Hip Arthroplasty With the Use of a Reconstruction Cage and Porous Metal Augment to Treat Massive Acetabular Bone Loss: A Midterm Follow-Up

Background: Acetabular reconstruction in the context of massive acetabular bone loss is challenging. In rare scenarios where the extent of bone loss precludes shell placement (cup-cage), reconstruction at our center consisted of a cage combined with highly porous metal augments. This study evaluates survivorship, complications, and functional outcomes using this technique. Methods: Patients with minimum 2-year follow-up were included. Baseline characteristics were collected. Preintervention and postintervention ambulatory scores were collected. Kaplan-Meier (KM) survival analysis for cage failure requiring revision surgery was conducted. Binomial regression analysis was performed to assess for correlation of aseptic cage failure with baseline characteristics. Preintervention and postintervention ambulatory aid requirements were compared. Results: A total of 41 patients were identified. Mean follow-up was 6.4 years (range 2.8-11.0). Four (9.8%) aseptic cage revisions were identified. Aseptic KM survival analysis was 87.4% (95% confidence interval 75.3-99.6) at 10 years. Aseptic KM survival was 45.0% versus 92.8% at 9 years (P=.14) for patients with vs without pelvic discontinuity. KM survival for all-cause failure was 61.6% (95% confidence interval 44.0-79.2) at 10 years. Binomial regression did not demonstrate correlation of cage failure with baseline characteristics. Wilcoxon signed-rank test demonstrated a significant reduction in ambulatory aide requirement after surgery (mean rank 11.47 vs 9.00, Z = -2.95, P=.003). Conclusion: In scenarios of massive acetabular bone loss where a cup-cage is not a viable option, good survivorship free from aseptic cage failure can be expected at mid-term follow-up using an antiprotrusio cage combined with porous metal augments. Success requires extensive experience in revision surgery. (C) 2022 Published by Elsevier Inc.