ABSTRACT
PURPOSE: This study investigated the effectiveness of a relative motion flexion orthosis (RMFO) for increasing the range of motion for boutonniere deformity. METHODS: We included 28 patients aged 13-62 years with chronic boutonniere deformity who could complete 0° proximal interphalangeal (PIP) joint extension with the pencil test and were stage 1 according to the Burton classification of boutonniere deformity. At the initial hand therapy appointment, the RMFO was made. The duration of the orthosis usage at the initial therapy session, after stopping the use of the orthosis (posttreatment), and at the follow-up period were noted. RESULTS: The mean time for orthosis usage of all patients was 11.7 weeks (6-40 weeks). The mean initial active distal interphalangeal joint flexion was 47° (0° to 90°) and improved to 66.8° (5° to 110°). The mean initial extension lag of the PIP joint was 22.5° (5° to 55°) and improved to 12° (0° to 30°). This did not change between discontinuation of the orthosis and final follow-up. CONCLUSIONS: The use of RMFO is effective in increasing active distal interphalangeal joint flexion and improving PIP extension in patients with Burton stage 1 chronic boutonniere deformity. TYPE OF STUDY/LEVEL OF EViDENCE: Therapeutic IV.