Clinical and research applications of synthetic bone substitutes in equine veterinary medicine: A systematic review

BACKGROUND: Bone grafting in equine medicine offers a promising contribution to treating orthopaedic developmental diseases and chondral, osteochondral and segmental bone defects. Among grafts, synthetic bone substitutes-alloplastics-show favourable biological properties addressing numerous limitations presented by autografts, xenografts and allografts. OBJECTIVES: To compile and disseminate clinical data and research findings from existing publications on the use of alloplastics in horses. STUDY DESIGN: Systematic review. METHODS: Following Preferred Reporting Items for Systematic Reviews and Meta-analysis 2020 guidelines, literature searches were conducted in PUBMED, Scopus and Web of Knowledge. The inclusion criteria covered case reports and research articles on the use of alloplastics in the horses. The selected research articles were grouped considering clinical and experimental studies. A risk of bias assessment was performed for the research articles. RESULTS: Use of synthetic bone substitutes in horses has been described in 17 publications to date, grouped as 5 case reports and 12 research articles. The latter were subdivided by main study issue-as involved subchondral cystic lesion, aneurysmal bone cyst and chondral, osteochondral or segmental bone defects. The four treatment models were distinguished and described. MAIN LIMITATIONS: The lack of clinical and alloplastics data in some records. Clinical evaluation in some studies was inconsistent or incomplete. A risk of bias particularly arises from missing data, outcome measurement and the reported results. CONCLUSIONS: In equine medicine, hydroxyapatite, calcium phosphate and β-tricalcium phosphate were the leading alloplastics applied. When applied alone, they demonstrated osteoconductive and osteoinductive properties, while the addition of biologically active additives-especially autologous bone marrow-enhanced these biological properties toward osteogenic and chondrogenic effects. Treatment outcomes were generally favourable, although segmental bone defect treatment requires considering the limitations associated with weight-bearing effects. These findings suggest alloplastics in horses may be particularly beneficial for treating certain bone diseases.