Cross-cultural adaptation and validation of the Foot and Ankle Ability Measure (FAAM) into Spanish for Chile and LATAM

Abstract

Background

The Foot and Ankle Ability Measure (FAAM) assess physical function in musculoskeletal pathologies of the foot and ankle.

Method

The aim of this study was to translate, culturally adapt and validate the FAAM into Spanish for Chile and LATAM and assess its validity and reliability in patients with non-traumatic surgical orthopaedic pathologies. After translation and adaptation this retrospective cohort study included 940 participants answering FAAM and SF-36 scale.

Results

A high response rate (98%) with no floor or ceiling effect is reported. Excellent internal consistency for the scale (Cronbach’s α = 0.972) and subscales (ADLs = 0,974 and Sport = 0,954) were obtained. The principal component factor analysis gave two factors explaining 66% of the variance and reporting the same item structure of the original version. The FAAM-CL sub-scales had direct and significant correlations with the SF-36 components and subcomponents.

Conclusions

The FAAM-CL was culturally adapted and demonstrated a high rate of reliability, validity, and ability to evaluate foot and ankle pathologies among Spanish-speaking patients.

Level of Evidence

III

1

Introduction

In the field of orthopaedics, Patient Reported Outcome Measures (PROMs) have emerged as fundamental tools for evaluating and measuring the outcomes of clinical procedures from the patient’s perspective. These scales allow for a standardised and effective patient classification, diagnosis, treatment, and follow-up . PROMs are designed in a specific language and validated according to the culture of their target population, thus making translation and cultural adaptation crucial for ensuring their reliability and validity , . This underscores the importance of tailoring evaluation tools to specific linguistic and cultural contexts to maintain their relevance and accuracy across different populations.

The FAAM is a scale designed to assess physical function in musculoskeletal pathologies of the ankle and foot and was initially validated in 2005 by Martin and colleagues . It consists of 21 items on activities of daily living and 8 items on sports activities. The FAAM has been validated in twelve languages, including German, Persian, French, Italian, Japanese, Portuguese, Thai, Dutch, Turkish, Portuguese, Spanish (for Spain), Chinese and recently Danish ,,,,,,,,,,, . Despite the Spanish for Spain validation, to date, no cultural adaptation or validation of the FAAM has been conducted for use in the Chilean neither LATAM population.

The lack of a validated version of the FAAM in Chilean and LATAM Spanish represents a significant limitation for both research and clinical practice in Chile and other Spanish-speaking countries in South America. The availability of a valid and reliable instrument is crucial to ensure accurate patient assessment, comparability of research results, and improvement in clinical decision-making. Thus, this study addresses this gap by culturally adapting and validating the FAAM in LATAM Spanish, ensuring it maintains the same relevance and accuracy as its original versions.

This manuscript describes the linguistic adaptation and validation of the Chilean Spanish version of the “Foot and Ankle Ability Measure” (FAAM).

2

Methods

This paper reports the adaptation and validation of the FAAM-CL.

Our Ethical Committee approved this study and informed consent was obtained. A retrospective cohort sample from a prospectively collected data base (between 2019 and 2023) of outpatients attending a foot and ankle orthopaedic clinic were included; patients from 11 to 87 years old; with foot and ankle orthopaedic pathology (even contralateral); surgery indication and fluent in Spanish. Patients with traumatic injury, neurological dysfunction, psychiatric or cognitive disorder and writing or reading disabilities were excluded.

2.1

Translation and cross-cultural adaptation

The original score was translated into Spanish and back-translated into English, following the World Health Organization guidelines .

This process included a professional native Spanish (Chilean) translator, blind to the study, who translated the original English version into Spanish. Then a first Bilingual Committee reviewed and edited the translation. The resulting version was then back translated into English by a second translator (native English speaker) without prior knowledge of the scale. The translation and back-translation aimed for conceptual equivalence rather than a literal word-for-word translation. A second Bilingual Committee discussed and resolved any discrepancies, and developed a preliminary version of the FAAM-CL.

To assess the correct understanding of items a pilot evaluation was carried out with the preliminary version of the FAAM-CL. A sample of 20 participants with the same characteristics as the final population answered the score for this pre-test.

2.2

Validation

A cross-sectional design was used to test the reliability and validity of the Spanish translated version

Every participant answered both scales, the adapted FAAM and the SF-36.

