Longitudinal MRI follow-up of non-reducible posterior disc displacement accompanied by bone marrow oedema in the mandibular condyle.

Serial MRI was used to examine the long-term course of posterior disc displacement (PDD) after non-surgical treatment. Serial MRI was performed on a 63-year-old woman with PDD accompanied by bone marrow oedema (BME) in the mandibular condyle. The patient had joint pain of the right temporomandibular joint (TMJ) and posterior open bite immediately after manual reduction of TMJ dislocation. Initial MRI of the right TMJ showed non-reducible PDD and subchondral BME. The patient underwent non-surgical treatment, and symptoms improved. The first follow-up MRI after 5 months showed non-reducible PDD, expansion of BME and erosion of the mandibular condyle. 1 year and 8 months after the initial examination the patient was asymptomatic, and a second follow-up MRI showed resolution of both BME and erosion, despite the persistence of non-reducible PDD. The MRI findings suggest that BME in the mandibular condyle complicating PDD is a reversible change, and may contribute to joint pain. This case report complements previous observations of the longitudinal course of PDD after non-surgical treatment.