Arthrocentesis of the TMJ
Arthrocentesis is a safe and rapid procedure used to treat a multitude of disorders affecting the temporomandibular joint (TMJ). The popularity of this procedure followed the success of arthroscopic surgical procedures with initial application for the treatment of disk displacement without reduction. Since that time, arthrocentesis has been described for other clinical indications; however, it is not indicated for all joint disorders. The procedure does not change the shape or position of the disk or the structure of the mandibular condyle and glenoid fossa. Pathology involving bony degeneration, osteophytes and bone spicules, disk perforation, or fibro-osseous ankylosis is not amendable to arthrocentesis. Treatment is generally necessary when other non-surgical and pharmacologic methods have failed.
The type of pain associated with the TMJ is multifaceted. Possible sources of pain include impingement, compression, and inflammatory changes in the retrodiscal tissues; inflammatory changes in the synovial membrane with joint effusion; and capsulitis. Biochemical investigations of TMJ synovial fluid obtained through arthroscopic lavage and arthrocentesis have yielded information regarding the pathophysiology of pain in the TMJ. Lavage and lysis of the joint space allows for removal and dilution of inflammatory mediators, which may contribute to the reduction of pain. Elevated protein levels in synovial fluid parallel the degree of inflammation because of increased permeability of the synovial membrane to plasma proteins. Joint effusion detected on T 2 -weighted magnetic resonance images reflects hypertrophic synovial lining and exudation from inflamed tissues. Joint effusion is observed in joints at a more advanced degree of internal derangement.
Before arthrocentesis is performed, patients must undergo appropriate diagnosis and treatment planning. This is based upon medical history, visual analogue pain scales (if indicated), and clinical and radiographic findings. Clinical examination should include interincisal opening, lateral excursions, deviation on opening, along with documentation of any occlusal discrepancies. Auscultation of the joint may be performed to ascertain any clicks or crepitus, which may indicate disc displacement or degenerative joint disease, respectively. Radiographic imaging would initially include a panoramic screening film followed by other appropriately indicated imaging modalities including tomographs, computed tomography, magnetic resonance imaging, or nuclear medicine studies. Non-surgical management for internal derangement without reduction improves symptoms comparably to surgical intervention; however, improvement takes a longer time. Patients with TMJ internal derangements without reduction do not respond to non-surgical management benefit from arthrocentesis and/or arthroscopic lysis and lavage.
TMJ internal derangements have been described to progress through clinical stages, initially presenting as clicking with normal interincisal opening and progressing to limited opening lacking translatory movement where clicking ceases because of a nonreducible disc. Excessive loading on the joint with a nonreducible, anteriorly displaced disc, which restricts the ability of the condyle to translate on the articular surfaces, is treated effectively with arthrocentesis of the superior joint space. The major indications for arthrocentesis are as follows:
- Acute and chronic limitation of opening because of anteriorly displaced disc without reduction
- Chronic pain with good range of motion and anterior disc displacement with reduction
- Degenerative osteoarthritis
TMJ open lock occurs where the condyle is entrapped anterior to a lagging disc. This has been reported to be effectively treated with arthrocentesis and should be distinguished from TMJ condylar dislocation where the condylar head is locked anterior to the articular eminence. Contra-indications to TMJ arthrocentesis would be those patients who have not undergone appropriate conservative/non-surgical and pharmacologic treatment, demonstrate bony or fibrous ankylosis, or have extracapsular sources of pain.