Large Animal Adult with Sequestrum

You see a larger animal at first as opposed to a foal except for in the case on miniatures

Signs/Symptoms
Lame on the affected leg
History of trauma
Hard mass on the affected leg
Possible draining tract (cloaca)

Radiographs
Dense fragment of bone(sequestrum)  in line with the cortex surrounded by an area of lysis/radiolucency and that  is surrounded by an area of denser bone/sclerosis(involucrum)

Management 
Remove the dead fragement of bone surgically,  which will remove the source of infection
Systemic and local antibiotics should be used based on culture and sensitivity

Prognosis
Guarded  until bone fragment is removed and then fair


How/Why Different
The growth plate  is closed, so the prognosis is much better
Bones are mature so bone  deformity  is not a sequelae
Young animals  are more likely to have hematogenous spread where with adults are more    likely to have exogenous introduction of the bacteria
Young animals are more likely to develop an abscess under the periosteum
Older animals more likely to develop  a cloaca due to the tightly  adhere d periosteum
Mature animal has a better prognosis because the growth plate is closed and is unlikely to be adversely affected by spread of the infection