Objective: This study is aimed to evaluate the efficacy of series of 4 consecutive injections of medium molecular weight hyaluronic acid (MMW-HA) within the superior joint space (SJS) in patients with internal derangement of temporomandibular joint (TMJ-ID).
Patients and methods: In this prospective interventional clinical trial (case series), twenty patients with TMJ-ID were treated with four consecutive injections of 1 ml of MMW-HA with one-week intervals. All patients followed one week after each of the four injections and at one, three, and six months after the fourth injection. The postoperative evaluation included maximum unassisted mouth opening (MUMO), modified Helkimo's clinical dysfunction index, and pain intensity on a visual analog scale (VAS).
Results: All patients showed clinical improvement after MMW-HA injection. The pain, as well as clinical dysfunction index values, showed improvement just after the first injection, while MUMO needed a second injection to start a significant improvement. The fourth injection added a very minute improvement. These improvements continue to the end of the follow-up period.
Conclusion: Viscosupplementation is an effective simple minimally invasive treatment option for treatment of TMJ-ID in case of failure of conservative treatment that easily performed in outpatient clinic. Two injections showed to be enough for clinical improvement however randomized controlled trials are required to compare between different protocols regarding number and intervals of HA injections.