Objective To evaluate the results of patients operatively treated transverse plus posterior wall fractures of the acetabulum.Methods Review forty-five patients who had operated for transverse plus posterior wall fractures of the acetabulum 1 retrospectively with fracture displacement,from August 1993 to January 2005 in Department of Orthopaedics,Beijing Shunyi Hospital.The radiographs were graded according to the criteria described by Matta.The functional outcome was evaluated using a modification of the clinical grading system developed by Merle d'Aubigné and Postel.Result Forty-five patients were followed up 16 to 48 months with an average of 34 months.The radiographic result was excellent in seventeen patients,good in eighteen,fair in seven,and poor in four.The clinical outcome at the time of final follow- up was graded as excellent in fourteen patients,good in twenty- two,fair in eight,and poor in two.Conclusion Operative treatment for transverse plus posterior wall fractures of the acetabulum has a satisfying therapeutic effect.The appropriate operation time,reasonable operation approach,anatomic reduction and stable internal fixation is the key to obtain good results.