Reliability, concurrent validity, and clinical feasibility of measurement methods determining volume in patients with lower limb lymphedema and healthy controls

Abstract

Purpose To investigate reliability, concurrent validity, and clinical feasibility of measurements assessing volume in patients with lower limb lymphedema (LLL) and healthy controls. Materials and methods To investigate intra- and interrater reliability, 47 patients with LLL and 30 healthy controls were assessed three times by two assessors. To investigate between session reliability, 50 participants were reassessed two weeks later. Each assessment included measurements of the midline region (hip circumference; suprapubic volume), leg volume (perimeter every 4 cm; Perometer®), and foot volume (water displacement; figure-of-eight method). Concurrent validity was assessed with correlation coefficients. Measurements were timed and practical limitations were reviewed. Clinical trial registration number: NCT: 05269264. Results Measurements of the total volume of different regions showed weak to very high intraclass correlation coefficients (ICCs) (0.131–998). Absolute and relative volume differences had lower ICC values (0.360–0.976). A strong correlation was found between the total volumes of the same region. The Perometer® and figure-of-eight method were the fastest method for leg and foot volume, respectively. Conclusions The assessed total volumes might be more valuable in assessing the evolution of volume in bilateral LLL than the calculated absolute and relative differences between both limbs. The Perometer® and figure-of-eight method were the most time efficient for leg and foot volume, respectively. Implications for rehabilitation Lymphedema is a chronic condition for which a reliable and clinically feasible assessment of volume is essential for the diagnosis, treatment decisions, and the evaluation of the treatment. This study shows that the total leg/foot volumes were more reliable than the calculated absolute and relative differences between both limbs and could therefore more valuable to evaluate bilateral lower limb lymphedema. For the assessment of leg volume, the Perometer® was the most reliable and fastest method. For the evaluation of the foot volume, the figure-of-eight method was overall the best method.