Inter‐ and Intra‐Rater Reliability of Myotonometric Assessment of the Mechanical Properties of Caesarean Section Scar Skin Using the MyotonPRO With an L‐Shaped Probe

BACKGROUND: Myotonometry is a noninvasive method for assessing the mechanical properties of soft tissues, including muscles and skin. The L-shaped probe, designed specifically for skin assessment, may be useful for evaluating caesarean section (C-section) scars. However, reliability data for MyotonPRO measurements of C-section scars with this probe are limited. This study aimed to evaluate the inter-rater and intra-rater reliability of measuring the mechanical properties of C-section scar skin using the MyotonPRO with the L-shaped probe. MATERIALS AND METHODS: Twenty-five women (23-42 years) with C-section scars were examined. Two raters conducted the myotonometric assessments over two consecutive days. Measurements were taken with the participant supine, using the L-shaped probe at six points around the scar (three above, three below; positioned at the scar's endpoints and centre), each tested in three directions (right, left and upward/downward). Reliability was analysed using the intraclass correlation coefficient (ICC) with 95% confidence intervals (CIs), the standard error of measurement (SEM), minimal detectable change (MDC), coefficient of variation (CV) and Bland-Altman plots. RESULTS: Inter-rater reliability was good to excellent (ICC = 0.75-0.90), while intra-rater reliability was moderate to good, with slightly lower ICCs for consecutive-day measurements. SEM, MDC and CV values supported these findings, showing lower measurement error and narrower variability ranges between raters than within repeated measurements by the same rater. CONCLUSION: The MyotonPRO with the L-shaped probe provides reliable inter- and intra-rater measurements of C-section scar skin mechanical properties, making it a valuable tool for scar evaluation.