Cross-Cultural Adaptation and Validation of the Lower Extremity Measure Into German

Abstract

Introduction: The Lower Extremity Measure (LEM) was developed to provide a specific instrument to detect changes in physical function in patients with hip fracture. Of 29 questions, 3 have a valid “not applicable” answer option. The goal of this study was to validate the LEM in German and to determine the added value to the physical functioning (pf) subscale of the Short Form 36 (SF-36). Materials and Methods: The LEM was translated according to published guidelines and administered to patients with hip fracture (31 A1-A3 and 31 B1-B3) shortly after surgery (baseline), at 3 months (3M), and for reliability testing at 3 months plus 1 week (3M+). The reproducibility, internal consistency, floor and ceiling effects, construct validity, and responsiveness of the German LEM were assessed. Results: A total of 106 patients completed the LEM and SF-36 (mean age 75.5; 67% women) at baseline (mean of 4.9 days after operation), and 88 completed both questionnaires at both the 3M and 3M+ assessments. At each assessment time point, between 6% and 23% of the patients answered 7 questions as “not applicable.” Reproducibility and internal consistency were high (intraclass correlation coefficient = 0.93; Cronbach's α = .96). No floor effect (0%) and a minor ceiling effect (7.87%) were found for the total LEM score. The strongest correlation was found between the LEM and the SF-36 subscale pf (Spearman ρ = .93). Responsiveness was similar for the SF-36 pf subscale and the LEM when using effect size (SF-36 pf 0.71 vs LEM 0.72) and better for the LEM when using standardized response mean (SF-36 pf 0.65 vs LEM 0.76). Discussion: The German LEM is a reliable, valid, and responsive measure for the self-assessment of patients after hip fracture surgery. As a number of questions are not applicable to elderly patients, the added value of this lengthy questionnaire in these often frail, sometimes cognitively impaired patients is still open for debate.