A retrospective investigation on disc displacement in sagittal fracture of mandibular condyle and its association with joint ankylosis development

Abstract

The purpose of this study was to evaluate disc displacement in condylar sagittal fracture and potential influence on TMJ ankylosis formation. Total 33 sagittal fractures of mandibular condyles (SFMCs) in 19 patients were included, 19 involved joints of 12 cases obtaining the prognosis of non-ankylosis and 14 involved joints of 7 cases being ankylosed after a systematic conservative treatment. Retrospectively, the change of discs in position were investigated by magnetic resonance imaging corresponding to mild, moderate and severe displacement of SFMCs based on computed tomography image, and comparison was carried out between ankylosis and non-ankylosis groups. Results showed that in non-ankylosis group presented mild displacement (type I) in 5 SFMCs and moderate displacement (type II) in 14 SFMCs. All type I SFMCs and 5 of 14 type II SFMCs did not display disc displacement. Whereas, the rest of type II SFMCs had disc displacement. In ankylosis group, all SFMCs were severe displacement the articular disc was anteriomedially displaced together. This study concluded that moderate and severe displaced SFMCs usually entailed displacement of the articular discs. The severe SFMC highly sustained TMJ ankylosis.