The prevalence of flatfoot among Saudi population: A systematic review

INTRODUCTION

Flatfoot, also known as pes planus, is a foot deformity characterized mainly by a collapsed medial arch, plantar flexion of the talus, medial rotation of the talus, eversion of the calcaneus, and abduction of the forefoot.^[1] Hindfoot valgus and forefoot supination are two of the numerous deformities that cause the term flatfoot.^[2] The exact cause of flatfoot deformity is not well known despite its correlation with multiple factors, including age, gender, weight, race, and type of footwear.^[3]

In children, the clinical manifestations of flatfoot extend from being flexible and painless to rigid and painful.^[2] Although flexible flatfoot is considered physiological in most children, it can induce pain, which can be exacerbated by loading activities and eventually lead to early fatigue and medial foot callus.^[2] In contrast, children with rigid flatfoot experience more discomfort than the flexible type, as they encounter growing pain, muscle contractures, functional limitation, and fatigue associated with joint malalignment.^[2]

Flatfoot can also be acquired in adulthood. Patients may vary from being relatively asymptomatic to showing apparent symptoms.^[4] Symptoms might include ankle pain, bony bumps, and a gradual onset of vague pain in the medial foot, which may worsen with activity.^[4] According to two systematic reviews done in 2017 and 2018, there are no universally accepted criteria for diagnosing flatfoot.^[5,6] Only three methods were recommended for further research, including the Chippaux-Smirak index, Staheli arch index, and foot posture index.^[5] Therapeutic interventions are usually not required in managing flexible flatfoot since it typically resolves during the child’s first decade.^[2,7] However, children with rigid flatfoot may benefit from conservative therapy or surgical interventions.^[7,8] On the other hand, adults with flatfeet may use orthoses, braces, and shoe modifications as medical treatment. However, reports have shown minimal improvements in many adult cases compared to children.^[9]

No systematic reviews were found studying the Saudi population based on comprehensive searching. Therefore, this study aimed to systematically review all related studies that estimated the prevalence of flatfoot among the Saudi population in both children and adults and list the associated factors.

MATERIAL AND METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and Joanna Briggs Institute (JBI) reviewer’s manual were followed to perform this systematic review of the literature on the prevalence of flatfoot among the population live Saudi Arabia (Saudi and non-Saudi).^[10,11] The protocol was registered and approved by King Abdullah International Medical Research Center (KAIMRC).

RESULTS

The searched and screened articles were arranged according to the PRISMA flowchart [Figure 1]. The review yielded 361 published studies, of which 83 duplicates were excluded, and 278 were screened based on title and abstract. Two hundred and seventy were excluded due to irrelevant population and medical conditions resulting in eight eligible studies. However, after a full-text review, no further studies were excluded from the study. After the qualitative assessment, two out of the eight studies were excluded due to invalid diagnostic instruments and inaccurate outcomes reporting. Therefore, a total of six studies were included based on the authors’ selection criteria. Manual searching did not reveal additional eligible articles.

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Figure 1:

The of flatfoot among Saudi population Preferred Reporting Items for Systematic Reviews and Meta-analyses flow diagram.

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Studies main characteristics

A total of six studies, of which 6190 participants were included, published between January 2006 and March 2021, met the inclusion criteria. In addition, their quality was checked and had valuable quality scores [Figure 2].

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Figure 2:

Quality assessment scores of each included study using Joanna Briggs Institute critical appraisal tool.

