Periprosthetic femoral fractures around well-fixed implants: Use of cortical onlay allografts with or without a plate

Background: Periprosthetic femoral fractures around hip replacements are increasingly common. When the femoral component is stable, open reduction and internal fixation is recommended in all but exceptional cases. The purpose of this study was to evaluate the outcome of treatment of fractures around stable implants with cortical onlay strut allografts with or without a plate. Methods: A survey of our four centers identified forty patients with a fracture around a well-fixed femoral stem treated with cortical onlay strut allografts without revision of the femoral component. There were fourteen men and twenty-six women, with an average age of sixty-nine years. Nineteen patients were treated with cortical onlay strut allografts alone, and twenty-one were managed with a plate and one or two cortical struts. All of the patients were followed until fracture union or until a reoperation was done. The mean duration of follow-up was twenty-eight months for thirty-nine patients. One patient, who was noncompliant with treatment recommendations, had a failure at two months because of a fracture of the plate and graft. The primary end point of the evaluation was fracture union; secondary endpoints included strut-to-host bone union, the amount of final bone stock, and postoperative function. Results: Thirty-nine (98%) of the forty fractures united, and strut-to-host bone union was typically seen within the first year. There were four malunions, all of which had <10degrees of malalignment, and one deep infection. There was no evidence of femoral loosening in any patient. All but one of the surviving patients returned to their preoperative functional level within one year. Conclusions: Cortical onlay strut allografts act as biological bone plates, serving both a mechanical and a biological function. The use of cortical struts, either alone or in conjunction with a plate, led to a very high rate of fracture union, satisfactory alignment, and an increase in femoral bone stock at the time of short-term follow-up. Although this study did not address the potential for later allograft remodeling, our findings suggest that cortical strut grafts should be used routinely to augment fixation and healing of a periprosthetic femoral fracture.