Patient-reported outcome measure
LEFS Calculator
Lower Extremity Functional Scale
The LEFS is a 20-item patient-reported questionnaire that measures difficulty with everyday lower limb activities on a single 0 to 80 scale, where 80 indicates no difficulty and a change of 9 points is the smallest difference patients reliably notice.
What the LEFS score means
LEFS scores run from 0 to 80, where a higher score is better. The bands below are conventional reporting categories, not diagnostic cut-offs.
- Severe limitation0–20
- Marked limitation21–40
- Moderate limitation41–60
- Mild limitation61–75
- Minimal to no limitation76–80
Clinically important thresholds
A change in score only matters if it exceeds the smallest difference patients actually notice. Every threshold below is reported with the population it was derived in — a threshold quoted without its population is not usable.
| Type | Value | Subscale | Population | Follow-up | Source |
|---|---|---|---|---|---|
| MCID | 9 points | — | Adults with lower limb musculoskeletal dysfunction | — | Binkley JM 1999 |
| MDC | 9 points (90% confidence) | — | Adults with lower limb musculoskeletal dysfunction | — | Binkley JM 1999 |
| MCID | 9 points | — | Knee osteoarthritis and post-arthroplasty | Rehabilitation episode | Stratford PW 2004 |
MCID is the smallest change a patient perceives as meaningful. PASS is the score above which patients consider their state acceptable. SCB is a substantial rather than minimal benefit. MDC is the smallest change exceeding measurement error.
How the score is calculated
Stated in full so the calculation can be independently checked, and reproduced by hand if needed.
Each of the 20 items is scored from 0 (extreme difficulty or unable to perform the activity) to 4 (no difficulty). The LEFS score is the simple sum of all 20 item scores, giving a total from 0 to 80. A higher score means better function. The total is sometimes expressed as a percentage of maximal function by dividing by 80 and multiplying by 100.
Missing data
The developers published no rule for substituting missing items. All 20 items must be answered for a valid score; a partial total is reported here as provisional and should not be compared against published thresholds.
Instrument profile
- Developer
- Jay M. Binkley, Paul W. Stratford, Sue Ann Lott, Daniel L. Riddle
- Institution
- McMaster University, Canada
- First published
- 1999
- Items
- 20
- Response format
- 5-point difficulty scale, scored 0–4
- Score range
- 0 to 80
- Direction
- Higher score = better
- Recall period
- Today
- Completion time
- About 5 minutes
- Age range
- Adults
- Regions
- Knee, Hip, Foot & Ankle
- Conditions
- Lower limb musculoskeletal disorder, Knee osteoarthritis, Ankle sprain, Hip pain, Post-operative lower limb rehabilitation
- Procedures
- Total knee arthroplasty, Total hip arthroplasty, ACL reconstruction, Ankle fracture fixation
- Languages
- English, Spanish, Dutch, Turkish, Portuguese, Chinese
- Test–retest (ICC)
- 0.94 (95% CI 0.89–0.97)
- Internal consistency
- Cronbach's alpha 0.96
- Validity
- Correlates strongly with the SF-36 physical function subscale (r ≈ 0.80) and more weakly with its mental health subscale, as expected of a function-specific measure.
- Responsiveness
- Responsive across the whole lower limb, which is its main advantage over joint-specific measures when the affected joint varies within a caseload.
- Ceiling effect
- Ceiling effect in young, highly active patients, many of whom score 78–80 while still reporting sport-specific limitation.
Normative values
Reference values from published cohorts, for comparison against the score you calculated.
| Population | Age | Mean | SD |
|---|---|---|---|
| Healthy adults, no lower limb complaint | — | 77–80 | — |
| Adults presenting to outpatient physiotherapy with a lower limb problem | — | 40–50 | — |
When to use the LEFS
Well suited to
- Mixed lower limb caseloads where a single instrument must cover hip, knee and ankle patients comparably.
- Tracking rehabilitation progress, where its 9-point MCID is well established and easy to apply.
- Settings needing a short, quickly scored measure rather than a multi-subscale instrument.
Limitations and poor fits
- When the question is specifically about one joint — the KOOS, HOOS or FAOS discriminate better within their own joint.
- In young athletes, where the ceiling effect masks meaningful sport-level limitation.
- When pain, function and quality of life need to be distinguished from one another, since the LEFS returns a single number.
LEFS compared with other instruments
Instruments measuring a related construct, with the practical difference between them.
| Instrument | Items | Range | What it adds |
|---|---|---|---|
| KOOS | 42 | 0–100 | The KOOS is a 42-item patient-reported questionnaire that scores knee function as five separate subscales — Symptoms, Pain, Activities of Daily Living, Sport and Recreation, and Quality of Life — each from 0 (extreme problems) to 100 (no problems). |
| HOOS | 40 | 0–100 | The HOOS is a 40-item patient-reported questionnaire that scores hip function as five separate subscales — Symptoms, Pain, Activities of Daily Living, Sport and Recreation, and Hip-related Quality of Life — each from 0 (extreme problems) to 100 (no problems). |
| FAAM | 29 | 0–100 | The FAAM is a 29-item patient-reported questionnaire for musculoskeletal disorders of the leg, foot and ankle that produces two separate subscale scores — Activities of Daily Living from 21 items and Sports from 8 items — each expressed from 0% (unable to perform the listed activities) to 100% (no limitation). |
| HOS | 26 | 0–100 | The Hip Outcome Score is a 28-item patient-reported questionnaire for non-arthritic hip conditions that yields two independent percentage scores — an Activities of Daily Living subscale, administered as 19 questions of which 17 are scored, and a 9-item Sports subscale — each running from 0% (unable to perform the listed activities) to 100% (no difficulty at all). |
Copyright and permitted use
Published openly because it is the question every clinician and researcher asks before using an instrument, and almost nobody answers it.
The LEFS was published in full in Physical Therapy in 1999 and its authors placed no licensing programme around it. It is reproduced freely in clinical practice and research, and no fee is charged.
References
- Binkley JM, Stratford PW, Lott SA, Riddle DL. The Lower Extremity Functional Scale (LEFS): scale development, measurement properties, and clinical application. Physical Therapy. 1999.PMID 10201543
- Stratford PW, Kennedy DM, Hanna SE. Condition-specific Western Ontario McMaster Osteoarthritis Index was not superior to region-specific Lower Extremity Functional Scale at detecting change. Journal of Clinical Epidemiology. 2004.PMID 15504636
- Mehta SP, Fulton A, Quach C, Thistle M, Toledo C, Evans NA. Measurement properties of the Lower Extremity Functional Scale: a systematic review. Journal of Orthopaedic & Sports Physical Therapy. 2016.PMID 27427862
Editorial status
Not yet reviewedQueued for clinical review by Sam Tuffun, PT, DPT. Sign-off has not taken place — this is a placeholder assignment, not a completed review.