A finite element analysis of tibial tritanium cones without stems in varying bone defects

Abstract

Background: In the UK around 10% of hip and knee arthroplasties are revision operations. At revision total knee arthroplasty (rTKA), bone loss management is critical to achieving a stable bone-implant construct. Though tritanium cones have been used to manage bone defects in rTKA, their biomechanical performance with varying defects remains unknown.Methods: Uncontained tibial bone defects at four anatomic locations, with varying depths and widths (Type T2A and T2B) were investigated computationally in a composite tibia which was subjected to four loading scenarios. The ability of the tritanium cone to replace the tibial bone defect was examined using the outcome measures of bone strain distribution and interface micromotions.Results: It was found that anterior and lateral defects do not significantly alter the strain distribution compared with intact bone. For medial defects, strain distribution is sensitive to defect width; while strain distributions for posterior defects are associated with defect width and depth. In general, micromotions at the bone-implant interface are small and are primarily influenced by defect depth.Conclusions: Our models show that the cone is an acceptable choice for bone defect management in rTKA.Since all observed micromotions were small, successful osteointegration would be expected in all types of uncontained defects considered in this study. Tritanium cones safely accommodate uncontained tibial defects up to 10mm deep and extending up to 9mm from the centre of the cone. Medial and posteriorly based defects managed with symmetric cones display the greatest bone strains and asymmetric cones may be useful in this context.

Pre-existing knee osteoarthritis and severe joint depression are associated with the need for total knee arthroplasty after tibial plateau fracture in patients aged over 60 years

“…If considering acute TKA to manage these fractures, Schatzker II, III, and IV fractures can be considered Anderson Orthopaedic Research Institute (AORI) type 2a defects (uncontained defect in a single plateau) 25 that can be managed acutely with metaphyseal fixation using cones, sleeves, or augments. 18 Where lateral augments are difficult to implant via a medial parapatellar approach for Schatzker II defects due to the patella tendon, metaphyseal fixation devices such as asymmetric cones [26][27][28] or sleeves 29 have made TPF defects much easier to manage at acute TKA. 18 Bicondylar Schatzker V and VI fractures can similarly be considered as AORI type 2b (uncontained affecting both plateaus) or type 3 (severe metaphyseal deficiency) defects, and may require long stem diaphyseal fixation in addition to metaphyseal augmentation if acute TKA is to be performed.…”

Excellent mid‐ to long‐term survival of tantalum metal cones in a case series of revision knee arthroplasty with severe bony defects

“…Currently, there is no evidence that one of these fixation philosophies yields better results for RTKA, but many surgeons move to shorter cemented stems together with TMC [ 19 ]. It is not clear yet if this approach to reduce stem tip pain works well with AORI type 3 defects [ 38 ].…”

Acute Total Knee Arthroplasty for Unicondylar Tibial Plateau Fracture Using Metaphyseal Cones

“…It can be difficult to place lateral augments through a medial parapatellar approach due to the patellar tendon. The geometry of asymmetric metaphyseal cones [ [20] , [21] , [22] ] is well suited to filling the unicondylar lateral depression associated with TPFs ( Fig. 2 ).…”