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Updated: Jul 9, 2026
Knee Arthrocentesis in Adults
Published on: February 25, 2022
A Retrospective Cohort Study of Two- Vs. Four-Injection Intra-Articular Sodium Hyaluronate Regimens for
Jia Kang1, Xingyu Lyu1, Jiannan Zhao1
1State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, Department of Orthognathic and TMJ Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
Objective:
Intra-articular sodium hyaluronate injection is an effective treatment for temporomandibular joint anterior disc displacement without reduction (ADDWoR), although the optimal number of injections remains unclear. This study compared the efficacy of 2- and 4-injection regimens, assessing maximum mouth opening (MMO) and temporomandibular joint (TMJ) pain measured by the visual analogue scale (VAS).
Methods:
Patients with ADDWoR treated at our TMJ clinic were retrospectively reviewed and classified into 2-injection and 4-injection groups. All patients underwent arthrocentesis followed by intra-articular sodium hyaluronate injection at 2-week intervals. MMO and TMJ pain VAS scores were recorded at baseline and 6 months. Differences were analysed statistically, with p < 0.05 considered significant.
Results:
A total of 108 patients were included: 40 in the 2-injection group and 68 in the 4-injection group. Both groups showed significant improvement after treatment, with increased MMO and reduced VAS scores (all p < 0.0001). Compared with the 2-injection group, the 4-injection group showed no significant additional benefit in either MMO gain (p = 0.3682) or pain reduction (p = 0.2684). Interestingly, younger patients showed greater improvement in mouth opening than older patients (p < 0.0001), whereas pain reduction did not differ significantly between age groups (p = 0.2427).
Conclusion:
Both the 2- and 4-injection regimens were effective in improving MMO and reducing TMJ pain in patients with ADDWoR. The 4-injection regimen did not show a statistically significant additional benefit over the 2-injection regimen. A shorter injection course may reduce patient burden. Notably, younger patients showed greater mouth-opening improvement.