[Intramedullary pressure in the femur during boring and nailing with modern compression interlocking nails--risk of fat embolism?].

Fat embolism syndrome occurs in only 0.9-4% of patients with long bone fractures and especially with intramedullary nailing. Earlier publications have shown that intramedullary manipulation, e.g. reaming and nailing, can produce high pressures of up to 1 bar. The design of the new non-slotted interlocking compressions nails seems to increase the pressure in the femoral cavity. We measured the intramedullary pressure during reaming of the marrow cavity and insertion of compression nails (OSTEO), using cadaver femora and a piezo pressure transducer. We simulated a proximal fracture and performed 30 drilling and 20 nailing procedures. On average we detected a maximum pressure of 0.26 bar during drilling and 0.63 bar during nailing. During reaming the pressure increased when the reamer had passed the narrow diaphysis and reached the metaphysis. When the tried to enlarge the femoral canal by pushing and pulling the reamer repeatedly we measured high pressure peaks. During nailing we detected short impulses lasting a few milliseconds. The results show that the new compression nail do not produce higher intramedullary pressure than slotted nails. It is possible to avoid a dangerous pressure level by using a careful operative technique.