Classification of temporomandibular joint erosion, arthritis, and inflammation in patients with juvenile idiopathic arthritis

Developing standards for MRI evaluation of joints in children with juvenile idiopathic arthritis utilizing the temporomandibular joint as a model

The treatment of a patient with juvenile idiopathic arthritis (JIA) is best monitored with standardized and validated tools to measure joint changes over time. Treatment approaches are best indicated if the clinicians are aware of the structural status of the joint at a given time, especially in anatomically deep joints for which clinical assessment is limited. Magnetic resonance imaging (MRI) is of utmost importance for assessment of deep joints and extra-articular soft tissue of the entire body for which ultrasound may be suboptimal. Because the distinction between pathologic and physiologic joint changes on MRI is key for proper diagnosis and treatment of patients with arthropathies, a comprehensive standardized approach is needed to effectively measure outcomes of growing joints of children with JIA. Such an approach is essential for both clinical assessment and to conduct clinical trials in patients with JIA treated in different centers around the world. To meet this need, several international imaging collaborative research groups have been developing MRI scales over the past years, including the MRI in JIA (JAMRI) special interest group within the Outcome Measures in Rheumatology (OMERACT) research network. This manuscript reviews the efforts of the OMERACT JAMRI working group to generate and validate pediatric MRI scoring systems for different joints in children with JIA that can have ubiquitous utilization anywhere in the world. In particular, it describes the different steps of development and validation of an MRI scale using the TMJ as a model.

Temporomandibular joint involvement in patients with Juvenile Idiopathic Arthritis: comparison of ultrasonography and magnetic resonance imaging in assessing the periarticular space width

OBJECTIVES

This study aimed to compare the performance of Ultrasonography (US) and Magnetic Resonance Imaging (MRI) in assessing the Lateral Periarticular Space (LPAS) of Temporomandibular Joints (TMJs) in patients with Juvenile Idiopathic Arthritis (JIA).

METHODS

The LPAS width was evaluated in two different patient groups. In the JIA group, including 29 children (13 ± 2.8 years) with JIA, the LPAS width was measured with both MRI and US. In the healthy group, including 28 healthy children (12.6 ± 2.5 years), the LPAS width was measured only with US. Comparisons of LPAS width based on patient groups and TMJ contrast enhancement in MRI were evaluated by applying the Mann-Whitney U test. Correlation and agreement between MRI and US measurements in JIA group were tested using Spearman rank correlation and Bland-Altman method.

RESULTS

The LPAS width was significantly greater in the JIA group than in the healthy group. In the JIA group, the LPAS width was significantly greater in TMJs with moderate/severe enhancement than those with mild enhancement. A positive significant correlation between MRI and US measurements of LPAS width was found in the JIA group. In the same group, Bland-Altman method showed a good level of agreement between MRI and US measurements.

CONCLUSION

Although, US cannot replace MRI in the evaluation of TMJ in patients with JIA, US could be used as a supplementary imaging method to MRI in assessing the TMJ disease.

MRI of the temporomandibular joint in children with juvenile idiopathic arthritis: protocol and findings

Contrast-enhanced magnetic resonance imaging (MRI) is the technique of choice for diagnosis and monitoring of temporomandibular joint (TMJ) disorders in patients with juvenile idiopathic arthritis (JIA), as it is able to visualize both soft tissue and osteochondral changes. Approximately 40% of children with JIA develop inflammatory and chronic osteochondral changes observable on imaging, which if left untreated can lead to significant facial growth impairment, including facial asymmetry and retrognathia. MRI of the TMJ plays a paramount role in diagnosis and treatment monitoring in JIA since early signs of TMJ involvement are difficult to detect clinically and with physical examination. Findings of TMJ arthritis may be classified into acute and chronic domains. Early or acute manifestations include joint effusion, bone marrow edema, synovial thickening, and increased joint enhancement. With disease progression, there are characteristic osteochondral changes, including deformity of the mandibular condyle with shortening of the mandibular ramus, bone erosions, and disk abnormalities. In this pictorial essay, we describe a consensus MRI protocol for the study of the TMJ and illustrate the degree of normal and pathological MRI findings using currently available MRI scoring systems of the TMJ developed for JIA.

Cone beam computed tomography in the assessment of TMJ deformity in children with JIA: repeatability of a novel scoring system

BACKGROUND

The temporomandibular joint (TMJ) is frequently involved in juvenile idiopathic arthritis (JIA). Diagnostic imaging is necessary to correctly diagnose and evaluate TMJ involvement, however, hitherto little has been published on the accuracy of the applied scoring systems and measurements. The present study aims to investigate the precision of 20 imaging features and five measurements based on cone beam computed tomography (CBCT).

