Metal-Backed Patella: A Reasonable Alternative in a Bone-Preserving Approach in Revision TKA

Introduction: Patellar management during revision TKA (rTKA) remains challenging. Metal-backed patella (MBP) with highly porous titanium coating applied by 3D printing may provide improved fixation in TKA, especially in patients with limited bone stock. The primary aim of this study was to assess implant survivorship among patients who received a new-generation MBP during revision TKA. Secondary aims were to assess (1) healthcare utilization, and (2) preoperative and 1-year PROMs. Methods: This was a retrospective review of patients who received a MBP during rTKA from 2017-2022. In total, 31 patients achieved an average follow-up of 3.0 years (SD 1.5 years). Knee injury and Osteoarthritis Outcome Score (KOOS) Pain, KOOS Physical Function Shortform (PS), KOOS Joint Replacement (JR) and Veterans RAND 12-Item Health Survey Mental Component Score (VR-12 MCS) were obtained preoperatively and at 1-year. Most patients had prior ipsilateral prosthetic joint infection (PJI; n=22, 71%). Results: MBP implant survivorship was 96.8%. No patients had evidence of patellar component aseptic loosening. The average patellar thickness was 11.8 mm (SD 2.3 mm). After rTKA, most patients were discharged to facility following surgery (n=24, 77.4%). There were 5 patients (16.1%) readmitted within 90-days, and no deaths within 1-year. Significant improvement was found in KOOS Pain (p<0.001), and KOOS JR (p=0.005), but not KOOS PS (p=0.080) or VR-12 MCS (p=0.279). Conclusions: Titanium 3D printed MBP resulted in excellent implant survivorship with major improvements in pain and overall joint health. Thus, MBP appears to be a viable patellar component option in revision TKA.