Temporomandibular joint pathosis in patients with myofascial pain: a comparative analysis of magnetic resonance imaging and a clinical examination based on a specific set of criteria.

Objective: We sought to determine the prevalence of joint diseases in patients with either of 2 forms of myofascial pain (with and without limited mouth opening) and to verify the accuracy of temporomandibular joint-related clinical diagnoses through the use of magnetic resonance imaging (MRI).
Study Design: On the basis of the results of a clinical examination carried out according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD), 61 patients were divided into 2 subgroups. The first group consisted of 36 patients who had myofascial pain with limited mouth opening (MPLO), whereas the other 25 patients were diagnosed with myofascial pain without limited mouth opening. MRI was carried out on all patients. The clinical joint-related diagnoses from RDC/TMD were compared with MRI results.
Results: Patients with MPLO often had joint diseases that were not detected by means of a clinical examination alone. The kappa statistic was used to compare MRI and clinical diagnoses, confirming poor agreement in patients with MPLO (kappa=0.13) and acceptable agreement in patients with myofascial pain without limited mouth opening (kappa=0.72).
Conclusion: Restricted mandibular mobility is frequently associated with temporomandibular joint diseases that were not identified during a clinical examination. Therefore, an adaptation of the classification scheme used for the RDC/TMDs may result in the improvement of the sensitivity of clinical joint-related diagnoses, especially in patients with MPLO.