Comprehensive Analysis of Zachary’s Modification of Jones Tendon Transfer in Isolated High Radial Nerve Palsy

Abstract

Introduction: The radial nerve is the most frequently injured nerve caused by fractures of the humeral shaft. It results in loss of hand function which can considerably impair the person’s ability to perform normal activities of daily living as well as professional competence. Primary nerve repair provides best results but is often not possible because of badly traumatised nerve or late presentation. In such cases, tendon transfers are considered best to restore lost functions. Among the various transfers described for radial nerve palsy, Jones tendon transfer was popular and often practiced but the procedure had a major shortcoming of using both the wrist flexors. The Zachary’s modification is postulated as more advantageous as it preserves one wrist flexor. Aim: The study is intended to critically analyse modified Jones tendon transfer and discuss its implications with other standard methods of tendon transfer. The results of the study were evaluated extensively with emphasis on surgical details and finer technical skills. Materials and Methods: In this retrospective cohort study carried out in the Department of Plastic Surgery in eastern Uttar Pradesh, the clinical records from January 2017-December 2019, were studied to isolate the patients with high radial nerve palsy. A total of 26 patients were found to fulfil the inclusion criteria and their records were comprehensively analysed. Modified Jones tendon transfer was used. Postoperative results were evaluated using Bincaz score. Results: Amongst the data of total 26 patients studied 80.77% patient’s, radial nerve was injured due to fracture of the humerus.With metacarpophalangeal joints extended, wrist extension was 48.6°±9.64°, the minimum being 20°. Wrist flexion was 54.8°±10.25°. The position of metacarpophalangeal joints was vital to get rid of the tenodesis effect. Neutral position of the metacarpophalangeal joints has been defined at 0° without hyperextension. The study demonstrated deficit of 18°±6.78° short of the neutral position. Thumb extension and subsequent opening of first web space was more limited and we obtained 37.6°±7.51° with incomplete thumb extension in four patients. Abduction of the thumb at carpometacarpal joint and interphalangeal joint extension returned to normal range. Seventeen patients rated the results as excellent using postoperative evaluation by Bincaz score. Conclusion: Flexor Carpi Ulnaris (FCU) based tendon transfers returned encouraging results in high radial nerve palsy. Technical superiority in performing modified Jones tendon transfer was essential to obtain good results in patients with isolated high radial nerve palsy.