Bone Plate Composed Of A Ternary Nanohydroxyapatite/Polyamide 66/Glass Fiber Composite: Biocompatibility In Vivo And Internal Fixation For Canine Femur Fractures

Bone plates have been applied to fix fractures for over a hundred years. Metal plates are the gold standard. However, an increasing number of clinical practices and animal experiments have shown that metal plates have had incidents of failure due to their rigid fixation and long-term complications. Degradable composites present the advantages of a lower elastic modulus and absorbable properties but are unsuitable for load-bearing applications. Nondegradable bone plates composed of a nanohydroxyapatite/polyamide 66/glass fiber (n-HA/PA66/GF) composite are prepared, which have enough strength and a low elastic modulus for an internal fixation device. To better assess its function as a bone plate, animal experiments are conducted using a canine load-bearing femur fracture model. The results show that the n-HA/PA66/GF plate can fix fractures effectively. Gross observation, radiographic films, and histological analysis all show that the n-HA/PA66/GF plate leads to a secondary (indirect) union with obvious callus formation, whereas the titanium plate leads to primary (direct) union due to rigid fixation. Furthermore, the histological results reveal that new bone grows at the interface and that the n-HA/PA66/GF plate can integrate with native bone tissue. Consequently, the n-HA/PA66/GF composite shows good potential as a bone plate to fix loading-bearing bone fractures.