Long-term complications are frequently present, such as leg length discrepancy, gait disturbance and chronic low-back pain. Recently it is principle that it is mandatory to restore the anatomy of pelvic ring structure and to fixistably by means of internal fixation or extemal fixation for successful outcome after unstable pelvicring injury.

26 cases of unstable pelvic bone fracture were treated operatively at the authors hospital between 1992 and 1994. We analyse the clinical and the radiological result. The following results were obtained.

1. The incidence of the unstable pelvic bone fracture was 26 cases(18.4%) of all pelvic bone fractures(141 cases).

2. By the classification of modified Tile, type B1 were 8 cases, type B2(3 cases). type C1(7 cases) and type C3(8 cases).

3. Associated organ injury were found most commonly in the acetabular fracture(8 cases), and other extremity fracture(8 cases), genitourinary system(6 cases) and hemopenitoneum(4 cases).

4. The specific fracture pattern was classified according to various anatomical locations such as transsymphysis(7 cases), transpubic(7 cases), combination of the trassymphysis and traspubic(1 cases), trassacroiliac(7 cases), transiliac(9 cases), transsacral(1 case) and sacroiliac fracture dis location(1 case).

5. According to the fracture location, following methods of stabilization were applied. For the ante rior portion of pelvic ring, plates(13 cases), external fixators(3 cases) and wirings(3 cases) were used. For the posterior portion of pelvic ring, plates(9 cases), percutaneous iliosacral screws(3 cases) and lag screw(1 case) were used.

6. The results revealed as excellent in 20 cases, good in 5 case and fair in 1 case.

7. Postoperative complications were fixation failure(2 cases), metal failure(1 case) and nerve injury(1 case).