The floating hip injury: patterns of injury

Objective: To evaluate the relationship between mechanism of injury, type of femoral fracture and type of acetabular fracture in floating hip injury. Design: Historical retrospective. Patients: Twenty consecutive patients who sustained a floating hip injury, i.e. simultaneous ipsilateral fracture of the acetabulum and the femur. Intervention: Statistical analysis of the correlation between the mechanism of injury and fracture type. Results: Two main patterns of floating hip injury were observed. The first is the posterior type, which occurs due to a longitudinal force along the femur that causes first, a posterior type fracture of the acetabulum and thereafter, a midshaft femoral fracture. The second pattern is the central type, caused by a lateral blow to the greater trochanter, which then causes a central fracture-dislocation of the acetabulum and a proximal fracture of the femur. Conclusions: This observation explains the biomechanical nature of this injury and has treatment related implications.