The Foot & Ankle Disability Index, or FADI, is a patient-reported outcome measure used to assess foot and ankle function, pain and activity limitation. It can help monitor how a client’s foot or ankle problem affects daily activity and sport, but it does not diagnose a condition, confirm injury or clear someone for sport on its own.

Introduction

Foot and ankle conditions can affect walking, stairs, running, sport, work tasks, balance confidence and daily activity.

The Foot & Ankle Disability Index, commonly called the FADI, is a patient-reported outcome measure that asks the client to rate difficulty with daily activities and pain related to their foot or ankle.

The FADI is often discussed alongside the FADI Sport subscale, which captures higher-demand activities such as running, jumping and sport-specific function.

It is commonly used for:

• ankle sprain
• chronic ankle instability
• post-injury ankle function
• sport-related foot and ankle limitations
• return-to-running monitoring
• return-to-sport progress tracking
• general foot and ankle disability assessment
• comparison with other foot and ankle outcome measures

Systematic review evidence has identified the FADI and FAAM as appropriate patient-assessed tools for quantifying functional disability in people with chronic ankle instability, while also noting that measurement properties and meaningful change values vary across instruments and populations.  

Quick Summary

• Outcome measure: Foot & Ankle Disability Index
• Abbreviation: FADI
• Related scale: FADI Sport
• Body region: Foot and ankle
• Type: Patient-reported outcome measure
• Main purpose: Assess foot and ankle-related disability, pain and function
• FADI items: commonly described as 26 items
• FADI Sport items: commonly described as 8 items
• Scoring direction: Higher percentage scores indicate better function
• Lower scores mean: Greater perceived disability or limitation
• Best used for: Baseline assessment, reassessment, sport function monitoring and progress tracking
• Key limitation: FADI does not diagnose a specific condition or determine return-to-sport readiness on its own

What Is the Foot & Ankle Disability Index?

The FADI is a foot and ankle patient-reported outcome measure.

It is designed to assess how a foot or ankle problem affects:

• daily function
• pain
• walking
• stairs
• standing
• personal activities
• work or routine activity
• higher-level function when FADI Sport is used

The FADI is commonly described as having:

• 26 total items in the main FADI
• 22 activity-related items
• 4 pain-related items
• a separate 8-item FADI Sport section for higher-level activity

The main FADI and FADI Sport are usually scored separately.

The Foot and Ankle Ability Measure, or FAAM, was later developed from the FADI framework, with changes including removal of some pain-related items from the activities scale while retaining the Sports subscale structure.  

Why It Is Used

The FADI is used because physical testing alone may not show how a client is experiencing their foot or ankle problem.

A client may have improving range of motion or strength but still report:

• difficulty walking longer distances
• pain during stairs
• poor confidence with uneven ground
• difficulty running
• reduced sport participation
• pain after activity
• fear of recurrence
• difficulty with work or recreational tasks

The FADI may help professionals:

• establish a baseline
• measure self-reported disability
• monitor change over time
• identify daily activity limitations
• identify sport-related limitations through FADI Sport
• support client education
• guide reassessment conversations
• combine subjective and objective findings in Measurz

It should be used to support assessment reasoning and progress tracking, not as a stand-alone diagnostic tool.

What It Measures

The FADI measures the client’s perceived difficulty and pain related to foot and ankle function.

It may provide insight into:

• daily activity difficulty
• walking tolerance
• stair function
• standing tolerance
• pain during functional activity
• sport and recreation limitations
• higher-level physical function when FADI Sport is included

The FADI does not directly measure:

• ligament integrity
• tendon structure
• joint damage
• fracture healing
• swelling volume
• strength
• balance
• range of motion
• readiness to return to sport

Who It Is Useful For

The FADI may be useful for:

• exercise professionals
• rehabilitation practitioners
• strength and conditioning coaches
• sport and performance coaches
• allied health support teams
• movement assessment professionals
• students learning outcome measures
• professionals using Measurz or MAT for structured progress tracking

It may be relevant for clients with:

• ankle sprain
• chronic ankle instability
• foot pain
• ankle pain
• post-injury foot or ankle symptoms
• sport-related ankle limitations
• functional instability symptoms
• persistent pain after ankle injury
• post-operative foot or ankle rehabilitation, where appropriate

Most published FADI measurement-property research has focused heavily on chronic ankle instability and athletic or active populations, so interpretation should be cautious when applying it to other foot and ankle conditions.  

