Temporomandibular Joint Structural Derangement and General Joint Hypermobility

Aim: To explore the relationship between general joint hypermobility (GJH) and displacement of the temporomandibular joint (TMJ) disc as evident from magnetic resonance imaging (MRI). Methods: Fifth finger extension, thumb apposition, elbow extension, knee extension, trunk flexion, and ankle dorsiflexion were measured in 66 young female patients with MRI-evident TMJ internal derangement (ID) and in 30 age-matched female controls. The Beighton score of each subject was measured quantitatively. The possible association between TMJ ID and mobility of a single joint or index of GJH, ie, the Beighton score, were assessed with one-way ANOVA with post-hoc Bonferroni and chi-square test, respectively. Correlations of the mobility of every measured joint were also explored. Results: Very few of the TMJ ID patients and control subjects were diagnosed with GJH according to the Beighton score. The Beighton score did not differentiate between subjects with and without TMJ ID. Subjects with TMJ ID, especially patients with MRI-evident disc displacement without reduction, seemed to have a stiffer trunk than controls, but this may not be of clinical relevance. The mobilities of paired joints were significantly correlated; however, the mobilities of different anatomical joints seemed to be independent. Conclusion: Based on the Beighton score, GJH does not seem to be a reliable indicator of the presence of TMJ ID. Keywords: Beighton score, general joint hypermobility, internal derangement, temporomandibular joint