Bioactive materials driven primary stability on titanium biocomposites

Area of Science:

• Biomaterials Science
• Orthopedic Engineering
• Tribology

Background:

• Titanium alloy (Ti6Al4V) is a common choice for total hip arthroplasty (THA) due to its mechanical properties.
• Ti6Al4V lacks inherent bioactivity, necessitating coatings like hydroxyapatite (HAp) and tricalcium phosphate (TCP) for bone integration.
• Surface metal matrix composites offer a promising route to enhance the bioactivity and bonding of titanium implants.

Purpose of the Study:

• To investigate the tribological performance of Ti6Al4V-HAp and Ti6Al4V-TCP biocomposites.
• To evaluate the frictional response and surface damage of these composites against bone tissue.
• To determine the impact of surface roughness on implant stability for total hip arthroplasty applications.

Main Methods:

• Biocomposites (10vol% β-TCP or 10vol% HAp in Ti6Al4V) were fabricated using hot pressing (HP).
• Two surface finishing conditions were prepared: polished (Ra=0.3-0.5μm) and sandblasted (Ra=2.1-2.5μm).
• Tribological testing was conducted using bovine cortical bone as the counter-surface.

Main Results:

• Static friction increased with surface roughness for the biocomposites.
• Kinetic friction showed an inverse trend with surface roughness.
• Polished surfaces demonstrated improved primary implant stability compared to rough surfaces.

Conclusions:

• Contrary to conventional approaches, polished Ti6Al4V-HAp or Ti6Al4V-TCP biocomposite surfaces enhance primary implant stability.
• The bioadhesive properties of HAp/β-TCP are expected to improve secondary implant stability.
• These findings suggest a novel design strategy for more stable total hip arthroplasty implants.