Commonest site of fracture leading to fat embolism is -

FAT EMBOLISM and ARDS Fracture through a large marrow-filled cavity almost inevitably results in small showers of fat emboli being swept to the lungs. This can usually be accommodated without serious consequences, but in some cases (and especially in those with multiple injuries and severe shock, or in patients with associated chest injuries) it results in progressive respiratory distress and multi-organ failure (adult respiratory distress syndrome). Blood gases should be measured if this is suspected and signs such as shoness of breath, restlessness or a rise in temperature or pulse rate should prompt a search for petechial haemorrhages over the upper body, axillae and conjunctivae. Treatment is suppoive, with the emphasis on preventing hypoxia and maintaining blood volume. X RAY OF FAT EMBOLISM REF:Apley&;s system of ohopaedics- 9th edn- pg no 866.