Complications of distal femur megaprostheses.

Initially indicated for tumor surgery only, the reliability and modularity of megaprostheses of the knee, and in particular of the distal femur, have broadened indications for revision of standard knee prostheses with significant bone destruction and for trauma surgery, particularly in elderly patients. In oncologic surgery, implant survival is 80% at 5 years, but almost half will be revised by 15 years, sometimes with multiple revision. Complications are numerous; infection is the most common and the main cause of amputation. Mechanical stress is significant and, despite technological progress, no ideal implant exists. Although design is simple, the technique is demanding, to limit risk of loosening, fracture and patellar complications. Managing these complications requires good knowledge of knee prostheses in general and of techniques specific to megaprostheses. Level of evidence: V; expert opinion.