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

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.

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.

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.

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.