Abstract: Objective To compare the effectiveness of intra-articular injection of hyaluronic acid (HA) and physical therapy for temporomandibular joint anterior disc displacement without reduction (ADDwoR). Methods A total of 72 patients with ADDwoR who completed the treatment in the authors' department from February 2018 to August 2020 were included. 36 patients received intra-articular injection of HA, and Thirty-six patients received individualized comprehensive physiotherapy. Outcome assessment measures were maximum active mouth opening (MMO), visual analogue pain score (VAS) (0-10), jaw functional limitation scale (JFLS) and effective rate before, during and after treatment. SPSS 26.0 software package was used for data analysis of chi square test, t test and univariate analysis of variance. The difference was statistically significant in P＜0.05. Results Compared with before treatment, there were significant differences in MMO, VAS and JFLS during and after treatment in the two groups (P＜0.05). There were significant differences in MMO between the two groups during and after treatment（F=11.160，P＜0.05；F=6.766，P＜0.05）. Compared with the injection group, the MMO of physical therapy group increased during and after treatment by 2.5 mm (95% CI:1.1-4.0, P=0.001) and 3.1 mm (95% CI:1.0-5.3, P=0.005). Twenty-five cases（69.4%）were effective in the injection group, and 27 cases (75.0%) were effective in the physical therapy group. There was no significant difference in the effective rate between the two groups (χ2=0.277, P>0.05). Conclusion Both physical therapy and intra-articular injection of HA can reduce the pain, increase the maximum active mouth opening and improve the mandibular function of ADDwoR patients. Physical therapy has a better effect on MMO.

Key words: intra-articular injection, hyaluronic acid, physical therapy, temporomandibular joint, anterior disc displacement without reduction