Two-Year Survivorship and Outcomes of a Three-Dimensional Printed Metaphyseal Cone in the Setting of Revision Total Knee Arthroplasty.

Abstract

Poor metaphyseal fixation secondary to bone loss in revision total knee arthroplasty (TKA) continues to be challenging. One technique to increase implant stability is the use of novel three-dimensional (3D) printed titanium metaphyseal cones with adjunctive stems for added fixation. However, the survival of these novel constructs is poorly understood. Therefore, we sought to examine 3D-printed titanium metaphyseal cone components in revision TKA for aseptic as well as septic reasons and aimed to evaluate: (1) revision-free survivorships; (2) patient-reported outcomes measures (PROMs); (3) postoperative medical complications; and (4) radiographic outcomes. A consecutive series of 62 patients who underwent revision TKA with use of a titanium metaphyseal cone at a single institution between September 1, 2015 and May 31, 2021 were examined. The patients had a minimum follow-up period of 2 years (mean, 40 months, range, 24-72 months). PROMS included Knee Injury and Osteoarthritis Outcome Score Joint Replacement (KOOS-JR) scores at baseline and last clinical follow-up. Overall, when excluding infections, the combined implant survivorship was 96% (52 out of 54), while it was 95% (35 out of 57) for aseptic revisions and 100% (17 out of 17) for septic revisions. Reasons for revisions within the aseptic revision cohort included loosening (5%) as well as periprosthetic joint infections (PJIs) (7.5%). All failures following an index septic revision were due to PJI. Mean KOOS scores at baseline as well as at final follow-up was 43 points (range, 16-80) and 70 points (range, 34-100), respectively. None of the patients had medical complications. Other than the loosening reported (only femoral component), of the surviving patients no patients had evidence of progressive radiolucencies. The use of titanium cones in revision TKA provides good revision-free survivorship at 2 years. Further research is warranted on the longer-term survivorship of 3D-printed titanium cones. The current study has found that 3D-printed titanium cones can be incorporated as part of the revision knee surgeon's armamentarium.