Intraoperative femoral head dislodgement during total hip arthroplasty: a report of four cases.

Dislodgment of trial femoral heads and migration into the pelvis during total hip arthroplasty is a rarely reported complication with limited published cases. There are three primary mechanisms of femoral head separation: dislodgement during reduction attempt, disassociation from anterior dislocation while assessing anterior stability, and during dislocation after implant trialing. If the trial femoral migrates beyond the pelvic brim, it is safer to finish the total hip arthroplasty and address the retained object after repositioning or in a planned second procedure with a general surgeon. We recommend operative retrieval since long-term complications from retention or clinical results are lacking.