Tantalum Cones Provide Durable Mid-term Fixation in Revision TKA

Multiple studies have reported favorable short-term outcomes using tantalum cones to reconstruct massive bone defects during revision TKA. However, longer-term followup is needed to determine the durability of these reconstructions. We wished to determine the mid-term (1) reoperation rates for septic and aseptic causes, (2) radiologic findings of osseointegration, and (3) clinical outcomes based on the Knee Society score in patients who underwent revision knee arthroplasty with tantalum cones for severe bone loss. We retrospectively evaluated records of 18 patients (18 knees) who underwent revision knee arthroplasty with use of tantalum cones between 2005 and 2008; the primary indications for use of this approach were to reconstruct massive bone defects classified as Anderson Orthopaedic Research Institute Types 2B and 3. During this period, all defects of this type were treated with this approach and no cones were used for more-minor defects. A total of 26 cones (13 tibial and 13 femoral) were implanted. There were 12 female and six male patients with a mean age of 73 years (range, 55-84 years) at the time of revision. The indication for the revision included aseptic loosening (five patients) and second-stage reimplantation for deep infection (13 patients). Patients were followed for a mean of 6 years (range, 5-8 years). No patient was lost to followup. Clinical and radiographic outcomes were assessed with the Knee Society clinical rating system and radiographic evaluation system. There have been two reoperations for recurrent infection; at surgery, the two cones showed osseointegration. No evidence of loosening or migration of any implant was noted on the most recent radiographs. Knee Society knee scores improved from a mean of 31 points before surgery to 77 points at latest followup (p < 0.001), and function scores improved from a mean of 22 points to 65 points (p < 0.001). Tantalum cones for reconstruction of massive bone defects in revision knee arthroplasty provided secure fixation with excellent results at average followup of 6 years, although this series included relatively few patients. These devices are a viable option for surgeons to use in situations with severe bone loss. Further studies with longer followups are needed to confirm the durability of these reconstructions. Level IV, therapeutic study.