Cross-cultural Adaptation and Validation of the Patient and Observer Scar Assessment Scale 3.0: Thai Linear Scar...

Scarring is a common outcome of surgical procedures, traumas, burns, and infections, often leading to aesthetic and functional concerns. The Patient and Observer Scar Assessment Scale (POSAS) is widely used for scar evaluation, incorporating both patient and observer perspectives. The latest POSAS version 3.0 includes enhanced assessment criteria for the evaluation of generic and linear scars. This study aims to translate, culturally adapt, and validate POSAS version 3.0 for Thai patients for the assessment of linear scars.

A systematic 6-step translation process was conducted following POSAS guidelines, adhering to international cross-cultural adaptation guidelines. The validation study included 57 patients with surgical scars assessed by 2 facial plastic surgeons, using both the POSAS 3.0 (Thai version) and the Vancouver Scar Scale (VSS).

The findings revealed good internal consistency for both observer (Cronbach α = 0.885) and patient (Cronbach α = 0.858) assessments, outperforming VSS (Cronbach α = 0.545). Intra- and interrater reliability were strong, with intraclass correlation coefficients reaching 0.902 for observers and 0.899 for patients. POSAS observer scores correlated strongly with VSS scores (r = 0.771, P < 0.001), whereas patient-reported scores showed moderate correlation (r = 0.583, P < 0.001).

The Thai linear version of POSAS 3.0 is a reliable and valid tool for scar assessment, providing an accessible, cost-effective, and comprehensive method for clinical and research applications.