Effects of soft tissue injury to the temporomandibular joint: report of 8 cases.

Our aim was to describe the effects of soft tissue injury to the temporomandibular joint (TMJ), to analyse possible reasons for it, and to evaluate the results of treatment. Eight patients (12 joints) who developed disorders of the TMJ after trauma to the mandible without fracture of the condyle were treated in our department from 2009 to 2010. Magnetic resonance imaging (MRI) and computed tomography (CT) were used to check the condition of the joint. Five patients had their joints explored to relieve pain and improve mouth opening. MRI showed all 12 joints had displaced discs. CT showed that the surface of the condylar bone was "intact" immediately after injury but destroyed later in 8 joints. Exploration showed fibrous ankylosis in 5, osteoarthritis with intra-articular adhesions in 2, and internal derangement in 1. Four were treated by costochondral graft (CCG) with 7 symptomatic joints. The disc was repositioned in 1 case with 1 affected joint. The mean maximal incision opening at follow-up were significantly better than the one before treatment (mean 34 compared with 23 mm, p=0.02). Pain in the TMJ was relieved by operation in all patients so treated. The other 3 patients (4 joints) had no treatment because their symptoms were minor and mouth opening was not restricted. Soft tissue injuries of the TMJ can potentially lead to internal derangement, osteoarthrosis, and possibly fibrous ankylosis, which should be considered during follow-up. Displacement of the disc and damage to the condylar cartilage seem to be the causes of these complications. Surgical management is effective in the short term.