Abstract: Objective: To explore the clinical characteristics of traumatic temporomandibular joint ankylosis (TMJA) secondary to condylar sagittal fractures. Methods: Thirty-one patients with a total number of 48 ankylosed temporomandibular joints secondary to condylar sagittal fractures, in the Hospital of Stomatology, Wuhan University during the period of 2001-2010, were retrospectively reviewed. Results: The mean age of patients at injury was 15.6 years old, and 23 patients (74.2%) was less than 16 years old. The time interval between initial injury and presentation of TMJA varied from 3 months to 20 years, with a mean disease course of 6.5 years. The articular discs were observed displaced or disrupted in all 48 ankylosed joints. Histopathology of ankylosed joint revealed that the medially displaced condylar fragments showed the changes of disusatrophy, while cartilaginous metaplasia and ossification were found in the lateral osseous fusions and hyaline degeneration was observed in the disrupted articular discs. Conclusion: Traumatic TMJA secondary to condylar sagittal fractures usually occurred in the adolescents. The damaged articular disc should be account for the development of TMJA. Furthermore, the osseous fusions were initially originated from the lateral of joint surface. Chondrification and endochondral ossification were responsible for the formation of osseous fusions.

Key words: Condylar fractures, Temporomandibular joint, Ankylosis