The "flosting knee" is the term applied to the flail knee joint segment resulting from a fracture of the shaft of adiacent metanhysis of the ipsilateralfemur and tibia. The various methods of treatment of the "floating knee" were adapted by many authors according to degree of the comminution, degree of the soft tissue injury, general condition state of the fracture. Authors experienced the floating knee in 52 cases on 51 patients who were treated at Soon Chun Hyang University Hospital in the period of 4 years and 5 months from January 1985 to June 1989 and among them, 45 cases were treated by operative method and 7 cases by conservative methods at least one of the femur and tibia, The results were as follews;1. Floating Knee occured six times more in male and the peak age was third and fourth decades. 2. The most common cause of fractures was traffie aecident and there was difficulty in diagnosis of ligamentous disruption of the ipsilateral knee. 3. The common fracture site were middle one third and the most common fracture shape was comminuted in both femur and tibia. 4. A good or excellent functional result was aohieved in treated with open reduction and rigid fixation of both fracture and there were no significant difference in group of the internal fixation of both femur and tibia. 5. Intramedullary nailing on the femur and plate fixation on the tibia provided rigid fixation of fracture and the it made possible early joint motion exercise and ambulation and the average healing time of fracuture was much shortened. 6. The most common concomitant injury were soft tissue injury and delayed or nonuion and osteomyelitis were developed more frequently in the plate and screw fixation group of the open fracture.