Temporomandibular joint morphology following post-traumatic ankylosis in 26 patients.

This study evaluated the joint morphology on coronal computed tomography of ankylosed temporomandibular joints in 26 patients. All patients developed ankylosis following blunt trauma. Post-ankylosis joint morphology was assessed to determine if the precursor condylar fracture could be identified and this was compared to the condylar fracture prevalence to determine if any condylar fractures have an increased risk factor for ankylosis. Mean age at presentation was 20.9+/-14.41 years (range 6-58) and mean age at injury was 13.84+/-13.81 years (range 3-53). Thirty-seven joints were ankylosed in 26 patients (11 bilateral, 15 unilateral) with 27 joints in 19 patients showing vestiges of a medially dislocated condylar fracture (72.9% of joints). The prevalence of MDCF at our unit over a period of 6 months was 16.8% (16 of 95 condylar fractures). This suggests that a medially dislocated condylar fracture is more likely to ankylose than other condylar fractures. A hypothesis is proposed to explain this increased risk.