The safety and efficiency of a new strategy to remove the well-fixed cementless acetabular components in revision hip arthroplasty: a retrospective comparative study

Background Removing a well-fixed acetabular cup is technically challenging with the risk of complications during revision hip arthroplasty. A new strategy was developed to detach the cup from the acetabulum by impacting on the ring with a designed instrument. This study aimed to investigate the safety and efficiency of the new strategy in removing the well-fixed acetabular components by comparing them with those removed using the Explant Acetabular Cup Removal System. Methods This retrospective study included 70 patients who underwent revision total hip arthroplasty in our center between 2019 and 2022. Patients with acetabular removed by the new technique (n = 32) or the Explant System (ES) were recruited (n = 38), followed up for a minimum of 2 years. The new strategy aimed to break the connection between bone and cup by impacting on the ring of cup with a designed instrument to create a vertical shear force (VSF) along the hemispherical shape of the acetabular surface. The diameter of the removed and re-implanted cup, severity of acetabular bone defect, hip joint function score, and complications were retrieved and compared between the two groups. The Wilcoxon-Mann–Whitney test (two-tailed) was used to assess intergroup differences in the acetabular cup size, bone defect severity, preoperative and final follow-up Harris Hip Scores (HHS). Intergroup differences in bone grafting and metal augment utilization were analyzed using chi-square tests. Results The average and median diameter of the revised cup was 1.7 mm and 2 mm larger than that of the removed cup in the VSF group, while 3.2 mm and 3.0 mm in the ES group. Metal augments were more frequently used in the ES group than in the VSF group. The patients were followed up for an average of 34 months in the VSF group and 50 months in the ES group, and none of them required re-revision due to acetabular component loosening. The mean HHS improved in both groups. Conclusion The VSF strategy is safe, efficient, and cost-effective in removing the well-fixed acetabular cup while preserving bone stock during revision hip arthroplasty.