Histological osseointegration of Tutobone: first results in human.

The aim of this study was to evaluate the histological and radiological osseointegration characteristics of implanted solvent-preserved cancellous bovine bone substitution material Tutobone after opening-wedge osteotomy and hip arthroplasty in human. The baseline hypothesis connected to the usage of bovine bone substitute materials is the assumption of temporary structural support, integration in the surrounding bone, bioresorption and replacement with vital bone. This hypothesis is based on numerous studies evaluating sintered bovine grafts showing good osseointegration and stability. Studies analyzing cancellous bovine grafts such as Tutobone hardly exist. The only rabbit defect model showed 100% remodeling of Tutobone after 26 weeks. However, no histological data are available on application of this xenograft in patients. In this study, nine patients biopsies were collected about 11 months after application of Tutobone. Unlike animal studies, the results showed incorporated avital graft remnants (47%) as well as new bone formation (53%) of the total mineralized area. Radiological evaluation confirmed increasing signs of osseointegration and an incomplete resorption. In conclusion, degradation and replacement of bovine graft seems to be less accelerated in patients than the animal study indicated. Nevertheless, Tutobone shows an excellent biocompatibility, good osteoconductive characteristics and may represent a useful alternative to autogenous graft.