Abstract
Introduction: The only currently published regional outcome measure for the lower limb is the Lower Extremity Functional Score (LEFS). It is criticised for poor clinical utility through administration, scoring and completion time and through poor methodological characteristics including item redundancy, missing data, error range and responsiveness. A new tool, the Lower Limb Disability Questionnaire, was developed to overcome these attributes. Methods: Both tools were investigated through direct headto- head comparison in an outpatient-population sample of convenience from six physiotherapy clinics (n = 80). This provided methodological and practical characteristics with prospective repeated measure subgroups (n = 48) providing responsiveness and change score values. Results: The LLDQ demonstrated test-retest reliability and internal consistency with face, content and construct validity shown through the development methodology. The head-to-head comparison provided values for construct and criterion validity. The psychometric values for error range, using Standard Error of the Measurement (SEM = 3.8%) and Minimum Detectable Change (MDC90 = 8.9%) and responsiveness, through Standardized Response Mean (SRM = 2.03), were preferable to the LEFS without a tendency toward item redundancy. The LLDQs practical clinical characteristics demonstrated shorter completion and scoring times with lower user response error and no missing or absent data responses. Conclusions: This study, though small and lacking sample population diversity, demonstrated the potential for the LLDQ as a viable lower limb regional outcome measure in a clinical setting. The preferred utility, practical characteristics and sound measurement properties indicate a formal investigative study on a significant population sample is warranted.