When to Use This Outcome Measure

Use the FADI when you want to understand how a foot or ankle problem affects the client’s perceived function and pain.

It may be useful at:

• initial assessment
• onboarding
• post-injury baseline
• reassessment
• return-to-run planning
• return-to-sport planning
• after a training block
• after a rehabilitation phase
• discharge or progress review

Use FADI Sport when the client has higher-level sport or recreation goals.

This may include clients returning to:

• running
• jumping
• cutting
• pivoting
• field sport
• court sport
• gym-based performance
• recreational sport

When Not to Use or When to Be Cautious

Use caution when:

• the client cannot understand the questionnaire
• language or literacy affects responses
• many items are not relevant to the client
• the client has multiple body regions affecting function
• the score is being used as a clearance decision
• the client has not attempted sport but is completing FADI Sport
• the wrong version or scoring method is used
• missing items are not handled consistently

The FADI should not be used to:

• diagnose a condition
• confirm a ligament injury
• confirm chronic ankle instability
• determine tissue healing
• explain symptoms on its own
• replace physical assessment
• replace professional judgement
• clear someone for sport

Equipment or Resources Required

• FADI questionnaire
• FADI Sport questionnaire, if relevant
• Scoring guide or calculator
• Measurz recording workflow
• Client-reported symptom notes
• Baseline and retest dates
• Optional related physical measures, such as:
  • ankle range of motion
  • weight-bearing lunge test
  • calf raise testing
  • foot and ankle strength testing
  • single-leg balance
  • Y-Balance Test
  • hop testing
  • running assessment
  • pain score

Administration Protocol / Practice

Setup

Explain the purpose of the FADI before the client completes it.

Example wording:

“This questionnaire helps us understand how your foot or ankle is affecting your daily function, pain and activity. It does not diagnose the problem by itself, but it helps us track your progress over time.”

Format

The FADI can be completed:

• on paper
• digitally
• before a session
• during reassessment
• independently
• with assistance if needed

The FADI Sport section should be used when higher-level activity and sport function are relevant.

Client Instructions

Ask the client to:

• answer based on their current foot or ankle condition
• choose the response that best reflects their experience
• answer every item where possible
• avoid overthinking each response
• ask for clarification if they do not understand an item
• complete the same version at each retest

Completion Method

Record whether the FADI was completed:

• independently
• digitally
• on paper
• verbally
• with assistance

This helps with repeatability and interpretation.

Assistance Rules

If assistance is needed:

• explain the instructions without leading the answer
• do not tell the client which response to choose
• record that assistance was provided
• use the same assistance approach at retest where possible

Missing Item Handling

Do not guess missing responses.

If an item is missed:

• record the missing item
• use the scoring method supported by the version being used
• avoid comparing scores if missing item handling differs between sessions

If too many items are missing, record the result as incomplete or interpret cautiously.

Scoring Process

Each item is commonly scored on a 0–4 scale.

The main FADI raw score is commonly calculated out of 104 points.

The FADI Sport raw score is commonly calculated out of 32 points.

Scores are often converted to a percentage.

General scoring direction:

• Higher percentage score: better function / less disability
• Lower percentage score: more disability / greater limitation

Retesting Considerations

Retest at meaningful points, such as:

• baseline
• after a rehabilitation phase
• after a training block
• when symptoms change
• before return to running
• before return to sport
• at discharge or review

Record the client’s activity exposure at each retest because scores may change depending on whether they have actually returned to the activities being scored.

Safety Notes

The FADI is a self-report questionnaire, so it does not create physical testing risk.

However, worsening scores may indicate the need for:

• further assessment
• review of training load
• review of pain or swelling
• referral where appropriate
• additional physical testing

Scoring and Interpretation

The FADI is usually scored as a percentage of the maximum possible score.