METHODS

Imaging and clinical data from 84 participants in the Norwegian study on juvenile idiopathic arthritis, the NorJIA study, were collected. Altogether 20 imaging features and five measurements were evaluated independently by three experienced radiologists for intra- and interobserver agreement. Agreement of categorical variables was assessed by Fleiss', Cohen's simple or weighted Kappa as appropriate. Agreement of continuous variables was assessed with 95% limits of agreement as advised by Bland and Altman.

RESULTS

"Overall impression of TMJ deformity" showed almost perfect intraobserver agreement with a kappa coefficient of 0.81 (95% CI 0.69-0.92), and substantial interobserver agreement (Fleiss' kappa 0.70 (0.61-0.78)). Moreover, both "flattening" and "irregularities" of the eminence/fossa and condyle performed well, with intra- and interobserver agreements of 0.66-0.82 and 0.55-0.76, respectively. "Reduced condylar volume" and "continuity" of the fossa/eminence had moderate intra- and interobserver Kappa values, whereas continuity of the condyle had Kappa values above 0.55. Measurements of distances and angles had limits of agreement of more than 15% of the sample mean.

CONCLUSIONS

We propose a CBCT-based scoring system of nine precise imaging features suggestive of TMJ deformity in JIA. Their clinical validity must be tested.

MRI in the Assessment of TMJ-Arthritis in Children with JIA; Repeatability of a Newly Devised Scoring System

RATIONALE AND OBJECTIVES

The temporomandibular joint (TMJ) is commonly involved in children with juvenile idiopathic arthritis. The diagnosis and evaluation of the disease progression is dependent on medical imaging. The precision of this imaging is under debate. Several scoring systems have been proposed but transparent testing of the precision of the constituents of the scoring systems is lacking. The present study aims to test the precision of 25 imaging features based on magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Clinical data and imaging were obtained from the Norwegian juvenile idiopathic arthritis study, The NorJIA study. Twenty-five imaging features of the TMJ in MRI datasets from 86 study participants were evaluated by two experienced radiologists for inter- and intraobserver agreement. Agreement of ordinal variables was measured with Cohen´s linear or weighted Kappa as appropriate. Agreement of continuous measurements was assessed with 95% limit of agreement according to Bland-Altman.

RESULTS

In the osteochondral domain, the ordinal imaging variables "loss of condylar volume," "condylar shape," "condylar irregularities," "shape of the eminence/fossa," "disk abnormalities," and "condylar inclination" showed inter- and intraobserver agreement above Kappa 0.5. In the inflammatory domain, the ordinal imaging variables "joint fluid," "overall impression of inflammation," "synovial enhancement" and "bone marrow oedema" showed inter- and intraobserver agreement above Kappa 0.5. Continuous measurements performed poorly with wide limits of agreement.

CONCLUSION

A precise MRI-based scoring system for assessment of TMJ in JIA is proposed consisting of seven variables in the osteochondral domain and four variables in the inflammatory domain. Further testing of the clinical validity of the variables is needed.

In children and adolescents with temporomandibular disorder assembled with juvenile idiopathic arthritis - no association were found between pain and TMJ deformities using CBCT

Background

Children and adolescents with juvenile idiopathic arthritis (JIA) may suffer from temporomandibular disorder (TMD). Due to this, imaging diagnosis is crucial in JIA with non-symptomatic TM joint (TMJ) involvement. The aim of the study was to examine the association between clinical TMD signs/symptoms and cone-beam computed tomography (CBCT) findings of TMJ structural deformities in children and adolescents with JIA.

Methods

This cross-sectional study is part of a longitudinal prospective multi-centre study performed from 2015–2020, including 228 children and adolescents aged 4–16 years diagnosed with JIA, according to the International League of Associations for Rheumatology (ILAR). For this sub-study, we included the Bergen cohort of 72 patients (32 female, median age 13.1 years, median duration of JIA 4.5 years). Clinical TMD signs/symptoms were registered as pain on palpation, pain on jaw movement, and combined pain of those two. The severity of TMJ deformity was classified as sound (no deformity), mild, or moderate/severe according to the radiographic findings of CBCT.

Results

Of 72 patients, 21 (29.2%) had pain on palpation at and around the lateral pole, while 41 (56.9%) had TMJ pain upon jaw movement and 26 (36.1%) had pain from both. Of 141 TMJs, 18.4% had mild and 14.2% had moderate/severe structural deformities visible on CBCT. CBCT findings were not significantly associated with either the pain on palpation or the pain on jaw movement. A significant difference was found between structural deformities in CBCT and the combined pain outcome (pain at both palpation and movement) for both TMJs for the persistent oligoarticular subtype (p = 0.031).

