Correlation between pain and synovitis in patients with internal derangement of the temporomandibular joint.

A correlation between pain scores by questionnaire and synovitis index via arthroscopic inspection was made in 28 patients with internal derangement of the temporomandibular joint (TMJ) with closed lock. A statistically significant but weak correlation was found between the visual analog scale of pain and the index of distribution of synovitis. However, in the questionnaire, pain on chewing had a positive correlation with both the intensity and distribution of synovitis in the TMJ. This study indicates that synovitis is one cause of TMJ pain in patients with closed lock.