Femoral Head-Trunnion Dissociation Secondary to Corrosion of a Modular Total Hip Replacement: A Case Report

We report a rare case of modular femoral head-trunnion dissociation. The patient presented with a sudden onset of groin pain and an inability to bear weight. Intermittent clunking was reported to have started around five years after implantation of the hip replacement. The duration of symptoms, radiographic findings, and analysis of the retrieved components support the theory of chronic trunnion failure due to corrosion.

This is, to our knowledge, the first case of dissociation of the femoral head from the trunnion in which substantial macroscopic wear of the trunnion was observed and likely contributed to the dissociation. A new onset of clicking or clunking should be investigated as it may be a harbinger of head-neck dissociation.