Conclusions

There was no association between painful TMD and CBCT imaging features of the TMJ in patients with JIA, but the oligoarticular subtype of JIA, there was a significant difference associated with TMJ pain and structural CBCT deformities.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01870-z.

Comparison of the condyle-fossa relationship and resorption between patients with and without Juvenile Idiopathic Arthritis (JIA)

INTRODUCTION

The most common disease in pediatric rheumatology is juvenile idiopathic arthritis (JIA). JIA is considered to be an autoimmune disease with an onset before the age of 16. The temporal mandibular joint (TMJ) has been reported to be involved in up to 87% of patients with JIA. Even though substantial research has been conducted on JIA, limited research has studied to understand its effect on the condyle-fossa relationship and to evaluate resorption amount on condyle by using a scoring system.

AIM

The purpose of this study was 1) to compare condyle - fossa relationships in the temporomandibular joint (TMJ), 2) was to score condylar resorption by using a TMJ indexing system in patients with JIA and without JIA.

METHODS

The present retrospective cross-sectional study included cone-beam computed tomography (CBCT) images obtained from the sagittal, coronal, and axial slices. In the multidisciplinary Pediatric Rheumatology Outpatient Clinic at The University of Alabama at Birmingham (UAB) children with JIA are also examined by a group of orthodontists working in the same institute from October 2018 to July 2019. The predictor variable consists of patients with JIA and without JIA. The primary outcome variables are the depth of the mandibular fossa, joint spaces, axial angles, medio-lateral width, and condyle resorption. Other study variables were age and sex. In this study, the measurements obtained from 2 different groups (with JIA and without JIA) are compared using a t-test, where Tukey is utilized to adjust for multiple comparisons. The left and right joints are analyzed separately as the paired t test conducted showed a significant difference between the 2 joints (P < .05).

RESULTS

The study was comprised of 34 patients diagnosed with JIA and 34 healthy subjects. The depth of the mandibular fossa, the anterior joint spaces, the axial angles, and the resorption index showed statistically significant differences between the JIA and healthy groups in both left and right sides (P < .05). However, there was no statistically significant difference in the posterior joint spaces and mediolateral width between JIA and healthy groups in both sides (P > .05).

CONCLUSIONS

The results of our study presented the destructive potential of juvenile idiopathic arthritis by using CBCT. CBCT scanning is a helpful tool in the evaluation of the radiographic result of TMJ.

Assessing the Reliability of the OMERACT Juvenile Idiopathic Arthritis Magnetic Resonance Scoring System for Temporomandibular Joints (JAMRIS-TMJ)

Contrast-enhanced magnetic resonance imaging (MRI) remains the most comprehensive modality to assess juvenile idiopathic arthritis (JIA)-related inflammation and osteochondral damage in the temporomandibular joints (TMJ). This study tested the reliability of a new JIA MRI scoring system for TMJ (JAMRIS-TMJ) and the impact of variations in calibration and reader specialty. Thirty-one MRI exams of bilateral TMJs were scored independently using the JAMRIS-TMJ by 20 readers consisting of radiologists and non-radiologist clinicians in three reading groups, with or without a calibrating atlas and/or tutorial. The inter-reader reliability in the multidisciplinary cohort assessed by the generalizability coefficient was 0.61–0.67 for the inflammatory and 0.66–0.74 for the damage domain. The atlas and tutorial did not improve agreement within radiologists, but improved the agreement between radiologist and non-radiologist groups. Agreements between different calibration levels were 0.02 to 0.08 lower by the generalizability coefficient compared to agreement within calibration levels; agreement between specialty groups was 0.04 to 0.10 lower than within specialty groups. Averaging two radiologists raised the reliability above 0.8 for both domains. Therefore, the reliability of JAMRIS-TMJ was moderate-to-good depending on the presence of specialty and calibration differences. The atlas and tutorial are necessary to improve reliability when the reader cohort consists of multiple specialties.

An ultrasound protocol for temporomandibular joint in juvenile idiopathic arthritis: a pilot study

OBJECTIVES

As it is well known, the diagnosis of temporomandibular joint (TMJ) involvement in patients affected by Juvenile Idiopathic Arthritis (JIA) is important to avoid the impairment of mandibular growth. In this context, Magnetic Resonance Imaging (MRI) is the gold-standard for detection of TMJ involvement, however it is expensive and requires patients' collaboration. The aim of this study was to evaluate if ultrasound may be used as an alternative tool to investigate the acute signs of TMJ involvement in JIA patients.

