Mid-term Survivorship and Functional Outcomes of Metaphyseal Sleeves for Addressing Anderson Orthopaedic Research Institute (AORI) Type 2 and 3 Bone Defects in Revision Total Knee Arthroplasty.

Introduction Revision Total Knee Arthroplasty (RTKA) is a complex procedure challenged by significant bone loss, necessitating effective restoration techniques. This study investigates the clinical outcomes and complications of metaphyseal sleeves in RTKA with severe metaphyseal bone loss, aiming to evaluate their efficacy over a minimum four-year follow-up. Methods This was a retrospective observational study on 29 patients who underwent RTKA with Anderson Orthopaedic Research Institute (AORI) type II or III bone defects using porous coated tibial and/or femoral metaphyseal sleeves from December 2016 and January 2019. Data collection included demographic information, etiology for revision, and functional outcomes assessed by the Knee Society Score (KSS) and Oxford Knee Score (OKS). Statistical analysis and Kaplan-Meier survival analysis were performed. Results The cohort comprised patients with a mean age of 62.6 years (SD=7.8), predominantly female (N=21, 71.4%). The primary indication for RTKA was aseptic loosening (N=18, 62.1%) followed by Prosthetic Joint Infection (PJI). Significant improvements were noted in the range of motion. Both KSS (Pre-op:57.97 vs. Post-op:73.59) and OKS (Pre-op:15.86 vs. Post-op:30.66) showed highly significant improvement (p<0.0001). Radiographic assessments indicated stable component position and signs of osseous integration without any osteolysis. No sleeve-related complications were observed. Survival analysis demonstrated a high cumulative survival probability over the study period. Conclusion Metaphyseal sleeves offer a viable solution for managing severe bone loss in RTKA, providing stable fixation, restoring joint line kinematics, and facilitating stress distribution to the metaphyseal region. This study corroborates the effectiveness of metaphyseal sleeves in challenging revision scenarios, aligning with previous research.