Bone grafts, bone substitutes and orthobiologics: the bridge between basic science and clinical advancements in fracture healing

Abstract

The biology of fracture healing is better understood than ever before, with advancements such as the locking screw leading to more predictable and less eventful osseous healing. However, at times one's intrinsic biological response, and even concurrent surgical stabilization, is inadequate. In hopes of facilitating osseous union, bone grafts, bone substitutes and orthobiologics are being relied on more than ever before. The osteoinductive, osteoconductive and osteogenic properties of these substrates have been elucidated in the basic science literature and validated in clinical orthopaedic practice. Furthermore, an industry built around these items is more successful and in demand than ever before. This review provides a comprehensive overview of the basic science, clinical utility and economics of bone grafts, bone substitutes and orthobiologics.

Keywords: bone graft; bone graft substitute; fractures; nonunion; orthobiologics.

Figure 1:

(A) AP Radiograph of a hypertrophic nonunion of a subtrochanteric femur fracture, eleven months following cephalomedullary rod fixation. Coronal (B) and sagittal (C) CT images of the hypertrophic nonunion. (D) AP radiograph of the knee, showing insufficient effectively-unicortical screw fixation, which led to excess implant motion at the fracture site.

Figure 2:

(B) PA and (C) lateral radiographs of a distal humeral atrophic nonunion, thirteen-months following open reduction and internal fixation of a comminuted, open distal humerus fracture. (A) Extensive soft tissue damage and periosteal stripping at the time of injury likely contributed to inadequate vasculature and for healing.

Figure 3:

AP radiograph of a periprosthetic femur fracture following cable fixation augmented with a cortical strut femoral allograft.

Figure 4:

(A) AP radiograph of a large, segmental femur fracture with a sizeable diaphyseal defect. (B) postoperative AP radiograph of the fracture following bridge plating and implantation of iliac crest bone graph, DBM and BMP. (C) AP radiograph taken ten months following injury showing expansive bone formation and subsequent hypertrophic nonunion following hardware failure, treated with rigid intramedullary fixation.