Comparison of Two Disc Repositioning Techniques Based on Jaw Motion Analysis—An Ambispective Cohort Study

ABSTRACT Background Temporomandibular joint (TMJ) disc repositioning (DR) is an effective treatment for anterior disc displacement (ADD). However, postoperative joint motion lacks comprehensive objective evaluation and comparison between different surgical methods. Materials and Methods Patients who need TMJ DR surgery at our center between November 2023 and September 2024 were enrolled and divided into 2 groups for comparison: arthroscopic group (AS) and open suturing (OSu) group. Mandibular and condyle movement, pain and quality of life were assessed preoperatively (T0), at 3 months (T1), and 6 months (T2) postoperatively using the ultrasonic Jaw Motion Analyser (JMA; zebris) system and Visual Analog Scale (VAS) scores. The differences between the 2 groups and at different time intervals were compared by generalized estimating equations. Results A total of 106 patients were included with the median age of 17 years. There were 35 patients in OSu group and 71 in AS group. After DR, maximum mouth opening (MMO) was significantly increased and pain VAS was decreased. However, condylar translation length (CTL) of the DR joint, laterotrusion and protrusion were decreased ( p < 0.05), while condylar rotation (CR) was increased ( p < 0.05). With no significant differences between AS and OSu groups at T0 ( p > 0.05), MMO, CR and laterotrusion were superior in the AS group than OSu group at T1. There were no significant differences between the two groups at T2 ( p < 0.05). Conclusion DR surgery improves MMO by increasing condylar rotation but decreasing condylar translation. AS group demonstrated faster recovery in mandibular movement and pain relief than OSu group.