Aims: To assess the prevalence of posterior disc displacement (PDD) in patients with temporomandibular disorders (TMD) through a systematic review of the literature and meta-analysis, as well as to assess features associated with PDD such as chief complaint, signs and symptoms, morphologic condyle and disc alterations, and PDD management.
Methods: A systematic literature search was performed in the US National Library of Medicine's PubMed/MEDLINE and Cochrane Library databases to identify all peer-reviewed, English-language manuscripts related to PDD. A critical appraisal checklist provided by the Joanna Briggs Institute for studies reporting prevalence data was used to assess the quality of the included manuscripts. A meta-analysis was conducted using software MetaXL 5.3 (EpiGear International Pty Ltd) add-in for Microsoft Excel. Pooled prevalence and 95% confidence intervals (CIs) were calculated using the software. Heterogeneity of the included studies was assessed using the Higgins I2 test and Cochran's Q (with P value; < .05 was considered significant).
Results: A total of 21 articles were selected for qualitative data synthesis: 2 case reports, 14 observational studies, and 5 studies that reported PDD in various conditions. Quantitative data analysis was performed for the 14 observational studies, of which 13 reported prevalence with respect to the number of joints affected and 9 reported prevalence with respect to the number of patients affected. The overall pooled prevalence of PDD for the number of joints affected was 0.7% (95% CI: 0.005 to 0.008). The pooled prevalence of PDD for the number of patients was 0.9% (95% CI: 0.007 to 0.011). PDD was found to be associated with osseous changes, including changes in the morphology of the condyle, disc, and articular eminence; osseous abnormalities (erosion, osteophytes); and joint effusion.
Conclusion: This meta-analysis showed a very low prevalence rate of PDD in TMD patients. The limited literature did not allow conclusions to be drawn about the PDD-related features.