41 JIA patients who had TMJ MRI reported by radiology physicians were included in the study. Detailed demographic and clinical characteristics of the patients are shown in Table 1 and Table 2.
Table 1
Clinical and demographical characteristics of patients
| n (%) |
Gender |
Male | 20 (48.7%) |
Female | 21 (51.2%) |
Age (y) (median, IQR) | 11.55 ± 4.21 (3.6–17.3) |
Age at Diagnosis |
Early-Onset | 18 (43.9%) |
Late-Onset | 23 (56.01%) |
Disease Duration (y) (median, IQR) | 3.16 ± 1.05 (0.5-7) |
JIA Subtype |
Oligoarticular Onset | 13 (31.7%) |
Polyarticular Onset | 15 (36.5%) |
Systemic Onset | 5 (12.1%) |
Enthesitis-Related | 4 (9.7%) |
Juvenile Psoriatic Arthritis | 0 (0.0%) |
Number of Involved Joints |
1–4 | 18 (43.9%) |
≥5 | 23 (56.01%) |
ESR (mm/h) |
High (> 20) | 22 (52.6%) |
Normal | 19 (47.4%) |
CRP (mg/dl) |
Pozitive (> 0.05) | 19 (47.4%) |
Negative | 22 (52.6%) |
Treatment |
NSAID | 31 (75.6%) |
DMARD | 38 (92.6%) |
Steroids | 30 (73.1%) |
Biological Agents | 7 (17.0%) |
Treatment Response |
Good | 24 (58.5%) |
Bad | 17 (41.5%) |
(CRP: C-Reactive Protein; dl: deciliter; ESR: Eritrocyte Sedimentation Rate; h: hour; IQR: Inter Quarteral Range; JIA: Juvenile Idiopathic Arthritis; mg: miligram; mm: millimeter; n: number; NSAID: Non Steroid Anti Inflammatory Drugs; DMARD: Disease Modifying Anti-Rheumatological Drugs; y: years) |
Table 2
Comparison of clinical and demographical characteristics of patients with or without TMJ involvement (JIA: Juvenile Idiopathic Arthritis, MRI: Magnetic Resonance Imaging, n: number, TMJ: Temporo Mandibular Joint, y: years, *p < 0.05)
| TMJ MRI Arthritis Findigs (+) (n: 21) | TMJ MRI Arthritis Findigs (+) (n: 20) | p |
Age at Diagnosis (y) 0–8 (Early-Onset) 8–16(Late-Onset) | 14 (66,67%) 7 (33,33%) | 4 (20.00%) 16 (80,00%) | 0,003* |
Disease Duration (y) | 3,88 ± 2,57 | 2,45 ± 01,50 | 0,037* |
JIA Subtype Oligoarticular Onset Polyarticular Onset Systemic Onset Enthesitis-Related | 3 (14,29%) 11 (52,38%) 6 (28,57%) 1 (4,76%) | 12 (60,00%) 2 (10,00%) 3 (15,00%) 3 (15,00%) | 0,006* 0,005* 0,402 0,563 |
Average Number of Involved Joints | 0,86 ± 0,36 | 0,25 ± 0,44 | 0,0001* |
Number of Involved Joints 1–4 >5 | 3 (14,29%) 18 (85,71%) | 15 (75,00%) 5 (25,00%) | 0,0001* |
These patients divided into 2 main groups according to TMJ MRI findings. Patients with acute or chronic arthritis findings on TMJ MRI were considered as patients with TMJ involvement. 21 (51.2%) patients had arthritis findings on MRI of the TMJ. In our study, the frequency of TMJ involvement in JIA patients was 51.2% (Fig. 1). Of the patients with arthritis on TMJ MRI, 6 (28.5%) had acute arthritis and 15 (71.4%) had chronic arthritis findings (Fig. 2A).
Clinical symptoms and/or findings suggestive of TMJ involvement of JIA were present in 6 patients (28.5%) with evidence of involvement on TMJ MRI. One patient had retrognathia and the other had micrognathia, these two patients had no recorded history of jaw pain, crepitation, or difficulty in chewing, while the other four patients had complaints of jaw pain and noise from the jaw while chewing. Among our patients with TMJ involvement, 71.5% were asymptomatic (Fig. 2B). All patients with clinical symptoms and signs related to TMJ were found to have TMJ involvement on MRI.
20 of the patients included in the study had TMJ Ultrasonographies (USGs) obtained and reported by a radiologist; none of these USGs showed any evidence of TMJ involvement. Of the patients with arthritis findings on MRI of the TMJ, 9 (42%) had a USG of the TMJ, all of which were reported as normal.
