Chronic ankle instability (CAI) is a frequent sequela of lateral ankle sprains, particularly in physically active individuals. It is characterized by recurrent episodes of the ankle “giving way,” pain, and compromised functional performance, often leading to long-term limitations in sports and daily activities. The prevalence of CAI has been reported to be particularly high among female athletes, with foot structure and biomechanics considered important contributing factors to its development [1,4].

The foot arch plays a critical role in maintaining proper load distribution, balance, and ankle stability during movement. Deviations in arch height—such as pes planus (low arch) or pes cavus (high arch) have been associated with altered lower limb kinematics, reduced shock absorption, and compromised postural control, thereby increasing the risk of CAI [1,5]. In particular, athletes with abnormal arch height may demonstrate impaired dynamic postural stability, reduced ankle muscle strength, and joint misalignment, which collectively predispose them to recurrent ankle injuries [2,5].

Recent studies have explored the correlation between foot alignment and chronic ankle instability, highlighting that structural foot abnormalities may influence not only static posture but also functional stability during athletic movements [2,3]. Additionally, systematic reviews support the notion that individuals with CAI often exhibit identifiable deviations in foot and ankle alignment [3]. Early identification of at-risk individuals using arch height measurements may allow for targeted preventive strategies[6].

This observational study was undertaken to assess the correlation between foot arch height and the incidence of chronic ankle instability in a healthy adult population. The findings aim to enhance the understanding of foot structure as a modifiable risk factor for ankle instability and contribute to better clinical screening and management protocols.

Study Design and Setting:

This was a cross-sectional observational study conducted at the Department of Orthopaedics, Singareni Institute of Medical Sciences / GMC, Ramagundam, Telangana. The study was carried out over a period of three months, from April to June 2025.

Study Population:

The study included 100 participants, aged 18 years and above, who attended the outpatient orthopaedic clinic during the study period. Participants were selected irrespective of gender or physical activity level.

Inclusion Criteria:

Individuals aged ≥18 years

Participants with no acute musculoskeletal injury at the time of examination

Willingness to participate and provide informed consent

Exclusion Criteria:

History of recent lower limb fracture or surgery (<6 months)

Presence of congenital foot deformities or neuromuscular disorders

Active infection or acute injury in the lower limb

Data Collection Procedure:

Foot arch height was measured using the Arch Height Index (AHI), calculated as the ratio of the dorsum height at 50% of foot length to the total foot length (in standing position). Based on standard values, participants were categorized into three groups:

1. Low arch (pes planus)
2. Normal arch
3. High arch (pes cavus)

Chronic ankle instability (CAI) was assessed through participant history of recurrent ankle sprains, feelings of "giving way," and using a standardized questionnaire (such as the Cumberland Ankle Instability Tool – CAIT, score <24 indicating CAI).

Cumberland Ankle Instability Tool (CAIT)

Instructions: Please answer each question for the ankle in question by choosing the option that best describes your condition.

• On a scale of 0–30, what score best describes your ankle function during your daily activities?

30 = Normal        0 = Totally impaired

→ Write your number here: _______

• Do you ever feel like your ankle is going to give way?

1. Never (3)
2. Rarely (2)
3. Frequently (1)
4. Very frequently (0)

• During everyday activity (walking, stairs, etc.), does your ankle ever give way?

1. Never (5)
2. Sometimes (3)
3. Often (0)

• When walking on an uneven surface, does your ankle ever give way?

1. Never (5)
2. Sometimes (3)
3. Often (0)

• When running or hopping, does your ankle ever give way?

1. Never (5)
2. Sometimes (3)
3. Often (0)

• If you were to land awkwardly on your foot, what would happen?

1. Nothing (5)
2. It would wobble but recover (3)
3. It would give way (0)

• Do you have pain in your ankle?

1. Never (5)
2. Occasionally (3)
3. Frequently (0)

• Does swelling occur in your ankle?

1. Never (5)
2. Occasionally (3)
3. Frequently (0)

• How often do you do any activities that would typically make your ankle feel unstable?

1. Frequently (5)
2. Sometimes (3)
3. Never (0)

Scoring:

Maximum Score = 30

CAI likely if Score < 24

Statistical Analysis:

Descriptive statistics were used to summarize demographic variables. The Chi-square test was applied to examine the association between arch type and CAI. Binary logistic regression was conducted to calculate the odds ratios (OR) with 95% confidence intervals (CI) for CAI in different arch types, using the normal arch as the reference group. A p-value <0.05 was considered statistically significant. Data analysis was performed using SPSS version 25.0.

