Temporomandibular joint dysfunction syndrome: a close association with systemic joint laxity (the hypermobile joint syndrome)
Sixty-two patients admitted for elective reconstructive surgery of the temporomandibular joint (TMJ) and eight seen as outpatients with a chief complaint of TMJ dysfunction during the same time interval were evaluated for possible etiologic factors contributing to the disease. All hospitalized patients had severe, end-stage degenerative changes within the TMJ, whereas outpatients had less severe disease and did not require surgery. TMJ dysfunction in some patients was said to be a result of established causes including bruxism, malocclusion, and trauma. No patient in this series had evidence of a systemic inflammatory polyarthritis. Of the 70 patients, 38 (54%) met criteria, based on those of Carter and Wilkinson, as modified by Beighton et al., sufficient to warrant a diagnosis of the hypermobile joint syndrome. Five patients had classic Ehlers-Danlos syndrome and therefore were not patients with "benign hypermobility," and an additional two cases were described as "marfanoid" and as possible Ehlers-Danlos syndrome, respectively. Radiographs showed TMJ hyperextensibility in four hypermobile patients. Long-term surgical outcome was identical in the hypermobile and nonhypermobile groups. The incidence of hypermobility in this series is strikingly higher than the expected incidence in an otherwise population. Magnetic resonance images of the TMJs on separate groups of asymptomatic normal and hypermobile women identified excessive anterior movement in the hypermobile group, together with abnormal anterior disk position in some. We hypothesize that hypermobility within the TMJ may cause accelerated disk destruction and degenerative disease.