SkinFibroMeter in lower extremity lymphedema assessment: Reliability, correlation with ultrasound, and the...

ObjectivesThis study aimed to determine the inter- and intra-rater reliabilities of the SkinFibroMeter in individuals with lower extremity lymphedema. The secondary aim was to examine its correlation with skin/subcutaneous tissue thickness and establish minimal detectable change (MDC₉₅) values.MethodsThirty lower extremities with physician-diagnosed lymphedema were included in this cross-sectional study. Tissue stiffness was assessed at standardized anatomical sites using the SkinFibroMeter® by four raters with varying clinical experience. Skin and subcutaneous tissue thickness were measured at the same points via ultrasound (US). Inter- and intra-rater reliabilities were evaluated using intraclass correlation coefficients (ICC), and the standard error of measurement and MDC₉₅ were calculated.ResultsParticipants had a mean age of 68 ± 11.9 years, a mean BMI of 34.0 ± 6.0 kg/m², and a mean limb volume of 10,020 ± 3,148 mL. Intra-rater reliability ranged from moderate to excellent (ICC = 0.600-0.976), while inter-rater reliability varied by site (ICC = 0.647-0.941), with the highest agreement at 20 cm above the patella and the lowest at the foot dorsum. Bland-Altman analysis confirmed acceptable absolute agreement across rater pairs with negligible systematic bias. Low-to-moderate positive correlations were observed between the indentation values of the SkinFibroMeter and skin thickness (r = 0.377-0.556, p < .05), whereas negative correlations were found with subcutaneous thickness at several points (r = -0.508 to -0.421, p < .05). No statistically significant correlation was found between localized stiffness and total limb volume (r = -0.023, p = .907). MDC₉₅ values ranged from 0.013 to 0.158.ConclusionThe SkinFibroMeter demonstrates acceptable clinical reliability, with values representing a complex interplay of dermal thickness, interstitial hydration, and tissue compliance rather than global limb size or pure fibrosis. This is the first study to establish MDC₉₅ thresholds, providing clinicians with reference baselines for treatment-related changes. Future studies should incorporate larger, stage-homogeneous cohorts using 3D scanning and shear-wave elastography for comprehensive tissue characterization.