Management of inflammatory temporomandibular joint collapse in children

Abstract

Juvenile idiopathic arthritis is the most common pediatric rheumatologic condition.( Abramowicz et al., 2016 Jul) 2 The etiology and pathogenesis have not been fully elucidated; a combination of environmental and certain immunogenic factors is suspected. This review will provide current knowledge and concepts of diagnosis and management of children with JIA and TMJ arthritis.

1. Introduction

Juvenile idiopathic arthritis (JIA) describes a group of heterogenous arthritides that result in destruction of hard and soft tissues in a single or multiple joints in children.^1,2 The term ‘juvenile idiopathic arthritis’ was implemented in the late 1990s by the International League of Associations for Rheumatology to create standardization between the American term ‘juvenile rheumatoid arthritis’ and the European term ‘juvenile chronic arthritis’.³ The term ‘idiopathic’ was introduced due to the lack of a definitive identifiable etiology.

JIA is the most common pediatric rheumatologic condition affecting at least 300,000 children in the United States (US). International prevalence ranges from 8 to 400 per 100,000.¹ The diagnosis is made in children 16 years old or younger with persistent arthritis for at least 6-weeks characterized by joint effusion, stiffness, limited range of motion and calor without an alternative diagnosis. The temporomandibular joints (TMJs) are involved in more than 40% of patients and can lead to joint deformity, asymmetry, malocclusion, obstructive sleep apnea, retrognathia and/or significant physical and psychological morbidity.^4,2, 5, 6

Treatment involves a multidisciplinary approach including rheumatologist, oral maxillofacial surgeons (OMS), orthodontists, radiologists, pediatric dentists, physical and psychological therapists and orofacial pain specialists.⁷

The aim of this article is to provide a review of the current knowledge regarding etiology, diagnosis and management of children with JIA and TMJ involvement.

1.1. Temporomandibular joint arthritis

The understanding of the pathology of TMJ arthritis has changed over the past years and it is now thought to represent a multifactorial condition mediated by growth delay, degeneration, deformity, mechanical overloading, dysfunction and compensation of the dentofacial structures.⁵ Impairment of condylar growth is believed to be perpetuated by metabolic changes in the articular structures.⁵ Growth delay and a suboptimal joint health result in chronic low-grade inflammation which imposes further TMJ destruction.⁵

In patients with JIA, the timing of TMJ involvement has variable effects on growth and development of dentofacial structures. Impairment in condylar growth can be seen in patients who are skeletally immature.⁵ When both joints are involved, reduced vertical posterior ramus height develops and results in mandibular retrognathism.⁵ When joint involvement is unilateral, mandibular asymmetry and a maxillary occlusal cant develop.⁵ It is important to note that, the degree of asymmetry and dentofacial compensation depends on the onset of JIA in relation to the patient’s growth but the severity of TMJ deformity does not always correlate with the facial abnormality.⁵ In skeletally mature patients, the TMJ degeneration can lead to a loss of condylar height resulting in an open bite deformity.⁵

1.2. Clinical presentation and classification

The classification of JIA includes 8 subgroups based on history, clinical characteristics and laboratory findings: 1) systemic onset, 2) persistent oligoarthritis, 3) extended oligoarthritis, 4) rheumatoid factor-positive polyarthritis, 5) rheumatoid factor–negative polyarthritis, 6) psoriatic arthritis, 7) enthesitis-related arthritis and 8) undifferentiated arthritis.³

TMJ involvement in JIA is suspected when facial asymmetries or condylar abnormalities present in children. When compared to idiopathic condylar resorption (ICR), JIA is typically accompanied by synovitis and an ongoing history of appendicular joint inflammation.¹ Clinical presentation may involve muscle pain and tenderness which may be difficult to differentiate from myofascial pain disorder (MPD).² However, TMJ arthritis in children with JIA is usually asymptomatic, especially in its early stages.^1,8 In patients with JIA, when the disease process is advanced, orofacial pain and jaw dysfunction are more evident.

The orofacial examination of patients with JIA starts with assessment of the symptom presentation and medical history.⁹ Although pain has not been found to be a reliable indicator of inflammation in JIA patients, they should be asked about the presence of orofacial symptoms such as: location, intensity, frequency, character, environment and alleviating/aggravating factors.^6,9 TMJ evaluation should then be performed including evaluation of maximal incisal opening (MIO), deviation and latero-protrusive movements to establish a baseline for follow-up.^9,7

1.3. Diagnosis

A multidisciplinary approach and the evaluation of radiologic and laboratory abnormalities is often necessary for the diagnosis of JIA.⁷ Patients with JIA have at least two of the following clinical features for more than 6 weeks: joint swelling, pain/tenderness with motion, limitation of joint motion, and calor overlying the joint.⁶ Limited maximal incisal opening (MIO) and deviation of the jaw with opening has a high sensitivity and specificity for synovitis.¹

Skin and nail changes are common in psoriatic arthritis.¹ Uveitis is also seen in oligoarthritis and HLA-B27 positive enthesitis-related arthritis.¹ Laboratory analysis is typically without abnormalities often leading to delayed referrals and diagnosis. However, some patients may present with anemia and/or elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP).¹ JIA in children is phenotypically different from that of adults with rheumatoid arthritis with only 5–10% of children demonstrating serum positivity for rheumatoid factor (RF) and anti-cyclic citrullinated peptide (CCP) antibodies.¹ Systemic onset JIA uniquely manifests with signs of systemic inflammation such as fever, rash, anemia, lymphadenopathy, hepatosplenomegaly and/or serositis.¹

