Ankle arthritis is not specific to JIA diagnosis

MRI revealed inflammatory features in the ankle and midfoot of children with a clinical diagnosis of arthritis, not only in those with juvenile idiopathic arthritis (JIA), but also in those who did not have a final JIA diagnosis, according to a retrospective case-control study.

The single-center study was conducted at a center for pediatric rheumatology in Poland in 44 children aged 5 to 16 years (35 girls and 9 boys) with clinically suspected active ankle arthritis. Participants’ symptoms included ankle pain, swelling, tenderness, or limitation of movement associated with pain persisting more than 6 weeks. All participants underwent an MRI of the ankle that covered the area from the tibiotalar joint to the metatarsophalangeal joints.

JIA was confirmed in 22 (50%) of study group participants, including 14 patients with oligoarthritis, 6 with undifferentiated JIA, 1 with systemic JIA, and 1 with enthesitis-related arthritis. More lesions were identified in the JIA group than in the non-JIA group, with only 6 children free of lesions: 2 (4.5%) in the JIA group and 4 (9.0%) in the non-JIA group. MRI revealed inflammatory features in 38 (86%) of total study patients. No significant differences were found in either gender or mean age between the JIA group and the non-JIA group. The duration of arthritis in JIA patients ranged from 5 to 144 months (mean, 35.41 months) and in non-JIA patients from 6 to 36 months (mean, 17.6 months).

The most common findings in both groups were effusion in the tibiotalar joint (68% in the JIA group vs 64% in the non-JIA group) and effusion in the subtalar joint (64% vs 59%, respectively). However, tenosynovitis was the only lesion that was significantly more common in the JIA group than in the non-JIA group. In addition, advanced active inflammatory lesions were diagnosed in more than half (55%) of the JIA group and in none of the non-JIA group.

Thoughts from Dr. Farber

JIA remains an elusive diagnosis to pin down at times; it traditionally is based on a variety of factors, with no pathognomonic findings. There may be valid reasons for ordering an MRI of the ankle in these patients, but using the MRI to make a diagnosis is not one of them.

Reference

Ostrowska M, Michalski E, Gietka P, Mańczak M, Posadzy M, Sudoł-Szopińska I. Ankle magnetic resonance imaging in juvenile idiopathic arthritis versus non-juvenile idiopathic arthritis patients with arthralgia. J Clin Med. 2022;11(3):760. doi:10.3390/jcm11030760