Lower Extremity Functional Scale (LEFS)

The Lower Extremity Functional Scale (LEFS) is a validated Patient-Reported Outcome Measure (PROM) designed to evaluate lower extremity function. The test was developed by Binkley et al. (1999) to measure functional status in a variety of musculoskeletal conditions such as hip osteoarthritis (OA), total hip and knee replacement (THR and TKR), as well as post-traumatic rehabilitation【1】.

The questionnaire consists of 20 items covering a wide range of activities with progressively greater physical demands, from walking between rooms to running on uneven ground【2】. LEFS is free to use and is typically administered in paper form.

How is the test performed?

LEFS is a self-reported questionnaire in which the patient answers the following question:“Today, do you or would you have any difficulty performing the following activities?”

This question applies to each of the 20 listed activities. For every item, the patient selects one of the following response options:

• 0: Extreme difficulty or unable to perform activity

• 1: Quite a bit of difficulty

• 2: Moderate difficulty

• 3: A little bit of difficulty

• 4: No difficulty

Procedure

• Introduction and preparation: The administrator introduces the questionnaire, explaining its purpose and how the responses will be used to assess functional limitations.

• Completion: The patient reviews each item and answers based on their current functional level.

• Sample activities include:

  • Walking between rooms

  • Climbing stairs

  • Participating in sports

  • Running short distances

  • Lifting or carrying heavy objects

  • Squatting

• Scoring: Scores are summed into a total score ranging from 0 to 80.

  • 80 = no functional limitations

  • 0 = extreme functional limitations

Interpretation of results

• Higher scores indicate better function, while lower scores reflect greater disability.

• Minimal Clinically Important Difference (MCID): A change of at least 9 points is considered clinically meaningful【6】.

• Standard Error of Measurement (SEM): Typically ranges from 3.7 to 4 points, depending on diagnosis and population【7】.

Advantages and limitations

Advantages:

• Quick to administer (approx. 5 minutes)

• Requires no special training for the administrator

• Useful for tracking progress and treatment outcomes over time

• Demonstrates strong reliability and validity across multiple patient populations【6】

Limitations:

• Not condition-specific, which may reduce sensitivity in certain populations

• Ceiling and floor effects are rare but may occur in patients with very high or very low functional levels【6】

Evidence for LEFS

Reliability

• Test–retest reliability: Excellent (ICC = 0.86 for all patients; ICC = 0.94 for chronic patients)【1】

• Interrater reliability: High, with ICC values up to 0.90 in different studies【7】

Validity

• High correlation with other relevant instruments such as SF-36 and the WOMAC Physical Function scale【8】

• Low to marginal floor effects, strengthening content validity【6】

Responsiveness

• Highly sensitive to clinically meaningful changes

• Minimal Detectable Change (MDC): 9 points【6】

• Demonstrates better responsiveness than the SF-36 Physical Function Subscale, making it a valuable tool in clinical practice【1】

Clinical applications and populations

LEFS is primarily designed for adults with lower extremity musculoskeletal disorders, including:

• Hip osteoarthritis, total hip and knee replacements (THR and TKR)

• Rehabilitation after trauma or orthopedic surgery

• Patients with stroke or chronic pain【6】【9】

It is also useful for rehabilitation following ACL reconstruction and for ankle fractures, where it demonstrates high sensitivity and specificity【7】.

Sources:

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.        Mehta SP, Fulton A, Quach C, Thistle M, Toledo C, Evans NA. Measurement properties of the Lower Extremity Functional Scale: a systematic review. J Orthop Sports Phys Ther. 2016;46(3):200-216.

3.        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. J Clin Epidemiol. 2004;57(10):1025-1032.

4.        Stratford PW, Kennedy DM, Woodhouse LJ. Performance measures and patients’ self-report to monitor recovery following total hip and knee arthroplasty. Clin Orthop Relat Res. 2006;447:72-78.

5.        Alcock GK, Werstine MS, et al. Longitudinal changes in the Lower Extremity Functional Scale after anterior cruciate ligament reconstructive surgery. Clin J Sport Med. 2012;22(3):234-239.

6.        Pua YH, Cowan SM, Wrigley TV, Bennell KL. The Lower Extremity Functional Scale could be an alternative to the Western Ontario and McMaster Universities Osteoarthritis Index physical function scale. J Clin Epidemiol. 2009;62(10):1103-1111.

7.        Lin CW, Moseley AM, Refshauge KM. The Lower Extremity Functional Scale has good clinimetric properties in people with ankle fracture. Phys Ther. 2009;89(6):580-588.

8.        Kennedy DM, Stratford PW, et al. Assessing recovery and establishing prognosis following total knee arthroplasty. Phys Ther. 2008;88(1):22-32.

9.        Verheijde JL, White F, et al. Reliability, validity, and sensitivity to change of the Lower Extremity Functional Scale in individuals affected by stroke. PM R. 2013;5(10):882-890.