Objectives The evaluation of health-related quality of life and physical function is important for determining therapeutic strategies following ankle injuries. The Anglo-American Foot and Ankle Ability Measure (FAAM) is a valid and reliable self-reported measure to detect functional deficits in chronic lateral ankle instability. The purpose of this study was to translate, cross-culturally adapt and validate the FAAM questionnaire for use with German-speaking patients with chronic lateral ankle instability.

Patients/Participants Preoperative and conservatively treated patients with chronic lateral ankle instability. Sport students and volleyball athletes served as control groups.

Main Outcome Measurements The FAAM was forward and back translated, cross-culturally adapted and validated. The study population completed the FAAM-G questionnaire twice within 3–5 days. Additionally, the patients were scored with the Good ankle laxity classification system. Test–Retest reliability, construct validity and internal consistency were calculated.

Results Reliability and validity of the FAAM-G were examined in presurgical chronic ankle instability patients (n=24), conservatively treated chronic ankle instability patients (n=17), university sport students (n=31) and volleyballers (n=37).

Test–retest reliability revealed fair, good, or excellent reliability (inter-class correlation coefficient (ICC)=0.590–0.998; ρ=0.528–1.000). Construct validity, tested between the FAAM-G subscores and the Good et al ankle laxity classification system demonstrated strong correlations (ρ = −0.819 to −0.861).

Conclusions The original FAAM questionnaire was successfully translated and cross-culturally adapted from English to German. Corresponding to the Anglo-American version, the FAAM-G is a reliable and valid questionnaire for self-reported assessment of pain and disability in German-speaking patients suffering from chronic ankle instability.