk of the development of CLBP., The increased anterior pelvic tilt leads to greater stress on lumbar pelvic region, thereby developing the low back pain. The proportion of females with LFA (87.5%) was clearly greater than that of males (12.5%) among the patients with CLBP in the present study.
All the measurements were taken in standing position. Significant associations of foot arch type with gender had been observed in studies that measured the foot arch type in functional position. Among the patients with CLBP, the females were predominantly higher (64%) than the males, indicating that the females are more susceptible to CLBP than males. This finding was consistent with previous observations made in local and other study populations.,,, The prevalence of CLBP in females may be attributed to various psychosocial factors such as less pain coping strategies, higher sensitivity, psychological distress, low economy, and less compliance to treatment. Given the hormonal changes following menopause, females are more prone to have chronic diseases such as osteoporosis, osteopenia, and osteoarthritis which are identified as the risk factors for CLBP.
A complex array of risk factors is known to be contributed to the condition. Hence, detecting the effect of foot arch types on CLBP would be assisted in identifying the people at risk of CLBP; thereby, it would be easy for the patients to seek for medical advice before achieving the severe disability level.
Level of disability
The level of disability (minimal, moderate, severe, crippled, and bed-bounded) among patients with CLBP was calculated according to the percentage scores obtained in the Oswestry low back pain disability questionnaire (ODQ). No bed-bounded patients were found in this study as it was conducted among those who physically attended the clinic. Instead of evaluating the disability level of the patients with CLBP, most of the previous studies have reported only the disability scores out of 50 in the ODQ. Hence, it was difficult to place the findings of this study in the context of previous literature. Observation of mean value of disability score of 22.88 (SD + 5.89) in patients with CLBP was slightly exaggerated when compared with the previous research conducted among patients with CLBP worldwide,,
A significant positive correlation was found between CLBP disability score and the NRS pain score (r = 0.54; n = 50; P < 0.01), suggesting that pain and disability are interrelated in CLBP. Similar observations have been made in the past. Pain-related fear and psychological behavioral changes due to the low back pain might be leading to limitations in activity levels or disability. Results of the present study revealed no significant association between the foot arch type and the disability level of CLBP (P = 0.08), probably due to the reduced sample size.
| Conclusions|| |
Further research with large sample size comprising different geological locations, ages, both genders, and different ethnic groups in Sri Lanka are suggested to make firm conclusions on association of LFA with CLBP. There was no significant association between foot arch types and gender among patients with CLBP. The majority of CLBP patients had the severe level of disability followed by the level of moderate disability. The pain and the disability level among the patients with CLBP seems to be highly correlated. The majority of the patients with CLBP sought treatment after reaching the level of severe disability. Measures to raise awareness and motivational measures to encourage early treatment-seeking behaviors could also be suggested.
This was the first study done in Sri Lanka to evaluate the difference of the types of foot arch between CLBP patients and healthy people. Limitations in available time and resources of this undergraduate study hindered the collection of data from a larger sample. Comparison of foot arch types of these groups with that of Asian and global populations will also be of value.
The authors would like to acknowledge the support given by the Research Stream of Physiotherapy Degree Program of Faculty of Medicine, Colombo, special permissions granted by the director of NHSL, the consultant rheumatologist of DRR of NHSL, and support given by the senior physiotherapist in DRR of NHSL.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3]