Clinical Findings

Primary osteoarthritis, which usually is seen in older individuals, is insidious in its onset; it generally produces only mild discomfort, and individuals rarely complain about the condition. Secondary osetoarthritis usually occurs in younger patients (20 to 40 years old) and tends to be painful. In contrast to primary degenerative joint disease and rheumatoid arthritis, it often is limited to only one TMJ, although it may become bilateral in the late stages, and involvement of other joints is uncommon. The condition is characterized by TMJ pain that is increased by function, joint tenderness, limitation of mouth opening, and occasional clicking and popping sounds. In the late stages, crepitation may be noted in the joint.

Imaging Findings

The earliest radiologic feature of osetoarthritis of the TMJ, whether primary or secondary, is subchondral sclerosis in the mandibular condyle. If the condition progresses, condylar flattening and marginal lipping may be noted. In the later stages, erosion of the cortical plate, osteophyte formation, or both may occur. Breakdown of the subcortical bone occasionally may result in the formation of bone cysts. Although changes in the articular fossa generally are not as severe as changes in the condyle, cortical erosion sometimes can be seen. Narrowing of the joint space also occurs in the late stages; this is indicative of concomitant degenerative changes in the intra-articular disk. Although changes in the TMJ usually can be seen on plain radiographs, sagittal and coronal computed tomography (CT) scans are the preferred modality for imaging the bony structures.

Diagnosis

The diagnosis of osteoarthritis is based on the patient’s history and clinical and radiographic findings. A history of trauma or parafunctional oral habits is often reported. Involvement is generally unilateral, and no significant changes are observed in any of the other joints. The pain tends to be well localized, and the TMJ is often tender to palpation.

Treatment

Treatment of degenerative arthritis of the TMJ is usually medical, as in other joints of the body. It involves the use of nonsteroidal anti-inflammatory drugs, application of heat, eating a soft diet, limitation of jaw function, and use of a bite appliance to control parafunction if the patient has a chronic habit of clenching or grinding the teeth. Arthrocentesis has also been shown to be helpful.^4,5 Physical therapy with thermal agents, ultrasound, and iontophoresis also can be beneficial, and isotonic and isometric exercises are used to improve joint stability after acute symptoms have subsided. The use of intra-articular steroid injections is controversial; they should be used only in patients with acute symptoms that do not respond to other forms of medical management. Because of the potentially damaging effects of long-acting steroids,^4,6 they should be limited to no more than three or four single injections given at 3-month intervals. Intra-articular injection of high-molecular-weight sodium hyaluronate given twice, 2 weeks apart, has been shown to have essentially the same therapeutic effect as a steroid injection, without the potential adverse effects.^5,7

When the acute symptoms have been controlled, therapy is directed toward control of factors possibly contributing to the degenerative process. Unfavorable loading of the joint is eliminated by replacement of missing teeth to establish a good, functional occlusion; by correction of any severe dental malrelationships through orthodontics or orthognathic surgery; and by continued use of a bite appliance at night to control teeth-clenching or teeth-grinding habits.^6,8

In patients in whom medical management for 3 to 6 months fails to relieve the symptoms, surgical management may be indicated. Surgery involves removal of only the minimal amount of bone necessary to produce a smooth articular surface. Unnecessary removal of the entire cortical plate, as occurs with the so-called condylar shave procedure or high condylotomy, can lead to continuation of the resorptive process in some instances, and should be avoided if possible.

Clinical Findings

Patients with rheumatoid arthritis of the TMJ have bilateral pain, tenderness, swelling in the preauricular region, and limitation of mandibular movement. These symptoms are characterized by periods of exacerbation and remission. Joint stiffness and pain are usually worse in the morning and decrease during the day. The limitation in mandibular movement worsens as the disease progresses; the patient also may develop an anterior open bite.

Imaging Findings

Although radiographic changes may not be noted in the early stages of the disease, about 50% to 80% of patients show bilateral evidence of demineralization, condylar flattening, and bone erosion as the disease progresses, so the articular surface appears irregular and ragged. Erosion of the glenoid fossa also is seen sometimes. Narrowing of the joint space is caused by destruction of the intra-articular disk. With continued destruction of the condyle, loss of ramus height can lead to contact of only the posterior teeth and an anterior open bite.

Diagnosis

Rheumatoid arthritis is diagnosed on the basis of the history, clinical and radiographic findings, and confirmatory laboratory tests. Distinguishing features for rheumatoid arthritis and degenerative arthritis of the TMJ are shown in Table 51-3.

Treatment

Treatment of rheumatoid arthritis of the TMJ is similar to that provided for other joints.^7,10 Anti-inflammatory drugs are used during the acute phases, and mild jaw exercises are used to prevent excessive loss of motion when acute symptoms subside. In severe cases, disease-modifying drugs, such as methotrexate, and biologic agents, including etanercept, infliximab, adalimumab, certolizumab, golimumab, abatacept, tocilizumab, and rituximab, may be used pending systemic presentation. Orthognathic surgery may be necessary in patients with an anterior open bite after the disease goes into remission, or in patients in whom ankylosis develops after that condition is corrected.

