Early fatigue failures of cemented, forged, cobalt-chromium femoral stems at the neck-shoulder junction.

Abstract

Femoral component fracture is a rare but well-documented complication after total hip arthroplasty. Historically, most stem fractures have occurred at the middle third of the implant, where proximal stem loosening and solid distal stem fixation result in cantilever bending and eventual fatigue failure. In contrast, we report 2 early fatigue failures of well-positioned, well-fixed, cemented, forged, cobalt-chromium femoral components at the neck-shoulder junction. A contributing factor to the implant failures was heavy laser etching in a region of the implant subjected to high stresses, leading to decreased fatigue resistance and subsequent fracture.