Byline: Wei-Chin. Chang, Yen-Ching. Chang, Chi-kung. Lin, Yuan-Wu. Chen
Mandibular condylar trauma is the most common cause of temporomandibular joint (TMJ) ankylosis. The pathogenesis of this condition is typified by fibrous or bony tissue replacement of the two articular surfaces, resulting in an inability to open the mouth. Treatment includes joint interpositional arthroplasty to remove the ankylosed tissue and meniscus. After smoothing the ankylotic joint surface, autogenous or alloplastic material is used to replace the meniscus. We present a case of TMJ ankylosis treated with interpositional arthroplasty and a Silastic graft. The patient suffered joint trauma that was treated with intermaxillary fixation and insufficient instruction for mouth opening exercise. The patient subsequently developed Type II bony ankylosis in left TMJ, which was diagnosed on clinical examination, and computed tomography. Interpositional arthroplasty with a Silastic autopolymerizing membrane was performed through a preauricular approach. Postoperatively, mouth opening improved significantly from an interincisal distance of 3-28 mm. Surgical and physical therapy accomplished good wound healing without re-ankylosis after two years of follow-up.
Temporomandibular joint (TMJ) ankylosis affects joint movement, speech, mastication, and oral hygiene. The pathogenesis of TMJ ankylosis remains unclear, [sup] but there are several hypotheses, [sup] such as intra-articular hematoma, [sup] extracapsular hematoma, [sup] distraction osteogenesis, [sup] hypertrophic nonunion, [sup] hypercoagulability, [sup] and genetic predisposition. [sup] After a condylar fracture, intra-articular hematoma with prolonged immobility induces intracapsular hematoma, and bone can form as a result of metaplasia in nonosteogenic connective tissue. This period of immobility is the agent promoting ankylosis.
The Sawhney classification [sup] for TMJ ankylosis describes four disease types. In Type I disease, the articular surface is flatted and deformed with minimal bony fusion. In Type II, bony fusion is present at the outer edge of the articular surface with limited areas of fusion. In Type III, a block-like, bony bridge traverses the ramus and zygomatic arch, but the medial side of the upper ramus lacks bony fusion. In Type IV disease, the most severe form of ankylosis, the bony block encompasses the ramus and zygomatic arch.
Joint ankylosis should be initially treated nonsurgically, followed by surgical intervention if necessary. Gap arthroplasty, interpositional arthroplasty, and total joint reconstruction are options depending on the severity of joint ankylosis and the meniscus deformity.
The therapeutic goal in the present case was to achieve jaw function. Treatment comprised gap arthroplasty, removal of the deformed meniscus and condylar fragment, and replacement of interpositional material with alloplastic material...