Among patients with TMJ involvement, 11 (52.3%) had polyarticular onset, 6 (28.5%) had systemic onset, 3 (14.29%) had oligoarticular onset, and 1 (4.7%) had enthesitis-related JIA (Fig. 2A). The rate of polyarticular-onset JIA was statistically significantly higher in the group with involvement on TMJ MRI compared to the group without involvement (p = 0.005) and the risk of polyarticular-onset type was 9.9 (1.82–53.8) times higher in the group with involvement compared to that without involvement (Table 2). The rate of oligoarticular-onset JIA was statistically significantly lower in the patient group with TMJ involvement than in that without TMJ involvement (p = 0.003), and the risk of oligoarticular-onset type was 0.11 (0.2–0.5) times higher in the group with involvement than in that without involvement (Table 2). There was no statistically significant difference in the distribution of other subtypes between the two groups (Table 2).
Among the patients with arthritis findings on TMJ MRI, 14 (66.6%) had early-onset JIA and 7 (33.3%) had late-onset JIA (Fig. 1B). In the patient group with TMJ involvement, the age of early onset was found to be statistically significantly higher (p = 0.003) (Table 2).
The average duration of disease from the onset of JIA to the time of TMJ MRI was 3.88 ± 2.57 years in the patient group with arthritis findings on TMJ MRI and 2.45 ± 01.50 years in the patient group without findings. The average duration of disease was statistically significantly higher in the patient group with TMJ involvement (p = 0.037) (Table 2) (Fig. 2A).
In patients with arthritis findings on TMJ MRI, the average number of involved joints was statistically significantly higher than in patients without arthritis findings (p = 0.0001). 18 (85.21%) of the patients with TMJ involvement had involvement of 5 or more joints, and the rate of multiple joint involvement was significantly higher in this patient group (p = 0.003) (Table 2) (Fig. 2A).
There was no statistically significant difference in the distribution of ANA positivity and RF positivity between the patient groups with and without arthritis findings on TMJ MRI (p = 0.606, p = 0.592) (Fig. 2B).
HLA B27 positivity was detected in 1 (4%) of patients with TMJ involvement, while HLA B27 positivity was detected in 6 (30%) of patients without TMJ involvement. In the group of patients with arthritis findings on TMJ MRI, HLA B27 positivity was statistically significantly lower than the other group (p = 0.032). ESR and CRP positivity and the average ESR values were significantly higher in the patient group with arthritis findings on TMJ MRI (p = 0.0001, p = 0.001, p = 0.0001) (Fig. 2B).
When the treatment distribution was analyzed, 31 (75.6%) of the patients were receiving Non Steroidal Anti Inflammatory Drugs (NSAIDs), 38 (92.6%) were receiving Disease Modifying Anti Rheumatic Drugs (DMARDs), 30 (73.1%) were receiving steroids and 7 (17%) were receiving biological agents (Table 1). NSAID use in the patient group with arthritis findings on TMJ MRI was significantly lower than in those without arthritis findings (p = 0.005). There was no statistically significant difference between the use of DMARDs in the two patient groups (p = 0.521). Steroid use and biologic agent use were significantly higher in the patient group with arthritis findings on TMJ MRI (p = 0.005, p = 0.045) (Table 3).
Table 3
Comparison of treatments, compliance, and response of treatments between patients with or without TMJ involvement
| TMJ MRI Arthritis Findigs (+) (n: 21) | TMJ MRI Arthritis Findigs (+) (n:20) | p |
NSAID + - | 9 (42,86%) 12 (57,14%) | 1 (5,00%) 19 (95,00%) | 0,005* |
DMARD + - | 1 (4,76%) 20 (95,24%) | 2 (10,00%) 18 (90,00%) | 0,521 |
Steroid + - | 1 (4,76%) 20 (95,24%) | 10 (50,00%) 10 (50,00%) | 0,001* |
Biological Agents + - | 15 (71,43%) 6 (28,57%) | 19 (95,00%) 1 (5,00%) | 0,045* |
Tx Compliance Good Bad | 7 (33,33%) 14 (66,67%) | 17 (85,00%) 3 (15,00%) | 0,001* |
TX Response Good Bad | 5 (23,81%) 16 (76,19%) | 19 (95,00%) 1 (5,00%) | 0,0001* |
(NSAID: Non Steroid Anti İnflammatory Drugs, DMARD: Disease Modifying Anti-Rheumatological Drugs, MRI: Magnetic Resonance Imaging, n: number, TMJ: Temporo Mandibular Joint, y: years, *p < 0.05) |
Logistic regression analysis as well as the variables of age at diagnosis, average disease duration, total number of joints involved, presence of clinical symptoms and findings suggestive of TMJ involvement, HLA B27 positivity, elevated ESR and average ESR values, CRP positivity, use of NSAIDs, steroids, biologic agents, and disease subtypes were performed to determine the factors affecting the risk of TMJ involvement, and it was found that high number of joints involved (p = 0.02) and elevated ESR (p = 0.027) were the factors that increased the risk of TMJ involvement.