Recent improvements in total knee arthroplasty (TKA) surgical technique, instrumentation, and prosthetic design have decreased the incidence of extensor mechanism complications following TKA. The majority of these complications continue to be secondary to errors in surgical technique. Extensor mechanism complications following TKA include soft-tissue impingement, instability, patellar fractures, patellar component failures, and extensor mechanism rupture. Both nonsurgical and surgical treatment may be used in the management of these complications. However, the majority of these complications are avoidable with attention to proper surgical technique and selection of appropriate patellar components in TKA.