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Catastrophic Trunnion Failure in an Anatomic Titanium Alloy Stem
Benjamin P Pruitt1, Simon C Mears1, Andrew E Apple2
1Department of Orthopaedic Surgery, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
Introduction:
Certain titanium alloy stems have been shown to be susceptible to failure at the neck with catastrophic trunnion failure. Failure has been particularly noted in the single wedge Accolade 1 stem design. Other stems also used this alloy including the anatomic designed Citation stem.
Methods:
This case series details 3 catastrophic failures of the TMZF version of the Citation femoral stem.
Results:
Each of these failures appear to be attributed to cyclical wear of the TMZF trunnion against the cobalt chromium femoral head. Wear resulted in ultimate implant failure and significant metal debris in the joint capsule at the time of revision surgery.
Discussion:
While surgeons are aware of the risk of catastrophic failure for the Accolade 1 stem, failure may similarly happen in the TMZF Citation stem. Surgeons should monitor these implants with care and discuss the potential for trunnion failure with their patients.
