The patient has a closed distal femur periprosthetic fracture with a stable implant, Lewis and Rorabeck type 2 fracture. The displaced component is meta-diaphyseal with a non-displaced fracture extension ending at the level of the implant (see Fig. 11.2).

The recommended treatment options for this patient include locking distal femur plate vs. a retrograde intramedullary implant. Both have been shown to provide superior fixation when compared to traditional nonlocking plates [7, 8]. In this case we chose to use an intramedullary nail. The intramedullary nail requires a smaller exposure which is a concern in this obese patient with multiple comorbidities. It also allows distribution of forces over a longer construct in a fracture that extends into the diaphyseal region of the femur [8]. Some studies have shown lower nonunion rates in intramedullary nails when compared to locking plates [9, 10]. Considerations that should be made for an intramedullary nail include adequate bone stock distal to fracture for locking screws, a stable implant, and an implant that will facilitate nail insertion. Relative contraindications include hip hardware (i.e., existing intramedullary nail proximally) or existing hip arthritis that may require hip arthroplasty in the near future. In these cases, retrograde intramedullary implant may be possible if there is an adequate amount of space between the distal tip of any existing fixation in the proximal femur and the proximal tip of retrograde fixation so as not to create a stress riser.

A retrograde intramedullary nail was placed through the intercondylar notch through small portion of previous skin exposure. Careful consideration was taken to protect the polyethylene and femoral component with the soft tissue protector. The nail was then placed in a standard manner. Appropriately sized nail was inserted and locked with 2 screws proximally and 3 screws distally. Patient was made weight bearing as tolerated in the immediately postoperative period (see Fig. 11.3).

The patient has a closed distal femur periprosthetic fracture with a stable implant, Lewis and Rorabeck type 2 fracture. Fracture is at the level of the anterior femoral interface with mild comminution and transverse (see Fig. 11.4).

The recommended treatment options for this patient include locking distal femur plate, retrograde intramedullary implant, or revision knee arthroplasty. Intraoperative assessment of the distal femur component is necessary to ensure that it remains well fixed. If it does remain well fixed, it appears that adequate bone stock to avoid a revision knee replacement. An intramedullary implant is not a great option due to distal fracture location which will not accommodate adequate distal locking screws. A locking distal femur plate has been shown to be an effective treatment option for this fracture and is superior to nonlocking plates which have significantly higher rates of malunion, nonunion, and reoperation rates [7]. Allograft may be utilized as an adjunct to distal femur plating [11] or even intramedullary fixation [12], when additional stability or biology may be required. The use of allograft strut fixation either alone, or in conjunction with plate and/or intramedullary fixation, is largely surgeon preference but has been shown to provide reliable fracture union, improved alignment, and increased femoral bone stock with a high incorporation rate [13].