A New Method to Control Tendon Tension in the Transfer of Extensor Indicis Proprius to Extensor Pollicis Longus Rupture.

This study evaluated the outcomes of extensor indicis proprius (EIP) transfer based on varying degrees of thumb extension after EIP transfer and elongation of the EIP. A total of 24 cases with extensor pollicis longus (EPL) ruptures who underwent EIP to EPL transfer were analyzed prospectively. The EIP transfer was performed with neutral wrist positioning. In group I (12 cases), EIP and EPL were sutured on the thumb in neutral state at interphalangeal joint, and the mean EIP elongation of this group measured 0.2 cm (range, -0.5 to 0.5 cm). In group II (12 cases), EIP and EPL were sutured on the thumb in full extension state at interphalangeal joint, and the mean EIP elongation measured 0.7 cm (range, 0.5-1.5 cm). The mean follow-up period was 13.5 months. The 2 groups were compared based on thumb motion, grip strength, pinch power, and the Disabilities of the Arm, Shoulder, and Hand questionnaire score. Extension of the thumb at the interphalangeal joint was -5.2° in group I and 7.2° in group II, demonstrating statistically significant differences. No significant differences were found between the 2 groups in other parameters. In EIP transfer, thumb in extension after transfer and EIP elongation is recommended for restoring thumb extension at the interphalangeal joint.