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All studies were conducted in Saudi Arabia from various geographical regions. The majority of the participants (5076; 82%) were from the Western region of Saudi Arabia, with only 533 (8.6%) from the central and 581 (9.4%) from the southern. Out of all the participants, only 208 (3.4%) were non-Saudis living in Saudi Arabia. The participants’ age ranged from 4 years to 40 years. Bourgleh et al. and Alsuhaymi et al. included the pediatric population with a mean age of 4.2 and 10.5, respectively. Abdel Fattah et al., Almaawi et al., Khan et al., and Alahmari et al. reported adult participants with a mean age of 19.1, 37, 21.3, and 21.7, respectively. All studies included both genders except for Abdel Fattah et al. participants, as only males were included. Females were 2328 (37.6%) and males were 3862 (62.4%) of the total number. Body mass index (BMI), age, and gender were the common factors studied. The studies main characteristics are summarized in [Table 2]. The included studies used several assessment instruments with various cutoff values to detect the presence of flatfoot [Table 3].

Table 2: Studies main characteristics.

Study name (author/ year)	Geographic location (region/city)	Participants population	Sample size	Age in years (Mean ± SD)	Gender, n (%)	Studied variables
Abdel Fattah et al., 2006	Western Taif	Male army, Recruitment Center at Al-Hada Armed Forces Hospital	2100	19.13 ± 0.43	Males only	Body mass index Residence Foot site Mobility Heel condition Associated deformities in the knee Other congenital deformities History of accident Family history History of rheumatoid Usual wear during childhood
Almaawi et al., 2019	Central Riyadh	Outpatients, Department of Orthopedics, College of Medicine, King Saud University	533 Saudis: 417 (78.2%) Non-Saudis: 116 (21.8%)	37 ± 11.26	Females: 315 (59.1) Males: 218 (40.9)	Height Weight Body mass index Nationality
Alsuhaymi et al., 2019	Western Almadinah Almunawwarah	Students, various summer schools	403	10.5	Females: 210 (52.1) Males: 193 (47.9)	Height Weight Body mass index Participation in sports History of pain in the foot and ankle after physical activity Location of the pain Duration of activity that causes pain Flat foot type
Bourgleh et al., 2019	Western Jeddah	Outpatients, private pediatric orthopedic clinic	2321 Participants with normal musculoskeletal variation: 764 (32.9%) Saudis: 672 (88%) Non-Saudis: 92 (12%)	4.2 ± 3.6	Females: 1367 (58.9) Males: 954 (41.1)	Not reported
Khan et al., 2020	Western Jeddah	Students, applied medical sciences at King Abdulaziz University	252	21.28 ± 1.29	Females: 146 (57.9) Males: 106 (42.1)	Body mass index Flexibility of the whole body Flexibility of the ankle
Alahmari et al., 2021	Southern Abha	Outpatients, Physiotherapy Outpatient Department, King Khalid University	581	Males: 2182 ± 1:57 Females: 21:68 ± 1:73	Females: 290 (49.9) Males: 291 (50.1)	Height Weight Body mass index Balance Functional mobility Joint hypermobility

Table 3: Included studies’ assessment instrument and cutoff values.

Study name (author/year)	Assessment instrument	Cutoff values
Abdel Fattah et al., 2006	Planter footprints were applied and classified according to denis	Footprint was then classified as three grades: Grade 1: The support of the foot lateral edge is half the support of the metatarsal Grade 2: The support of the foot central zone and forefoot are equal Grade 3: The support in the foot central zone is greater than the metatarsal support width
Almaawi et al., 2019	Three types of footprints parameters: Clark’s angle Chippaux-Smirak index Staheli index	Clark’s angle: Normal: Between 42° and 54° Flat arch<41° High arch>55° Chippaux-Smirak index: Normal arch if the ratio is between 25% and 45% Flat arch >45% High arch <25% Staheli index: High arch (0.1–0.4) Normal arch (0.5–0.7) Flat arch (0.8–1.2)
Alsuhaymi et al., 2019	Footprint method was applied on both feet (Foot Imprinter Apex Harris Mat Set) Staheli’s Arch Index	Flatfoot: Staheli plantar arch index >1.15
Bourgleh et al., 2019	As reported by a certified pediatric orthopedic surgeon’s musculoskeletal evaluation In accordance with the standard protocol through data record forms X-ray test was requested in some cases based on the necessity	Not reported
Khan et al., 2020	Foot posture index-6 item version (FPI-6)	Foot posture was classified as: Normal (0–5) Pronated (+6–+12) Supinated (-1–-12) Maximum supination and pronation (indicated by grades of+12 and –12, respectively)
Alahmari et al., 2021	Foot posture index (FPI)	Each criterion scoring followed a scale of –2, –1, 0, +1, or+2 Scores were added for each criterion: Highly supinated foot: –5 to –12 Supinated foot: –1 to –4 Normal foot: 0 to+5 Pronated foot: +6 to+9 Highly pronated foot: +10 to+12

