SEDL / STP / STP1301-EB / STP12033S

The Importance of Fatigue Loading When Assessing Liner/Shell Distraction Resistance and Congruency for Modular Acetabular Components

Fosco, DR
Applied Technology Group, Research and Development, Wright Medical Technology, Inc., Arlington, TN

Buchanan, DJ
Applied Technology Group, Research and Development, Wright Medical Technology, Inc., Arlington, TN

Pages: 12    Published: Jan 1997

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Abstract

Modular acetabular components are now widely used in total hip arthroplasty (THA). A primary performance requirement for these two-piece acetabular cup designs is to maintain in vivo locking integrity between the polyethylene liner and the metal acetabular shell. Standards have been proposed that include the measurement of static push-out and lever-out forces to evaluate the mechanical integrity between the shell and liner. However, there are many variables that may affect in vivo performance. A modification of the proposed test standards is recommended to include moderate fatigue cycling, since fatigue has a demonstrated effect on distraction resistance and the potential for in vivo disassembly.