Purpose: This study analyzed the long-term effect of arthrocentesis for severe closed lock of the temporomandibular joint (TMJ) and reevaluated the pathogenesis of this condition based on the data obtained.
Patients and methods: Thirty-nine patients (40 joints) who had experienced sudden-onset, persistent limited mouth opening were the subjects of this study. After unsuccessful noninvasive treatment, arthrocentesis of the upper compartment of the affected TMJ was performed using saline. The follow-up, which consisted of patient self-assessment and clinical examination, ranged from 6 to 37 months (mean, 16.6 +/- 12.0 months). Visual analog scales were used for preoperative and postoperative self-evaluation of pain and dysfunction on forced mouth opening and for assessment of overall change in these parameters postarthrocentesis. Maximal mouth opening (MMO), contralateral movement (CLM) and protrusive movement of the jaw, and presence of joint noises were noted preoperatively and at clinical follow-up examinations.
Results: At 6 to 37 months postarthrocentesis, MMO and CLM had increased significantly (from a mean of 23.10 +/- 5.15 mm to 44.25 +/- 4.96 mm, and from a mean of 4.81 +/- 2.36 mm to 8.20 +/- 1.90 mm, respectively; P < .001). Functional improvement was associated with a significant reduction in pain and dysfunction levels (from a mean of 9.24 +/- 2.90 to 1.45 +/- 1.74, and from a mean of 9.26 +/- 2.82 to 2.68 +/- 2.80, respectively, on a scale of 0 to 15; P < .001). The overall improvement, as expressed in pain and dysfunction levels, was about 95%, with no recurrence of severe closed lock.
Conclusions: Arthrocentesis for sudden-onset closed lock provided sustained normal joint function and marked pain relief. Because the available literature shows that arthrocentesis changes neither disc position nor disc shape, it places in doubt the concept of a displaced and deformed disc limiting joint function. Rather, the efficacy of lavage in resolving closed lock suggests that the condition is the result of sudden adherence of the normally shaped disc to the fossa, rendering it incapable of sliding. The characteristic features of sudden-onset, limited mouth opening warrants classification of this disorder as an independent entity within the realm of TMJ disturbances.