Wk 3, Case 4 - Review

Patient History
4-year-old patient with no known injury complaining of right ankle pain and inability to bear weight.

Findings
SKELETAL/BONES:
Marked diffuse edema throughout the distal tibial chondral epiphysis with extensive surrounding soft tissue inflammation (loss of the normal apophyseal hyperintensity). Low-grade osteoedema through the distal tibial metaphysis. Diffuse intermediate-grade osteoedema throughout the talus, predominantly around the tibiotalar articulation. Marked diffuse high signal tibiotalar capsulosynovial thickening associated with a complex effusion.

Low-grade osteoedema through the plantar calcaneus.

Preservation of the cortical outline (no cortical destruction/dehiscence). No subperiosteal fluid collection.

No micro- or macro-trabecular fracture.

ARTICULATIONS:
Tibiotalar joint/talar dome: Complex tibiotalar effusion with particulate debris. Extensive capsulosynovial thickening.

Ankle mortise/syndesmosis: The ankle mortise is in anatomic alignment. No syndesmotic widening.

Chopart joint: Unremarkable.

Midfoot/hindfoot: Unremarkable.

Lisfranc joint: The Lisfranc joint is intact, without fracture or joint space widening.

LIGAMENTS:
High ankle: Intact. Diffuse reactive edema extending along the interosseous membrane.

Low ankle: Intact.

Subtalar/Chopart: Intact.

TENDONS:
Reactive tenosynovial thickening involving the posterior tibial tendon and flexor digitorum longus at the level of the joint. No tenosynovial effusion.

GENERAL:
Sinus tarsi: Unremarkable.

Muscles: Diffuse muscle edema of the distal tibialis posterior.

Soft tissue: Extensive soft tissue swelling centered around the tibiotalar articulation.

Plantar fascia: Intact.

Neurovascular complex/tarsal tunnel: Unremarkable. No evidence of entrapment neuropathy.

Intra-articular/loose bodies: None.

Impressions
1. Acute or subacute inflammatory tibiotalar arthritis (favoring septic arthritis, or less likely JIA or juvenile idiopathic arthritis with a developing area of avascular necrosis involving the tibial epiphysis). Tibiotalar capsulitis with associated complex effusion containing particulate debris (possibly purulent). Regional myositis (tibialis posterior). No intraosseous, subperiosteal or soft tissue abscess.
2. Recommend joint aspiration and analysis.