Arthroscope-guided intra-articular injection of chitosan-hyaluronate gel mixture vs hyaluronic acid in the treatment of temporomandibular joint internal derangement: a randomized controlled clinical trial.

This study compares the effectiveness of arthroscope-guided intra-articular injections of sodium hyaluronic acid (HA) and chitosan-hyaluronate (CH) hybrid gel for patients with anterior disc displacement without reduction (ADDw/oR) of the temporomandibular joint (TMJ). A randomized controlled trial was conducted on 20 patients with symptomatic ADDw/oR. The study protocol was registered in the ClinicalTrials.gov (NCT06426199). Patients were randomly assigned in a 1:1 ratio to receive HA or CH injections following arthroscopic lavage. Randomization was computer-generated, allocation was concealed in sealed opaque envelopes, and outcome assessors were blinded. Outcomes (pain by VAS, maximum mouth opening (MMO), and lateral excursions) were assessed at baseline, 3 months, and 6 months. Both groups showed significant improvements in pain and joint function, while the CH group demonstrated superior outcomes, with greater increases in MMO (42.3 vs 33.6 mm at 3 months; 44.9 vs 37.1 mm at 6 months) and significantly lower pain scores (median 2 vs 3.5 at 6 months; P = 0.032). Lateral excursions improved in both groups, with the CH group showing more consistent progress. Joint clicking showed no significant differences. The CH gel provided more significant and sustained improvements in MMO and pain relief compared to HA. Its regenerative properties, prolonged therapeutic effects, and ability to enhance joint lubrication suggest CH as a promising alternative for managing TMJ internal derangements.