The effect of surface material and roughness on bone screw stability

Area of Science:

• Biomaterials Science
• Orthopedic Surgery
• Materials Engineering

Background:

• Bone screw interface stability is crucial for successful orthopedic procedures.
• Titanium screws are widely used, but their interface stability can be influenced by surface properties.
• Optimizing osteointegration is a key goal in improving implant performance.

Purpose of the Study:

• To compare the bone screw interface stability of titanium screws with different surface treatments.
• To evaluate the impact of osteointegration ability and surface texture on screw stability.
• To determine the effectiveness of fluor-hydroxyapatite coating versus titanium coating and polished surfaces.

Main Methods:

• Sixty titanium tapered screws were divided into three groups: polished (Group A), rough titanium-coated (Group B), and rough fluor-hydroxyapatite-coated (Group C).
• Screws were implanted in sheep femurs and tibiae, with groups analyzed at one and three months post-surgery.
• Bone screw interface stability was assessed using extraction torque measurements and histological analysis of bone-screw contact.

Main Results:

• Group C (fluor-hydroxyapatite) showed significantly higher extraction torque than Group A at one month and both Group A and B at three months.
• Histological analysis revealed high bone-screw contact in Groups B and C, while Group A exhibited fibrous tissue encapsulation.
• Extraction torque increased significantly from one to three months for Group C, indicating progressive osseointegration.

Conclusions:

• Osteointegration ability, particularly enhanced by fluor-hydroxyapatite coating, is a critical factor for optimizing bone screw stability.
• Surface texture also plays a significant role in achieving robust bone-implant integration.
• Utilizing screws with superior osteointegration properties holds promise for positive clinical outcomes in orthopedic applications.