METHODS

Lateral periarticular space (LPAS) and joint effusion were evaluated by ultrasound in a study Group A of 8 JIA children (11.6±3.5 years old) with 14 TMJs involved, as confirmed by MRI, and in a control Group B of 7 healthy children (9.3±1.2 years old) without temporomandibular disorders (TMD). The LPAS width values were compared between the two groups using the Mann-Whitney test. The ultrasound images of the JIA group were then matched with the corresponding MR images; the Spearman Rank Correlation test and the Bland-Altman test were used to evaluate the differences.

RESULTS

The LPAS values in Group A were statistically significantly higher than those in Group B (p < 0.001). There was no overlap of the LPAS values confidence intervals (CIs) between the two groups. No signs of joint effusion were identified in groups A and B. The Spearman test applied to the values of LPAS measured in ultrasound and the corresponding MR images showed a proportional positive correlation with a ρ of 0.623 and a p < 0.05.

CONCLUSIONS

Ultrasound can detect differences in the TMJ features between JIA patients and healthy patients and it might be used as a follow-up tool in the assessment of TMJ involvement in subject affected by JIA.

Discrete Choice Experiment on a Magnetic Resonance Imaging Scoring System for Temporomandibular Joints in Juvenile Idiopathic Arthritis

OBJECTIVE

To determine the relative importance weights of items and grades of a newly developed additive outcome measure called the juvenile idiopathic arthritis (JIA) magnetic resonance imaging (MRI) scoring system for temporomandibular joints (TMJ, JAMRIS-TMJ).

METHODS

An adaptive partial-profile discrete choice experiment (DCE) survey using the 1000Minds platform was independently completed by members of an expert group consisting of radiologists and non-radiologist clinicians to determine the group-averaged relative weights for JAMRIS-TMJ. Subsequently, an image-based vignette ranking exercise was done, during which experts individually rank-ordered 14 patient vignettes for disease severity while blinded to the weights and unrestricted to JAMRIS-TMJ assessment criteria. Validity of the weighted JAMRIS-TMJ was tested by comparing the consensus-graded, DCE-weighted JAMRIS-TMJ score of the vignettes with their unrestricted image-based ranks provided by the experts.

RESULTS

Nineteen experts completed the DCE survey and 21 completed the vignette ranking exercise. Synovial thickening and joint enhancement showed higher weights per raw score compared to bone marrow items and effusion in the inflammatory domain, while erosions and condylar flattening showed non-linear and higher weights compared to disk abnormalities in the damage domain. The weighted JAMRIS-TMJ score of the vignettes correlated highly with the ranks from the unrestricted comparison method, with median Spearman's rho of 0.92 (intra-quartile range: 0.87-0.95) for the inflammation and 0.93 (0.90-0.94) for the damage domain.

CONCLUSIONS

A DCE survey was used to quantify the importance weights of the items and grades of the JAMRIS-TMJ. The weighted score showed high convergent validity with an unrestricted, holistic vignette ranking method.

Current status of MR imaging of juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is the most common chronic arthropathy in the pediatric population. Although the diagnosis is essentially clinical for many affected joints, MR imaging has become an important tool for the assessment of joints that are difficult to evaluate clinically, such as temporomandibular and sacroiliac joints, and for screening of inflammatory changes in the entire body by whole body MRI (WBMRI) assessment. The utilization of MR imaging is challenging in the pediatric population given the need for discrimination between pathological and physiological changes in the growing skeleton. Several multicentric multidisciplinary organizations have made major efforts over the past decades to standardize, quantify, and validate scoring systems to measure joint changes both cross-sectionally and longitudinally according to rigorous methodological standards. In this paper, we (1) discuss current trends for the diagnosis and management of JIA, (2) review challenges for detecting real pathological changes in growing joints, (3) summarize the current status of standardization of MRI protocols for data acquisition and the quantification of joint pathology in JIA by means of scoring systems, and (4) outline novel MR imaging techniques for the evaluation of anatomy and function of joints in JIA. Optimizing the role of MRI as a robust biomarker and outcome measure remains a priority of future research in this field.

