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Updated: Apr 16, 2026

Individualized Stem-positioning in Calcar-guided Short-stem Total Hip Arthroplasty
Published on: February 27, 2018
Trunnion-Head Stresses in THA: Are Big Heads Trouble?
Carlos J Lavernia1, David A Iacobelli2, Jesus M Villa2
1The Center for Advanced Orthopedics at Larkin Hospital, South Miami, Florida.
Abstract:
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.
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