Extensor Pollicis Brevis Tendon Transfer for Thumb Reconstruction in Radial Nerve Palsy: A Comparative Cadaveric Study.

PURPOSE: In this study, we proposed a new tendon transfer method for thumb function reconstruction to treat radial nerve injuries. We specifically focused on enhancing thumb radial abduction by transferring the palmaris longus (PL) to the extensor pollicis brevis (EPB) while preserving the first compartment.

METHODS

Eight freshly frozen cadaver specimens were used to compare our proposed technique (transferring the PL to the EPB while preserving the first compartment) with the Tsuge method (transferring the extensor pollicis longus (EPL) and fixing the abductor pollicis longus to the flexor carpi radialis). Thumb radial deviation, palmar abduction, and interphalangeal joint extension angles were measured at various traction forces.

RESULTS

This method demonstrated superior efficiency in thumb radial abduction (especially at traction forces of 15 N and 20 N) compared to the Tsuge method.

CONCLUSIONS

Using the proposed method, the thumb extension and abduction functions can be reconstructed without requiring a pulley. However, concerns were raised about potential inadequate interphalangeal joint extension, although this can be mitigated by suturing the EPB and EPL. Our findings indicate that this method is suitable for our biomechanics study, suggesting its potential applications for cases in which radial nerve injuries necessitate tendon transfer.

CLINICAL RELEVANCE: The proposed method of transferring the PL to the EPB achieves more effective radial deviation of the thumb than the Tsuge method, highlighting its clinical applicability.