[Posttraumatic temporomandibular joint ankylosis: clinical development and surgical management].

Objective: To investigate the patterns of condylar fractures associated with temporomandibular joint ankylosis (TMJA) and treatment methods and results based on the different types of ankylosis.
Methods: Forty-two joints of ankylosis in 31 patients with were categorized to four groups according to Sawhney's classification and undergone surgical treatment as follows: a joint release and disc reposition for Type I ankylosis, a dissection of bony block and disc reposition for Type II; a dissection of full-joint and employment of the temporal myofascial flap as interposition for Type III; a radically dissection of full joint followed by ramus distraction osteogenesis and genioplasty for Type IV. All of patients were followed up for 9 to 54 months with an average of 30 months. The range of mouth opening and temporomandibular joint (TMJ) function were assessed. Condylar fractures were retrospectively investigated on the patterns and the course of ankylosis development. Macroscopical visualization on the osseously ankylosed sites and disc displacement were analyzed in comparison with the radiological findings.
Results: Condylar sagittal and comminuted fractures were most susceptible to TMJA. Early fibrous ankylosis occurred usually at the 4th or 5th month post-traumatically with an average month opening of 18.3 mm. The articular discs were found displaced in all cases and early bony bridge formed at a limited area where there was no disc as cushion. During fellow-up, considerable improvement in mandibular movement was attained with a stable joint function and mouth opening range of over 30 mm except for two cases in which ankylosis relapsed.
Conclusions: Condylar sagittal and comminuted fractures are most likely to cause ankylosis. Early surgical intervention could reduce the disc and avoid the later ankylosis.