Periprosthetic fractures after total knee arthroplasty.

Fractures around total knee arthroplasties are challenging clinical problems and include the following: stress fractures of the pelvis and femoral neck, supracondylar femur fractures, fractures of the proximal tibial metaphysis and diaphysis, and patellar fractures. Treatment focuses on restoration of the patient's prefracture functional status. The etiology of supracondylar femur fractures is multifactorial and treatment includes immobilization, retrograde intramedullary nailing, open reduction and internal fixation, and revision arthroplasty. The "Less Invasive Stabilization System" plate has recently been added to the list of viable fixation options. Tibial metaphyseal and diaphyseal fractures are less common and usually treated with revision arthroplasty. In the absence of maltracking or component loosening, vertical patellar fractures often respond to immobilization. Disruption of the extensor mechanism may require cerclage wiring or even extensor mechanism allografting if chronic. Conventional tension band wiring usually fails. Patellar fractures are controversial and problematic.