The presence of periosteum is essential for the healing of large diaphyseal segmental bone defects reconstructed with trabecular metal: a study in the femur of goats.

Large segmental diaphyseal bone defects can be reconstructed with massive structural allografts, but this technique is associated with high complication rates. Tantalum tabecular metal implants have been successfully used to restore bone defects associated with revision total knee or hip arthroplasties. The aim of this study was to investigate if tantalum cylinders could be used to reconstruct large load bearing segmental diaphyseal bone defects in the presence or absence of a periosteum coverage. Segmental bone defects were reconstructed with tantalum cylinders with or without preservation of the periosteum and stabilized by an intramedullary nail. Radiological analysis was performed postop and at 26 weeks follow-up. New bone was labeled with fluorochromes at 13 and 26 weeks follow-up. Reconstructions were tested mechanically and subsequently investigated histologically. Contra-lateral femurs were used as controls. Clinically all goats returned to normal functional loading after 2 weeks allowing unlimited weight bearing. Radiologically, all tantalum cylinders with periosteum coverage united with the host bone. Reconstructions with cylinders without periosteum coverage lead to radiological nonunion in five out of six cases. The strengths of the reconstruction with and without periosteum preservation were respectively 102.1% and 24.5% compared to controls. In the periosteum covered implants, bone contact was found at all levels of the tantalum cylinder and more and deeper bone ingrowth was found in this group. Tantalum cylinders seem a safe and reliable alternative for a massive cortical graft to reconstruct large diaphyseal bone defects in a goat model if healthy periosteum is present.