This study focuses on individuals who have a distal femur fracture. A distal femur fracture is a condition in which the bone breaks in several pieces above the knee joint, requiring surgery. The purpose of the study is to determine which of two types of treatment for distal femur fracture will result in less pain and best recovery (i.e., walk faster, return to daily activities). One treatment option is called surgical fixation. The surgeon fixes the bone with plates or nails, screws, and cables/wires along the side of the fractured bone to hold it together. The other treatment method is called distal femoral replacement, in which the surgeon replaces the knee joint with an artificial knee prosthesis. While both surgeries have been shown to treat fractures successfully, surgeons do not know which one is best. The goal of the study is to directly compare the two treatments to learn which is better (or if they have the same results). Participants will be randomly assigned to receive either distal femoral replacement or surgical fixation.