DISCUSSION

This is the first systematic review that revealed a wide range of flatfoot prevalence among the Saudi population. The prevalence of flatfoot reported by different authors worldwide had great variations. The fact that the authors used different methods could explain these differences. Among adults, globally, a cross-sectional study conducted in Spain estimated the prevalence of flatfoot as 26.62% in 835 patients over the age of 40, with a higher incidence in older patients.^[1] Japan which showed nearly identical results to Spain’s exhibited a prevalence of 26.5%, with 340 (242 women and 98 men) participants aged 60 and above who were neither hospitalized nor disabled in their regular activities.^[14] In Saudi Arabia, Almaawi et al. used three different footprint parameters: Clark’s angle, Chippaux-Smirak index, and Staheli index, to define foot arch.^[15] As shown in [Table 4], there are wide variations between the results of each parameter in the study. However, the Chippaux-Smirak and Staheli indices exhibited a significant concordance in diagnosing flatfoot with kappa value >0.8 and P < 0.05.^[15] In India, a cross-sectional study was done in 2017 with 500 healthy Indian participants (250 males and 250 females) aged 18–21 years who reported a flatfoot prevalence of 13.6% (12.8% of males and 14.4% of females).^[16] Abdel-Fattah et al. reported a flatfoot prevalence of 5% in 2100 male army recruits in Taif, Saudi Arabia, in a similar age group.^[17] Worth noting, there may be an inherent bias as known patients with flatfoot would not apply to the military. In addition, Khan et al. concluded that among 252 participants aged 18–25 years, 64 (25%) of the cases had flatfoot using FPI-6 in Jeddah, Saudi Arabia.^[18] Noticeably, females showed a higher flatfoot prevalence (81.75%) than males (18.75%).^[18] According to Alahmmari et al. article, out of 581 individuals, 110 (18.9%) pronated and 41 (7.1%) hyperpronated feet were found; similar to the previous literature, females (21.0%) had greater pronation rates than males (16.8%).^[19] Likewise, in Boston, the United States, a study reported that the incidence of flatfoot in females is higher by 3% than in males.^[20]

In children, flatfoot has been reported as one of the most common foot disorders internationally.^[3] A study in Austria that included 835 children aged 3–6 years reported that 44% of them had flexible flatfoot, and males had a greater tendency.^[21] In Taiwan, a study with 2083 children aged 7–12 years estimated that 59% had flatfoot.^[22] Similarly to Austria, flatfoot is twice as common in males as in females.^[21,22] A cross-sectional study was conducted in Islamabad on 714 students aged 6–10 years.^[23] It showed that the prevalence of flatfoot was 14.8% and more common in males as in the Taiwanese and Austrian studies.^[21-23] In Jeddah, Bourgleh’s et al. study aimed to determine the normal musculoskeletal variations in 2321 children (88% Saudis) who were <12 years of age, and reported that 309 (41.9%) had flatfeet.^[24] In Alsuhaymi et al. article, the 7–8-year-old group had the highest rate of flatfoot out of 403 school-aged children from various summer schools in Almadinah Almunawwarah, similar to the Taiwanese study.^[25]