Imaging assessment of children presenting with suspected or known juvenile idiopathic arthritis: ESSR-ESPR points to consider

Juvenile idiopathic arthritis (JIA) is the most common paediatric rheumatic disease. It represents a group of heterogenous inflammatory disorders with unknown origin and is a diagnosis of exclusion in which imaging plays an important role. JIA is defined as arthritis of one or more joints that begins before the age of 16 years, persists for more than 6 weeks and is of unknown aetiology and pathophysiology. The clinical goal is early suppression of inflammation to prevent irreversible joint damage which has shifted the emphasis from detecting established joint damage to proactively detecting inflammatory change. This drives the need for imaging techniques that are more sensitive than conventional radiography in the evaluation of inflammatory processes as well as early osteochondral change. Physical examination has limited reliability, even if performed by an experienced clinician, emphasising the importance of imaging to aid in clinical decision-making. On behalf of the European Society of Musculoskeletal Radiology (ESSR) arthritis subcommittee and the European Society of Paediatric Radiology (ESPR) musculoskeletal imaging taskforce, based on literature review and/or expert opinion, we discuss paediatric-specific imaging characteristics of the most commonly involved, in literature best documented and clinically important joints in JIA, namely the temporomandibular joints (TMJs), spine, sacroiliac (SI) joints, wrists, hips and knees, followed by a clinically applicable point to consider for each joint. We will also touch upon controversies in the current literature that remain to be resolved with ongoing research. KEY POINTS: • Juvenile idiopathic arthritis (JIA) is the most common chronic paediatric rheumatic disease and, in JIA imaging, is increasingly important to aid in clinical decision-making. • Conventional radiographs have a lower sensitivity and specificity for detection of disease activity and early destructive change, as compared to MRI or ultrasound. Nonetheless, radiography remains important, particularly in narrowing the differential diagnosis and evaluating growth disturbances. • Mainly in peripheral joints, ultrasound can be helpful for assessment of inflammation and guiding joint injections. In JIA, MRI is the most validated technique. MRI should be considered as the modality of choice to assess the axial skeleton or where the clinical presentation overlaps with JIA.

Condylar alterations and facial growth in children with juvenile idiopathic arthritis

Purpose

The aim of this retrospective study was to evaluate facial growth in children with juvenile idiopathic arthritis (JIA) by means of lateral head cephalometric radiographs and relate the findings to temporomandibular joint (TMJ) condylar changes on panoramic radiographs.

Methods

Radiographic and medical records were evaluated in 65 children with JIA. Cephalometric and panoramic analyses were performed for the impact of condylar changes on facial growth. We compared children with condylar alterations, minor or major, with those without condylar alterations.

Results

Based on panoramic radiographs, no condylar alterations were seen in 27 of the 65 children and condylar alterations were seen in 38 children (i.e., 23 had minor and 15 major condylar alterations). The cephalometric analyses of the children with condylar changes showed significant growth disturbances with a more retrognathic mandible (SNB; p = 0.03), retruded chin position (SNPog; p = 0.02), larger mandibular angulation (ML/NSL; p = 0.009) and maxillary angulation (NL/NSL; p = 0.03) compared with children without condylar alterations. Children with minor condylar alterations had a significantly more retruded chin position (SNPog) than those with no condylar changes (p = 0.04).

Conclusions

Condylar changes in the TMJ, judged on panoramic radiography, in children with JIA, have impact on craniofacial growth. Even minor alterations seem to have an impact.

Ultrasound detected changes in joint cartilage thickness in juvenile idiopathic arthritis

AIM

The purpose of this study was to investigate the changes in joint cartilage thickness in different subtypes of juvenile idiopathic arthritis (JIA) using ultrasound, comparing them with healthy children and to evaluate the relationship with disease duration and inflammatory markers.

METHODS

We conducted a cross-sectional study comprising of 27 cases of JIA and 54 age- and sex-matched healthy children. Bilateral wrist, knee and ankle joint cartilage thicknesses were measured by ultrasound as per European League Against Rheumatism standard guidelines and compared them between JIA subtypes as well as between cases and control.

RESULTS

Descriptive analysis of the whole cohort revealed the mean age of the study population was 8.3 ± 3.2 years with mean cartilage thicknesses at the wrist, knee and ankle being 1.40 ± 0.89 mm, 1.57 ± 0.78 mm and 1.41 ± 0.85 mm, respectively. The median cartilage thicknesses of wrist, knee and ankle joints of JIA cases (n = 27) and healthy controls (n = 54) were 1.01, 1.35, 1.05 and 1.95, 2.00, 1.95, respectively. The joint cartilage thickness was significantly reduced in JIA in comparison to the healthy cohort (P < 0.01). Diseased boys suffered greater cartilage damage in knee joints compared to girls; the polyarticular variety of cases had thinner knee cartilage in comparison to the oligoarticular subtype. Further, it was found that joint cartilage destruction is independent of inflammatory markers and disease duration.

CONCLUSION

Significant cartilage thinning in addition was found in JIA children, particularly in the polyarticular subtype, and more in boys than girls, which is independent of disease duration and inflammatory markers, using ultrasound as a primary investigative tool.

