References values and standardized testing protocols for performance-based and patient-reported outcome measures among individuals with lower limb amputation.

Introduction: Reliable reference data and standardized administration procedures for outcome measures are critical to guide rehabilitation, justify prosthetic prescription, and evaluate treatment outcomes in individuals with lower limb amputation (LLA). Although numerous performance-based and patient-reported measures are used in this population, few studies provide both population-specific reference values and detailed testing protocols. This study describes standardized administration procedure and presents reference values for commonly used outcome measures categorized by functional K-level and amputation level to support consistency in clinical and research applications. Materials and methods: Data was collected from the initial visit of a larger longitudinal study across three medical research centers. Participants included 58 adults (aged 18-89) with unilateral or bilateral transtibial or transfemoral amputation, all using at least one definitive prosthesis for ≥6 months and classified at K2 level or higher. Participants completed 8 performance-based and 11 patient-reported outcome measures. Results: Data was reported by K-level and amputation level (unilateral transtibial, unilateral transfemoral, bilateral). Some discrepancies were observed in various assessments compared to prior studies, possibly due to methodological and demographic differences. 10 Meter Walk Test speeds reported here were up to 31% faster than previous studies, potentially due to differences in track length and calculation methods. Conclusion: This study provides standardized administration guidelines and population-specific reference values for widely used performance-based and patient-reported outcomes in adults with LLA. Although these data are not intended to establish formal normative values due to limited sample size, they provide clinically relevant benchmarks for contextualizing individual performance, and support goal setting. By detailing test procedures and observed score distributions, these findings promote methodological transparency, improve comparability across studies, and support evidence-based prosthetic care and rehabilitation. Clinical Trial Registration: https://clinicaltrials.gov/study/NCT03930199, identifier NCT03930199.