Migration of the trabecular metal monoblock acetabular cup system

Fifty-one primary total hip arthroplasties were performed using Trabecular Metal Monoblock Acetabular Cup System (Zimmer Inc, Warsaw, IN). In a 2-year prospective study, its behavior was closely monitored by clinical, radiologic, and component migration assessment by Ein-Bild-Röntgen-Analyse method. There were no complications. The mean Harris hip score was improved from 41 to 95. A polar gap at the postoperative radiograph was noted at 25% of the arthroplasties, most of which subsequently filled with bone within 6 months. The mean total absolute migration was 0.67 mm. The implant showed excellent early clinical and radiographic behavior. The 2-year migration rate study, as index of long-term survival and success, showed very good early implant stability and, in all cases except one, superior to the available studies for similar design acetabular cups.