Biomechanical and In Vivo Evaluation of Skin-Device Interface Integration in Percutaneous Osseointegrated Prostheses

Suboptimal integration at the interface between percutaneous components of osseointegrated prostheses and the skin is associated with adverse outcomes, such as infection and prosthetic loosening, thereby limiting clinical utility. This study aimed to elucidate the biomechanical and biological mechanisms underlying skin-device interface integration, with the goal of informing structural optimization of percutaneous prosthetic designs.

A combined finite element analysis and in vivo animal model approach was employed. A three-dimensional finite element model, comprising bone, prosthetic components, skin, and soft tissues, was constructed based on anatomical data from the human lower limb to simulate mechanical responses and evaluate structural performance. Percutaneous implants fabricated from porous tantalum alloy were implanted in New Zealand white rabbits. Integration at the skin-device interface was assessed using histological and hematological analyses.

Finite element modeling demonstrated that a porous disc-shaped implant design produced greater localized maximal stress within the device compared with a straight-tubular configuration, while concurrently reducing stress distribution in surrounding muscle and cutaneous tissues. Deformation under equivalent loading conditions was also significantly lower, suggesting that the disc-shaped configuration may effectively attenuate mechanical loads transferred to the surrounding soft tissues. Furthermore, the tantalum-based implant exhibited lower stress and deformation compared with its porous titanium alloy counterpart. In vivo findings showed increased fibroblast density, more organized collagen fiber alignment, and enhanced vascularization surrounding the tantalum alloy implants.

The disc-shaped porous tantalum alloy structure significantly enhanced percutaneous skin-device interface integration, offering a promising design strategy for enhancing the clinical performance of osseointegrated prosthetic devices.