Application of the skin and bone integrated pylon with titanium oxide nanotubes and seeded with dermal fibroblasts.

BACKGROUND: Direct skeletal attachment of limb prostheses is associated with high rate of transcutaneous infection and loosening of the fixture in the medullary canal prompting for careful assessment of various means for enhancing the skin-device and bone-device interface. The skin and bone integrated pylon system constitutes a technological platform for different modifications being evaluated previously. OBJECTIVES: The current study assessed the combination of nano-treatment skin and bone integrated pylon with its pre-seeding with dermal fibroblasts. We hypothesized that this combination will enhance cell interaction with skin and bone integrated pylon compared to nano-treatment and the fibroblast seeding when done separately. STUDY DESIGN: The feasibility and safety of in-bone implantation of the skin and bone integrated pylon with nanotubes was investigated in vitro and in vivo in the animal model. METHODS: TiO2 nanotubes were fabricated on the skin and bone integrated pylon, and the fibroblasts taken from rabbit's skin were cultured on the pylons before implantation. RESULTS: The in vitro experiments demonstrated higher cellular density in the samples with a nanotubular surface than in the non-modified pylons used as control. There were no postoperative complications in any of the animals during the 6-month observation period. Subsequent scanning electron microscopy of the pylon extracted from the rabbit's femur showed the stable contact between the pylon and soft tissues in comparison to control samples where the patchy fibrovascular ingrowth was detected. CONCLUSION: The promising results prompt further investigation of the integrative properties of the nanotextured skin and bone integrated pylon system seeded with dermal fibroblasts and its optimization for clinical application. CLINICAL RELEVANCE: The study is devoted to the development of more safe and efficient technology of direct skeletal attachment of limb prostheses aimed in improving quality of life of people with amputations.

Two-stage implantation of the skin- and bone-integrated pylon seeded with autologous fibroblasts induced into osteoblast differentiation for direct skeletal attachment of limb prostheses.

Angio- and osteogenesis following the two-stage (TS) implantation of the skin- and bone-integrated pylon seeded with autologous fibroblasts was evaluated. Two consecutive animal substudies were undertaken: intramedullary subcutaneous implantation (15 rabbits) and a TS transcutaneous implantation (12 rabbits). We observed enhanced osseointegrative properties of the intramedullary porous component seeded with fibroblasts induced into osteoblast differentiation, as compared to the untreated porous titanium pylon. The three-phase scintigraphy and subsequent histological analysis showed that the level of osteogenesis was 1.5-fold higher than in the control group, and significantly so (p < 0.05). The biocompatibility was further proved by the absence of inflammatory response or encapsulation and sequestration on the histology assay. Treatment of the transcutaneous component with autologous fibroblasts was associated with nearly a 2-fold decrease in the period required for the ingrowth of dermal and subdermal soft tissues into the implant surface, as compared to the untreated porous titanium component. Direct dermal attachment to the transcutaneous implant prevented superficial and deep periprosthetic infections in rabbits in vivo.

Porous composite prosthetic pylon for integration with skin and bone.

This article presents results of the further development and testing of the "skin and bone integrated pylon" (SBIP-1) for percutaneous (through skin) connection of the residual bone with an external limb prosthesis. We investigated a composite structure (called the SBIP-2) made of titanium particles and fine wires using mathematical modeling and mechanical testing. Results showed that the strength of the pylon was comparable with that of anatomical bone. In vitro and in vivo animal studies on 30 rats showed that the reinforcement of the composite pylon did not compromise its previously shown capacity for inviting skin and bone cell ingrowth through the device. These findings provide evidence for the safe and reliable long-term percutaneous transfer of vital and therapeutic substances, signals, and necessary forces and moments from a prosthetic device to the body.