Temporomandibular Joint Disorders: Clinical exam may be helpful in the diagnosis
Clinical Bottom Line
If the pre-test probability is intermediate (e.g. 50%), the post-test probability for positive test results increases to 81%. The validity of the reference standard was not specified in the article; there is evidence that MRI may be the best reference standard.
Schiffman EL, Anderson GC, Fricton JR, Burton K, Schellhas KP. Diagnostic criteria for intrarticular temporomandibular disorders. Community Dent Oral Epidemiol 1989;17:252-257.
Is your clinical diagnosis of: internal derangement correct when presented with a patient with the following clinical [history of locking, preauricular pain, reproducible and reciprocal click, reduced mouth opening (35 mm), local muscle tenderness, reduced joint play] and tomography findings (diminished anterior translation of both condyles, no osseous changes)?
You do a MEDLINE search (1988 - 1998) using the MESH heading 'temporomandibular joint disorders' you find one article assessing a cluster of clinical tests and tomography.
- Gold Standard - A reference test (arthrotomography) was used. A blind comparison was made. However, it was not clear if the reference test was performed independently of the clinical tests. The validity of the reference standard was not specified.
- Study Setting - tertiary care
|Diagnostic Criteria||Internal Derangement||No Internal Derangement||Likelihood Ratio|
If the pre-test probability is intermediate (e.g. 50%) then a positive clinical test would be helpful, yielding a post-test probability of 81%.
If the pre-test probability is low (e.g. 20 %) then the clinical test is not useful (post-test probability = 52%).
- Diagnostic test: diagnostic criteria for intraarticular TM disorder (Table 3 of the paper) included positive history of mandibular limitation, no reciprocal click, no coarse crepitus, maximum opening less than or equal to 35 mm, passive opening stretch less than 40 mm, contralateral movement less than 7 mm, no S-curve deviation and tomography findings of decreased translation of the ipsilateral condyle.
- Uncertain if the reference standard that was used was the best available
- Unclear if the reference standard performed independently of the clinical tests
Anita Gross; February 16, 1999.