Classification of temporomandibular joint osteoarthrosis and internal derangement. 1. Diagnostic significance of clinical and radiographic symptoms and signs.

In the clinical setting, diagnosis primarily depends on the history and present status of the patient, and on the examiner's expertise in physical examination and interpretation of conventional radiographs. In order to evaluate the diagnostic significance of clinical and radiographic variables, the authors used magnetic resonance imaging as the 'golden standard' for articular disk position. A total of 90 temporomandibular joints (TMJs) were available for the study. Group I (representing 'normal' disk position) comprised eight joints (8.9%); group II (representing reducing disk), 34 joints (37.8%); and group III (non-reducing disk), 48 joints (53.3%). Nine anamnestic, 15 clinical, and three radiographic variables obeyed pre-defined univariate selection criteria. Relatively high sensitivities were found for clicking-related variables in MR-group II, and for variables related to movement restriction in MR-group III. None of the symptoms or signs appeared to be pathognomonic for either one of the diagnostic groups. Principal component analysis revealed 13 factors that could be grouped into three major categories, representing impairment of joint mechanics, joint pain and tenderness, and radiographically detectable degenerative changes, respectively. Discriminant analyses showed that symptom combinations, which included clinical variables related to joint mechanics, appeared to provide the most useful diagnostic information. It is concluded that reducing and permanent disk displacement can be distinguished in many cases using clinical and radiographic variables. However, there is considerable variability within these groups. To establish a specific clinical diagnosis, a more detailed classification of osteoarthrosis and internal derangement is desirable.