Psoriatic Arthritis

Psoriatic arthritis occurs in approximately one-third of patients who have cutaneous psoriasis. It can have a sudden onset, can be episodic in nature, and may show spontaneous remission.^9,12 Often only one TMJ is involved. Symptoms include TMJ pain and tenderness, restricted jaw movement, and crepitation, mimicking the symptoms of rheumatoid arthritis.^9,12 Radiographic changes are nonspecific and cannot be distinguished easily from those of other types of arthritis, particularly rheumatoid arthritis and ankylosing spondylitis.^13,14 They usually involve erosive changes in the condyle and glenoid fossa associated with extreme narrowing of the joint space.^11,15,16 In severe cases, ankylosis may develop, reflected occasionally in new bone formation at earlier stages.^12,17

The diagnosis usually is based on the triad of psoriasis, radiographic evidence of erosive arthritis, and a negative serologic test for rheumatoid factor. Even in the presence of a rash, however, the diagnosis cannot be absolutely confirmed. The differential diagnosis always should include rheumatoid arthritis, reactive arthritis, ankylosing spondylitis, and gout.

Treatment of psoriatic arthritis of the TMJ is similar to that of rheumatoid arthritis, and is driven essentially by the imperative to treat the systemic inflammatory disease process.^13,18–21 Surgery is necessary if ankylosis occurs.

Ankylosing Spondylitis

About one-third of patients with ankylosing spondylitis develop TMJ involvement several years after onset of the disease. Pain and limitation of jaw movement are the most common symptoms, and ankylosis can develop in advanced cases.^8,11,14,22 On radiographic examination, about 30% of patients show erosive changes in the condyle and fossa and narrowing of the joint space.^15,23 In long-standing cases, a more florid osteophytic response is sometimes seen during quiescent periods. The severity of the changes seems to be related to the severity of the disease. Treatment of ankylosing spondylitis of the TMJ is generally medical and is part of the total management of the patient. Physical therapy is used to improve jaw mobility, and bite appliances are used, when indicated, to reduce parafunctional stress on the joint. If ankylosis develops, surgery is the treatment of choice.²⁴

Reactive Arthritis

Reactive arthritis of the temporomandibular joint is more common in males than in females. It is characterized by recurrent pain, swelling, and limitation of mouth opening.²⁵ Radiographically, condylar erosion may be evident.²⁶ Treatment is similar to that of the other seronegative spondyloarthropathies, consisting of nonsteroidal anti-inflammatory drugs, intra-articular steroids, and disease-modifying drugs. If a specific triggering bacterial infection can be identified, an appropriate antibiotic should be prescribed.

Clinical Findings

Infectious arthritis generally results in unilateral pain, tenderness, swelling, and redness in the region of the TMJ. Chills, fever, sweating, and systemic findings characteristic of the specific type of infection also are present. Often the teeth cannot be occluded because of swelling within the joint. In pyogenic forms of infectious arthritis, fluctuation may be noted in the joint region. Patients with Lyme disease show characteristic skin lesions and often positive serology.^18,29

Imaging Findings

Radiographic findings are usually normal in early stages of the disease because of lack of bony involvement, but the intra-articular accumulation of pus or inflammatory exudate may cause separation of articulating surfaces, which can be detected on magnetic resonance imaging (MRI). Later, depending on the severity and chronicity of the infection, varying degrees of bony destruction, ranging from damage to the articular surface of the mandibular condyle to extensive osteomyelitis, may be seen. In the late stages, fibrous or bony ankylosis may occur. In children, infectious arthritis can affect growth of the condyle, resulting in facial asymmetry.

Treatment

Treatment of infectious arthritis includes the use of appropriate antibiotics, proper hydration, control of pain, and limitation of jaw movement. Arthrocentesis with Ringer’s solution one to three times weekly until acute symptoms subside has also been recommended.³² Suppurative infections may require aspiration, incision, and drainage, or sequestrectomy. When bone loss has been extensive, reconstructive procedures may be necessary. In children in whom mandibular growth has been affected, a costochondral graft can be used to correct facial asymmetry and re-establish growth of the mandible.

Gout

Gouty arthritis of the TMJ occurs most frequently in men older than 40 years and usually is preceded by involvement of one or more joints of the feet or hands. The attack usually occurs suddenly, and the joint becomes swollen, painful, red, and tender. Recovery may occur in a few days, and remission can last for months to years.

When attacks are infrequent, radiographic changes may not be noted for a long time. Because so few cases have been reported, the precise radiographic changes that occur have not been well documented. Calcified areas in the disk, destruction of the hard tissues of the joint, condylar exostoses and spurring, and the presence of tophi have been described.^21,33–35 The initial approach to treatment of gout involving the TMJ is medical. If symptoms are not controlled, however, surgical débridement of the joint and arthroplasty may be indicated.