Foot and Ankle Disability Index (FADI)

What It Is

The FADI is a region-specific, self-reported outcome measure developed by Martin, Burdett, and Irrgang (1999) to assess functional limitations in patients with foot and ankle conditions, most commonly used in chronic ankle instability research.

Structure & Setup

The FADI has two components:

1. FADI Activities Subscale (26 items)
Assesses activities of daily living (ADL). Items cover tasks like:

• Standing, walking on even/uneven ground

• Going up and down stairs

• Walking on hills, curbs

• Squatting, coming up on toes

• Walking initially, for 5 and 10 minutes

2. FADI Sport Subscale (8 items)
Assesses higher-level sport and activity demands:

• Running, jumping, landing

• Starting and stopping quickly

• Cutting/lateral movements

• Low-impact activities

Scoring

Questions 1-22 of the Activity Subscale and questions 1-8 of the Sports Subscale are rated on the following 5-point Likert scale:

• 4 = None at all

• 3 = Slight

• 2 = Moderate

• 1 = Extreme

• 0 = Unable to do

Questions 23-26 of the Activities Subscale are rated on the following 5-point Likert scale:

• 4 = No pain

• 3 = Mild

• 2 = Moderate

• 1 = Severe

• 0 = Unbearable

A "Not Applicable" option is also available and those items are excluded from scoring.

Final score is calculated as:

(Total points earned ÷ Total possible points) × 100

Resulting in a percentage score from 0–100, where 100% = no disability.

Reliability & Sensitivity

Hale & Hertel (2005) examined the FADI in subjects with chronic ankle instability and found it to be a reliable and sensitive tool for detecting functional deficits in this population — supporting its use as both a diagnostic and outcomes tracking instrument.

Use in Research

The Dekker et al. (2017) study applied the FADI alongside other patient-reported outcome measures (PROMs) in total ankle replacement patients, correlating scores with range of motion — suggesting the FADI captures functional change meaningful enough to correlate with objective physical measurements.

Key Strengths

• Region-specific (more sensitive than general functional scales)

• Separates daily living from sport demands

• Simple percentage scoring is easy to interpret and track over time

• Well-validated in chronic ankle instability populations

Original Literature:

Martin, R. L., R. G. Burdett, and J. J. Irrgang. “Development of the foot and ankle disability index (FADI).” J Orthop Sports Phys Ther 29.1 (1999): A32-A33.

Additional Literature:

Hale, Sheri A., and Jay Hertel. “Reliability and sensitivity of the Foot and Ankle Disability Index in subjects with chronic ankle instability.” Journal of Athletic training 40.1 (2005): 35.

Dekker, Travis J., et al. “The Value of Motion: Patient-Reported Outcome Measures Are Correlated With Range of Motion in Total Ankle Replacement.” Foot & ankle specialist (2017): 1938640017750258.

• Select a response that most clodely describes your condition in the last week.

• If the activity in question is limited by something other than your foot or ankle, mark not applicable (N/A).