Evaluation of Hand Function Using Relative Motion Extension Concept (with or Without Night Wrist Orthosis) or Dynamic Extension Orthosis for Extensor Tendon Injuries in Zones 4–6—A Randomized Controlled Trial

This study aimed to compare outcomes of early active motion (EAM) using the relative motion extension (RME) approach to outcomes of early passive motion (EPM) with a dynamic extension orthosis (DEO) and to evaluate whether the RME-only approach is equivalent to the RME-plus approach. Fifty adults were randomized into one of the three intervention groups receiving the DEO, RME only, or RME plus orthosis. The score of the Jebsen-Taylor hand function test (JTHFT) without writing and QuickDASH at T1, all measures of mobility at T1 and T2, and grip strength were better in the RME-only and RME-plus group compared to the DEO group, whereas the values of Patient Evaluation Measure (PEM) at T1 and T2, as well as QuickDASH score at T2, orthosis adherence, and the patient's comfort while wearing the orthoses did not statistically significantly differ among the three groups. The RME concept after extensor tendon injuries in zones 4-6 is superior to the DEO protocol in terms of earlier regain of hand function. The DEO and RME protocols were equivalent regarding patients' adherence and satisfaction with the orthosis. We found no differences in the RME-plus and RME-only protocols, indicating the safe use of the RME-only protocol in single extensor tendon injuries in zones 4-6.