Bony ankylosis of the temporomandibular joint: follow-up of 70 patients treated with arthroplasty and acrylic spacer interposition.

This paper presents the author's experience with interpositional arthroplasty using an acrylic cylinder in 70 cases of bony ankylosis of the temporomandibular joint. Ankylosis followed trauma in all but one patient. The diagnosis was established when restriction of mouth opening was associated with roentgenologic evidence of deformation of the condyle, obliteration of the joint space, and abnormal bone formation in and around the joint. The pathologic changes were classified into four types depending on severity, and each type influenced the treatment. Surgical treatment included creation of a transversely elliptical gap between the two bony components of the joint using a neurosurgical burr and perforator and a chisel through a preauricular approach and interposition of an acrylic cylinder. This maintained the gap, facilitated movement, and encouraged nonunion. The results following a long follow-up of 2 to 10 years showed uniformly good results with a range of mouth opening varying from 2 to 5 cm. Only three bilateral cases recurred and two others had a limited range of mouth opening, with interincisor distance varying from 2 to 2.5 cm.