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

backgroundRemoving a well-fixed acetabular cup is technically challenging with the risk of complications during revision hip arthroplasty. Established tools like the Explant Acetabular Cup Removal System (ES) are effective but can be time-consuming to set up and use, and their application is limited by design constraints and availability. A novel, simple strategy was developed to detach the cup by impacting its ring with a designed instrument to generate a vertical shear force (VSF). This study aimed to evaluate the safety and efficiency of using the VSF technique as a rapid, bone-preserving initial step in the removal sequence, with the ES serving as a subsequent rescue option if needed.

methodsThis 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.

resultsThe 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.

conclusionThe VSF strategy is a simple, rapid, cost-effective and bone stock preserve technique for removing a well-fixed acetabular cup. It can be used as a primary choice during revision surgery, with the Explant System readily available as a subsequent rescue option if needed.