Large Head Metal-on-Metal Total Hip Arthroplasty Using the Durom Acetabular Component at Minimum 1 Year Interval

Large head metal-on-metal total hip arthroplasty recently has received significant attention in the press and scientific literature. Data regarding clinical outcome with these designs is lacking. The purpose of this study is to compare the clinical and radiographic outcomes of a metal-on-metal acetabular component (Durom, Zimmer) with a modular titanium acetabular component (Trilogy, Zimmer) at minimum 1 year follow-up interval. This case controlled study utilized a prospective arthroplasty database. All Durom acetabular components placed at a single institution with a minimum 1-year follow-up were included (n = 57). All procedures were performed by the same surgeons at the same institution. Failure was defined as revision or persistent moderate/severe groin pain as determined by the Harris Hip Score. All proportions were compared using Fisher Exact Test and a level of significance was set at P < .05. There were no significant differences between the Durom or Trilogy groups regarding age, sex, or diagnosis. Failure rates were significantly higher for the Durom group (8 of 57, 14%) than for the Trilogy group (0 of 100, 0%) (P < .001). All acetabular components in both groups appeared radiographically stable. Despite the lack of radiographic evidence of loosening, no significant bone in-growth was noted at the time of revision of the Durom components (n = 2). With the numbers available, we could not demonstrate any patient-related or surgical-related factors predictive of failure for the Durom components. This study demonstrated that the monoblock cobalt chromium metal on metal Durom acetabular component failed at a significantly higher rate at 1 year than the Trilogy titanium modular acetabular component with crosslinked polyethylene (14% vs 0%). Further study is needed to determine the scientific basis for the observed significant increase in the short-term failure rates for the Durom acetabular component.