Is the Anchored Disc Phenomenon a Truly Distinct Entity? A Systematic Review.

PURPOSE: This review aimed to examine whether the anchored disc phenomenon (ADP) is truly a distinct entity, independent of the closed-lock condition attributed to nonreducible disc displacement. MATERIALS AND METHODS: Clinical and/or diagnostic imaging studies addressing the anchored disc or ADP were considered. Articles eligible for inclusion were written in English; were conducted in humans; showed, in their titles or abstracts, any of the keywords used in the search method; included some type of disc imaging system; and related disc mobility to disc position. Of 18 potentially relevant articles, 10 were included. RESULTS: Of the studies, 9 used magnetic resonance imaging and 1 used double-contrast cone-beam computed tomography. In 1,691 joints, 270 discs (16%) were shown to be anchored in a normal (41%) or displaced (59%) position. Of 149 displaced anchored discs, 52 were reducible and 97 were nonreducible. Intra-articular adherences, synovitis, and adhesions were common arthroscopic findings in patients with the ADP. CONCLUSIONS: The temporomandibular joint anchored disc shown by disc imaging systems is worthy of inclusion in the existing categories of temporomandibular joint internal derangement. Classification of the ADP as a distinct entity still awaits a consensual definition of the problem, validation of the underlying hypothesis, and clarification of the natural history of the phenomenon.