The Cumberland Ankle Instability Tool (CAIT) is a simple 9-item, validated and specific tool for diagnosing chronic lateral ankle instability. This rating scale was first published in 2006, and it is a useful tool as a diagnostic criterion, as a screening tool, a prognostic tool, a outcome and clinical picture severity measure tool.
The CAIT-I questionnaire will be developed involving forward-backward translation, a final re-evaluation made by a representative multidisciplinary expert committee and the realization of a prefinal version to establish a proper correspondence with the original English version.
Once an acceptability analysis has been conducted, the following will be analyzed: 1- The validity of the construct by comparing the CAIT-I data with those of the SF-36 using Pearson's correlations ; 2- An Exploratory Factorial Analysis and one of Internal Consistency; 3 Sensitivity analysis through the development of ROC curves and analysis of the area under the curve. In a subset of at least 36 participants the investigators will determine the internal responsiveness on 4 points using an ANOVA (P \<.05). The scores of participants with Chronic Instability will be analyzed to determine the presence of ceiling or floor effects. Standard psychometric techniques will be used.
The validation of the psychometric properties of the instrument will start after it will been administered digitally, via a link to a website built using LimeSurvey, an application based on a MySQL database that allows the realization of online surveys, to a sample population of at least 197 subjects (a priori sample number calculated through the G \* Power program) aged 18 or more recruited through sports associations and health professionals who work with sports subjects. Through this link, from the time it will be online up to 16 November 2021, the participants will be able to access the online questionnaire, only after accepting a form for requesting consent to the processing of personal data updated pursuant to article 13 of the GDPR 2016 / 679, in force in all European Union countries from 25 May 2018. Inclusion criteria: - Age ≥18 years - Agreement to voluntarily sign informed consent to participate in the study. Exclusion criteria: - Inability to understand the written Italian language - Pregnancy - Having undergone an ankle-foot surgery in the last 6 months.
Upon enrollment, participants will answer a demographics questionnaire, the CAIT-I, and the SF-36. If they will take part in the reliability portion, then they filled out the CAIT-I and SF-36 a second time within 4 to 9 days.
For the statistical analysis standard psychometric techniques will be used, such as reliability assessments, convergent and discriminant validity tests of each item and of the construct in its entirety, empirical validity tests in relation to the clinical status and formal tests to assess their accuracy to ends to test the hypotheses.
The investigators hypothesize to be able to reproduce a tool that reflects the characteristics of the CAIT in the original language and therefore it will prove to have, even in its Italian version, an acceptable psychometric performance as an outcome and screening measure for chronic ankle instability. The CAIT-I will show to be a useful tool that can be used as a functional outcome measure for the Italian population, to monitor both the state of health and residual functional limitation in adults.
