Management of extensor mechanism disruptions occurring after total knee arthroplasty.

Extensor mechanism disruption from quadriceps tendon rupture, patellar fracture, or patellar tendon rupture is an uncommon complication of total knee arthroplasty. Extensor mechanism disruption can occur either intraoperatively or postoperatively. Common intraoperative causes include avulsion or tendon injury arising from excessive tension during surgical exposure, improper patellar resection, and devascularization due to injudicious lateral retinacular release or multiple prior surgeries. The usual postoperative causes are tissue necrosis arising from infection, component malalignment, and trauma. A wide range of treatment options is available for managing these difficult problems, and recent advances in alternative techniques for reconstruction have yielded promising results.