Ethical Consideration:

The study was approved by the Institutional Ethics Committee of Singareni Institute of Medical Sciences / Government Medical College, Ramagundam. Informed consent was obtained from all participants prior to inclusion in the study.

The present study included a total of 100 participants, comprising 52 males and 48 females. The mean age of the participants was 27.3 ± 6.2 years, with the majority falling within the 26–35-year age group (44%) as shown in Table 1.

Table 1: Demographic Characteristics of Study Participants (n = 100)

Based on the arch height index, participants were categorized into three groups: low arch (n = 34), normal arch (n = 46), and high arch (n = 20). The prevalence of chronic ankle instability (CAI) was observed to be highest among participants with high arch (55.0%) and low arch (52.9%), while only 21.7% of those with normal arches reported CAI. These distributions are detailed in Table 2.

Table 2: Distribution of Foot Arch Type and Chronic Ankle Instability (CAI)

A chi-square test was performed to assess the association between foot arch type and the presence of chronic ankle instability. The results revealed a statistically significant association (χ² = 12.78, df = 2, p = 0.0016), indicating that foot arch height significantly correlates with the incidence of CAI (Table 3).

Table 3: Association between Foot Arch Type and CAI – Chi-square Test

A statistically significant association was found between foot arch type and chronic ankle instability (p < 0.01).

Further, binary logistic regression analysis was conducted to evaluate the risk of CAI based on foot arch type, using normal arch as the reference group. Participants with a low arch had an odds ratio (OR) of 4.18 (95% CI: 1.56–11.17, p = 0.004), while those with a high arch had an OR of 4.57 (95% CI: 1.48–14.12, p = 0.008), both demonstrating significantly increased odds of developing chronic ankle instability compared to those with normal arch height (Table 4).

Table 4: Odds of Chronic Ankle Instability Based on Arch Type (Reference = Normal Arch)

The present study demonstrated a statistically significant association between foot arch height and the incidence of chronic ankle instability (CAI). Participants with either low or high foot arches were found to have significantly greater odds of experiencing CAI compared to those with normal arches. These findings reinforce the hypothesis that deviations in foot structure play a critical role in impairing ankle stability.

Postural control and neuromuscular coordination are key determinants in the maintenance of ankle joint integrity. Riemann et al. highlighted that individuals with CAI often exhibit deficits in postural stability, which may be further exacerbated by abnormal foot morphology [7]. These structural deviations, particularly in arch height, may disrupt normal loading patterns and proprioceptive feedback, contributing to instability and recurrent sprains.

In a recent study among soccer players, Alanazi identified abnormal foot alignment and altered biomechanics as predictors of CAI, supporting the idea that intrinsic anatomical factors such as arch height can predispose athletes to instability [8]. Furthermore, Yang et al. emphasized that addressing biomechanical abnormalities—such as foot arch issues should be a fundamental aspect of both conservative and surgical management strategies for CAI [9].

The clinical relevance of differentiating types of ankle instability was underscored by Gribble, who recommended precise biomechanical evaluation as a basis for targeted interventions [10]. Pain is another important dimension, as highlighted by Al Adal et al., who found a high prevalence of chronic pain among CAI patients likely influenced by cumulative microtrauma and abnormal joint mechanics [11]. Additionally, Fraser et al. noted the involvement of midfoot and forefoot structures in lateral ankle sprains and CAI, suggesting that comprehensive foot assessments are essential for effective rehabilitation planning [12].

In light of these insights, our study underscores the importance of including foot arch assessment as part of routine musculoskeletal evaluations, especially in individuals with a history of ankle sprains. Preventive strategies, such as arch-specific orthotics, proprioceptive training, and strengthening programs, may significantly reduce the risk of chronic instability.

Despite these limitations, this study highlights the importance of incorporating foot structure assessment in routine clinical evaluation of patients at risk for ankle instability. Early identification of individuals with abnormal arch morphology may enable the implementation of targeted preventive strategies, such as orthotic support, balance training, and proprioceptive rehabilitation, to reduce the burden of CAI.

This study demonstrated a significant correlation between foot arch height and the incidence of chronic ankle instability (CAI). Individuals with both low and high arches were found to be at a significantly higher risk of developing CAI compared to those with normal arches. These findings highlight the biomechanical influence of foot morphology on ankle joint stability. Assessing arch height as part of routine clinical evaluation can help identify individuals at risk for recurrent ankle sprains and instability. Early interventions such as orthotic support, proprioceptive training, and preventive rehabilitation can be strategically implemented to reduce the likelihood of CAI and improve long-term functional outcomes.

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