Is anterior disc displacement without reduction associated with temporomandibular joint condylar height in juvenile patients younger than 20 years?

PURPOSE: Because disc displacement might be accompanied by degenerative changes in the condyle, this study explored the association between condylar height and anterior disc displacement without reduction in juvenile patients. MATERIALS AND METHODS: This was a retrospective cohort study that enrolled a sample of patients younger than 20 years with unilateral disc displacement without reduction. All patients had 2 magnetic resonance imaging records taken from January 2010 to June 2013 (interval, >6 months). Condylar height, disc length, and displacement distance were measured. The predictor variable was joint status (healthy vs affected side), and the outcome variables were changes in condylar height, displacement distance, and disc length over time. SAS 9.13 was used for analysis and the P value was set at .05. RESULTS: One hundred twenty-four patients (101 female and 23 male; mean age, 16.4 yr; mean interval, 13.6 months) were included. During the interval, the condylar height of the healthy side increased 0.75 mm, whereas the condylar height of the affected side decreased 0.41 mm. The disc of the affected side was shortened and more anteriorly displaced. CONCLUSION: Anterior disc displacement without reduction could be accompanied by a decrease in condylar height in juvenile patients, and the disc might be shortened and more anteriorly displaced.