**6.4 Cumberland ankle instability tool**

*Essentials in Hip and Ankle*

4.No guessing as an answer

**6. Questionnaires and functional scales**

**6.1 Lower extremity functional scale**

health survey (*r* = .80 and .64, respectively).

**6.2 Foot and ankle ability measure**

**6.3 Foot and ankle outcome score**

a.A correct answer may not due to guessing but reflect the person's ability.

This implies that only one latent ability accounts for the individual's response for each of the items contained on the instrument, which is exactly the unidimensionality mentioned throughout this section. Both factor analysis and the Rasch model can ascertain this aspect of construct validity. Those items that did not fit to the

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 instru-

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.

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

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.

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

model should be revised or eliminated accordingly with scale's goals.

ment selection to the target population or the right patient.

**74**

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 severity of functional ankle instability.


**Table 1** summarizes the main psychometric properties of each instruments reported above.