The role of imaging in juvenile idiopathic arthritis

INTRODUCTION

The prognosis of juvenile idiopathic arthritis (JIA) has changed dramatically due to the availability of novel drugs. Prompt diagnosis and treatment are essential to prevent permanent joint damage. As a result, methods to improve JIA diagnosis and prognosis are of high priority to tailor treatment strategies and maximize their efficacy. Musculoskeletal ultrasound and magnetic resonance imaging are more sensitive than clinical examination and radiography in the detection of joint involvement and might play a substantial role to optimize the management of JIA. Areas covered: This review compiles an inventory of potential uses of imaging studies in the modern practice of pediatric rheumatology, together with a critical analysis of the major challenges that are still to be addressed. Imaging appearance of normal growth-related changes of the musculoskeletal system will be discussed. Expert commentary: Knowledge of the evolving patterns of skeletal maturity is paramount to define pathological findings and avoid misinterpretations. Establishing a novel radiological algorithm for a rational use of imaging in JIA is of high priority to allow a speedier integration of imaging into the clinical workflow and decision-making process.

Imaging of temporomandibular joint abnormalities in juvenile idiopathic arthritis with a focus on developing a magnetic resonance imaging protocol

Inflammation and damage in the temporomandibular joint (TMJ) often develop without clinical symptoms but can lead to severe facial growth abnormalities and impaired health-related quality of life, making early diagnosis of TMJ changes crucial to identify. Inflammatory and osteochondral changes detectable through magnetic resonance imaging (MRI) occur in TMJs of approximately 40% of children with juvenile idiopathic arthritis (JIA), and no other imaging modality or physical method of examination can reliably detect these changes. Therefore contrast-enhanced MRI is the diagnostic standard for diagnosis and interval monitoring of JIA. However the specific usage of MRI for TMJ arthritis is not standardized at present. There is a recognized need for a consensus effort toward standardization of an imaging protocol with required and optional sequences to improve detection of pathological changes and shorten study time. Such a consensus imaging protocol is important for providing maximum information with minimally necessary sequences in a way that allows inter-site comparison of results of clinical trials and improved clinical management. In this paper we describe the challenges of TMJ imaging and present expert-panel consensus suggestions for a standardized TMJ MRI protocol.

Toward Establishing a Standardized Magnetic Resonance Imaging Scoring System for Temporomandibular Joints in Juvenile Idiopathic Arthritis

OBJECTIVE

The temporomandibular joints (TMJs) are frequently affected in children with juvenile idiopathic arthritis (JIA). Early detection is challenging, as major variation is present in scoring TMJ pathology on magnetic resonance imaging (MRI). Consensus-driven development and validation of an MRI scoring system for TMJs has important clinical utility in timely improvement of diagnosis and serving as an outcome measure. We report on a multi-institutional collaboration toward developing a TMJ MRI scoring system for JIA.

METHODS

Seven readers independently assessed MRI scans from 21 patients (42 TMJs, from patients ages 6-16 years) using 3 existing MRI scoring systems from American, German, and Swiss institutions. Reliability scores, scoring system definitions, and items were discussed among 10 JIA experts through 2 rounds of Delphi surveys, nominal group voting, and subsequent consensus meetings to create a novel TMJ MRI scoring system.

RESULTS

Average-measure absolute agreement intraclass correlation coefficients (avICCs) for the total scores of all 3 scoring systems were highly reliable at 0.96 each. Osteochondral items showed higher reliability than inflammatory items. An additive system was deemed preferable for assessing minor joint changes over time. Eight items were considered sufficiently reliable and/or important for integration into the consensus scoring system: bone marrow edema and enhancement (avICC 0.57-0.61, smallest detectable difference [SDD] ± 45-63% prior to redefining), condylar flattening (avICC 0.95-0.96, SDD ± 23-28%), effusions (avICC 0.85-0.88, SDD ± 25-26%), erosions (avICC 0.94, SDD ± 20%), synovial enhancement and thickening (previously combined, avICC 0.90-0.91, SDD ± 33%), and disk abnormalities (avICC 0.90, SDD ± 19%).

CONCLUSION

A novel TMJ MRI scoring system was developed by consensus. Further iterative refinements and reliability testing are warranted in upcoming studies.

