|Considerations involving preexisting arthroplasty in the femur|
In patients with previous hip arthroplasty and a distal femoral fracture, consideration must be given to not creating a stress riser between a distal implant and proximal prosthesis. If at all possible, when such a situation occurs, the prosthesis and the distal femoral implant should overlap to decrease the stress riser effect and lower the risk of further periprosthetic fracture. In patients that already have a total knee replacement and sustain a distal femoral fracture, careful consideration needs to be given to reconstruction, often with the help of specialist in knee arthroplasty reconstruction surgery. Careful preoperative planning must be undertaken to ensure that any reconstruction will fit around the prior knee arthroplasty. Some knee replacements will have no space between the femoral condyles and so will not allow retrograde femoral nailing. The exact type of knee replacement that has been inserted must be known before a retrograde femoral nail is considered.