[Periprosthetic fractures after total knee arthroplasty].

The increasing implantation rates of knee arthroplasties are associated with a growing prevalence of complications like periprosthetic fractures. Underlying patient, implant and/or operation technique-related risk factors contribute to these fractures which often occur after minor trauma. In the diagnostic process, fracture dislocation, implant stability, and integrity of the extensor mechanism have to be assessed. Valid classification systems are available to guide treatment decisions. Treatment goals are precise reposition, stable fixation, restoration of function, and early mobilization. In the case of an operative revision, the surgeon has to know the implanted device and has to be prepared for extended procedures and revision arthroplasty. Less invasive fixation devices like retrograde nailing or LISS are often sufficient to stabilize femoral supracondylar fractures, while loosening of the implant often requires extended exchange arthroplasty. Tibial fractures are often associated with osteolysis and bone loss which has to be addressed with bone grafts or augmented revision implants. Long-stemmed implants allow bypassing of the reconstructed defect and provide a stable solution for early mobilization. Patella fractures with stable or asymptomatic implants and continuity of the extensor mechanism should be treated conservatively. If reconstruction becomes necessary, results are often associated with significant functional limitations.