Periprosthetic loss of bone mineral density after cementless porous tantalum and cemented total knee arthroplasties: a mean of 11-year concise follow-up of a previous report

Abstract Background Our previous study showed that the decrease in relative change of bone mineral density in the lateral part of the tibia was significantly less in the group treated with the cementless porous tantalum component than in the group treated with the cemented cobalt-chromium tibial component up to five years after the operation. However, the longer-term benefits of porous tantalum tibial component on bone mineral density has not been proven. The aim of this study was to update a matched cohort study at minimum 6 years follow-up period. Methods Twenty patients with a porous tantalum tibial component and eighteen patients with a cemented cobalt-chromium-alloy tibial component was investigated more than 6 years in the current study. The mean follow-up period was 11.4 years. Dual x-ray absorptiometry was used to measure the bone mineral density. Results The decrease in relative change of bone mineral density in the lateral aspect of the tibia was significantly less with the porous tantalum tibial component than that with the cemented cobalt-chromium tibial component up to five years. However, at finial follow-up period, no significant difference was observed in the relative change of bone mineral density between the two groups. No prosthetic migration or periprosthetic fracture was detected in either group. Conclusion The present study is one of the studies with the longest follow-up period on bone mineral density after total knee arthroplasty. Porous tantalum tibial component did not have a favorable effect on the bone mineral density of the proximal tibia after total knee arthroplasty for long-term.