Presentation
Ankle and forefoot pain with history of old trauma.
Patient Data
Navicular bone is flattened and sclerotic with cortical irregularity. Severe pes planus.
Pes planovalgus. Abnromal talonavicular alignment with
Talonavicular articulation shows an inferiorly angled talar head with subchondral edema, cortical erosions, cartilage eburnation, and small geodes at anterior margin of talar head, more marked on lateral side. The navicular bone shows flattening, reduced volume, sclerosis , marrow edema, cortical buckling, and severe arthritic changes at talonavicular joint.
There is interstitial edema and partial tears at the calcaneocuboid, calcaneonavicular, calcaneofibular and anterior talofibular ligaments. Thickening and scarring at posterior talofibular ligament is also observed.
Preachilles bursa shows free fluid, appears irregular and reveals a small ossific focus.
The flexor hallucis longus tendon is surrounded by free fluid along the tendon sheath, and as the intraarticular free fluid is minimal, this is in keeping with tenosynovitis.
Case Discussion
MRI ankle study reveals findings consistent with post traumatic avascular necrosis of navicular bone (Kohlers disease) and associated advanced degenerative changes at talonavicular joint, high grade lateral ligament tears, flexor hallucis longus tenosynovitis and chronic preachilles bursitis.