What does a score of 43.75 on the Lower Extremity Functional Scale (LEFS) indicate?

Lower Extremity Functional Scale (LEFS) Score of 43.75: Interpretation

A LEFS score of 43.75 out of 80 indicates moderate functional impairment of the lower extremity, representing approximately 55% of maximum function. This score suggests the patient experiences significant difficulty with daily activities involving the lower extremity but retains more than half of their functional capacity.

Understanding the LEFS Scoring System

The LEFS is a validated 20-item patient-reported outcome measure where each item is scored from 0 (extreme difficulty or unable to perform) to 4 (no difficulty), yielding a maximum total score of 80 points 1, 2.

• Higher scores indicate better functional status
• Lower scores indicate greater functional limitation
• The scale demonstrates excellent psychometric properties with high internal consistency (Cronbach's α = 0.98-0.99) and test-retest reliability (ICC = 0.97-0.998) 1, 2

Clinical Interpretation of 43.75/80

This score places the patient in the moderate impairment range:

• The patient can perform approximately 55% of lower extremity functional activities without significant difficulty 1
• Substantial limitations exist in activities such as walking, stair climbing, squatting, running, or prolonged standing 1, 3
• The score suggests the patient likely requires ongoing rehabilitation or intervention 1

Minimal Clinically Important Difference (MCID)

To determine if treatment is effective, look for score changes:

• The minimal detectable change (MDC) at 90% confidence is approximately 9-10 points 2, 3
• Changes of 2.2 points represent the standard error of measurement at 95% confidence 1
• Improvements exceeding 9-10 points indicate true functional change beyond measurement error 2, 3

Clinical Context Considerations

The interpretation should account for:

• Acute vs. chronic conditions: The LEFS can distinguish between acute and non-acute conditions with high accuracy (area under curve = 0.95) 1
• Age factors: The LEFS has been validated across age groups from children (8 years) through adults 3
• Specific pathology: The score's meaning varies by diagnosis—knee osteoarthritis, ankle injuries, and post-surgical conditions all use this scale 1, 4, 5

Practical Application

For ongoing management:

• Reassess regularly to monitor treatment effectiveness, as the LEFS demonstrates excellent responsiveness to change with large effect sizes across acute, subacute, and chronic conditions 1
• Set realistic goals: Aim for improvements of at least 9-10 points to ensure clinically meaningful change 2
• Consider the 15-item or 10-item versions if the full 20-item scale is burdensome, as shortened versions maintain excellent psychometric properties 4, 5

Correlation with Physical Function

This LEFS score correlates with:

• Moderate limitations on physical function subscales of general health measures (SF-36) 1, 2
• The patient likely experiences moderate difficulty with physical functioning domains but minimal impact on mental health components 2