Magnetic resonance imaging interpretation of temporomandibular joint disc position in mandibular condylar fractures: A fossa-based reference approach.

This study aimed to evaluate temporomandibular joint disc position on magnetic resonance imaging after mandibular condylar fractures using a fossa-based reference system, and to compare it with conventional condyle-based assessment. Patients with mandibular condylar fractures who underwent magnetic resonance imaging were retrospectively reviewed. Disc position was assessed using both a condyle-based reference and a fossa-based reference system. With the fossa-based approach, disc position was described using continuous spatial parameters, including anterior displacement angle, horizontal displacement distance, and inferior displacement distance. Associations between disc position parameters and radiographic findings were analyzed. 46 patients with 66 condylar fracture joints were included. Using the condyle-based reference system, most discs were classified as having a normal position. In contrast, assessment relative to the temporomandibular fossa demonstrated a broad spatial distribution of disc position. Disc position parameters differed among fracture types. Disc-condyle decoupling was associated with greater variability in disc position parameters, whereas joint effusion showed no significant association with disc position parameters. In general, a fossa-based reference allows disc position to be described as a continuous spatial distribution and provides an alternative framework for interpreting magnetic resonance imaging findings in condylar fracture cases.