Bone grafts and biomaterials substitutes for bone defect repair: A review

Abstract

Bone grafts have been predominated used to treat bone defects, delayed union or non-union, and spinal fusion in orthopaedic clinically for a period of time, despite the emergency of synthetic bone graft substitutes. Nevertheless, the integration of allogeneic grafts and synthetic substitutes with host bone was found jeopardized in long-term follow-up studies. Hence, the enhancement of osteointegration of these grafts and substitutes with host bone is considerably important. To address this problem, addition of various growth factors, such as bone morphogenetic proteins (BMPs), parathyroid hormone (PTH) and platelet rich plasma (PRP), into structural allografts and synthetic substitutes have been considered. Although clinical applications of these factors have exhibited good bone formation, their further application was limited due to high cost and potential adverse side effects. Alternatively, bioinorganic ions such as magnesium, strontium and zinc are considered as alternative of osteogenic biological factors. Hence, this paper aims to review the currently available bone grafts and bone substitutes as well as the biological and bio-inorganic factors for the treatments of bone defect.

Graphical abstract

Most common specific targets of relevant bioinorganic ions in their role of therapeutic agents revealed by current researches [273].

Highlights

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  Autologous bone graft is the gold standard clinical material for bone regeneration in term of osteoconduction and osteoinduction. However, limited availability and donor site morbidity are concerned.

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  Bone allograft becomes to the second higher option for orthopaedic procedures due to the availability in various forms and large quantities. Unfortunately, reduced osteoinductivity may lead to inferior healing as compared with the use of autologous grafts.

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  Hence, synthetic bone substitutes and biological factors e.g. calcium phosphate (CaP) cements and ceramics, hydroxyapatite (HAp) and recombinant human bone morphological proteins (rhBMP-2 and rhBMP-7) are considered, either alone or combined, for bone tissue regeneration.