This study compared the short-term efficacy of two treatments (local anesthetics (A) and local anesthetics and lavage (AL)) in patients with permanently displaced discs and temporomandibular disorder (TMD) pain. 45 patients participated in the single-blind randomized controlled trial. All patients had received: a Research Diagnostic Criteria/TMD diagnosis of disc displacement without reduction; and magnetic resonance imaging confirmation of non-reducing disc displacement. Participants were randomized to treatment with A or AL and were assessed at baseline and at 1 and 3 month follow-ups. The primary outcome measure defining success was reduction in pain intensity of at least 30% during jaw movement. At the 3 month follow-up, the success rate was 76% for A and 55% for AL. Both groups reported similar pain relief with no significant difference between the groups. Similar trends were observed for outcome measures in the physical functioning, emotional functioning, and global improvement domains with no significant difference between the groups. Use of lavage to supplement extra-articular local anesthetic treatment of painful jaw movements at non-reducing discs does not appear to improve TMD pain and mouth opening capacity in the short term