Chronic extensor mechanism insufficiency in total knee arthroplasty (TKA).

Chronic insufficiency of the knee extensor mechanism is a very challenging pathology to treat. An insufficient extensor mechanism negatively affects implant survival and patient outcomes. The causes of insufficiency can be several, and the surgeon has to be prepared to manage them intraoperatively and postoperatively. Various reconstructive techniques have been proposed, but traditional results in patients with a total knee arthroplasty are usually inferior to those patients with native knee joints. It is of primary importance to understand the anatomy, and tailor the correct treatment to the patient.