The purpose of this study was to compare the efficacy and the complications of intra-articular temporomandibular joint (TMJ) injections in 40 patients with osteoarthritis of the TMJ. The subjects were randomly divided into two groups, and the patients received either two intra-articular injections with sodium hyaluronate or two intra-articular injections with corticosteroids, 14 days apart. The effect of the treatment was evaluated 14 days, 1 and 6 months after the initial injection and was based on the following measurements: pain intensity, pain localization, joint sounds, mandibular function and complications. Both groups of patients had less pain intensity at the 6-month follow-up, and there was significantly less pain intensity in the group of patients receiving sodium hyaluronate compared with corticosteroids (P = 0.001). A decrease in crepitation was seen in both groups. In the 20 subjects receiving sodium hyaluronate both the mandibular vertical opening and protrusion increased significantly (P < 0.000). Lateral movement from the affected side increased both in subjects injected with sodium hyaluronate (P = 0.024), and those injected with corticosteroids (P = 0.042). In conclusion, this study confirms that injections in the TMJ with sodium hyaluronate or corticosteroids may reduce pain and improve function in patients with osteoarthritis. The injections were more effective in patients with only TMJ pain compared with patients suffering from both TMJ and myofascial pain. Injection with sodium hyaluronate was significantly more effective in decreasing pain intensity than corticosteroids. Temporary pain after injections may be observed.

Aim:  We compared the osseous changes in the temporomandibular joint (TMJ), assessed on computed tomography (CT) examinations, before and after two intra‐articular TMJ injections of sodium hyaluronate or corticosteroid, in patients with osteoarthritis of the TMJ and related these to the clinical findings of pain, function and complications. Material and methods:  Forty patients were randomly allocated into two groups for two intra‐articular injections with the two drugs. The effect of treatment was evaluated before and 6 months after the injections. Bilateral TMJ examinations with high resolution CT were obtained in 36 patients before and 6 months after treatment. Treated and contralateral TMJs were evaluated for the presence of osteoarthritic osseous abnormalities by two reviewers independently. Results:  Injection with sodium hyaluronate was significantly more effective in decreasing pain intensity than corticosteroid. Progression, regression and no change of osseous abnormalities were demonstrated in 14, 10 and 12 TMJs, respectively, 6 months after treatment. Decreased pain intensity and increased vertical mandibular opening were observed in the majority of patients where progression of osseous changes was observed on CT. Conclusions:  Injections in the TMJ with sodium hyaluronate or corticosteroid may reduce pain and improve function in patients with osteoarthritis. Progression, regression and no changes were observed in treated as well as untreated TMJs. Radiological evaluation of progression of osteoarthritis does not always reflect the clinical signs and symptoms.