Temporomandibular joint atlas for detection and grading of juvenile idiopathic arthritis involvement by magnetic resonance imaging

Contrast-enhanced magnetic resonance imaging (MRI) is considered the diagnostic standard for identifying involvement of the temporomandibular joint by juvenile idiopathic arthritis. Early or active arthritis is shown as bone marrow oedema, joint effusion, synovial thickening and increased joint enhancement. Subsequent joint damage includes characteristic deformity of the mandibular condyle, bone erosion, disk abnormalities and short mandibular ramus due to impaired growth. In this pictorial essay, we illustrate normal MRI findings and growth-related changes of the temporomandibular joint in children. The rationale and practical application of semiquantitative MRI assessment of joint inflammation and damage are discussed and presented. This atlas can serve as a reference for grading temporomandibular joint arthritis according to the scoring systems proposed by working groups of OMERACT (Outcome Measures in Rheumatology and Clinical Trials) and the EuroTMjoint research network. Systematic assessment of the level of inflammation, degree of osteochondral deformation, and growth of the mandibular ramus by MRI may aid in monitoring the course of temporomandibular joint arthritis and evaluating treatment options.

Clinical predictors of temporomandibular joint arthritis in juvenile idiopathic arthritis: A systematic literature review

AIM

To assess the level of evidence for subjective and objective parameters in clinical orofacial examination and determine if predictors for temporomandibular joint (TMJ) involvement in juvenile idiopathic arthritis (JIA) patients exist in the current literature.

METHOD

A comprehensive systematic electronic search strategy was performed in all major medical databases in June 2015. Studies were selected independently by two reviewers in accordance with a prespecified protocol and a risk of bias assessment for all included studies. Subjective examination outcome measures assessed were pain, decreased TMJ function, and TMJ sounds. The objective outcome measures assessed were maximal incisor opening, mandibular asymmetric opening, condylar translation, protrusion, myofascial pain on palpation, facial asymmetry, and micro- or retrognathism.

RESULTS

The electronic database search identified 345 unique citations. After application of our strict, predefined inclusion and exclusion criteria, 21 articles were included and data extracted. The study heterogeneity did not allow for meta-analyses. No singular outcome measure can be suggested as a predictor of TMJ involvement in JIA, as sensitivity and/or specificity is too low compared to contrast-enhanced magnetic resonance imaging.

CONCLUSION

The current low level of evidence and study heterogeneity do not allow us to conclude on singular clinical outcome measures. To increase study comparability, we call for a standardized terminology and evidence-based guidelines for clinical orofacial examination parameters in JIA patients.

Juvenile idiopathic arthritis and rheumatoid arthritis: bacterial diversity in temporomandibular joint synovial fluid in comparison with immunological and clinical findings

Temporomandibular joint (TMJ) involvement in juvenile idiopathic arthritis (JIA) occurs in up to 80% of affected children. The purpose of this study was to investigate the presence of bacterial DNA in synovial fluid, and to compare this with clinical and immunological findings in children with JIA, adults with persistent JIA, and adults with rheumatoid arthritis, in order to detect whether bacteria contribute to inflammation in TMJ arthritis. Synovial fluid and skin swab samples were collected from 30 patients (54 TMJs). Bacterial detection was performed using 16S rRNA pyrosequencing. Bacterial DNA was detected in 31 TMJs (57%) in 19 patients (63%). A positive statistically significant correlation was registered between bacterial DNA detected in TMJ synovial fluid and the following factors: total protein concentration in synovial fluid, interleukin 1β, tumour necrosis factor alpha, adrenocorticotropic hormone, and adiponectin, as well as the duration of the general medical disease. Fourteen different bacterial species were detected in synovial fluid. Bacterial DNA in TMJ synovial fluid without contamination was detected in more than 50% of the patients. Studies are needed to evaluate the consequences of this bacterial DNA in synovial fluid with regard to TMJ arthritis.

Temporomandibular Joint Disorders and Orofacial Pain

Temporomandibular disorders (TMD) affect 5% to 12% of the United States population. This article discusses common conditions related to temporomandibular joints, including disc displacements, inflammatory disturbances, loose joint bodies, traumatic disturbances, and developmental conditions. Also addressed are the appropriate imaging modalities and diagnostic criteria for TMD.

Temporomandibular joint diagnostics using CBCT

The present review will give an update on temporomandibular joint (TMJ) imaging using CBCT. It will focus on diagnostic accuracy and the value of CBCT compared with other imaging modalities for the evaluation of TMJs in different categories of patients; osteoarthritis (OA), juvenile OA, rheumatoid arthritis and related joint diseases, juvenile idiopathic arthritis and other intra-articular conditions. Finally, sections on other aspects of CBCT research related to the TMJ, clinical decision-making and concluding remarks are added. CBCT has emerged as a cost- and dose-effective imaging modality for the diagnostic assessment of a variety of TMJ conditions. The imaging modality has been found to be superior to conventional radiographical examinations as well as MRI in assessment of the TMJ. However, it should be emphasized that the diagnostic information obtained is limited to the morphology of the osseous joint components, cortical bone integrity and subcortical bone destruction/production. For evaluation of soft-tissue abnormalities, MRI is mandatory. There is an obvious need for research on the impact of CBCT examinations on patient outcome.

