Examination of Joint Effusion Magnetic Resonance Imaging of Patients with Temporomandibular Disorders with Disc Displacement

In this study, we investigated joint effusion in patients with temporomandibular disorders (TMDs) with disc displacement. The magnetic resonance (MR) images of 97 temporomandibular joints (TMJs) were evaluated, and the appearance of joint effusion was investigated. Myofascial pain and TMJ pain were considered in addition to the duration from manifestation. Disc displacement with and without reduction, as well as the region and the area of joint effusion, were investigated using the MR images. Fisher's test was used for the analyses. Joint effusion was recognized in 70 TMJs, including 55 in the superior articular cavity, 1 in the inferior articular cavity, and 14 in both the superior and inferior articular cavities. The appearance of joint effusion did not differ with the existence of myofascial pain or TMJ pain. The region of joint effusion did not differ between disc displacement with and without reduction. A larger area of joint effusion was recognized in disc displacement without reduction (<i>p</i> < 0.05). The results showed that the amount of synovial fluid in the joint effusion did not change with the existence of myofascial pain or TMJ pain. Joint effusion commonly appeared in disc displacement without reduction.