2.2.1

Foot and Ankle Ability Measures (FAAM)

The FAAM it is a self-report scale to evaluate change in physical functioning of patients with foot and ankle musculoskeletal disabilities. Comprises two subscales: Activities of Daily living (ADLs): 21 items and Sport: 8 items (Likert), scored from 0 to 4. Additionally, the scale has an “extra item” to evaluate perception of current functionality level (How would you rate your current level of function?) and two questions to qualitative evaluate the percentage of functionality perceived for ADLs and Sports.

To calculate the final scores for each subscale, the points for each answered item are added, multiplied by 100 and then divided by the total number of possible points: 84 for the ADLs and 32 for Sport. A higher score means better level of physical functioning.

2.2.2

Medical Outcome Study (MOS) SF-36

The validated version of the Medical Outcome Study (MOS) SF-36 , it comprises 36 items; evaluates the state of health or disease; it is divided into two components: physical (PC) and mental components (MC); the components are subdivided into: PC: physical function, role physical, bodily pain and general health. MC: vitality, social functioning, role emotional and general mental health. The scores are transformed into a 0–100 scale. Higher scores represent better health status.

2.2.3

Sample size

By general convention to validate a score a range between 7 and 10 answers by each item of the scale to validate is needed to achieve enough power , . Generally accepted as well, for factor analysis, is considering poor samples lower than 100 participants, fair for 200, good for 300, very good for 500 and excellent for 1000 cases ,, .

2.2.4

Data analysis

Descripted analyses included percentage, mean and standard deviation. The quality of the data was represented by percentages of missing data and scale completeness cut-off was set at a minimum of 95% to be kept for further analyses.

Acceptability was evaluated using item frequency distribution and central tendency measures. This included: Score range: use of all the possible response choices for each item; Mean, median scores and Standard Deviation (These parameters should be roughly equivalent within a scale or subscale); Floor and ceiling effects and skewness: a high percentage (>20%) of floor or ceiling effect may compromise the discriminative ability of the scale; Item-internal consistency, correlation between the specific item and its corresponding sub-scale: Coefficients (r) higher than 0.4 were considered acceptable; Item-discriminant validity: Correlation between a specific item and its subscale compared with the correlation with the other subscale. It is expected to have higher correlations within its own subscale; and very strong to perfect correlations (r > 0.8) are not expected since it indicates no addition of significant information.

Internal construct validity: Since each subscale of the FAAM measures different aspects of the same construct, it is hypothesised to have moderate to strong correlations (Pearson’s r) between them. Internal construct validity included: Convergent validity: moderate to strong correlations between the subscales (r 0.3–0.7) indicate sufficient convergent validity and Divergent validity: low correlations between the subscales (r < 0.3) indicate sufficient divergent validity.

Internal consistency (reliability): Cronbach’s α and Guttman’s split-half coefficients were calculated. Coefficients higher than 0.7 were interpreted as a cut-off criterion of reliability.

External validity: Construct validity was assessed by comparing the scores of the adapted FAAM and the SF-36, expecting a medium-high direct correlation. This included: Convergent validity: moderate/strong direct and significant correlations were expected among ADLs and SF-36 PH and MH Components (and sub-components). Moderate direct and significant correlations were expected among FAAM-CL Sport and SF-36 PH and MHC (and sub-components). The participants of this study were outpatients attending a foot and ankle orthopaedic clinic with a variety of foot and ankle orthopaedic pathology with surgery indication, a wide age range (11–87 years old) and fluent in Spanish. Therefore, the FAAM-CL could be use in patients attending foot and ankle orthopaedic clinics.

Finaly, Discriminative validity of the FAAM-CL was addressed by a between-subjects t -tests and Pearson’s correlations, calculated comparing demographic characteristics; and initially sampling adequacy included Kaiser–Meyer–Olkin (KMO) test, Bartlett’s sphericity test; Exploratory; and Confirmatory Factor Analysis (EFA and CFA).

All analyses were performed using SPSS V.29. Results were considered significant with alpha levels lower than 0.05 (two-tailed).

3

Results

Data from 949 outpatients were included, of them 940 participants (99,05%) answer the ADLs subscale. Full answers were obtained from 881 participants (93,7%). The Sports Subscale was answered by 615 participants (64,8% of the total sample– this subscale applies only to people engaged regularly-at least twice a week- on sport activities) and full answers were obtained from 592 participants (96% of those answering the Sport Subscale). Of the total sample, 646 were women (68.1%); their ages ranged from 11 to 87 years old. Most participants hold a university degree (34.9%) and were a dependant worker (40.1%). ADLs subscale showed a mean of 66,5%; a median of 67,9 and an SD of 23,8. Sport subscale shows a mean of 48; a median of 46,9 and an SD of 29.9. See sociodemographic data in Table 1 .