The joints in juvenile idiopathic arthritis

Abstract

Juvenile idiopathic arthritis is the most common rheumatic entity in childhood. Imaging has become an important supplement to the clinical assessment of children with JIA. Radiographs still play an important role in the workup, and long-term follow-up in children with JIA, but are not sensitive to findings in the early disease stage. Both ultrasound and MRI are more sensitive to inflammatory changes than clinical assessment alone. However, the differentiation between normal findings and pathology can be challenging, particularly in early disease. The objective of this review is to discuss the role of imaging in JIA, describe the typical findings on different modalities and highlight the challenges we face regarding the reliability and accuracy of the different methods for imaging the joints in children with JIA.

Key Points

• Imaging is an important supplement to the clinical examination in JIA.

• Ultrasound is more sensitive for detecting synovitis than clinical examination alone.

• MRI can depict all relevant structures in joint inflammation.

• The differentiation between normal variants and pathology is difficult in children.

Reliability of clinical symptoms in diagnosing temporomandibular joint arthritis in juvenile idiopathic arthritis

OBJECTIVE

Temporomandibular joint (TMJ) arthritis, commonly considered oligoarthritic/asymptomatic, occurs frequently in children with juvenile idiopathic arthritis (JIA), and gadolinium-enhanced magnetic resonance imaging (Gd-MRI) has proved to be a sensitive diagnostic tool in this context. We compared the reliability of clinical examinations to Gd-MRI results in diagnosing the condition.

METHODS

Patients with JIA (134 consecutive) underwent routine clinical and Gd-MRI examinations. The clinical items examined were clicking, tenderness (TMJ/adjacent muscles), and mouth-opening capacity. Blinded MRI reading focused on inflammation (synovitis/hypertrophy). After statistical power analysis, the clinical findings for 134 healthy controls were included. Contingency analysis was used to determine the sensitivity, specificity, and frequency of clinical symptoms (JIA/healthy controls); Cohen's κ was used to establish the interrater reliability.

RESULTS

Statistically significant differences were observed between JIA and healthy control groups with regard to the concise screening items (power analysis > 0.95), whereas no differences in mouth-opening capacity were noted. In 80% of the patients with JIA, Gd-MRI revealed signs of TMJ arthritis, with positive correlations between concise screening items and Gd-MRI results. The average specificity was 0.81, but the sensitivity was low, at 0.42. Combining items led to a marked increase in the sensitivity (0.73). There was a high rate of both false-negative and false-positive results (corresponding to clinical underdiagnosis or overdiagnosis of TMJ arthritis).

CONCLUSION

Despite a relatively high specificity, clinical examination alone does not seem sufficiently sensitive to adequately detect TMJ arthritis. Thus, a relatively high number of cases will be missed or overdiagnosed, potentially leading to undertreatment or overtreatment. Gd-MRI may support correct diagnosis, thereby helping to prevent undertreatment or overtreatment.

Imaging of the temporomandibular joint in juvenile idiopathic arthritis

OBJECTIVE

Temporomandibular joint (TMJ) arthritis in children with juvenile idiopathic arthritis (JIA) is extremely common but frequently asymptomatic. Magnetic resonance imaging (MRI) with contrast remains the gold standard for identifying TMJ arthritis in JIA. A reliable scoring system with published MRI examples of typical acute and chronic TMJ arthritis changes will be invaluable for future prospective treatment trials of TMJ arthritis in JIA.

METHODS

MRIs were collected from routine clinical studies assessing TMJ arthritis in JIA. Representative images were selected for publication to depict acute (synovial fluid, bone marrow edema, and synovial enhancement) and chronic (pannus, disc derangement, and condylar head flattening and erosions) TMJ arthritis findings. A preliminary MRI-based scoring system for assessing degrees of acute and chronic TMJ arthritis was developed and tested for inter- and intrareader reliability.

RESULTS

TMJ MRIs representative of acute and chronic TMJ arthritis in JIA were selected from among thousands taken (>500 TMJ MRI studies annually at Children's of Alabama) since September 2007. Moreover, computed tomography scans depicting select bony changes (osteophyte formation, micrognathia) were chosen for publication. A description of the MRI protocol for assessing TMJ arthritis is included. A preliminary scoring system weighted for degree of acute and chronic TMJ arthritis MRI findings was found to have substantial inter- and intrareader reliability.

CONCLUSION

A published set of MRIs depicting representative acute and chronic changes will help establish a standardized scoring system to assess TMJ arthritis in children with JIA. Future validation will aid in assessing improvement during treatment trials of TMJ arthritis.