Synovial fluid level of myeloperoxidase enzyme following ultrasound-guided regenerative injections in patients with irreducible temporomandibular disc displacement: a double-blinded parallel randomized clinical trial.

BACKGROUND: Irreducible temporomandibular disc displacement (DDwoR) is a subtype of internal derangement of temporomandibular joint (TMJ-ID). Recognizing the risks related to DDwoR with its pathogenesis, the treatment of this disorder becomes essential. Prolotherapy, also known as regenerative injection therapy, has been emerging as one of the most promising approaches to treat patients with TMJ-ID. The current prospective parallel randomized clinical trial (RCT) was done to assess the effect of hypertonic dextrose (HD) regenerative injection and that of concentrated growth factors (CGF) in conjunction with a stabilization occlusal appliance (SA) in the management of DDwoR.

METHODS: Twenty-four patients suffering from DDwoR were randomly assigned to 2 equal groups; Group I (HD + SA), Group II (CGF + SA). Assessments were done before treatment, 1 week, 4 weeks, and 24 weeks after the treatment using the Visual Analogue Scale of Pain (VAS) and assisted maximum mouth opening (MMO). Moreover, synovial fluid (SF) samples were obtained for the analysis of the Myeloperoxidase enzyme (MPO) levels, before and 6 months after treatment.

RESULTS: A significant relief in pain was found in both groups at 1 month and lasted up to 6 months postoperatively (p < 0.001). Moreover, assisted MMO in both groups was significantly increased (p < 0.001). As for MPO levels in SF, by 6-months from the intra-articular injection, the enzyme levels were significantly reduced in both groups (p = 0.002). Although the MPO concentrations in the SF were significantly higher than that found after injection, there was a statistically insignificant difference between groups.

CONCLUSIONS: We concluded that injection of HD or CGF in the superior joint space could be a valuable treatment option for patients suffering from DDwoR. As both led to a positive impact on MMO, and the relief of joint pain with the decrease in levels of inflammatory biomarker inside the joint.

TRIAL REGISTRATION: The current trial is a prospective assessor and analyst blinded RCT that has been registered at ClinicalTrials.gov with identification number: NCT04557878, 1/4/2020.