Circumferential Measurements to Calculate Lower Limb Volume in Persons with Lymphedema: What Segment Length Is to Be Recommended?

Background: Circumferential measurements (CMs) every 4th cm are commonly used to assess lower limb volume (LLV), but fewer measurements would be less time-consuming. The aim of this study was therefore to establish the agreement between LLV measurements derived from CM every 4th cm (V4), 8th cm (V8), and 12th cm (V12), and to evaluate the intrarater test-retest reliability for each of the three measurement methods in persons with lower limb lymphedema (LLL). Methods and Results: Forty-two persons with unilateral or bilateral LLL were measured twice, 2 weeks apart. Volume measurements for the V4, V8, and V12 methods were derived using CM. The agreement was evaluated using intraclass correlation coefficient (ICC _3.1 ) and Bland-Altman graphs including 95% limits of agreement (LOA). The reliability was evaluated using ICC _2.1 and standard error of measurement (SEM%) and smallest real difference (SRD%). The agreement was high for the V4 and V8 methods (ICC 0.999), and for the V4 and V12 methods (ICC 0.998). The graphs revealed slightly higher agreement between the V4 and V8 than between the V4 and V12 methods visualized by the 95% LOA (-117 to 62 and -236 to 132 mL, respectively). For all three measurement methods, the test-retest reliability was high (ICC 0.993-0.995) and the measurement error low (SEM%: 1.2%-1.4% and SRD%: 3.4%-3.8%). Conclusions: The higher agreement between the V4 and V8 methods than between V4 and V12, and the high test-retest reliability in LLV measurements support the V8 method to replace the V4 method in persons with LLL.