Clinical course of jaw function recovery following surgical treatment in patients with temporomandibular joint ankylosis – correlation with mouth opening rehabilitation

Purpose Treatment of osseous temporomandibular joint ankylosis often requires a surgical procedure. While postoperative rehabilitation is important for prevention of relapse, the contributions of rehabilitation and period of such therapy remain unclear. The present study was performed to evaluate the effects of rehabilitation on range of mouth opening after TMJA surgery. Methods Twelve patients who underwent surgery for gap arthroplasty or interpositional arthroplasty were enrolled. The course of maximal incisal opening in patients divided by surgical method, gap size, and period of rehabilitation, particularly relapse of maximal incisal opening was analyzed. Results Average relapse of maximal incisal opening after surgery in patients with a gap size ≥ 15 mm was 12.0 ± 11.2 mm, while that in those with a gap size < 15 mm was 8.9 ± 12.6 mm. Average relapse of maximal incisal opening after surgery in patients with gap arthroplasty was 12.3 ± 7.6 mm, while that in those with interpositional arthroplasty was 7.5 ± 15.2 mm. Patients with a rehabilitation period of < 12 months after surgery showed an average relapse of maximal incisal opening of 14.1 ± 10.7 mm, while that in those who underwent rehabilitation for ≥ 12 months was 7.4 ± 16.3 mm. Conclusions During the relatively long-term clinical follow-up period of 24 months, the importance of rehabilitation was noted and the present results demonstrate its role in preventing relapse after TMJA surgery.