Utility of trephine reamers in revision hip arthroplasty.

Powered trephines used over a femoral component to disrupt the bone component interface can yield acceptable clinical and radiographic outcomes while minimizing direct mechanical injury and indirect thermal necrosis. Thirty-six patients required trephining for fractured stems (16), infection (8), malposition (7), modular junction failure (4), and acetabular exposure (1). Harris Hip Scores (HHS), radiographic healing, and complications were assessed at a follow-up of 50.01 mo. Mean HHS increased from 46.61 preoperatively to 87.78 postoperatively (p<.0001). Two patients suffered spontaneous postoperative periprosthetic fractures in the region of the trephined bone at 3 mo and 4 mo postoperatively. Despite undergoing ORIF with locked plates, they both re-fractured with necrotic bone observed at the time of revision. There is a 5.6% incidence of femoral shaft fractures near the region of trephined bone within 1 year of surgery. Given the location of these fractures, thermal necrosis may have occurred and consideration should be given to distally bypassing the region of the femur that has been trephined.