High survival rate at mid-term follow up of porous tantalum cones for bone defects in revision total knee replacement: A 3–11 years follow up report

Large metaphyseal bone losses are commonly encountered in revision total knee arthroplasty (rTKA). Anderson Orthopaedic Research Institute (AORI) type 2 and 3 defects generally require some metaphyseal fixation or augmentation. This study evaluates the midterm results of Porous Tantalum Trabecular Metal™ (TM) cones in revision TKA addressing severe bone loss.Patients who underwent revision TKA using metaphyseal cones and a varus-valgus constrained (VVC) implant from January 2010 to January 2018 at our institution were identified from a prospective research database. Pre-operative patient characteristics and operative data were reviewed. Postoperative outcomes were compared with pre-operative values. Primary study aims were to evaluate outcomes, including complications and re-operations, radiographic assessment of cones osteointegration, and survivorship.A total of 101 knees (101 patients) underwent revision TKA with 139 metaphyseal cones (80 tibial, 59 femoral). AORI defect classification was assessed intraoperatively. All patients were available for a minimum of 2 years of clinical and radiographic follow up. Mean follow up was 7.5 years (range 3-11 years). All patients showed significant improvement of clinical outcomes. Fifteen knees required re-operation and nine required revision of the implants, most commonly for recurrent infection (six of nine revisions) with cones removal. Kaplan-Meier survival analysis show a survival rate of 93.9% at 2 years and a survival rate of 90.2% at 5 and 11 years.This large series illustrates the utility of porous metaphyseal cones in revision TKA with promising clinical and radiographic results and a high survival rate at mid-term follow up.