Hip · Knee · Ankle · TKR · ACL · Binkley et al. 1999

LEFS Calculator

Score all 20 items using the complete 0–4 criteria to calculate lower extremity functional status, track MCID progress, and generate EMR-ready documentation. Validated for hip, knee, ankle, and all lower extremity conditions.

Clinically reviewed by Dr. Nikhil Mahajan, PT, MPT  ·  May 28, 2026
73 – 80 No / Minimal Limitation Full or near-full function
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41 – 72 Mild to Moderate Activity limitation present
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0 – 40 Severe Limitation Significant disability
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9 pts MCID / MDC90 Minimum meaningful change
Condition:
Scored 0 /20
Total Score 0 /80
Category Severe
MCID 9 pts
Scoring guide: 0 = Extreme difficulty / unable 1 = Quite a bit of difficulty 2 = Moderate difficulty 3 = A little bit of difficulty 4 = No difficulty
1
Any of your usual work, housework or school activities
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2
Your usual hobbies, recreational or sporting activities
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3
Getting into or out of the bath
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4
Walking between rooms
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5
Putting on your shoes or socks
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6
Squatting
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7
Lifting an object, like a bag of groceries from the floor
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8
Performing light activities around your home
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9
Performing heavy activities around your home
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10
Getting into or out of a car
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11
Walking 2 blocks
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12
Walking a mile
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13
Going up or down 10 stairs (about 1 flight of stairs)
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14
Standing for 1 hour
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15
Sitting for 1 hour
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16
Running on even ground
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17
Running on uneven ground
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18
Making sharp turns while running fast
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19
Hopping
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20
Rolling over in bed
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MCID Progress Tracker Optional

Enter a previous LEFS score to verify if change exceeds the 9-point MCID (MDC90 = 9 pts, SEM = ±5 pts)

0 of 20 items scored

LEFS — Score Interpretation Reference

Score Range Category Functional Description Clinical Action
73 – 80 No / Minimal Full or near-full functional status. Patient can perform all daily and most recreational activities. Discharge from active PT; maintenance HEP
61 – 72 Mild Limitation Most daily activities manageable; higher-demand tasks (running, heavy work) remain problematic. Home exercise with periodic review; RTS if ≥70
41 – 60 Moderate Basic ADLs manageable; significant restriction on community activities and higher demands. Active PT — strengthening, neuromuscular training
21 – 40 Moderate-Severe Significant activity restriction; difficulty with basic mobility and self-care tasks. Intensive PT; surgical consult if conservative Rx failed
0 – 20 Severe Dependent for most activities. Significant disability affecting independence. Urgent intensive PT; surgical evaluation recommended
MCID: 9 points Minimum Clinically Important Difference — required for meaningful improvement. MDC90 = 9 pts; SEM = ±5 pts.
RTS Threshold: ≥70 Return-to-sport clearance for ACL typically requires LEFS ≥70 alongside limb symmetry index >90%

What is the Lower Extremity Functional Scale (LEFS)?

The Lower Extremity Functional Scale (LEFS) is a patient-reported outcome measure developed by Binkley et al. (1999) to assess lower extremity functional status across a broad range of musculoskeletal conditions. Unlike condition-specific tools such as the KOOS (knee-specific), the LEFS spans all lower extremity joints — hip, knee, ankle, and foot — making it exceptionally versatile for mixed orthopedic caseloads. It is one of the most widely used patient-reported outcome measures in orthopedic physical therapy worldwide.

The LEFS consists of 20 items assessing activities from simple tasks (walking between rooms, sitting for 1 hour) to high-demand activities (running on uneven ground, hopping, making sharp turns while running). Each item is scored 0–4, and all 20 scores are summed for a total from 0 (unable to perform any activity) to 80 (no difficulty with any activity). A single composite score is produced — there are no subscales.

LEFS Reliability and Validity

The LEFS demonstrates excellent internal consistency (Cronbach's α = 0.96) and strong test-retest reliability (ICC = 0.86 for general population; 0.94 for chronic patients). Construct validity was confirmed through comparison with the SF-36 Physical Function subscale. The Standard Error of Measurement (SEM) is approximately 5 points. The MDC90 equals the MCID at 9 points — making 9 the single key threshold for clinically meaningful change.

