PURPOSE OF THE STUDY Facing the increasing number of priary and revision hip arthroplasties, the therapy of complex osseus defects becomes a crucial issue. Large acetabular defects cannot be treated with standard implant. Individual, customized implants based on 3D computed tomography (CT) scans are used for reconstruction. However, high complication and revision rates come along with final favorable outcomes. MATERIAL AND METHODS Eight patients underwent primary or revision total hip arthroplasty by an anterolateral surgical approach using patient matched implants based on 3D CT scans. Six patients with a Paprosky type IIIB acetabular defect, one patient with a nonunion acetabular and femoral neck fracture and one patient with a severe hip dysplasia were included. The clinical data and the Merle d'Aubigné score assessing the clinical outcome pre- and postoperatively were analyzed retrospectively. RESULTS Patient matched implants were used for eight patients (four male and four female). The mean Merle d'Aubigné score improved from 8.1 (range 2-11) pre-operatively to 13 (range 9-17) at the final follow-up (p < 0.01). Postoperative complications were recorded in 3 cases. CONCLUSIONS Customized implants of severe acetabular defects provide a solution with a favorable outcome. Nevertheless, dislocation presents a significant complication. A reduction of complications in order to achieve the optimal custome-made implant is desirable. Key words: revision arthroplasty, patient-matched implants, Paprosky IIIB defects, clinical outcome.