A type II lateral dislocation of bilateral intact mandibular condyles with a proposed new classification

Lateral displacement of the intact mandibular condyle is a rare entity, first described in detail and classified into two types (type I, type II) by Allen and Young in 1969. We experienced a rare case of type II lateral dislocation of the bilateral condyles with fracture of other parts of the mandible. It is reflected that delayed closed reduction gave an imperfect result, inducing ankylosis. Bilateral condylectomy with reconstruction of the head using costal cartilage was performed subsequently to improve arthropathy, with a 2-year satisfactory follow-up. A review of the literature shows that there are three types of type II lateral dislocations of the mandibular condyle, which are further related to the technical difficulty of reduction. We propose a new typing of type II lateral dislocations of the mandibular condyle. The clinical assessment for this condition is early reduction. Rather, open reduction is more definitive. However, unavoidable delay in reduction induces ankylosis of the joint, which sometimes necessitates condylectomy with or without arthroplasty.