Nerve compression after opponensplasty: a cadaveric study

Abstract

Background: We describe the differences in thumb opposition between different opponensplasty tendon transfers and determine the immediate pressure on the median and ulnar nerves incurred by each transfer. Methods: Using fresh frozen cadavers (8 specimens), opponensplasties were performed using extensor indicis proprius (EIP), flexor digitorum superficialis (FDS) with flexor carpi ulnaris (FCU) pulley, palmaris longus (PL, Camitz procedure), and PL utilizing the thenar fascia as a pulley (PLwP). Each tendon transfer was tensioned, and the thumb flexion, abduction and pronation were measured. The pressure on the median and ulnar nerves were measured for each tendon transfer at varying tensions. Results: There were no differences seen in flexion or pronation between any of the four tendon transfers. FDS, PL and PLwP demonstrated more abduction than the EIP transfer, however differences were less than 10°. EIP and FDS transfers caused significantly more pressure on the median nerve than PL or PLwP at high tendon tensions. Both EIP and FDS tendon transfers caused significantly more pressure on the ulnar nerve than PL or PLwP, and the pressure increased as tension on the transfer increased. No pressure differences were seen between PL and PLwP. Conclusions: No significant differences were seen in thumb flexion or pronation between the four tendon transfers. Differences were seen for abduction with EIP showing the least amount of abduction. EIP and FDS caused more median nerve compression than PL transfers at high tension. Both EIP and FDS tendon transfers cause more ulnar nerve compression than PL transfers at all tensions. Level of Evidence Level: V