Traumatic Posterior Fracture-dislocation of the Hip Complicated by a Floating Knee Fracture -Case Report-

Capital fractures associated with traumatic posterior dislocation of the hip are increasing in frequency because of the construction of higher buildings and high speed transport. We report a comparatively rare case of this type of fracture complicated by a floating knee fracture on the same side.The patient was a 68-year-old man who was injured when the car in which he was a front seat passenger collided with the railing of a bridge on October 7, 1993. He was taken to hospital by ambulance and admitted that day.Findings on admission included marked deformation and swelling extending from the left hip to the thigh, and he was unable to move his left lower limb. In addition, there was an open wound of about 1cm on the inside of his left leg.X-ray and CT findings included posterior dislocation and a capital fracture of the left hip, a fracture associated with a bone fragment in the diaphysis, and a tibial fracture.Accordingly, traumatic posterior fracture-dislocation of the hip and a floating knee fracture were diagnosed. The next day, open reduction of the hip was performed with removal of the femoral head and bone fragment.The fracture in the femoral diaphysis was fixed using a captured hip screw, and external fixation of the open tibial fracture was undertaken.Postoperatively complete non weight-bearing walking was started from the 4th month. To date, the course of his recovery has been good with no evidence of capital necrosis.The mechanism of injury and the diagnosis and treatment of this patient are discussed.