**6. Questionnaires and functional scales**

Measures should be chosen based on whether they have been designed for and have been used with people similar to the people to be measured. For example, to assess an elite athlete's functionality after an ankle sprain, sport subscale of the foot and ankle ability measure questionnaire should provide more clinical useful information than the whole lower extremity functional scale (LEFS). This is not because one instrument is better than the other is, but because it is a better instrument selection to the target population or the right patient.

The next section shows four self-report questionnaires that are currently available for measuring ankle-related functionality. Some systematic reviews report that these instruments have very good psychometric properties and are quite useful for clinical scenarios as well as for research contexts. A brief overview for each of them is provided. For full information, we suggest to read the original studies about their development.

#### **6.1 Lower extremity functional scale**

The LEFS is a measure of activity limitation developed for musculoskeletal conditions of the lower extremity. On this scale, participants rate the difficulty in performing 20 activities of the lower extremity on a 5-point Likert scale, rating grade 0, meaning "extreme difficulty or unable to perform activity," to grade 4, meaning "no difficulty". The responses are summed to give a score ranging from 0 to 80, with 0 indicating high functional limitation and 80 indicating low functional restriction. LEFS was tested in a heterogeneous population with different lower limb conditions and was found to have high internal consistency (.96) and high test-retest reliability (*r =* .86) and correlated well with the physical function subscale and the physical component summary scores of the medical outcomes study 36-item short-form health survey (*r* = .80 and .64, respectively).

#### **6.2 Foot and ankle ability measure**

The FAAM is composed of two subscales named activities of daily living (ADL) and sports subscale, respectively. ADL subscale has 21 items and the sports subscale 8 items. Each item is scored on a 5-point Likert scale anchored by 4 (no difficulty at all) and 0 (unable to do). Item score totals, which range from 0 to 84 for the ADL subscale and from 0 to 32 for the sports subscale, are transformed to percentage scores. A higher score represents a higher level of function for each subscale.

#### **6.3 Foot and ankle outcome score**

The FAOS is a 42-item questionnaire divided into 5 subscales: "pain" (9 items), "other symptoms" (7 items), "activities of daily living" (17 items), "sport and

**75**

**Table 1.**

*Patient-Report Outcome Measures for Ankle-Related Functionality*

recreation function" (5 items), and "foot- and ankle-related quality of life" (4 items). Each question can be scored on a 5-point Likert scale (from zero to four) and each of the five subscale scores is calculated as the sum of the items included.

The CAIT is a nine-item questionnaire designed to be a discriminative instrument of chronic ankle instability. The questionnaire is structured so that the feeling of instability is reported for different types of activities such as running, walking, hopping, and descending stairs. The nine items generate a total score from 0 to 30 for each foot, in which 0 is the worst possible score, meaning severe instability, and 30 is the best possible score, meaning normal stability. The CAIT is a reliable (ICC 0.96) instrument that can discriminate stable from unstable ankles and measure the

**Table 1** summarizes the main psychometric properties of each instruments

**LEFS FAAM FAOS CAIT**

Item selection and reduction by patients (n = 213) Experts: not involved

Subscale pain, rs = .96; subscale symptoms, rs = .89; subscale

rs = .85; subscale sports, rs = .92; subscale quality of life, rs = .92

Subscale pain, α = .94; subscale symptoms, α = .88; subscale ADL, α = .97; subscale sports, α = .94; subscale "quality of life," α = .92

ADL,

CAIT and LEFS (α = .50, P < .01) and VAS (α.76, P < .01) Construct validity and internal reliability were acceptable (α = .83; point measure correlation for all items, >0.5; item reliability index, .99)

ICC, 0,96

The threshold CAIT score was 27.5 (Youden index, 68.1); sensitivity was 82.9% and specificity was 74.7%.

No information No information

Experts and patients were involved in item generation and reduction

ICC = .89; SEM = 2,1 points Sport subscale: ICC = .87; SEM = 4,5 points

Cronbach alpha for ADL subscale, α = .96 in stable group (n = 79); in changed group, α = .98 (n = 164) Cronbach alpha for sport subscale from a combined sample, α = .98

MDC ADL subscale, 5.7 MDC Sport subscale, 12.3

Raw scores are then transformed to a 0 to 100, worst to best score.

*DOI: http://dx.doi.org/10.5772/intechopen.89509*

**6.4 Cumberland ankle instability tool**

severity of functional ankle instability.

**Validity** 92% of variance

explained at baseline Concurrent validity r = .80 and .87, at short and medium term follow up, respectively (correlation with Olerud-Molander ankle score)

**Reliability** No information ADL subscale:

short term; .90 long

AUC ROC = 0.79 (95% CI = 0.70-0.88)

*Main psychometric properties of ankle-related self-report measures.*

**Internal consistency** α = .92 at base line; .94

**Responsiveness** Guyatt = 1.99

term.

reported above.

recreation function" (5 items), and "foot- and ankle-related quality of life" (4 items). Each question can be scored on a 5-point Likert scale (from zero to four) and each of the five subscale scores is calculated as the sum of the items included. Raw scores are then transformed to a 0 to 100, worst to best score.
