Clinical and radiographic outcomes of revision total knee arthroplasty with a medial pivot design for aseptic failure.

Abstract

The use of medial pivot inserts in revision total knee arthroplasty (rTKA) remains limited, with more constrained designs often preferred. This study aimed to evaluate clinical, radiographic and complication outcomes of rTKA performed with a medial pivot insert for aseptic revision indications in selected patients with preserved ligamentous stability. A retrospective analysis was conducted on a prospectively maintained institutional registry. Sixty-three consecutive patients who underwent first-time rTKA with a medial pivot revision system between 2017 and 2023 were included. Indications for revision included aseptic loosening, instability, polyethylene wear and arthrofibrosis, in the presence of mild-to-moderate bone defects (Anderson Orthopaedic Research Institute [AORI] Type I or IIa) and preserved collateral ligament integrity. Clinical outcomes were assessed using the Knee Society Score (KSS), functional KSS (fKSS) and Western Ontario and McMaster Universities Osteoarthritis Index score. Radiographic evaluation included coronal and sagittal alignment parameters and the presence of radiolucent lines (RLLs). A <i>p</i> value < 0.05 was considered statistically significant. Minimum follow-up was 2 years. Significant improvements were observed in all clinical outcome measures and knee range of motion (ROM) from preoperative assessment to final follow-up (all <i>p</i> < 0.001). No significant differences in clinical outcomes were detected between patients with AORI Type I and Type IIa bone defects. Radiographic analysis demonstrated satisfactory restoration of coronal and sagittal alignment, with no evidence of component migration or loosening at final follow-up. RLLs were observed in three cases and were non-progressive. Two patients (3.2%) required reoperation for periprosthetic joint infection (PJI); no revisions for instability or mechanical failure were recorded. rTKA performed with a medial pivot insert for aseptic failure resulted in favourable clinical and radiographic outcomes with a low complication rate at short- to mid-term follow-up. These findings suggest that medial pivot designs may represent a viable option in carefully selected revision cases with mild-to-moderate bone loss and preserved ligamentous stability. Level IV.