Clinical history A 14 year old Arabian gelding presented with an injury adjacent to the head of the left 4th metatarsal bone. The age of the injury was not known, but healing of the soft tissues was incomplete with a moist skin lesion at the time of examination. A radiographic series of the metatarsal region was made. Examine the radiographs and make a diagnosis. (Note the enlargements) Radiographic diagnosis A comminuted fracture of the mid-portion of the 4th metatarsal was identified with some displacement of the fragments. Minimal bony response in the form of callus formation as well as reactive changes on the bony fragments suggested that the lesion is at least 2 weeks in duration. Careful examination of the fracture site revealed a single bone fragment that retained its original density and smooth margination without any reactive bone suggesting that it was a sequestrum (arrow). It is difficult in the site of a chronic healing fracture to identify specific radiographic changes that would support a diagnosis of osteomyelitis other than the sequestrum. Surgical curettage was performed 3 days later and a second radiographic study was made post-operatively. Examine that radiographic study. Radiographic diagnosis - post operatively Removal of the sequestrum and the comminuted bone fragments was accomplished in addition to curettage of the adjacent surface of the 3rd metatarsal bone. The horse was discharged with the lesion healing in an expected manner.
