Skip to Main Content

We have a new app!

Take the Access library with you wherever you go—easy access to books, videos, images, podcasts, personalized features, and more.

Download the Access App here: iOS and Android


In addition to describing lower extremity patient-based outcomes, this section also incorporates clinician-rated outcome measures designed to objectively and reliably rate an athlete's function. Although these tests may be sensitive in some patients, subjective complaints of difficulty with pivoting, cutting, and twisting may be the most sensitive determination of the ability to function. These concerns should be captured using patient-rated outcome measures.

Patient-Reported Outcome Measures

The following scales represent a selection of the wide range of lower extremity scales that are used clinically. Many other scales are available to clinicians and researchers.

Lower Extremity Functional Scale (LEFS)

The LEFS comprises 20 questions relating to a patient's ability to participate in everyday tasks, and can be used with patients with unilateral or bilateral lower extremity conditions. The patient selects a number from 0 (Extreme Difficulty or Unable to Perform Activity) to 4 (No Difficulty). Scores range from 0 to 80, with higher scores reflecting less disability.1

  • Minimal Detectable Change: 9

  • Minimal Clinically Important Difference: 9

Knee Injury Osteoarthritis and Outcome Score (KOOS)

This patient-rated outcome measure is designed for use by patients with knee osteoarthritis or by patients who have injuries that are associated with the development of osteoarthritis such as ACL tears and meniscal lesions. The patient responds to 42 items in terms of symptoms and disability over the past week. A normalized score ranging from 0 to 100 is calculated for each of five subscales: Pain, Other Symptoms, Activities of Daily Living (ADLs), Sports and Recreation Function, and Knee-related Quality of Life. Lower scores indicate more symptoms and larger life impact. A pediatric version, used in those aged 9 to 12, is also available at:

  • Minimal Detectable Change (for patients with knee injury):

  • Pain subscale: 6–6.1

  • Symptoms subscale: 5–8.5

  • ADL subscale: 7–8

  • Sport/Recreation subscale: 6–12

  • Quality of Life subscale: 7

  • Minimal Clinically Important Difference: 8–10. However, this value likely changes based on patient population, intervention, and time since initial injury.2

Foot and Ankle Ability Measure (FAAM)

The patient-rated FAAM consists of 21 items relating to ADLs and an 8-item sports subscale. Patients with leg, foot, and/or ankle disorders respond to the items on a 5-point scale, with lower scores indicative of greater levels of disability.

  • Minimal Detectable Change: 5.7 points (ADLs); 12.3 points (sports subscale)

  • Minimal Clinically Important Difference: 8 points (ADLs); 9 points (sports subscale)3

International Knee Documentation Committee – Subjective Knee Form (IKDC)

Specific to knee injuries, the IKDC is considered a good general measure for all knee conditions.4 The patient-reported IKDC includes 18 total items (7 for symptoms, 1 for sports participation, 9 for ADLs, and 1 for current knee function) with varying ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.