A Comprehensive Surgical Approach for Congenital Clasped Thumb: Introduction of a Modified Index Finger Rotation Flap.

Abstract

Purpose: This study evaluated the outcomes of reconstructive techniques combined with a modified index finger rotation flap for complex congenital clasped thumbs, focusing on functional improvement, aesthetic results, and donor site morbidity.

Methods: A retrospective review of nine patients (10 thumbs) who underwent modified index finger rotational flap reconstruction with Z-plasty donor site closure between 2022 and 2024 was conducted. Variables collected included patient demographics, preoperative first intermetacarpal angle, and postoperative outcomes, which included active radial and palmar abduction, metacarpophalangeal joint extension, donor site morbidity, and scar quality assessed using the patient and observer scar assessment scale.

Results: The mean age at surgery was 6 years and 5 months (range: 15-167 months), with an average follow-up of 12.7 months (range: 6-30 months). All patients healed without complications (eg, infection, flap necrosis, or revision). The mean preoperative intermetacarpal angle was 17.5°, consistent with moderate first web space contracture. At the final follow-up, the mean active radial abduction was 49.3°, and the mean palmar abduction was 50.6°. Full metacarpophalangeal joint extension of the thumb was achieved without extensor lag. No proximal interphalangeal joint flexion contracture or extensor lag of the index finger was observed. Scar quality outcomes were favorable, with all parents reporting satisfaction with both functional and aesthetic results.

Conclusions: The modified index rotation flap is an effective technique for reconstructing congenital clasped thumbs, offering improved functional and aesthetic outcomes with minimal donor site morbidity. It addresses palmar skin deficiency and first web space contracture, making it valuable for managing complex clasped thumb deformities.

Type of study/level of evidence: Therapeutic V.