Main FADI

• Common item count: 26 items
• Common raw score range: 0–104
• Converted score: percentage
• Higher score: better function
• Lower score: greater perceived disability

FADI Sport

• Common item count: 8 items
• Common raw score range: 0–32
• Converted score: percentage
• Higher score: better sport function
• Lower score: greater sport limitation

What a High Score May Suggest

A high FADI score may suggest:

• better perceived foot and ankle function
• less difficulty with daily tasks
• lower symptom impact
• better walking or stair tolerance
• greater confidence in daily activity

A high FADI Sport score may suggest:

• better perceived sport function
• better tolerance of higher-level activity
• greater confidence with running, jumping or cutting

What a Low Score May Suggest

A low FADI score may suggest:

• greater perceived disability
• more pain or difficulty with activity
• reduced walking or stair tolerance
• higher symptom impact
• lower confidence

A low FADI Sport score may suggest:

• difficulty with high-demand tasks
• reduced sport confidence
• reduced tolerance of running, jumping or cutting
• ongoing limitation despite daily activity improvement

What the Score Does Not Prove

A FADI score does not prove:

• the diagnosis
• the injured structure
• severity of tissue damage
• readiness to return to sport
• whether the client is safe to progress
• whether one intervention caused the change

How to Explain the Result Safely

Example wording:

“Your FADI score suggests your daily foot and ankle function is improving, but the Sport score shows higher-level activity is still more limited. This does not tell us exactly what tissue is involved, but it helps us track how your symptoms are affecting the activities that matter to you.”

What the Score May Mean in Different Client Populations

General Fitness Clients

For general fitness clients, the FADI may help show how foot or ankle symptoms affect:

• walking
• stairs
• gym training
• daily activity
• work tasks
• recreational exercise

Interpretation cautions:

• some sport items may not apply
• recent activity can influence answers
• pain expectations may affect responses

Sport and Performance Clients

For athletes, FADI Sport is often especially useful.

It may provide insight into:

• running tolerance
• jumping confidence
• cutting confidence
• ability to return to training
• sport-specific limitations

Interpretation cautions:

• high scores do not equal clearance
• sport exposure must be considered
• physical testing is still needed

Older Adults

For older adults, the FADI may help track how foot and ankle symptoms affect:

• mobility
• stairs
• standing
• confidence
• participation
• independence

Interpretation cautions:

• other conditions may affect responses
• general strength and balance may influence function
• sport subscale may be less relevant

Youth Clients

For youth clients, consider:

• reading level
• comprehension
• parent or guardian assistance
• sport exposure
• whether all items are relevant

If assistance is provided, record it clearly.

Clients With Chronic Ankle Instability

FADI has been studied in chronic ankle instability populations. A systematic review concluded that FADI and FAAM can be considered appropriate patient-assessed tools for quantifying functional disability in this group.  

Interpretation should still include:

• history of giving way
• recurrent sprain history
• balance testing
• strength testing
• hop or functional tests
• confidence and sport demands

Clients Returning After Injury

For clients returning after injury, FADI can help monitor whether perceived function is improving.

However:

• high scores should not be used as clearance on their own
• FADI Sport should be paired with physical testing
• sport-specific exposure should be documented
• changes should be compared with baseline

Post-Surgical or Post-Fracture Clients

FADI may be used in some post-surgical or post-fracture contexts, but evidence is more condition-specific and should be interpreted cautiously.

Scores may be influenced by:

• healing stage
• surgical restrictions
• pain medication
• swelling
• weight-bearing status
• activity restrictions
• medical advice

Meaningful Change, MCID, MDC and Responsiveness

Meaningful change helps determine whether a score change is likely to matter.

Key terms:

• MCID: smallest change that may be meaningful to the client or professional
• MDC: amount of change likely needed to exceed measurement error
• SEM: estimated measurement error around a score
• Responsiveness: ability of the questionnaire to detect change over time

FADI Meaningful Change Evidence

High-quality universal MCID, MDC or SEM values for the FADI across all foot and ankle populations appear limited.

A systematic review of chronic ankle instability outcome measures found that responsiveness was demonstrated for FADI, but reported that only FAAM had a minimal clinically important difference presented among the reviewed instruments.  

A clinical resource summary also notes that no MCID had been calculated for FADI at the time of its review, and that many FADI studies were focused on chronic ankle instability, limiting generalisability.  

Practical Interpretation

When interpreting FADI change:

• compare with the client’s own baseline
• look for consistent improvement across daily and sport function
• consider whether the client has increased activity exposure
• check pain, swelling, strength, ROM and balance changes
• use caution with small score changes
• avoid treating one score change as proof of recovery

When MCID or MDC Is Unavailable

When no matching MCID, MDC or SEM is available, interpretation should rely more heavily on:

• repeated measurement
• baseline comparison
• client goals
• pain change
• symptom behaviour
• function change
• sport exposure
• related physical assessment findings
• professional judgement

Normative Data, Reference Values or Comparative Data

Exact normative values for the full FADI across broad populations appear limited.

