Midterm Outcomes of a Bicruciate-Retaining Compared With the Bicruciate-Sacrificing Knee System.

BACKGROUND: The purpose of this study is to report midterm outcomes and survivorship of a bicruciate retaining knee arthroplasty compared with a bicruciate sacrificing anterior stabilized knee arthroplasty. METHODS: A retrospective comparative cohort analysis was performed of all patients who underwent primary total knee arthroplasty with the bicruciate retaining (XP) knee arthroplasty compared with an anterior stabilized (AS) cruciate sacrificing bearing. The XP system was used in 195 knees and was compared with 1471 knees in which the AS bearing was used. Patients were included in analysis if they had minimum 2-year follow-up or had a revision at any point. Preoperative and postoperative range of motion, Knee Society Scores, complications, and reoperations were evaluated. Unpaired t-test and chi-square analysis were performed. Kaplan-Meier survival analysis was performed for all-cause and aseptic survival. RESULTS: At an average of 5.2-year follow-up, 22 (11.3%) XP knees had been revised, compared with 23 (1.6%) AS knees (P < .001). Nineteen (9.7%) XP knees were revised for aseptic tibial loosening; one (0.1%) of the AS knees was revised for the same (P < .001). Nineteen of the XR revision surgeries (86.4%) were for aseptic tibial loosening. Compared with AS knees, the XP knees had significantly lower improvement in range of motion (3.2 deg vs 2.2 deg, P < .001), Knee Society (KS) pain scores (39 vs 35.7, P = .014), KS clinical scores (52.4 vs 46, P < .001), and KS functional scores (20.9 vs 15.5, P = .01). CONCLUSION: The bicruciate retaining Vanguard XP Total Knee System demonstrated an unacceptably high rate of aseptic tibial loosening without conferring the benefit of improved postoperative function relative to other available bearings.