Severity of temporomandibular joint disc displacement and generalized joint hypermobility in growing patients: a cross-sectional magnetic resonance image study

Background: This study aimed to investigate the association between the internal derangement of the temporomandibular joint (TMJ), in particular the severity of disc displacement (DD), and the presence of generalized joint hypermobility (GJH) in growing patients evaluated on magnetic resonance images (MRIs). The study also investigated the relationship between the stages of DD severity and age. Methods: This cross-sectional study has been conducted on a pre-orthodontic population (8–16 years). The GJH was assessed with the Beighton test (cutoff ≥ 4) and the final sample of 56 patients was divided into two groups: a study group, 30 subjects with GJH, and a control group, 26 subjects without GJH. The disc position was evaluated on MRI and the severity of DD was classified in four stages. Pearson’s χ2 Test was performed for the analysis of the statistical correlation. Results: A statistically significant relationship between GJH and disc position was found, in particular, a disc displacement with reduction (DDwR) and DD severity. A positive association also emerged between the severity of DD and age, that increased with increasing age. Conclusions: The research results suggest that there is an association between the presence of generalized joint hypermobility (GJH) and disc displacement (DD) in growing patients. Growing patients with GJH showed a higher severity of DD. In older patients, greater severity of DD was evident, suggesting that this condition may worsen with age during growth.