Trunnion-Head Stresses in THA: Are Big Heads Trouble?

J Arthroplasty. 2015 Jun;30(6):1085-8. doi: 10.1016/j.arth.2015.01.021. Epub 2015 Jan 21.


The effects of large heads on stresses at the THA trunnion-head junction and their impact on tribocorrosion/metal ion release remain controversial. A 12/14 3D-model of a stem with different head sizes was investigated. Material properties of titanium were assigned to the trunnion and cobalt-chrome/alumina to the heads. A load simulating walking single-leg stand phase was applied to the head. A total contact head-trunnion interface was assumed. The area underneath the junction underwent significant elevations in stresses as head size increased from 28- to 40-mm. Maximum principal stress doubled between 28 and 40-mm heads, regardless of head material. Stress levels had a direct correlation to head diameter. Stress increases observed using increasingly larger heads will probably contribute to head-trunnion tribocorrosion and ion release.

Keywords: Morse taper; corrosion; finite element analysis; large diameter head; total hip arthroplasty; trunnion.

MeSH terms

  • Arthroplasty, Replacement, Hip / instrumentation*
  • Arthroplasty, Replacement, Hip / methods*
  • Chromium Alloys
  • Femur Head / surgery
  • Finite Element Analysis
  • Hip Prosthesis*
  • Humans
  • Ions
  • Prosthesis Design
  • Stress, Mechanical
  • Tensile Strength
  • Titanium


  • Chromium Alloys
  • Ions
  • Titanium