Fretting corrosion in orthopaedic alloys

Area of Science:

• Biomaterials Science
• Orthopedic Surgery
• Mechanical Engineering

Background:

• Fretting corrosion is a wear mechanism affecting internal fixation devices at screwhead-plate junctions.
• Understanding this phenomenon is crucial for improving implant longevity and patient outcomes.

Purpose of the Study:

• To investigate the impact of fretting cycles and surrounding solution on implant material degradation.
• To compare the fretting corrosion resistance of common orthopedic implant alloys.

Main Methods:

• An in vivo simulation apparatus was developed to replicate fretting conditions.
• Tested implant materials included Co-Cr-Mo alloy, 316L stainless steel, and Ti-6A1-4V alloy.
• Evaluated material wear in 0.9% physiological saline and saline with 0.5% albumin over varying cycle counts.

Main Results:

• Material weight loss increased with fretting cycles, eventually plateauing.
• Co-Cr-Mo alloy and Ti-6A1-4V alloy exhibited less weight loss than 316L stainless steel.
• The addition of albumin to saline significantly reduced weight loss across all tested alloys, though Ti-6A1-4V showed notable abrasion.

Conclusions:

• The number of fretting cycles and solution composition significantly influence fretting corrosion.
• Albumin-containing solutions mitigate fretting corrosion in orthopedic implant alloys.
• Co-Cr-Mo and Ti-6A1-4V alloys demonstrate better resistance to fretting corrosion compared to 316L stainless steel under tested conditions.