Many-faceted rasch calibration of the foot function index-revised short form.

Many-faceted Rasch analysis revealed the FFI-RS had sound psychometric properties using the many-faceted Ranch analysis and retained 32 of the original items. Clinicians and researchers should consider weaknesses identified with items in the 'Difficulty" subscale and future work should be conducted to modify or develop items that will more accurately evaluate a wide range of foot function levels.