[Pathophysiologic consequences of various osteosynthesis procedures in polytrauma patients. Part I: Experimental studies of intramedullary pressure development in reamed and unreamed intramedullary nailing and plate osteosynthesis of the femur].

The aim of this study was to measure the intramedullary pressure (IP) of a) a reamed intramedullary nail (RN), b) an unreamed intramedullary nail (UN), and c) the AO-plate (PL) for stabilization of an experimental fracture of a sheep femur. The increase in IP whilst reaming or introducing intramedullary nails in long bone fractures is often said to be responsible for fat intravasation and secondary systemic and pulmonary damage after severe blunt trauma. 21 sheep were studied, 7 in each group (RN, UN, PL). The animal study was permitted by the local authorities. Under general anesthesia, the femoral fractures were produced by an oscillating saw, osteosynthesis was then performed whilst continuously measuring IP with a supracondylar IP-transducer-device. The results show similar intramedullary pressures measured during RN and during UN (maximal IP: UN: 203 mmHg, range 76-330; RN: 212 mmHg, range 70-425). The alternative extramedullary PL is not accompanied with any relevant increase of IP (maximal IP: 35 mmHg, range 16-70). In conclusion, RN and UN are not safe procedures concerning the danger of fat-intravasation by IP.