LEFS vs KOOS — Which to Use?

  • Use LEFS when: Multiple or non-specific lower extremity conditions, quick versatile screen, insurance documentation requiring one score, or when the condition involves hip or ankle.
  • Use KOOS when: Knee-specific subscale data (pain, symptoms, sport/rec, QOL separately) is needed for research or detailed monitoring of ACL or knee OA.
  • Use both when: Comprehensive knee assessment — KOOS provides domain-specific detail while LEFS tracks overall LE function.

Clinical Benchmarks by Condition

  • Knee OA (pre-TKR): Baseline LEFS approximately 35–50. Expected improvement post-TKR at 6 months: 20–30 points.
  • ACL Reconstruction (6 months): Mean LEFS approximately 55–65. Return-to-sport clearance typically associated with scores ≥70.
  • Hip OA (pre-THR): Baseline approximately 35–45. Expected improvement post-THR: 25–35 points.
  • Ankle fracture (3 months post-ORIF): Mean LEFS approximately 45–60.
  • Healthy community adults: 38% achieve a perfect score of 80 (Binkley et al., 1999).
Dr. Nikhil Mahajan, PT, MPT Doctor of Physical Therapy · Reviewed May 28, 2026 · View full credentials

Frequently Asked Questions

How is the LEFS score calculated?
The LEFS has 20 items each scored 0–4: 0 = extreme difficulty or unable to perform; 1 = quite a bit of difficulty; 2 = moderate difficulty; 3 = a little bit of difficulty; 4 = no difficulty. All 20 item scores are summed for a total from 0 (unable to perform any activity) to 80 (no difficulty with any activity). There are no subscales — a single composite score is reported.
What is the LEFS MCID and why does it matter?
The LEFS MCID (Minimum Clinically Important Difference) is 9 points, equal to the MDC90. The SEM is approximately 5 points (error range ±5). A change of 9 or more points between assessments represents a real change beyond measurement error that the patient will perceive as clinically meaningful. Changes of 5–8 points are real but may not be meaningful to the patient. Changes ≤4 points may represent measurement error.
When should I use LEFS instead of KOOS?
Use LEFS when: (1) the patient has hip, ankle, or foot involvement — KOOS is knee-only; (2) you want a quick single score across any lower extremity condition; (3) insurance requires a single functional outcome score. Use KOOS when: (1) you need knee-specific subscale data (pain, symptoms, sport/recreation, QOL); (2) documenting ACL or knee OA outcomes for research; (3) detailed knee domain tracking is clinically indicated. Use both for comprehensive knee assessment.
What is the LEFS return-to-sport threshold?
A LEFS score of ≥70 out of 80 is associated with successful return to pre-injury sport following ACL reconstruction. This threshold should be used alongside limb symmetry index >90% on hop testing and quadriceps strength testing, and psychological readiness assessment. No single score should be used in isolation for RTS clearance decisions.
How often should LEFS be administered?
LEFS should be administered at initial evaluation and then at 4–8 week intervals to monitor treatment response. Given the MCID of 9 points, more frequent administration (weekly) is unlikely to detect clinically meaningful change except in rapid post-operative recovery situations. Administer at discharge and at 3, 6, and 12 months post-operatively for outcome tracking.

References

  1. Binkley JM, Stratford PW, Lott SA, Riddle DL. The Lower Extremity Functional Scale (LEFS): scale development, measurement properties, and clinical application. Phys Ther. 1999;79(4):371-383.
  2. Watson CJ, et al. Reliability and responsiveness of the Lower Extremity Functional Scale and the Anterior Knee Pain Scale in patients with anterior knee pain. J Orthop Sports Phys Ther. 2005;35(3):136-146.
  3. Mehta SP, et al. Lower Extremity Functional Scale to assess changes in hip and knee function following total joint arthroplasty. J Bone Joint Surg. 2012.
  4. Stratford PW, Binkley JM. A comparison of the lower extremity functional scale (LEFS) and the knee outcome survey (KOS). J Orthop Sports Phys Ther. 1999;29(12):702-709.