Table 1

Demographic data (N = 940).

Variable N(%)
Sex Male 299(31.5)
Female 646(68.1)
Missing 4(0.4)
Age Media: 46.8 (SD) 17.8
< 47 371(39.1)
> 47 379(42.0)
Missing 179(18.9)
Education Primary 65(6.8)
Secondary 207(21.8)
Technic 162(17.1)
University 331(34.9)
Post Grade 117(12.3)
Missing 67(7.1)
Activity Student 133(14.0)
Domestic activities 84(8.9)
Dependant worker 381(40.1)
Self-employed 168(17.7)
Retired 101(10.6)
Unemployed 37(3.9)
Missing 45(4.7)

Data are presented as mean ± standard deviation (SD) for continuous variables (age) and as number (percentage) for categorical variables. Age refers to participant age at enrolment.

3.1

First Stage: Translation and cross-cultural adaptation

After the translation into Spanish, some wording was modified by the Bilingual Committee. After back translation, no meaningful discrepancies were found by the Committee. After the pilot language testing minor adjustments were made to develop the preliminary FAAM-CL (Appendix 1).

3.2

Second Stage: Validation process

The cut off for completion (95% of answered items) gives a 99.7% response rate. Score range showed high acceptability; each alternative was selected within the possible responses. FAAM-CL scores ranged from 0 to 100.

Floor and ceiling effect were not observed: The ADLs had 5,9% (56 patients) of Ceiling and no Floor was seen. The Sport subscale showed a 3,5% (33 patients) of Floor and 4,1% (39 patients) of Ceiling. Details in Table 2 .

Table 2

Descriptive and floor and ceiling effect of the FAAM Score (N = 940).

Score Subscale Mean (SD) Lowest score Cases (%) Highest Score Cases (%)
FAAM ADLs 66.5 (23.8) 0 (0) 56 (5.9)
Sport 47.9 (29.8) 33 (3.5) 39 (4.1)
SF-36 SF-36-PHC 57.0 (19.8) 0 (0) 0 (0)
SF-36-PF 62.4 (24.7) 6 (0.6) 43 (4.5)
SF-36-RP 58.2 (30.3) 39 (4.1) 102 (10.7)
SF-36-P 42.2 (22.6) 36 (3.8) 0 (0)
SF-36-GH 65.1 (22.8) 3 (0.3) 40 (4.2
SF-36-MHC 59.6 (15.5) 0 (0) 0 (0)
SF-36-VT 54.9 (20.4) 3 (0.3) 8 (0.8)
SF-36-SF 50.9 (11.7) 1 (0.1) 2 (0.2)
SF-36-RE 67.3 (29.6) 32 (3,4) 183 (19.3) #
SF-36-MH 65.1 (20.2) 2 (0.2) 21 (2.2)

# ceiling effect over the limit.

Floor effect: the percentage of participants scoring the lowest possible score on the scale. Ceiling effect: the percentage scoring the highest possible score. Values exceeding 15% indicate a significant floor or ceiling effect, which may suggest limited sensitivity of the instrument.

3.2.1

Acceptability

Item-internal consistency: Every item had a moderate to high correlation within each other. All item correlations meet the internal consistency criteria (r > 4).

Item-discriminant validity: All the items of the ADLs have a significant medium correlation with the score of Sport subscale. All items had higher correlations with the score of its subscale. Items ADLs 6 and 7 (r = 0,916); ADLs 4 and 5 (r = 0,922) and Sport items 23 and 24 (r = 0,910), showed a “very strong” (r > 0.9) correlation between them.

3.2.2

Internal construct validity

Evaluated comparing the subscales (since measures different aspects of the same construct). A medium-high direct correlation between the ADLs and Sport subscales (r =,729; p < 0,001) was observed indicating sufficient convergent and divergent validity.

3.2.3

Internal consistency

The FAAM-CL scale showed an excellent internal consistency, with an overall Cronbach alpha of.972 and Guttman’s split-half coefficients: Cronbach Alpha part 1:.962, part 2:.954.

3.2.4

External validity

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Sep 5, 2026 | Posted by in ORTHOPEDIC | Comments Off on Cross-cultural adaptation and validation of the Foot and Ankle Ability Measure (FAAM) into Spanish for Chile and LATAM

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