Foot and Ankle Outcome Score
Foot and Ankle Outcome Score (FAOS) · Also known as: FAOS
The Foot and Ankle Outcome Score (FAOS) is a 42-item patient self-report instrument designed to assess symptoms, function, and activity limitations in individuals with foot and ankle pathology. Developed by Roos and colleagues in 2001 and published in the Journal of Orthopedic & Sports Physical Therapy, the FAOS has become the standard outcome measure in foot and ankle surgery and rehabilitation research, providing comprehensive evaluation across pain, stiffness, physical function, sport/recreation, and foot-ankle-related quality of life.
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When to use it
The FAOS is indicated for any patient with foot or ankle pathology, including ankle sprains (acute and chronic), ankle instability, ankle osteoarthritis, Achilles tendinopathy, plantar fasciitis, midfoot injuries, and post-surgical foot-ankle rehabilitation. It is particularly valuable in orthopedic and sports medicine settings where foot-ankle outcome standardization is a priority, enabling comparison across treatment arms in clinical trials and longitudinal monitoring in clinical practice. The FAOS is preferred over older, non-validated foot-ankle scales because of its comprehensive five-subscale structure and strong psychometric properties. Use FAOS when detailed understanding of which foot-ankle domains are most affected is important (e.g., does the patient have pain or stiffness limiting function?).
Strengths & limitations
- Excellent test–retest reliability (ICC 0.77–0.96 per subscale) and internal consistency (Cronbach α 0.73–0.94); robust across age groups and foot-ankle pathologies.
- Five-subscale structure provides granular understanding of foot-ankle problems; allows identification of specific intervention targets (e.g., stiffness management vs. pain control vs. sport readiness).
- Highly responsive to change; sensitive to improvements in both conservative (physical therapy, bracing) and surgical interventions; MCID well-established (~10–15 points per subscale).
- Extensively used in foot-ankle surgery and rehabilitation research; freely available in >30 languages; integrated into electronic health records; enables meta-analysis across multicenter studies.
- Requires reading and comprehension at 6th–8th grade level; less suitable for populations with severe cognitive impairment, low literacy, or non-English speakers without validated translation.
- 42-item length is longer than some competing scales (e.g., single-item pain scale); may increase response burden in high-volume clinics, though completion time is still reasonable (10–15 minutes).
- Subscale independence is imperfect; Pain and Stiffness subscales are moderately correlated, making it difficult to isolate pure pain vs. ROM contributions to disability.
- Sport/Recreation subscale has only 4 items and may be insensitive in non-athletic populations; for sedentary patients, the subscale may be less informative.
Frequently asked
How do I interpret five different FAOS subscale scores instead of one overall score?
Each subscale tells a different story. High Pain, low Stiffness, normal ADL = patient has pain control issues but good mobility. High Pain, high Stiffness, low ADL = patient needs both pain and ROM intervention. Low Sport/Recreation with normal ADL = athlete readiness issue, not general dysfunction. Report all five subscales and identify which domain(s) require intervention.
Is FAOS suitable for both acute ankle sprains and chronic ankle instability?
Yes, but timing matters. For acute sprain (first 72 hours), allow acute swelling to resolve before baseline FAOS to avoid ceiling effects. For chronic instability (months after injury), FAOS is ideal—Symptoms and Sport/Recreation subscales capture chronic instability and fear-avoidance. Consider baseline at 2+ weeks post-sprain for acute populations.
What is the difference between FAOS and simple ankle functional scales?
FAOS is comprehensive and validated with strong psychometric properties; it measures pain, stiffness, ADL, sport, and quality of life. Older, non-validated scales (e.g., simple functional grades) are less reliable and not responsive to change. FAOS is the gold standard; use it for standardized, comparable outcomes in research and outcomes tracking.
Can I use FAOS in both the clinic and research settings?
Absolutely. FAOS is appropriate for clinical outcomes monitoring (e.g., pre-post-rehab comparison in one patient), longitudinal tracking, and comparative research (clinical trials, cohort studies). The five subscale structure is useful in both contexts. Ensure consistent administration timing and mode (paper vs. electronic) for reliable tracking.
Sources
- Roos EM, Brandsson M, Hugelhotz H, Klassbo M, Lohmander LS. Development and validation of the Foot and Ankle Outcome Score. J Orthop Sports Phys Ther. 2001;31(9):504-514. link ↗
How to cite this page
ScholarGate. (2026, June 3). Foot and Ankle Outcome Score (FAOS). ScholarGate. https://scholargate.app/en/sports-medicine/faos
Which method?
Set this method beside its closest kin and read them side by side — the library lays the books on the table; the choice is yours.
- Global Rating of Change ScaleSports Medicine↔ compare
- IKDC Subjective Knee FormSports Medicine↔ compare
- Lower Extremity Functional ScaleSports Medicine↔ compare
- Patient-Specific Functional ScaleSports Medicine↔ compare