Monitoring of incremental changes in maximum interincisal opening after gap arthroplasty omits the risk of Re-ankylosis

Purpose: The aim of this clinical study was to prospectively measure the incremental changes in the maximum interincisal opening (MIO) after 1 cm gap arthroplasty, compare these changes between unilateral and bilateral cases, and emphasize the importance of the monitoring of the MIO for at least 24 months.

Materials and methods: This prospective study enrolled 26 patients with TMJ ankylosis either unilateral or bilateral. The fingers assessment method was used to measure the MIO preoperatively, intraoperatively, and monthly postoperatively up to 24 months. All the patients had undergone 1 cm gap arthroplasty to release the ankylosis. The changes in MIO measurements of unilateral and bilateral cases were statistically compared. The physiotherapy was performed until the measurements had normal stable values.

Results: All the cases showed a significant decrease in MIO at the first three months. At 6 months, the MIO continuously increased up to 1 year. There was no difference between the unilateral and bilateral cases. At the end of the follow-up, all measurements showed normal stable values.

Conclusion: The monitoring of MIO is important to detect the early signs of re-ankylosis. It is the only way that can be used in which the early signs cannot be detected in radiographs.