Clinical construct validity and subgroup stability of the Romanian version of the Boston Carpal Tunnel Questionnaire in nerve-conduction-confirmed carpal tunnel syndrome – a cross-sectional study

INTRODUCTION: The Romanian Boston Carpal Tunnel Questionnaire (BCTQ) has been linguistically and internally validated, but data on clinical construct validity and subgroup stability in routine practice are limited. This study evaluated its performance in a consecutive outpatient sample of patients with idiopathic, electrophysiology-confirmed carpal tunnel syndrome (CTS) after exclusion of major secondary causes. METHODS: In this cross-sectional study, consecutive patients with idiopathic CTS diagnosed according to AAOS guidelines and confirmed by nerve conduction studies (NCS) were included. Clinical examination, grip strength testing, BCTQ, EQ-5D-5L (analyzed as an exploratory unweighted severity index), and electrophysiological assessment were performed within 7 days. Hand-level analyses were conducted using linear mixed-effects models to account for within-patient correlation and to assess associations with demographic and clinical variables. RESULTS: A total of 193 hands met electrodiagnostic criteria for CTS. Overall BCTQ scores did not differ significantly across age, sex, or education groups. SSS and FSS correlated with grip strength (ρ = -0.16/-0.39; p < 0.03), sensory and motor conduction velocities (SCV ρ = -0.33/-0.31; MCV ρ = -0.19/-0.27; p ≤ 0.012), unweighted EQ-5D-5L severity index (ρ = 0.38/0.59; p < 0.001), and the presence of Tinel's and Phalen's signs. Higher BCTQ scores were associated with worse NCS grades. In multivariable models, grip strength, nerve velocities, EQ-5D-5L, and clinical signs remained significant predictors (all p < 0.001). CONCLUSIONS: The Romanian BCTQ demonstrates expected associations with clinical, electrophysiological, and patient-reported measures, supporting its use as a complementary PRO in CTS assessment.