femoral stem dislocation caused by trunnionosis along with adverse local tissue reaction: a case report and a new technique of head to cone cementing

In total hip replacement (thr), fretting and corrosion at the modular head-neck junction (trunnionosis) may causeadverse local tissue reaction (altr). in this report, we presented a 34 years woman with a history of thr eight yearsago, presenting with acute pain and limping. the radiographic assessment revealed stem-head dislocation for whicha revision hip surgery was planned. surprisingly, we observed pseudotumor and tissue necrosis resulting from thebody’s reaction to cobalt-chromium alloy. the revision surgery entailed pseudotumor debridement and replacing thefemoral head with a new metal head (size 36, long). due to the separation of the femoral head on a stem, we fixedit on a stem using bone cement. the stem (omnifit®, stryker®) was well-fixed and retained to avoid fractures andinfection risk. this technique revealed an acceptable outcome without recurrence of altr after a one-year follow-up.our findings suggest that stem dislocation secondary to trunnionosis might be a long-term complication after thrwith subsequent altr.level of evidence: v