Low Young's Modulus TiNbSn Alloy Locking Plates Accelerate Osteosynthesis in Rabbit Tibiae

Area of Science:

• Biomaterials Science
• Orthopedic Engineering
• Materials Science

Background:

• Stress shielding, caused by Young's modulus divergence between implants and bone, can impede fracture healing.
• Commercially pure titanium (CP-Ti) exhibits a high Young's modulus, potentially leading to stress shielding.
• A novel beta titanium-niobium-tin (TiNbSn) alloy with a low Young's modulus (approx. 40 GPa) has been developed to address this issue.

Purpose of the Study:

• To evaluate the efficacy of TiNbSn alloy locking plates in promoting bone repair compared to CP-Ti locking plates.
• To assess the impact of TiNbSn alloy's low Young's modulus on early-stage bone healing and mechanical properties.

Main Methods:

• Osteotomy and osteosynthesis using TiNbSn alloy or CP-Ti locking plates were performed on rabbit tibias.
• Bone repair was assessed at 4 and 6 weeks post-surgery using micro-computed tomography (micro-CT), histomorphometry, immunohistochemistry, and mechanical testing.

Main Results:

• Micro-CT analysis at 4 weeks revealed significantly greater bone volume in the fracture callus for the TiNbSn group (61.3 mm³) compared to the CP-Ti group (34.3 mm³).
• The TiNbSn alloy group demonstrated significantly higher bone strength at 4 weeks post-osteotomy (133.7 N) compared to the CP-Ti group (81.3 N).
• Histomorphometry and immunohistochemistry further supported enhanced bone formation with TiNbSn alloy plates.

Conclusions:

• TiNbSn alloy locking plates demonstrate a superior positive impact on bone formation and strength restoration during the early phase of bone healing compared to CP-Ti.
• The low Young's modulus of the TiNbSn alloy appears to mitigate stress shielding, facilitating more effective bone repair.
• This TiNbSn alloy shows significant potential as an advanced biomaterial for orthopedic fracture fixation devices.