A primer on lower extremity outcome measurement instruments.

Tracing the roots of lower extremity outcome scales is an interesting and somewhat bemusing journey. A large number of different grading methods can be found with limited reliability and/or validity testing. The usefulness of these instruments in the assessment of patient outcomes after lower extremity interventions is worrisome. This article focuses on the most commonly used scales and demonstrates an alarming and incestuous pattern of cross-validation with moderate to weak associations between potentially unreliable and crudely validated original instruments.