MRI-detected joint effusion and disc displacement without reduction as independent predictors of pain in intraarticular temporomandibular joint disorders

INTRODUCTION: Intraarticular temporomandibular joint (TMJ) disorders are a leading cause of orofacial pain, but whether MRI findings predict symptoms remains unclear. MATERIALS AND METHODS: This retrospective study included 79 patients (158 TMJs) with intra-articular TMJ disorders. Predictors included disc displacement (DD), joint effusion grade (0-3), disc morphology, and osseous changes. Outcomes included pain severity (VAS), clicking, and crepitation. RESULTS: DD without reduction predicted higher pain severity (OR=2.51; p= .014). Effusion showed a dose-response relationship with pain across all grades (Grade 1: OR=3.23; Grade 2: OR=4.18; Grade 3: OR=8.93; p≤ .004), independent of DD type. Crepitation was most prevalent in Grade 1 effusion joints (23.6%), even without osseous changes. CONCLUSION: Joint effusion independently predicts pain severity in intraarticular TMJ disorders, distinct from DD type. Crepitation linked to mild effusion without osseous changes suggests it may not exclusively indicate end-stage degeneration. Effusion grading should be prioritized in MRI-based diagnosis.