Translation and validation of the Danish Foot Function Index (FFI-DK)

Area of Science:

• Orthopedics
• Rheumatology
• Physical Medicine and Rehabilitation

Background:

• Foot complaints significantly impact patient quality of life.
• Validated outcome measures are essential for assessing foot conditions.
• The Foot Function Index (FFI) is a widely used tool for evaluating foot problems.

Purpose of the Study:

• To translate and culturally adapt the Foot Function Index (FFI) into Danish.
• To evaluate the reliability and internal consistency of the Danish version of the FFI.
• To establish the validity of the Danish FFI for use in Danish-speaking populations.

Main Methods:

• Forward and backward translation protocol.
• Reliability assessment using intraclass correlation coefficient (ICC).
• Internal consistency evaluation with Cronbach's alpha.

Main Results:

• Excellent internal consistency for pain (0.99), disability (0.98), and activity limitation (0.98) subscales.
• Excellent test-retest reliability for all subscales and the total score (ICC range: 0.95-0.98).
• Bland-Altman analysis showed no significant or clinically relevant differences between test and retest.

Conclusions:

• The Danish translation of the FFI is a valid and reliable instrument.
• The Danish FFI is suitable for assessing foot function in Danish-speaking patients.
• This validated tool will aid in the management of foot complaints in Denmark.