Abstract
Bone loss in total knee replacement has different configurations and most condylar and plateau deficits are well managed with prosthetic augmentation. Cones are rarely, if ever, necessary for these deficits and when entire femoral condyles are absent distal segmental replacement has worked well. In the setting of severe intramedullary bone loss on the tibial or femoral side cones may be used to support deficit bone. This is the one indication for the use of cones.
The negative side of cones is that additional bone may be removed to fit a cone adequately. Many of the lesser areas of bone deficiency can be managed by the use of larger diameter stems for fixation. In a paper from Sandford et al. from the Vancouver group allograft results at 5 −10 year follow up had a similar success rate to cones. Rohl in a paper looking at cones and hybrid stems for bone loss in revision TKR found no difference in results at 3.5 years.
Cones cost $4,000–6,000 each and their utilization has been increasing greatly. At Hospital for Special Surgery in 2015 18 cones were used, this has increased to over 150 in 2017 at a cost of $800,000. The overutilization of cones adds considerably to the cost of a revision procedure. Cones have a place in revision TKR for bone loss but it is limited and they should be used in the most extreme cases where bone augmentation is required for structural stability.
