Total knee arthroplasty revision with trabecular tantalum cones: Preliminary retrospective study of 51 patients from two centres with a minimal 2-year follow-up.

BACKGROUND: Successful management of large bone defects is of crucial importance when performing revision total knee arthroplasty (TKA). Trabecular tantalum cones may improve prosthesis fixation via their potential for reconstructing a stable metaphyseal support. The objective of this study was to evaluate the clinical and radiological outcomes and the complications of tantalum cones in revision TKA. HYPOTHESIS: Trabecular tantalum cones provide stable and durable metaphyseal reconstruction when used during revision TKA. MATERIAL AND METHODS: Trabecular Metal™ cones (Zimmer, Warsaw, IN, USA) were used for 52 revision TKAs in 51 patients (mean age, 68±9 years) managed in two centres between 2008 and 2013. A rotating hinge prosthesis was chosen for 38 (73%) knees and a condylar constrained knee prosthesis for 14 (27%) knees, with 37 tibial and 34 femoral cones. The two most common reasons for revision surgery were aseptic loosening (n=22, 42%) and infection (n=19, 37%). The bone loss was severe in most cases. At each centre, after a mean follow-up of 34 months (range, 24-52 months), two independent observers assessed the Knee Society Score (KSS), range of motion, mechanical axis, and osteo-integration for each patient. RESULTS: Mean KSS increased from 46 preoperatively to 77 (P=0.001) at last follow-up and the mean KSS function from 39 to 57 (P=0.007). Mean range of motion improved from 93° (45°-120°) to 110° (65°-130°) (P=0.001). Mean postoperative mechanical axis was 180° (172°-190°). Radiographic evaluation showed evidence of osteo-integration for all cones. Four revisions were performed for recurrence of infection but none for mechanical failure. DISCUSSION: The findings of our study confirm the biomechanical and biological reliability of Trabecular Metal™ cones used to fill metaphyseal bone defects during revision TKA. LEVEL OF EVIDENCE: IV, retrospective therapeutic study.