The gold standard for diagnosis of TMJ inflammation is magnetic resonance imaging (MRI) with intravenous (IV) gadolinium.^6,10 The extent of enhancement of the intraarticular soft tissue correlates with the presence of synovitis and helps to assess the presence of active inflammation versus long-standing chronic arthritis.^1,6 MRI with contrast has multiple limitations (e.g. requirement for sedation in young patients, need for IV contrast administration, contraindication in the presence of kidney disease and/or cost^6,3,7). There is a physiologic synovitis in approximately 60% of children.⁶ Imaging modalities such as ultrasound and panoramic radiographs have been limited and unreliable in detecting changes related to TMJ arthritis and synovitis.^1,3

1.4. Management

The basis for management of systemic JIA depends on optimization of medical care and collaboration with pediatric rheumatologists. The goal is to provide a timely diagnosis, reduce articular inflammation, maximize function and limit disruption to growth.⁵ TMJ-specific assessment involves addressing the general disease activity, inflammatory status of the TMJs, progression of dentofacial deformity, level of skeletal maturity, and continued growth potential.⁵ For symptomatic patients, physical and splint therapy often prove beneficial.⁵ Orofacial symptoms and dysfunction are also managed with intra-articular lavage/arthrocentesis which may have anti-inflammatory effects.¹¹ Several authors have reported subjective improvement of symptoms and increase in MIO but few statistically significant differences when compared to the no-treatment groups.¹¹ Additionally, the use of intra-articular steroid injections has decreased over the past decade due to the risk of steroid-induced mandibular growth impairment and risk for ankylosis.^4,1,8

In 2017, the Surgical Task Force of the TMJaw research group identified ‘best practices in management of JIA-induced dentofacial deformities.’ From there, an algorithm was devised describing management options for patients with JIA. Surgical decision for joint preservation or joint reconstruction is based on progression versus quiescence of TMJ involvement and patient’s skeletal maturity.⁴

1.5. Systemic therapy

NSAIDs are the most commonly used medications followed by Disease-modifying anti-rheumatic drugs (DMARDs) such as methotrexate, sulfasalazine and leflunomide.¹ In patients who cannot tolerate DMARDs or those with resistant JIA, biologics (e.g. etanercept (Enbrel), adalimumab (Humira), and infliximab (Remicade)) have become increasingly used.¹

Methotrexate is the most commonly used DMARD. It is a folic acid analog that inhibits dihydrofolate reductase and the synthesis of purine and thymine.¹ This reduces T- and B-cell activation and the apoptosis of activated T-cells and decreases antibody production.¹ In patients with JIA, 60–70% significantly benefit when on methotrexate therapy.¹ Relevant side effects are common and include gastrointestinal toxicity, transient elevation in serum aminotransferase levels and ‘post-dosing reaction.‘¹ The post-dosing reaction is known to occur within 24 ​h and is characterized by malaise, fatigue, GI upset and occasional headaches, dizziness, fatigue.¹ Folic acid supplementation reduces side effects.¹ Methotrexate also places children at risk for immunosuppression and infection.¹ Biologics are known to be more immunosuppressive and have less long-term safety data available.¹

1.6. Joint preservation

Correction of mild to moderate dentofacial asymmetry can be achieved with orthopedic appliances such as the activator and the distraction splint.⁵ However, limitations include constant use of appliance and splint therapy, need for follow-up every 6–8 weeks, high caries risk, and/or potential for development of periodontal disease. In US, lack of insurance reimbursement is also a concern.^4,5 In Europe, orthopedic appliances are frequently used in patients with mild to moderate dentofacial deformities.⁵

In skeletally mature patients with moderate deformity and quiescent disease, joint preservation with orthognathic surgery or mandibular distraction osteogenesis (DO) are recommended.1, 4, 5 Orthognathic surgery is completed as a single procedure. Approximately half of patients who undergo DO will undergo future orthognathic surgery.⁵ Sometimes maxillary correction is not indicated as dentoalveolar growth will permit levelling of the occlusion when the ramus has been lengthened with DO or inverted L type osteotomy and can occur into the mid 20s.¹

In skeletally immature patients with no or minimal active TMJ disease, nonsurgical management with orthopedic appliance is recommended.¹ Only when the TMJ disease in is severe and debilitating should mandibular DO or joint reconstruction be considered.^4,5

1.7. Joint reconstruction

In the setting of severe condylar destruction and/or active disease that cannot be medically controlled, a joint reconstruction procedure with autologous or alloplastic material is warranted.^4,1 Costochondral grafts have been the gold standard since the 1970s due to their positive outcome and ability to grow with the patient.¹ However, some disadvantages include risk of resorption due to disease affecting the same biologic tissue, donor-site morbidity and TMJ ankylosis.¹ Alloplastic total joint replacement (TJR) with stock or custom-designed TMJ prostheses has recently been expanded to the pediatric population. TJR has the advantage of limiting arthritic destruction and reducing the need for multiple procedures which are sometimes associated with autogenous reconstruction.^1,5 The complications include possible erosion of surrounding bone and ongoing heterotopic bone formation.^1,5 Long term follow-up for TJR in children is limited. Children will likely require multiple TJRs in their lifetime since the longevity of TJR in adults has only been studied for 20 years, although there is some evidence of functional growth.^1,12,13