Comparative imaging of septic navicular osteomyelitis caused by a solar penetration injury in a 15‐day‐old Shire foal

Abstract

SummaryA 15‐day‐old female Shire foal presented for acute lameness after sustaining a solar penetration injury, due to a nail, to the right hind sole 4 days previously. The foal was moderately lame at walk; all vital parameters were within normal limits. Clinical examination of the foot found a 2 mm long slit‐like defect in the plantar third of the lateral body of the frog. Radiographs revealed an ill‐defined rounded radiolucency within the navicular spongiosa that was surrounded by a halo of increased radiopacity. Transcuneal ultrasound corroborated the findings and found the navicular bone lesion to be closely associated with a hypoechogenic region within the lateral lobe of the deep digital flexor tendon (DDFT) all of which was continuous with a hypoechogenic tract extending from the sole. Computed tomographic examination confirmed a tract extending from the solar surface into the lateral portion of the navicular bone and confirmed a suspected impacted bone fragment. A diagnosis of septic navicular osteomyelitis and bursitis was made. The tract, navicular bone and DDFT were surgically debrided and navicular bursa lavage performed. The foal initially recovered well but navicular bursal sepsis recurred 6 days post‐operatively and the foal was euthanised. This report provides comprehensive comparative imaging of septic navicular osteomyelitis and bursitis secondary to a solar penetration in a 15‐day‐old foal and highlights the importance of different imaging modalities in case assessment and management.