Temporomandibular joint internal derangement: relationship between joint pain and MR grading of effusion and total protein concentration in the joint fluid

The objective of this study was to determine whether there is any association between the protein concentration in the synovial fluid and (i) the amount of articular hydrops, as graded in magnetic resonance (MR) images, and (ii) joint pain in temporomandibular joints (TMJs) with and without displacement of the disc. This study involved 16 joints in 16 patients referred to our clinic with the complaint of pain and limited mouth opening. The control group consisted of 15 joints in 15 patients with unilaterally normal disc and condyle relationship and no pain while the opposite side had a non-painful joint with disc displacement without reduction (DDwoR). The subjects and controls were different individuals and only a single joint was used for each. Pain and dysfunction were evaluated by visual analogue scale. Bilateral proton density and T2 weighted images of the TMJs of the 31 subjects were analysed for fluid and condyle bony changes as well as disc position. The amount of fluid, identified as an area of high signal intensity in the region of the upper and lower joint spaces, was characterized as none, minimal, moderate or marked. Arthrocentesis was performed both for synovial fluid analysis of total protein concentration and the treatment of the joints with DDwoR. Total protein concentration was measured by using protein dye binding on spectrophotometry. All patients experienced a significant (P