However, related population-level reference data exist for foot and ankle outcome measures.

A 2020 study aimed to determine normative values for foot and ankle outcome measures, including FAAM ADL and FAAM/FADI Sport, in a sample representative of the normal adult United States population.  

This provides useful context, but it is not the same as a universal full FADI reference value.

Practical comparison guidance:

• Use the client’s own baseline as the most important comparison.
• Compare daily function and sport function separately.
• Consider age, sport, activity level and recent exposure.
• Use broad reference values as context, not pass/fail criteria.
• Avoid comparing full FADI and FAAM scores as if they are identical.
• Record the version and scoring method used.

For most Measurz use cases, the best practical comparison is:

• baseline score
• retest score
• activity exposure
• symptoms
• objective physical test results
• client goals

Reliability and Validity

The FADI has post-2000 evidence supporting its reliability and clinical usefulness, especially in chronic ankle instability populations.

A 2005 study examined the reliability and sensitivity of the FADI and FADI Sport in people with chronic ankle instability, supporting their use in athletic and active populations.  

The 2007 systematic review of chronic ankle instability instruments reported that:

• test-retest reliability was demonstrated for FAOS, FADI and FAAM
• responsiveness was demonstrated for FADI and FAAM
• FADI and FAAM were considered among the most appropriate patient-assessed tools for chronic ankle instability disability assessment
• some measurement-property gaps remained, including limited MCID evidence for FADI  

Reliability and validity are stronger when:

• the correct version is used
• the same scoring method is repeated
• all relevant items are completed
• FADI and FADI Sport are scored separately
• retesting occurs at meaningful time points
• results are interpreted alongside physical tests

Interpret cautiously when:

• many items are missing
• the client has not attempted sport
• the score is used without activity exposure context
• the score is applied to a population unlike the validation sample
• the score is used as a stand-alone clearance decision

Common Errors and Limitations

Common errors include:

• treating FADI as a diagnosis
• using FADI as return-to-sport clearance
• mixing FADI and FAAM scoring methods
• not recording whether FADI Sport was used
• not converting scores consistently
• ignoring missing items
• not recording completion method
• comparing scores without considering activity exposure
• over-interpreting small score changes
• using broad reference values as strict cut-offs

Limitations include:

• most evidence is stronger for chronic ankle instability than all foot and ankle conditions
• MCID, MDC and SEM values are limited for FADI
• self-report is influenced by confidence, expectations and recent activity
• sport scores may be misleading if sport has not been attempted
• FADI does not identify the exact physical cause of limitation
• it should be paired with physical assessment and client goals

Practical Applications

The FADI may help professionals:

• document baseline function
• monitor self-reported progress
• compare daily function and sport function
• support return-to-running discussions
• guide return-to-sport planning
• track chronic ankle instability symptoms
• improve client education
• strengthen Measurz reporting

For athletes, FADI Sport can help monitor higher-demand function during:

• running progression
• jumping progression
• cutting and agility progression
• return to training
• return to competition

For general population clients, the main FADI may help track:

• walking
• stairs
• standing
• daily function
• work or recreational activity

For Measurz users, FADI works best when combined with:

• ankle dorsiflexion ROM
• calf raise testing
• single-leg balance
• Y-Balance Test
• hop testing
• strength testing
• pain and swelling records

How to Record This in Measurz

Record:

• outcome measure name: Foot & Ankle Disability Index / FADI
• version used: FADI, FADI Sport or both
• date completed
• completion method: paper, digital, interview or assisted
• language/version used
• condition or presentation being tracked
• side involved: left, right or bilateral
• FADI raw score
• FADI percentage score
• FADI Sport raw score, if used
• FADI Sport percentage score, if used
• score range
• direction of scoring: higher score indicates better function
• missing items, if any
• assistance provided, if any
• current pain score, if relevant
• current symptoms
• current activity or sport exposure
• key functional limitations
• confidence or participation goals
• baseline comparison
• related physical assessment findings
• interpretation notes
• retest date
• referral or further assessment notes where appropriate

Record whether the main limitation appears to be:

• daily function limitation
• sport function limitation
• pain-limited function
• confidence-limited function
• mixed limitation
• unclear due to incomplete responses

This improves:

• repeatability
• communication
• client education
• assessment reasoning
• monitoring over time
• team consistency
• reporting quality

Related Outcome Measures / Internal Links

• Foot and Ankle Outcome Score / FAOS
• Lower Extremity Functional Scale / LEFS
• Knee Injury and Osteoarthritis Outcome Score / KOOS
• Lysholm Knee Scoring Scale
• Copenhagen Hip and Groin Outcome Score / HAGOS
• Hip Disability and Osteoarthritis Outcome Score / HOOS
• Pain Self-Efficacy Questionnaire / PSEQ
• Tampa Scale for Kinesiophobia / TSK

FAQs

What does the FADI measure?

