Failure of Universal 2 Wrist Joint Replacements: A Retrieval Study.

Area of Science:

• Orthopedic surgery
• Biomaterials science
• Failure analysis

Background:

• The Universal 2 total wrist arthroplasty, a common implant, exhibited poor long-term outcomes.
• Failures were linked to significant polyethylene damage and metallosis.

Purpose of the Study:

• To investigate the root causes of polyethylene damage in retrieved Universal 2 total wrist arthroplasty components.

Main Methods:

• Retrieval analysis of six Universal 2 wrists and two additional polyethylene components from a single center.
• Macroscale analysis and dimensional measurements of polyethylene components.
• Comparison with in vivo component orientation to pinpoint areas of material loss.

Main Results:

• Smaller implants were revised more frequently, with material loss predominantly on the ulnar side.
• Polyethylene failure occurred at the base of the ulnar-side blind hole, particularly in smaller sizes with thinner bases.
• Oxidation, indicated by discoloration and surface fatigue, was observed, with an average in vivo time of 13.8 years.

Conclusions:

• Polyethylene failure resulted from a combination of improper sterilization and a design flaw making smaller components thinner.
• Continued surveillance of patients with Universal 2 wrist implants is advised.