• BACKGROUND
    • Enhanced implant longevity through biological fixation is achievable using cementless total knee arthroplasty but concerns about patellar component failure have lingered because of prior experiences with older component designs. A new metal-backed patella (MBP) design was released which features a 3-dimensional printed porous titanium metal backing to improve biologic fixation potential and a unique compression molding technique to create a stronger interlock layer between the polyethylene and metal backing. Our study purpose was to determine the clinical and radiographic outcomes and survivorship of this novel cementless MBP.
  • METHODS
    • Our institutional registry identified 388 cementless MBP with minimum 2-year and 80 with minimum 5-year follow-up. Knee Injury and Osteoarthritis Outcome Score for Joint Replacement and 12-item Veterans RAND/Short Form Health Survey (VR/SF-12) scores were used to evaluate clinical outcomes. Aseptic loosening noted on radiographs as well as revision for any reason were the end points used to determine survivorship.
  • RESULTS
    • Improvement in the preoperative Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, VR/SF-12 physical health and mental health scores were all statistically significant at 2-year follow-up and the VR/SF-12 mental health score at 5-year follow-up. By radiologic criteria, biologic fixation of the patellar component was present in all except 1 case at 2 years (99.6%) and at 5 years (97.7%). Radiolucent lines were present in 15 cases (6.2%) at 2 years and in 6 cases (14%) at 5 years, but progressive increase in radiolucent lines was seen in only 4 cases. No component was revised for loosening; aseptic survivorship was 100%.
  • CONCLUSION
    • This 3-dimensional printed cementless patellar component shows excellent survivorship at 2-year and 5-year follow-up. We are hopeful about the long-term durability of this implant.