Single Tendon Transfer of the Flexor Carpi Ulnaris for High Radial Nerve Injury

Purpose. To evaluate the outcome after single tendon transfer of the flexor carpi ulnaris (FCU) to the digital extensors for high radial nerve palsy. Methods. Records of 10 patients aged 16 to 43 (median, 27) years who underwent single tendon transfer of the FCU to the digital extensors for high radial nerve palsy secondary to closed (n=4) or open (n=4) diaphyseal humeral fractures or deltoid injection (n=2) were reviewed. Two of the patients with open fractures also underwent treatment for non-union in a staged manner. Grip strength (power grip and precision grip) was measured monthly using an automated dynamometer. The range of motion of the wrist, and metacarpophalangeal joints of the thumb and fingers was measured monthly using a goniometer. Results. All patients were followed up for at least one year. Preoperatively, the overall power grip strength of the injured hands was about 1/5 of the normal hands. At 12 months, the mean improvement was 202.5% for overall power grip strength and 43% to 57% for precision grip strength parameters. Compared with the normal hands, the mean deficit of the operated hands was 39% for overall power grip strength and 32% to 37% for precision grip strength parameters. At 12 months, mean wrist extension was 50.4°, with about 10° lag in finger and thumb extension. The mean total active motion was 86.7° in the operated wrists and 128.1° in normal wrists. The decrease in wrist flexion and ulnar deviation was 7.8° and 6.8°, respectively. Conclusion. Single tendon transfer of the FCU is a viable option to restore hand function and strength following high radial nerve injuries.