Ultrasonographic and Clinical Outcomes of Pulsed Ultrasound Versus Pulsed Shortwave Diathermy in Mild-to-Moderate Carpal Tunnel Syndrome: A Randomized Controlled Trial

Background: To compare the clinical and ultrasonographic effects of pulsed therapeutic ultrasound (US) and pulsed shortwave diathermy (SWD) in patients with mild-to-moderate carpal tunnel syndrome (CTS). Methods: In this randomized controlled trial, 40 patients with electrophysiologically confirmed mild-to-moderate CTS were randomly allocated into two groups. Both groups received wrist splinting and tendon–nerve gliding exercises. The US group received 15 sessions of pulsed ultrasound therapy (3 MHz, 0.8 W/cm2), whereas the SWD group received 15 sessions of pulsed shortwave diathermy (80 Hz, 19.2 W). Outcomes were assessed at baseline, 1 month, and 3 months using ultrasonographic median nerve cross-sectional area (MNCSA) (primary outcome), Boston Carpal Tunnel Questionnaire (BCTQ), Visual Analog Scale (VAS) for pain, Douleur Neuropathique 4 (DN4), and handgrip strength. Results: Baseline demographic characteristics, including age (mean ± SD) and sex distribution, were comparable between groups (p > 0.05), although BCTQ Functional Status and Total scores differed significantly at baseline. Repeated-measures analyses demonstrated significant time effects for MNCSA and all secondary clinical outcomes, including BCTQ scores, VAS pain, DN4 scores, and grip strength (all p < 0.001; partial η2 range: 0.51–0.75), indicating moderate-to-large effect sizes. Both the US and SWD groups showed sustained improvements at the 1- and 3-month follow-ups, with no significant differences between treatment modalities (all group × time interaction p > 0.05). Conclusions: In patients with mild-to-moderate CTS, both US and SWD administered alongside splinting and exercise were associated with significant clinical and ultrasonographic improvements over 3 months. No significant difference was observed between the two modalities. Both treatments may be considered adjunctive options within conservative management, although further controlled studies are needed to clarify modality-specific effects.