Diagnosis And Treatment Of Acute Traumatic Temporomandibular Joint Disc Displacement And Its Pathological Study

[Objectives] To evaluate the diagnosis,progression,sequelae and pathological mechanism of acute traumatic temporomandibular joint disc displacement(ATDD),as well as to introduce the effective treatment for this disease.[Methods] 40 patients with 55 joints of ATDD treated from 2010 to 2015 in our department were reviewed.The patients with recent history of mandibular trauma and MRI confirmed disc displacement were included.The patients who had previous history of TMJ symptoms and CT confirmed condylar fracture in the affected side were excluded.All patients were divided into 3 stages: acute stage(?2 w),subacute stage(>2w,?2m)and chronic stage(>2 m).According to different treatments,the patients with results of followed-up were divided into conservative group(25 joints),surgical group with disc reduction operation(33 joints)and joint replacement group(13 joints).The average maximal mouth opening(MIO)and MRI imaging were followed up to evaluated the mandibular function and condyler bone resorption.The treatment effects of 3 groups were statistical analysised by SPSS 20.The pathlogical manifestations of the condylar which were resected due to osteoarthritis with or without acute trauma were compared.[Results] 43 joints of 32 patients were followed up for 2-64 months,with the average of 16.5 months.Among the acute and sub-acute stage,5 out of 26(19%)joints displayed bone resorption,while 22 out of 29(76%)joints among the chronic stage displayed bone resorption.In the surgical group(21 joints),the follow up results of MRI showed 1 joint(5%)of new bone growth,13 joints(62%)of no resorption,6 joints(28%)of slight bone resorption(5 joints had no change compared with pre-operation)and 1 joint(5%)of serious bone resorption.In the conservative group(25 joints),the follow up results of MRI showed 1 joint(4%)of no resorption,11 joints(44%)of slight bone resorption and 13 joints(52%)of serious bone resorption.The proportional of bone resorption in conservative group was significantly higher than in surgical group.The average MIO of conservative group was 24 mm.The average MIO of surgical group before and after operation were 25.6mm and 35.6mm,respectively.The post-operation MIO was significantly improved compared with both pre-operation and conservative group.The average MIO of joint replacement group after operation were 31.8mm,which was significantly improved compared with the average MIO before operation(16.1mm).The pathological study of posttraumatic osteoarthritis(PTOA)and chronic ostearthritis(OA)showed similar pathological characteristics of cartilage and bone resorption as well as inflammatory response of vascular proliferation,while the inflammation and resorption were more active in PTOA.[Conclusions] In conclusion,ATDD may cause bone resorption which will progressed to severe osteoarthritis or ankylosis.Surgically disc reposition as early as possible in the acute and sub-acute phases can effectively protect the condylar and significantly reduce the occurrence rate of above sequelae.PTOA also has the pathological characteristics of bone resorption and inflammation reaction which are similar with chronic OA,but the resorption of bone and inflammation reaction in PTOA are more active.