Long-Term Incorporation Properties of Allograft Bone Chips in Acetabular Reconstruction

• Applicant: Privatdozent Dr. Tim Rolvien
• Subject Area: Orthopaedics, Traumatology, Reconstructive Surgery
• Term: from 2019 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 424287554

Bone allograft is the second most common human transplant after blood components. The use of bone grafts is a common way to fill the bone defect (e.g. in complex fractures or revision operations) and ensure a stable foundation with sufficient clinical outcome. During revision operations of hip endoprostheses, large bone defects often occur in the acetabulum. Depending on the three-dimensional configuration of these acetabular defects, different bone replacement materials and techniques such as bone chips and structural bone grafts (both allogenic) or synthetic materials and metals are used. These materials and techniques are usually introduced into the acetabulum in combination with bone cement. It has not been conclusively clarified whether allogeneic bone grafts such as structural grafts and allograft chips serve only as avital filling material or are subjected to a continuous incorporation process.The aim of this project is to analyze the long-term qualitative incorporation properties of allograft bone chips. Thus, the first systematic evaluation of successfully implanted allograft chips will be conducted; and this represents the scientific basis for their successful clinical use in revision arthroplasty. The hypothesis of this project is that allograft chips:1) are successfully remodeled and incorporated (incorporated) by the host bone.2) are incorporated faster over time than structural allografts, while a certain defect size must not be exceeded for successful incorporation. 3) Remains that are not remodeled hypermineralize as a sign of the missing remodeling, whereby osteocytes and their canaliculi are not able to penetrate the allograft bone.For this purpose, a total of at least 20 hip explants are to be examined by histological and micro-morphological analysis in order to further clarify the integration properties between host bone and allograft bone. There are already 25 preparations available, of which at least 20 are expected to be used for analysis after comparison with the clinical data, graft identification and individual cutting. The existing scientific and methodological expertise, which I have gained in the course of my osteological research at the Department of Osteology and Biomechanics (IOBM), can be optimally combined with the clinical work in the orthopaedic clinic in this project.

• DFG Programme: Research Grants