Periprosthetic cortical bone remodeling in patients with an osseointegrated leg prosthesis

Qualitative studies have shown that the periprosthetic cortical bone may decrease in the first years after the implantation of an osseointegrated leg prosthesis (OILP) in patients with a transfemoral amputation. The resorption of periprosthetic cortical bone may endanger implant survival because of outbreak fractures and aseptic loosening. A decrease in periprosthetic bone quality may also lead to insufficient bone stock for potential revision surgery. This study quantified the periprosthetic bone changes and skeletal remineralization in 27 patients with an ILP (Integrated Leg Prosthesis)-type transfemoral OILP. Periprosthetic cortical thickness was analyzed from standard anteroposterior (AP) radiographs that were taken immediately postoperatively and at both 12 and 24 months post-implantation. The bone mineral density of the femoral hip neck on both sides was measured pre-operatively with Dual X-ray absorptiometry (DXA) and at 12 and 24 months post-implantation. Compared to that immediately post-operative, the periprosthetic cortical thickness increased significantly by 9.6% (p = 0.020) and 8.9% (p < 0.001) at 12 and 24 months, respectively. The change in bone mineral density of the hip neck on both sides was not significant. In contrast to previous observations, this study reports increased periprosthetic cortical thickness around the OILP implant in the first 2 years after implantation. These data indicate good prospects for implant survival and possibilities for revision surgery. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1237-1241, 2017.