Relationship between joint effusion, joint pain, and protein levels in joint lavage fluid of patients with internal derangement and osteoarthritis of the temporomandibular joint

Purpose: The purpose of this study was to investigate the relationship between the presence of joint effusion, joint pain, and protein levels in joint lavage fluid (JL) of patients with internal derangement (ID) and osteoarthritis (OA) of the temporomandibular joint (TMJ). Patients and Methods: Thirty-eight joints in 26 patients with ID and OA of the TMJ were studied. Magnetic resonance imaging (MRI) evidence of joint effusion was evaluated in T2-weighted images. Samples of JL were collected from the superior joint space during pumping manipulation, and the protein concentration was measured. The presence of pain was based on joint tenderness or a complaint of pain in the preauricular region during mouth opening or closing. Results: Joint effusion was demonstrated in 20 of 25 (80%) painful joints; a significantly higher incidence than in pain-free joints (5 of 13, 38.5%). The mean protein concentration (2.15 mg/mL) in JL from painful joints was significantly higher than in pain-free joints (1.22 mg/mL) (P < .05). Furthermore, the mean protein concentration (2.12 mg/mL) in JL from joints with effusion was significantly higher than in joints without joint effusion (1.27 mg/mL) (P < .05). Conclusions: These data demonstrate that painful joints are more likely to show joint effusion on MRI, and the protein levels in JL recovered from these joints is higher than in pain-free joints. These data also suggested that joint effusion may be related to the inflammatory changes seen in patients with ID and OA.