Multiple studies examined the association between gender and the presence of flatfoot.^[15,18,26] In Nigeria, a study revealed a significant association between flatfoot and gender, in which flatfoot was 3 times more prevalent in females than males.^[26] Similarly, two studies, Almaawi et al. and Khan et al. done in Saudi Arabia, have found that females are more prone to the development of flatfoot than males.^[15,18] Khan’s et al. article showed that wearing high heels among young adult females were a possible risk factor for the increased prevalence of flatfoot in females using the center of pressure excursion index.^[18] When comparing genders in Almaawi et al. study, females had a higher prevalence of foot pronation using Clark’s angle, while Chippaux-Smirak index and Staheli index showed higher prevalence in males.^[15] Contradictory to our studies, a study in the United States, Texas, concluded that flatfoot deformity was strongly associated with the male gender.^[27] This is thought to be due to the fact that the majority of participants were from the veteran population.^[27] Globally, the prevalence of flatfoot varies with age.^[27,28] Age was thought to be the primary predictive factor for flatfoot in a study done in Congo, Central Africa, where the youngest age group, 3–4 years, had a higher proportion of a descending medial arch.^[28] Consistent with the previous article, Bourgleh et al. examined the prevalence of flatfoot among children aged 12 years or younger, and concluded that the highest incidence age at presentation was between 3 and 4 years.^[24] Likewise, Alsuhaymi et al. studied children aged 7–14 years old and found that age was significantly associated with flatfoot.^[25] Among other age groups, the 7–8 years group was rated the highest in prevalence.^[25] Alahmari et al. investigated the significance of age in younger adults aged 18–25, while Almaawi et al. participants were older adults aged more than 45 years.^[15,19] Both found a significant relationship using different foot posture measurements.^[15,19] BMI is strongly related to the development of foot deformities.^[29] In one Indian study, the distribution of flatfoot was found to be most prevalent in individuals categorized as morbidly obese with a BMI of 40 or more.^[29] Thus, the study concluded a directly proportional relationship between BMI and flat-arched foot.^[29] Similar results also illustrated a significant correlation between high BMI and flatfoot, which multiple authors have concluded in various countries.^{[15,17,18,26]} This relationship is thought to be due to pressure over the foot arch caused by fat deposition, which leads to extreme mechanical loading while walking.^[26] Equivalent to the previous studies, in Saudi Arabia, four articles showed a significant correlation between the flat-arched foot and an increased BMI.^[15,17-19] Inconsistent with the aforementioned studies, Alsuhaymi et al. article showed no significant relationship.^[25] Notably, a slight increase in weight could crucially affect the plantar fascia, while a slight weight reduction can drastically decrease plantar loading.^[15] One study showed that losing more than 2 kg could ease foot pain and control functional limitations.^[15]

The literature regarding the use of footwear during early childhood and its association with the occurrence of flatfoot is consistent both globally and locally.^[17,30] In India, a survey that included 2300 children stated that children who wore shoes had a significantly higher prevalence of flatfoot than barefooted children.^[30] Likewise, Abdel Fattah et al. reported that the type of footwear used during early childhood was a key factor in diagnosing flatfoot later in life.^[17] This establishment was done by studying both children who wore shoes and those who were barefooted.^[17] To the best of our knowledge, only Abdel Fattah et al. examined the relationship between flatfoot and family history, which was a highly significant risk factor.^[17] Other multiple significant factors associated with flatfoot, such as hypermobility, functional mobility, the flexibility of the whole body, and balance, have been reported in several articles.^[18,19]

CONCLUSION

Most of the included studies reported that BMI, age, gender, residence, family history of flatfoot, type of footwear during childhood, hypermobility, functional mobility, balance, and ligaments laxity of the whole body had a significant impact on the prevalence of flatfeet.

RECOMMENDATIONS

High-quality multicenter epidemiological studies are required. Adopting standardized diagnostic instruments are essential to enable and identify the existence of flatfoot accurately and allow valid and generalizable recommendations.