A decrease in the molecular weight of hyaluronic acid in synovial fluid from patients with temporomandibular disorders.

Background: The molecular weight (MW) of hyaluronic acid (HA) in joints generally declines in inflammatory arthritis. As inflammation exists in certain temporomandibular disorders (TMD), we measured the MW of HA in synovial fluid (SF) recovered from patients with TMD and compared it with that from normal controls.
Methods: Synovial fluid was obtained from patients with TMD (21 TMJs) and normal controls (5 TMJs). The MW of HA was measured using high-performance liquid chromatography (HPLC).
Results: In the controls, the MW of HA in SF exceeded the detection limit, 3000 kDa. In contrast, 19 (90.5%) of 21 SF samples from patients showed a decreased MW of HA. The median MW of HA (1570 kDa) in TMD was significantly lower than that in the controls (P < 0.01).
Conclusion: The MW of HA in SF from patients with TMD is decreased.