The FADI measures self-reported foot and ankle disability, including difficulty with daily activities and pain.

What is FADI Sport?

FADI Sport is a separate sport-focused section used to assess higher-level activity such as running, jumping and cutting.

How is the FADI scored?

The main FADI is commonly scored out of 104 and converted to a percentage. FADI Sport is commonly scored out of 32 and converted to a percentage.

Does a higher FADI score mean better function?

Yes. Higher percentage scores indicate better perceived foot and ankle function.

Does FADI diagnose chronic ankle instability?

No. FADI may help quantify functional disability in people with chronic ankle instability, but it does not diagnose the condition on its own.

Is there an MCID for FADI?

High-quality universal MCID values for FADI appear limited. A systematic review found responsiveness evidence for FADI but noted that MCID was presented only for FAAM among the reviewed instruments.

Can FADI be used for return-to-sport decisions?

FADI Sport can support return-to-sport reasoning, but it should not be used as the only clearance measure. It should be combined with physical testing, sport exposure and professional judgement.

Should I use FADI or FAOS?

Both can be useful. FADI is commonly used for disability and sport function, especially in ankle instability contexts, while FAOS includes five separate foot and ankle subscales including quality of life.

Key Takeaways

• FADI is a foot and ankle patient-reported outcome measure.
• It assesses perceived disability, pain and daily function.
• FADI Sport assesses higher-level sport function.
• Higher scores indicate better function.
• FADI does not diagnose a condition or clear someone for sport.
• Evidence is strongest in chronic ankle instability and active populations.
• MCID, MDC and SEM values for FADI appear limited.
• Measurz should record the version, raw score, percentage score, FADI Sport score, completion method, missing items, activity exposure, baseline comparison and related physical findings.

References

Eechaute, C., Vaes, P., Van Aerschot, L., Asman, S., & Duquet, W. (2007). The clinimetric qualities of patient-assessed instruments for measuring chronic ankle instability: A systematic review. BMC Musculoskeletal Disorders, 8, 6. doi:10.1186/1471-2474-8-6

Hale, S. A., & Hertel, J. (2005). Reliability and sensitivity of the Foot and Ankle Disability Index in subjects with chronic ankle instability. Journal of Athletic Training, 40(1), 35–40. PMID:15902322

Houston, M. N., Hoch, J. M., & Hoch, M. C. (2015). Patient-reported outcome measures in individuals with chronic ankle instability: A systematic review. Journal of Athletic Training, 50(10), 1019–1033. doi:10.4085/1062-6050-50.9.01

Martin, R. L., Irrgang, J. J., Burdett, R. G., Conti, S. F., & Van Swearingen, J. M. (2005). Evidence of validity for the Foot and Ankle Ability Measure. Foot & Ankle International, 26(11), 968–983. doi:10.1177/107110070502601113

Matheny, L. M., Clanton, T. O., Rascoe, A. S., Lampley, A., Haytmanek, C. T., & McCarty, E. C. (2020). Patient reported outcome measures in the foot and ankle: Normative values do not reflect 100% full function. Knee Surgery, Sports Traumatology, Arthroscopy, 28, 1267–1273. doi:10.1007/s00167-020-06069-3

Picot, B., Hardy, A., Terrier, R., Tassignon, B., Lopes, R., & Fourchet, F. (2022). Which functional tests and self-reported questionnaires can help clinicians make valid return to sport decisions in patients with chronic ankle instability? A narrative review and expert opinion. Frontiers in Sports and Active Living, 4, 902886. doi:10.3389/fspor.2022.902886

Salar, N., Ghasemi, M. S., Razeghi, M., & Ghotbi, N. (2021). Translation, cross-cultural adaptation, reliability, and validation of the Italian version of the Foot and Ankle Disability Index. Acta Bio-Medica, 91(4), e2020144. PMID:32555091